Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
  • A61B5/7271—Specific aspects of physiological measurement analysis
  • A61B5/7278—Artificial waveform generation or derivation, e.g. synthesizing signals from measured signals
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
  • A61B3/0016—Operational features thereof
  • A61B3/0025—Operational features thereof characterised by electronic signal processing, e.g. eye models
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
  • A61B3/0016—Operational features thereof
  • A61B3/0041—Operational features thereof characterised by display arrangements
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
  • A61B3/02—Subjective types, i.e. testing apparatus requiring the active assistance of the patient
  • A61B3/08—Subjective types, i.e. testing apparatus requiring the active assistance of the patient for testing binocular or stereoscopic vision, e.g. strabismus
  • A61B3/085—Subjective types, i.e. testing apparatus requiring the active assistance of the patient for testing binocular or stereoscopic vision, e.g. strabismus for testing strabismus
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
  • A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
  • A61B3/113—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for determining or recording eye movement
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/03—Measuring fluid pressure within the body other than blood pressure, e.g. cerebral pressure ; Measuring pressure in body tissues or organs
  • A61B5/031—Intracranial pressure
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/40—Detecting, measuring or recording for evaluating the nervous system
  • A61B5/4058—Detecting, measuring or recording for evaluating the nervous system for evaluating the central nervous system
  • A61B5/4064—Evaluating the brain

Definitions

• the present invention relates to methods and kits for assessing physiologic function of the cranial nerves II, III, IV and VI, screening for, diagnosing, and quantitating the extent of elevated intracranial pressure, transtentorial herniation, concussion, normal pressure hydrocephalus, posterior fossa mass effect, optic neuropathy, neurodegenerative diseases, and diagnosing, localizing and monitoring progression of intracranial lesions and disease processes.
• the present invention also relates to methods and kits for assessing or quantitating conjugacy or disconjugacy of gaze or strabismus and for screening for, diagnosing, and assessing neurological diseases characterized by or featuring the same.
• the present invention relates to methods and kits for assessing or quantitating structural and non- structural traumatic brain injury and for screening for, diagnosing, and assessing the same.
• ICP intracranial pressure
• Hydrocephalus the most common pediatric neurosurgical condition in the world, has been well studied as a model for understanding the impact of elevated ICP.
• the visual disturbances and diplopia associated with hydrocephalus were first described by Hippocrates in approximately 400 B.C. (Aronyk, Neurosurg Clin N Am. 1993; 4(4):599-609).
• Papilledema, or swelling of the optic disc, and its association with elevated ICP was described by Albrecht von Graefe in 1860 (Pearce, European neurology 2009; 61(4): 244-249).
• Visual fields may be impaired in treated hydrocephalus (Zeiner et al, Childs Nerv Syst. 1985; 1(2): 115-122), and there is increased latency in light-flash evoked responses in acutely hydrocephalic children relative to their post treatment state (Sjostrom et al, Childs Nerv Syst. 1995; 11(7):381-387).
• Clinically apparent disruption of ocular motility may precede computed tomography (CT) findings in some acute hydrocephalics (Tzekov et al, Pediatric Neurosurgery 1991; 17(6):317-320 and Chou et al, Neurosurgery Clinics of North America 1999; 10(4):587- 608).
• CT computed tomography
• optic nerve (II) is most frequently analyzed because it can be visualized directly with ophthalmoscopy, and indirectly with ultrasound. Edema of the optic nerve appears earlier than ocular fundus changes, and resolves after treatment of elevated ICP (Gangemi et al, Neurochirurgia 1987; 30(2):53-55). Fluctuating elevated neural pressure leads to impaired axonal transport along the optic nerve after as little as 30 minutes in a rabbit model
• Axoplasmic flow stasis and intraneuronal ischemia may occur in the optic nerve exposed to chronically elevated ICP (Lee et al, Current Neurology and Neuroscience Reports. Feb 23 2012).
• the diagnosis of elevated intracranial pressure relies on history, physical exam, radiographic imaging, and possibly direct invasive assessment of the subarachnoid space or structures contiguous with it via cannulated needle tap of a shunt or monitoring device placement.
• Chemical dilatation of the pupil to assess for papilledema may be unpleasant for the examinee, relies on the experience of the examiner and obfuscates further examination of the pupillary reflex.
• Papilledema is not always a sensitive marker for hydrocephalus, and in one study was present in as few as 14% of patients with a shunt malfunction (Nazir et al., J Aapos 2009; 13(l):63-66) consistent with the relatively short intracranial course of II relative to cranial nerves III and IV. Compartmentalization of subarachnoid spaces is hypothesized to explain why papilledema may be present in a patient without elevated ICP, and not occur in patients with elevated ICP (Killer et al, Clinical & Experimental Ophthalmology 2009; 37(5):444-447).
• the process of spatial calibration may mask deficits in ocular motility. If there is a persistent and replicable weakness in movement of an eye, the camera will interpret the eye's ability to move in the direction of that weakness as the full potential range of motion in that direction due to the calibration process. In other words if the subject is directed to look at a position but consistently only moves halfway there, the calibration process will account for that when tracking subsequent eye movements and interpret movements to the halfway point as occurring at the full range of normal motion. If during calibration one eye only makes it halfway to the target, but the other eye is fully there, the camera will interpret both eyes as being together when one performs half the eye movement as the other. Thus binocular spatial calibration may preclude detection of disconjugate gaze unless each eye is calibrated separately using a dichoptic apparatus (Schotter, et al, PLoS One, 2012; 7: e35608).
• Conjugate gaze is the motion of both eyes in the same direction at the same time.
• the conjugate gaze is believed to be controlled by the following four different mechanisms: the saccadic system that allows for voluntary direction of the gaze, the pursuit system that allows the subject to follow a moving object, the optokinetic system that restores gaze despite movements of the outside world, and the vestibulo-ocular reflex system (VOR system) that corrects for the movements of the head to preserve the stable visual image of the world.
• the saccadic system that allows for voluntary direction of the gaze
• the pursuit system that allows the subject to follow a moving object
• the optokinetic system that restores gaze despite movements of the outside world
• VOR system vestibulo-ocular reflex system
• Disconjugate gaze or strabismus is a failure of the eyes to turn together in the same direction.
• Normal coordinated movements of the eyes produces conjugate gaze, in which the eyes are aligned for binocular 3 -dimensional vision. Misalignment results in loss of this vision.
• diplopia or double vision usually results and may be perceived as a blurred image if the two images are very closely aligned.
• Pathology usually resides either in the oculomotor muscles or their neuronal pathways including the medial longitudinal fasiculus, the paramedian pontine reticular formation, the medullary reticular formation, the superior colliculus, or the cranial nerves III, IV, or VI or their nuclei.
• binocular gaze conjugacy may only be assessable with simpler algorithms, such as following an object moving in a set trajectory (Cavezian, et al, Res Dev Disabil, 2010; 31 : 1102-1108).
• Talaian, et al, Res Dev Disabil, 2010; 31 : 1102-1108 When such tests are performed in conjunction with the remainder of the neurophthalmic and physical evaluation, one can localize neurologic lesions and quantitate ocular motility deficits with great accuracy. Despite this capability, these tests are not used routinely in the emergency setting due to the need for a trained practitioner to administer them, the requirement for sophisticated equipment, and the urgent nature of many neurologic disorders.
• One of the problems associated with the study of outcomes after brain injury is the heterogeneous nature of such injury in terms of etiology, anatomic sequelae, and physiologic and psychologic impact.
• the etiology of injury affects the anatomic sequelae and ranges from global mechanisms such as acceleration/deceleration and blast, to potentially more focal mechanisms such as blunt impact and penetrating trauma.
• Some injury mechanisms result in structural changes to the brain that can be visualized using conventional imaging such as MRI and CT scan, while other injuries appear radiographically normal.
• Acceleration/deceleration injury may result in structurally visible coup/contrecoup injuries and less visible diffuse axonal injury (DAI) (Cecil, et al, Journal of Neurosurgery, 1998; 88: 795-801) Acceleration/deceleration is also thought to be one of the potential mechanisms for concussion which is the most common form of civilian radiographically normal brain injury (Bayly, et al, Journal of Neurotrauma, 2005; 22: 845-856; Daneshvar, et al, Physical Medicine and Rehabilitation Clinics of North America, 2011; 22: 683-700).
• DAI diffuse axonal injury
• Concussion is brain injury, most often resulting from blunt impact, in the absence of structural abnormality by conventional radiographic imaging such as computed tomography (CT) scan (McCrory, et al, The Physician and Sports Medicine, 2009; 37: 141-159). Concussion may include transient loss or disruption of neurologic function.
• CT computed tomography
• subconcussion may be used to describe the sequelae of brain injury in the absence of transient loss or disruption of neurologic function. Both concussion and subconcussion as well as blast injury may be termed "non-structural" brain injury.
• Blast injury resembles blunt impact brain injury in that both may be associated with radiographically apparent cerebral edema and intracranial hemorrhage, however with blast injury the edema onset may be more rapid and severe, and there is greater likelihood of clinical vasospasm (Armonda, et al, Neurosurgery, 2006; 59: 1215-1225). Blast injury is very frequently radiographically normal, yet mild or moderate blast injury is strongly associated with post-traumatic stress disorder and other cognitive dysfunctions (Cernak, et al, The Journal of Trauma, 2001; 50: 695-706).
• Blast injury affects the brain through several mechanisms: primary brain injury caused by blast-wave induced changes in atmospheric pressure directly impacting the brain; secondary injury resulting from objects put in motion by the blast that impact the head, and tertiary injury resulting from the victim striking the head upon falling or being propelled into a solid object (Warden, The Journal of Head Trauma Rehabilitation, 2006; 21 : 398-402).
• Brain injury may be associated with short term sequelae including headaches and memory problems, and longer term problems including dementia, Parkinsonism and motor-neuron disease (Daneshvar, et al, Physical Medicine and Rehabilitation Clinics of North America, 2011; 22: 683-700). Both concussion and mild blast injury may be associated with post-traumatic stress disorder and cognitive impairment (Taber, et al, The Journal of Neuropsychiatry and Clinical Neurosciences, 2006; 18: 141-145). Clinical tests for concussion show poor test reliability (Broglio, et al, Journal of Athletic Training, 2007; 42: 509-514) and thus concussion remains a diagnosis that is difficult to treat because it is difficult to detect.
• ICP intracranial pressure
• Double vision and other ocular disturbances associated with elevated ICP were first described by Hippocrates in approximately 400 B.C. (Aronyk, Neurosurgery Clinics of North America, 1993; 4: 599-609). Papilledema, and its association with elevated ICP was described by Albrecht von Graefe in 1860 (Pearce, European Neurology, 2009; 61 : 224-249). In the post-radiographic era, acute and chronic pathology of the optic nerve and disc, and of ocular motility are well characterized in people with elevated ICP (Dennis, et al, Archives of ICP).
• the Illrd nerve (oculomotor) may be directly compressed by the medial aspect of the temporal lobe with frontal or temporal mass lesions, or diffuse supratentorial mass effect.
• the Vlth nerve (abducens) is anatomically vulnerable to infratentorial mass effect at the prepontine cistern and to hydrocephalus from stretch as it traverses the tentorial edge.
• Elevated intracranial pressure slows axoplasmic transport along cranial nerves
• the optic nerve (II) is most frequently analyzed because it can be visualized directly with ophthalmoscopy, and indirectly with ultrasound. Edema of the optic nerve appears earlier than ocular fundus changes, and resolves after treatment of elevated ICP Gangemi, et al, Neurochirurgia, 1987; 30: 53-55). Fluctuating elevated neural pressure leads to impaired axonal transport along the optic nerve after as little as 30 minutes in a rabbit model (Balarratnasingam, et al, Brain Research, 2011; 1417: 67-76).
• Axoplasmic flow stasis and intraneuronal ischemia may occur in the optic nerve exposed to chronically elevated ICP (Lee, et al, Current Neurology and Neuroscience Reports, 2012).
• the trochlear nerve (IV) followed by oculomotor (III) and then abducens (VI) has the greatest length of exposure to the subarachnoid space with the narrowest diameter, and thus may be most vulnerable to a pressure induced palsy (Hanson, et al, Neurology, 2004; 62: 33-36; Adler, et al, Journal of Neurosurgery, 2002; 96: 1103-1113) .
• the optic nerve (II) has approximately the same length of exposure as the abducens (Murali, et al, in Head Injury (ed. Paul Cooper and John Golfinos) (McGraw-Hill, 2000)), and thus papilledema, or swelling of the optic disc apparent on ophthalmoscopic examination may be a relatively late indicator of elevated ICP (Killer, et al, Clinical & Experimental Ophthalmology, 2009; 37: 444-447; Nazir, et al, J Aapos, 2009; 13 : 62-66).
• Papilledema is not always a sensitive marker for hydrocephalus leading to elevated ICP, and in one study was present in as few as 14% of patients with a shunt malfunction (Nazir, et al, J Aapos, 2009; 13 : 62-66) consistent with the relatively short intracranial course of II compared to cranial nerves III and IV. Compartmentalization of subarachnoid spaces is hypothesized to explain why papilledema may be present in a patient without elevated ICP, and not occur in patients with elevated ICP (Killer, et al, Clinical & Experimental Ophthalmology, 2009; 37: 444-447).
• the invention provides methods for localizing a central nervous system lesion in a subject by
• the lesion may feature increased intracranial pressure, and the lesion may be, for instance, subsequent to a trauma, a cerebrovascular accident (CVA), an aneurysm or other vascular lesion, a tumor whether malignant or benign, an infectious process, an inflammatory disease, a disruption of venous drainage, a pseudotumor, neurodegenerative disease,
• CVA cerebrovascular accident
• an aneurysm or other vascular lesion a tumor whether malignant or benign
• infectious process an inflammatory disease
• a disruption of venous drainage a pseudotumor, neurodegenerative disease
• Localizing the central nervous system lesion may be performed, for instance, by determining the side of the brain that is experiencing increased intracranial pressure.
• the side of the brain that is experiencing increased intracranial pressure may be determined, for instance, by determining eye movement on that side of the brain that is altered compared to the other side or that is altered compared to that subject's baseline eye movement or to a control subject's eye movement.
• the invention provides methods for diagnosing a central nervous system lesion in a subject by
• the lesion may feature increased intracranial pressure, and the lesion may be, for instance, subsequent to a trauma, a cerebrovascular accident (CVA), an aneurysm or other vascular lesion, a tumor whether malignant or benign, an infectious process, an inflammatory disease, a disruption of venous drainage, a pseudotumor, hydrocephalus or idiopathic.
• CVA cerebrovascular accident
• the invention provides methods for assessing and quantitating central nervous system integrity in a subject by
• the invention provides methods for detecting or screening for reduced or impaired cranial nerve function or conduction in a subject by
• the cranial nerve may be, for instance, one or more of II, III, IV or VI.
• the reduced or impaired cranial nerve function or conduction may be unilateral or bilateral and may be caused all or in part by increased intracranial pressure, and it may be caused all or in part by a localized or diffuse lesion or disease process.
• the reduced function of the cranial nerve may be due to pathology impacting the nerve itself, its associated nucleus or supranuclear inputs including, for instance, lesions affecting the cerebral cortex.
• the invention provides methods for detecting, diagnosing or screening for increased intracranial pressure in a subject by
• the increased intracranial pressure may be, for instance, 10%, 20%, 30%, 50%, 100%), 200%, 300% or more greater than normal.
• the invention provides methods for detecting, diagnosing, monitoring progression of or screening for a disease or condition featuring increased intracranial pressure by a) Tracking eye movement of both eyes of the subject;
• the disease or condition featuring increased intracranial pressure may be, for instance, a trauma, cerebrovascular accident (CVA), an aneurysm or other vascular lesion, a tumor whether malignant or benign, an infectious process, an inflammatory disease, a disruption of venous drainage, a pseudotumor, hydrocephalus or idiopathic.
• CVA cerebrovascular accident
• an aneurysm or other vascular lesion a tumor whether malignant or benign
• infectious process an inflammatory disease
• a disruption of venous drainage a pseudotumor, hydrocephalus or idiopathic.
• the invention provides methods for detecting, diagnosing or screening for concussion by
• the invention provides methods for detecting, diagnosing or screening for transtentorial herniation by
• the invention provides methods for quantifying the severity of normal pressure hydrocephalus, detecting or screening for shunt malfunction or optimizing valve pressure for treating normal pressure hydrocephalus by
• the invention provides methods for detecting or evaluating posterior fossa mass effect by
• the invention provides methods for detecting, screening for or diagnosing a disorder that impedes conductance through the optic disc or optic nerve by
• the invention provides methods for quantitating the extent of impairment of the entire central nervous system by
• the integrity of the central nervous system may be impaired by, for instance, trauma, stroke, a neurodegenerative disease, inflammation, an infectious process, a neoplastic process, vascular disease, an autoimmune disease, a genetic disorder or other causes.
• This aspect of the invention provides methods for quantitating the extent of global CNS impairment. This aspect of the invention takes advantage of the fact that more that 55% of the brain contributes to vision and visual acuity.
• the invention provides methods for quantitating or assessing cognitive integrity by
• the invention provides a kit useful for detecting or screening for reduced or impaired cranial nerve function or conduction, useful for detecting, diagnosing or screening for increased intracranial pressure, or useful for detecting, diagnosing, monitoring progression of or screening for a disease or condition featuring increased intracranial pressure containing a device for tracking eye movement, one or more means for analyzing eye movement tracking data such as, for instance, an algorithm or computer program, and instructions.
• Processing eye movement observations, making measurements of eye movement observations, determining distributions of values measured and performing statistical tests may all be accomplished using suitable computer software that may be included in such a kit.
• the invention provides methods for assessing conjugacy or disconjugacy of eye movement in a subject by
• the invention provides methods for diagnosing a disease
• the disease may be one of trauma, hydrocephalus, demyelination, inflammation, infection, degenerative disease, neoplasm/paraneoplastic syndrome, metabolic disease including diabetes, or vascular disruption such as stroke, hemorrhage or aneurysm formation.
• the disease may also be an ophthalmologic disease such as conjunctivitis, ophthalmoplegia, ocular injury or other diseases.
• the subject suffering from the disease may have a total sum of the differences between both x and y coordinates of the first eye compared to the second eye over the time tested that is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 150%, 200%, or two, three, four, five, six, eight, ten or more times greater than the total sum of the differences between both x and y coordinates of the first eye compared to the second eye over the time tested in a healthy control or in a reference value based upon one or more healthy controls or based upon the subject at a time before the disease.
• the invention provides methods for assessing and quantitating central nervous system integrity in a subject by
• the invention provides methods for detecting, monitoring progression of or screening for a disease or condition characterized by disconjugate gaze or strabismus by
• the disease may be one of trauma, hydrocephalus, demyelination, inflammation, infection, degenerative disease, neoplasm/paraneoplastic syndrome, metabolic disease including diabetes, or vascular disruption such as stroke, hemorrhage or aneurysm formation.
• the disease may also be an ophthalmologic disease such as conjunctivitis, ophthalmoplegia, ocular injury or other diseases.
• the subject suffering from the disease may have a total sum of the differences between both x and y coordinates of the first eye compared to the second eye over the time tested that is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 150%, 200%, or two, three, four, five, six, eight, ten or more times greater than the total sum of the differences between both x and y coordinates of the first eye compared to the second eye over the time tested in a healthy control or in a reference value based upon one or more healthy controls or based upon the subject at a time before the disease.
• the invention provides methods for quantitating the extent of disconjugate gaze or strabismus by
• the invention provides a kit useful for detecting, screening for or quantitating disconjugate gaze or strabismus, useful for diagnosing a disease characterized by disconjugate gaze or strabismus in a subject, useful for detecting, monitoring progression of or screening for a disease or condition characterized by disconjugate gaze or strabismus in a subject or useful for quantitating the extent of disconjugate gaze or strabismus, containing a device for tracking eye movement, one or more means for analyzing eye movement tracking data such as, for instance, an algorithm or computer program, and instructions. Processing eye movement observations, making measurements of eye movement observations, determining distributions of values measured and performing statistical tests may all be accomplished using suitable computer software that may be included in such a kit.
• the invention provides methods for assessing or quantitating structural and non- structural traumatic brain injury by
• eye movement of both eyes of the subject are tracked and analyzed.
• both x and y coordinates of eye position for one or both eyes of a subject are collected for at least about 100, 500, 1,000, 5,000, 10,000, 50,000, 100,000, 200,000 or more eye positions.
• the eye position is effectively the pupil position.
• the eye movement is tracked for about 30, 60, 90, 100, 120, 150, 180, 200, 220, 240, 270, 300, 360 or more seconds.
• the comparing eye movement of at least one eye of the subject to a normal or mean eye movement may feature comparing eye movement of at least one eye of the subject to the eye movement of the other eye of the subject or may feature comparing eye movement of at least one eye of the subject to the eye movement of an eye of one or more other subjects or controls.
• the comparing eye movement of at least one eye of the subject to a normal or mean eye movement may feature comparing the eye movement of both eyes of the subject to the eye movement of one or both eyes of one or more other subjects or controls.
• the method may feature collecting raw x and y cartesian coordinates of pupil position, normalizing the raw x and y Cartesian coordinates, and sorting the data by eye.
• the method may also feature calculating individual metrics, such as, for instance, segment mean, segment median, and segment variance.
• individual metrics such as, for instance, segment mean, segment median, and segment variance.
• specific metrics such as, for example,
• segment standard deviation and segment skew such as, for instance,
• segment normalized skew such as, for instance,
• the method may also feature calculating conjugacy of eye movement or variance from perfect conjugacy of eye movement, such as, for example,
• one or more of the L height, L width, L area, L varXrit, L varXlef, L varTotal, R height, R width, R area, R varYtop, R varXrit, R varXlef, R varTotal, Conj varX, Conj varXrit, Conj varXbot, Conj varXlef and Conj varYlef may be especially useful for demonstrating or detecting or assessing structural or non- structural traumatic brain injury such as, for instance, a concussion, subconcussion or blast injury. In some instances, two, three, four, five, six, seven, eight, nine, ten or more metrics may be observed or determined.
• a standard deviation or p value of 0.25, 0.3, 0.4, 0.5, 0.75. 0.8, 0.9, 1.0, 1.5, 2.0, 2.5 or more may reflect that a subject has structural or non- structural traumatic brain injury such as, for instance, a concussion, subconcussion or blast injury.
• the methods described herein may be used to detect concussion, subconcussion and blast injury and assess or determine the severity of the same.
• the invention provides methods for diagnosing a disease characterized by or featuring structural and non- structural traumatic brain injury in a subject by a) Tracking eye movement of at least one eye of the subject;
• eye movement of both eyes of the subject are tracked and analyzed.
• both x and y coordinates of eye position for one or both eyes of a subject are collected for at least about 100, 500, 1,000, 5,000, 10,000, 50,000, 100,000, 200,000 or more eye positions.
• the eye position is effectively the pupil position.
• the eye movement is tracked for about 30, 60, 90, 100, 120, 150, 180, 200, 220, 240, 270, 300, 360 or more seconds.
• the comparing eye movement of at least one eye of the subject to a normal or mean eye movement may feature comparing eye movement of at least one eye of the subject to the eye movement of the other eye of the subject or may feature comparing eye movement of at least one eye of the subject to the eye movement of an eye of one or more other subjects or controls.
• the comparing eye movement of at least one eye of the subject to a normal or mean eye movement may feature comparing the eye movement of both eyes of the subject to the eye movement of one or both eyes of one or more other subjects or controls.
• the method may feature collecting raw x md y cartesian coordinates of pupil position, normalizing the raw x and y Cartesian coordinates, and sorting the data by eye.
• the method may also feature calculating individual metrics, such as, for instance, segment mean, segment median, and segment variance.
• individual metrics such as, for instance, segment mean, segment median, and segment variance.
• specific metrics such as, for example,
• the method may also feature calculating conjugacy of eye movement or variance from perfect conjugacy of eye movement, such as, for example,
• one or more of the L height, L width, L area, L varXrit, L varXlef, L varTotal, R height, R width, R area, R varYtop, R varXrit, R varXlef, R varTotal, Conj varX, Conj varXrit, Conj varXbot, Conj varXlef and Conj varYlef may be especially useful for demonstrating or detecting or assessing structural or non- structural traumatic brain injury such as, for instance, a concussion, subconcussion or blast injury. In some instances, two, three, four, five, six, seven, eight, nine, ten or more metrics may be observed or determined.
• a standard deviation or p value of 0.25, 0.3, 0.4, 0.5, 0.75. 0.8, 0.9, 1.0, 1.5, 2.0, 2.5 or more may reflect that a subject has structural or non- structural traumatic brain injury such as, for instance, a concussion, subconcussion or blast injury.
• the methods described herein may be used to detect concussion, subconcussion or blast injury and assess or determine the severity of the same.
• the eye movement is tracked for about 30, 60, 90, 100, 120, 150, 180, 200, 220, 240, 270, 300, 360 or more seconds.
• the invention provides methods for assessing or quantitating structural and non- structural traumatic brain injury or diagnosing a disease characterized by or featuring structural and non-structural traumatic brain injury in a subject by
• eye movement of both eyes of the subject are tracked and analyzed.
• both x and y coordinates of eye position for one or both eyes of a subject are collected for at least about 100, 500, 1,000, 5,000, 10,000, 50,000, 100,000, 200,000 or more eye positions.
• the method may additionally feature sorting the data by eye.
• the one or more individual metric may be any one of
• segment standard deviation and segment skew such as, for instance,
• ment normalized skew such as, for instance,
• the method may also feature calculating conjugacy of eye movement or variance from perfect conjugacy of eye movement, such as, for example,
• one or more of the L height, L width, L area, L varXrit, L varXlef, L varTotal, R height, R width, R area, R varYtop, R varXrit, R varXlef, R varTotal, Conj varX, Conj varXrit, Conj varXbot, Conj varXlef and Conj varYlef may be especially useful for demonstrating or detecting or assessing structural or non- structural traumatic brain injury such as, for instance, a concussion, subconcussion or blast injury. In some instances, two, three, four, five, six, seven, eight, nine, ten or more metrics may be observed or determined.
• a standard deviation or p value of 0.25, 0.3, 0.4, 0.5, 0.75. 0.8, 0.9, 1.0, 1.5, 2.0, 2.5 or more may reflect that a subject has structural or non- structural traumatic brain injury such as, for instance, a concussion, subconcussion or blast injury. As such, the methods described herein may be used to detect concussion and assess or determine the severity of the same.
• the invention provides a kit useful for detecting, screening for or quantitating structural and non- structural traumatic brain injury in a subject, containing a device for tracking eye movement, one or more means for analyzing eye movement tracking data such as, for instance, an algorithm or computer program, and instructions. Processing eye movement observations, making measurements of eye movement observations, determining distributions of values measured and performing statistical tests may all be accomplished using suitable computer software that may be included in such a kit.
• the invention provides a computer system.
• the computer system or computing device 1000 can be used to implement a device that includes the processor 106 and the display 108, the eye movement/gaze tracker component 104, etc.
• the computing system 1000 includes a bus 1005 or other communication component for communicating information and a processor 1010 or processing circuit coupled to the bus 1005 for processing information.
• the computing system 1000 can also include one or more processors 1010 or processing circuits coupled to the bus for processing information.
• the computing system 1000 also includes main memory 1015, such as a random access memory (RAM) or other dynamic storage device, coupled to the bus 1005 for storing information, and instructions to be executed by the processor 1010.
• main memory 1015 such as a random access memory (RAM) or other dynamic storage device
• Main memory 1015 can also be used for storing position information, temporary variables, or other intermediate information during execution of instructions by the processor 1010.
• the computing system 1000 may further include a read only memory (ROM) 1010 or other static storage device coupled to the bus 1005 for storing static information and instructions for the processor 1010.
• ROM read only memory
• a storage device 1025 such as a solid state device, magnetic disk or optical disk, is coupled to the bus 1005 for persistently storing information and instructions.
• the computing system 1000 may be coupled via the bus 1005 to a display 1035, such as a liquid crystal display, or active matrix display, for displaying information to a user.
• a display 1035 such as a liquid crystal display, or active matrix display
• An input device 1030 such as a keyboard including alphanumeric and other keys, may be coupled to the bus 1005 for communicating information and command selections to the processor 1010.
• the input device 1030 has a touch screen display 1035.
• the input device 1030 can include a cursor control, such as a mouse, a trackball, or cursor direction keys, for communicating direction information and command selections to the processor 1010 and for controlling cursor movement on the display 1035.
• main memory 1015 implemented by the computing system 1000 in response to the processor 1010 executing an arrangement of instructions contained in main memory 1015. Such instructions can be read into main memory 1015 from another computer-readable medium, such as the storage device 1025. Execution of the arrangement of instructions contained in main memory 1015 causes the computing system 1000 to perform the illustrative processes described herein. One or more processors in a multi-processing arrangement may also be employed to execute the instructions contained in main memory 1015. In alternative implementations, hard-wired circuitry may be used in place of or in combination with software instructions to effect illustrative
• implementations are not limited to any specific combination of hardware circuitry and software.
• tracking eye movement may be performed using any suitable device such as, for example, an Eyelink® 1000 binocular eye tracker (500 Hz sampling, SR Research).
• the eye tracking movement samples may be obtained at any suitable frequency, such as for instance, 10 Hz to 10,000 Hz or more.
• the subject may be positioned an appropriate distance from the device, such as, for example, 10, 20, 30, 40, 50, 55, 60, 70, 80, 90 cm or more, or even a meter or more from the device screen.
• the subject's head may be stabilized, such as, for instance by using a chinrest or similar stabilizing mechanism.
• the subject may be seated or reclining.
• the presentation monitor of the device is adjusted so as to substantially match the subject's gaze direction.
• the tracking eye movement may be performed for a total of, for example, 30, 60, 90, 120, 150, 180, 200, 220, 240, 270, 300, 330, 360, 400, 450, 500 seconds or more, or for 5, 10, 15, 20, 25, 30, 45, 60, or 90 minutes or more.
• 1,000, 5, 000, 10,000, 20,000, 25, 000, 50,000, 75,000, 100,000, 150,000, 200,000, 250,000, 300,000 or more samples of eye position may be obtained.
• the tracking eye movement may be performed using a video oculography device, such as, for instance, goggles, or using a web-cam based tracking system.
• analyzing eye movement may be performed by any suitable means.
• a stimulus and an analysis stream are provided that allows interpreting raw eye position data.
• an algorithm may be provided for looking at pupil position directly thereby yielding information about ocular motility.
• a device is adapted into a novel mobile system that may analyze eye movement close in time or substantially concurrent to the eye movement itself.
• eye movement may be tracked in response to a visual stimulus.
• the visual stimulus may be, for instance, a video such as a music video that may move, for instance clockwise, along the outer edge, of a computer monitor.
• a video may be provided starting at the upper or lower, left or right hand corners, of a screen.
• the visual stimulus such as a video, e.g. a music video, may be provided in a substantially square aperture with an area of approximately 10, 12, 14, 16, 18, 20, 25, or degrees, for example, approximately 1/10, 1/8, 1/6, 1/5, 1 ⁇ 4, 1/3, 1 ⁇ 2 of the size of the screen or so.
• the visual stimulus such as, for example a music video
• a visual stimulus for instance, a music video may cover each edge of a monitor in about 2, 5, 10, 15, 20, 30, 45 or 60 seconds or so. Therefore, in some instances, a full cycle may take, for instance, 10, 20, 30, 40, 50, 60, 75, 100, 120, 150, 180 seconds or so.
• Multiple cycles of such a visual stimulus for instance a music video may be played, for instance, one, two, three, four, five, six, seven, eight, nine, ten, twelve, fifteen, twenty or more full cycles.
• the visual stimulus may be provided, the eye movement may be tracked, in effect, in some instances the video may be played for a total of, for example, 30, 60, 90, 120, 150, 180, 200, 220, 240, 270, 300, 330, 360, 400, 450, 500 seconds or more.
• a countdown video may be played in the starting position for, for instance, 5, 10, 15, 20, 25, or 30 seconds or more before beginning the visual stimulus, e.g. video, to provide subjects sufficient time to orient to the visual stimulus.
• the visual stimulus for instance a video, may be continued for an addition 2, 5, 10, 15, 20, 30, 45 or 60 seconds or so after the eye movement tracking is performed to reduce or substantially avoid boundary effects.
• the same result could be obtained by having the visual stimulus moving over any distance x relative to any amount of time t.
• the ideal stimulus would move however in the both the x and y Cartesian planes to optimize the assessment capability of the method.
• comparing eye movement of a first eye of the subject to eye movement of a second eye of the subject may be performed by analyzing data.
• Data from the tracking eye movement may provide an indication of whether an individual subject's gaze is conjugate (eyes are moving together) versus disconjugate.
• Comparing eye movement of a first eye of the subject to eye movement of a second eye of the subject may feature generating scatterplots.
• Comparing eye movement of a first eye of the subject to eye movement of a second eye of the subject may feature plotting the horizontal eye position along one axis and vertical eye position along an orthogonal axis.
• Such comparing eye movement of the subject to a control, or comparing eye movement of a first eye of the subject to eye movement of a second eye of the subject may feature generating, plotting pairs of (x,y) values, for instance, 50,000, 100,000 or more pairs of values (x,y). Such pairs of values (x,y) may be plotted representing, for instance, the two components of the instantaneous angle of pupil reflection (horizontal, vertical) over a period of time, for instance, 100 or 200 seconds or more.
• comparing eye movement of a first eye of the subject to eye movement of a second eye of the subject may feature generating figures substantially resembling boxes that reflect the trajectory traveled by the visual stimulation, such as when it moves across a screen.
• these figures substantially resembling boxes may look like, for instance, substantially equilateral rectangles or squares, reflecting the trajectory traveled by the visual stimulus across a screen.
• such figures may not substantially resemble a box, a rectangle or a square.
• the cranial nerve having reduced or impaired function or conduction may be identified.
• the figures generated that reflect the trajectory traveled by the visual stimulation may demonstrate abnormal distribution of or absence of normal plotting pairs in particular areas.
• Increased variability along the y-axis may for example reflect cranial nerve II dysfunction.
• Decreased variability along the y-axis, or decreased height to width ratio may reflect CN III dysfunction.
• Increased height to width ratio may reflect CN IV or VI dysfunction.
• the height of the box may be mathematically determined by assessing the position of the pupil as the video traverses the top and bottom of the presented visual stimulus. This "actual" height may be different from the perceived height mathematically, since the perceived height can represent aberrant pupillary motion due to the patient's ocular motility dysfunction.
• the integrity of the box walls may also be indicative of other types of dysfunction.
• Both cranial nerve palsies and mass effect may cause defects in box trajectory.
• Supratentorial mass lesions and CN III defects may impact the top and/or bottom of the box.
• Infratentorial mass lesions or CN VI palsies may impact the sides of the box.
• the upper left quadrant of the figure may reflect activity, function or conduction of cranial nerves III and VI
• the lower left quadrant of the figure may reflect activity, function or conduction of cranial nerves III and IV
• the upper right quadrant and the lower right quadrants may reflect activity, function or conduction of cranial nerve III.
• the upper and lower left quadrants of the figure may reflect activity, function or conduction of cranial nerve III
• the lower right quadrant of the figure may reflect activity, function or conduction of cranial nerve III
• the upper right quadrant and the lower right quadrant may reflect activity, function or conduction of cranial nerves IV and VI.
• Comparing eye movement of a first eye of the subject to eye movement of a second eye of the subject may feature determining the distribution of certain measurements in the control population and comparing the subject with these control distributions.
• visual stimulus trajectory may be divided into four time components, for instance, two, three, four, five, six or more repetitions of the first few, for instance, 2, 5, 10, 15, 20 or so seconds of each rotation cycle.
• comparing eye movement of the subject to a control may feature evaluating such variables as the relative variance in each arm, and the relative integrity of each arm.
• Comparing eye movement of the subject to a control, or comparing eye movement of a first eye of the subject to eye movement of a second eye of the subject may also feature measuring the integrity of each subject's values.
• the sides or arms of the figures e.g. the top of the box and the bottom of the box
• the resulting score may indicate how different the subject's values are compared with the control values, such as, for instance, in units of standard deviations.
• identifying the subject as having eye movement significantly different from the control, or identifying the subject as having eye movement of a first eye that is significantly different from eye movement of a second eye may be performed using a z-score. Because 95% of all values in a normal distribution lie within two standard deviations of the mean, a z-score of 2 may be used as a significance threshold. Subjects with z- scores above, for instance, 2 in either or both, or 1, 2, 3, or 4 sides or arms of the figures may be judged to have significant disturbances of ocular motility.
• identifying the subject as having eye movement significantly different from the control, or identifying the subject as having eye movement of a first eye that is significantly different from eye movement of a second eye may be performed by assessing whether it has or there is a difference that exceeds a
• Identifying the subject as having eye movement significantly different from the control, or identifying the subject as having eye movement of a first eye that is significantly different from eye movement of a second eye may feature determining relative variance.
• multiple such as 1,000, 2,000, 3,000, 5,000, 10,000, 20,000 or more point distributions may be generated by, for instance, taking multiple samples from a multiple number of values randomly chosen with replacement from the multiple control values.
• the relative variance in either or both, or 1, 2, 3, or 4 sides or arms of the figures may be compared respectively with the corresponding control distribution, and the percent of the control distribution with variance below that of the test value may be determined.
• a p-value of .05 a widely accepted measure of statistical significance corresponds to 95% of control values falling below the test value.
• subjects with variance higher than 95% of the values in the control distributions may be determined to have significant disturbances of ocular motility.
• the video may also move in other trajectories not resembling a rectangle, such as a triangle, circle or linear or nonlinear trajectories.
• the trajectories can be resolved into vectors along Cartesian coordinates (horizontal vertical or x,y) the same principles will apply.
• any trajectory e.g. any shape, or line, or curve, etc. studied over time may provide information about Central Nervous System function or dysfunction.
• Comparing the movement of one eye of a subject to the other eye of a subject may be performed by comparing the x,y Cartesian coordinates at any time point t, for example, by subtracting the x coordinate of the left eye from the x coordinate of the right eye or vice versa, or by subtracting the y coordinate of the left eye from the y coordinate of the right eye or vice versa.
• the sums of the differences between all of the x coordinates over the time tested informs regarding horizontal movement of the pupil.
• the sums of the differences in y coordinates over time informs regarding vertical movement of the pupil.
• the total sum of the differences between both x and y coordinates over the time tested may be totaled to obtain a measure of total disconjugacy of gaze, which is a surrogate marker for central nervous system integrity.
• a measure of total disconjugacy of gaze which is a surrogate marker for central nervous system integrity.
• CNS central nervous system
• Eye movement may also be tracked without using a moving stimulus. It is possible to assess conjugacy without having the stimulus move at all, but by assessing the x, y coordinates over times during naturalistic viewing. For example, eye movement may be tracked during television watching or live viewing of an environment without a specific viewing apparatus such as a monitor or screen.
• comparing the x or y Cartesian coordinates at any time point for the eye movement of a first eye of the subject to the respective x or y Cartesian coordinates at any time point for the eye movement of a second eye of the subject may be performed by analyzing data.
• Data from the tracking eye movement may provide an indication of whether an individual subject's gaze is conjugate (eyes are moving together) versus disconjugate.
• Comparing the x or y Cartesian coordinates at any time point for the eye movement of a first eye of the subject to the respective x or y Cartesian coordinates at any time point for the eye movement of a second eye of the subject may feature generating scatterplots.
• Comparing the x or y Cartesian coordinates at any time point for the eye movement of a first eye of the subject to the respective x or y Cartesian coordinates at any time point for the eye movement of a second eye of the subject may feature plotting the difference between the horizontal eye positions along one axis and time along an orthogonal axis, as well as the difference between the vertical eye positions along one axis and time along an orthogonal axis.
• Such comparing the x or y Cartesian coordinates at any time point for the eye movement of a first eye of the subject to the respective x or y Cartesian coordinates at any time point for the eye movement of a second eye of the subject may feature generating, plotting pairs of (x, y) values, for instance, 25,000, 50,000, 75,000, 100,000, 150,000 or more pairs of values (x, y).
• pairs of values (x, y) may be plotted representing, for instance, the two components of the instantaneous angle of pupil reflection (horizontal, vertical) over a period of time, for instance, 100 or 200 or 250 or 300 seconds or more.
• comparing the x or y Cartesian coordinates at any time point for the eye movement of a first eye of the subject to the respective x or y Cartesian coordinates at the time point for the eye movement of a second eye of the subject may allow generating plots assessing conjugacy of eye movements over time.
• Comparing the x or y Cartesian coordinates at any time point for the eye movement of a first eye of the subject to the respective x or y Cartesian coordinates at the time point for the eye movement of a second eye of the subject may feature determining the distribution of certain measurements in the control population and comparing the subject with these control distributions.
• visual stimulus trajectory may be divided into four time components, for instance, two, three, four, five, six or more repetitions of the first few, for instance, 2, 5, 10, 15, 20 or so seconds of each rotation cycle.
• comparing the x or y Cartesian coordinates at any time point for the eye movement of a first eye of the subject to the respective x or y Cartesian coordinates at any time point for the eye movement of a second eye of the subject may feature evaluating such variables as the relative variance in each arm, and the relative integrity of each arm.
• Comparing the x or y Cartesian coordinates at any time point for the eye movement of a first eye of the subject to the respective x or y Cartesian coordinates at the time point for the eye movement of a second eye of the subject may be performed by comparing the x, y Cartesian coordinates at any time point t, for example, by subtracting the x coordinate of the left eye from the x coordinate of the right eye or vice versa, or by subtracting the y coordinate of the left eye from the y coordinate of the right eye or vice versa.
• the sums of the differences between all of the x coordinates over the time tested informs regarding horizontal movement of the pupil.
• the sums of the differences in y coordinates over time informs regarding vertical movement of the pupil.
• the total sum of the differences between both x and y coordinates over the time tested may be totaled to obtain a measure of total disconjugacy of gaze, which may be a surrogate marker for central nervous system integrity.
• a measure of total disconjugacy of gaze which may be a surrogate marker for central nervous system integrity.
• CNS central nervous system
• Providing a sum of the differences between all of the x coordinates of the first eye compared to the second eye over the time tested or providing a sum of the differences in y coordinates of the first eye compared to the second eye over the time tested or both may be performed subsequent to comparing the x, y Cartesian coordinates at the time point t.
• This vector of difference may then be plotted graphically for purposes of assessment and interpretation.
• a variance of the data may be computed with respect to an expected mean of zero. This is significant because the code assumes that a healthy subject has zero vertical or horizontal pupil position difference between each eye.
• the variance for either horizontal (x) or vertical (substitute y for x) movement may be computed as follows:
• Providing a total sum of the differences between both x and y coordinates of the first eye compared to the second eye over the time tested may be performed by calculating the total variance in both the horizontal and vertical planes between the first and the second eyes.
• the total variance may be computed as follows:
• the Var x or the Var y or both, calculated as described herein may be 0.05, 0.07, 0.1, 0.15, 0.20, 0.25, 0.30, 0.40, 0.50, 0.60, 0.75, 0.90, 1.0, 1.10, 1.25, 1.50, 1.75, or 2.0 or more.
• the Var Tot calculated as described herein may be 0.1, 0.15, 0.20, 0.25, 0.30, 0.40, 0.50, 0.60, 0.75, 0.90, 1.0, 1.10, 1.25, 1.50, 1.75, 2.0, 2.50, 3.0 or 4.0 or more, in subjects having a neurological disease or condition characterized by or featuring disconjugacy of gaze or strabismus.
• Figure 1 (A and B) demonstrates that as the aperture containing a video moves in a rectangular pattern, different nerves move the pupils.
• Figure 1 A demonstrates movement of the left eye
• Figure IB demonstrates movement of the right eye.
• Cranial nerve III moves the pupil up and down.
• Cranial nerve VI moves it laterally. This data was obtained on a monocular eye tracker with sequential tracking of each eye. The video goes around five times with each tracking recorded in a separate color (red, green, cyan, magenta, blue).
• Figure 2 A and B represent the eye-box trajectory of a normal subject tracked binocularly (Figure 2A, left eye; Figure 2B right eye). Note that the eyes appear to be moving relatively the same, with some differences.
• Figure 2 C and D are time-course representations ( Figure 2C, left eye; Figure 2D right eye), in which the x-axis is the Cartesian coordinate of the eye position and the y-axis is time.
• Figure 3 demonstrates the binocular eye tracking of a subject who underwent surgical evacuation of an acute on chronic subdural hematoma.
• Figures 3 A and 3B represent eye-box trajectories (Figure 3A, left eye; Figure 3B right eye).
• Figures 3C and 3D are time-course representations (Figure 3C, left eye; Figure 3D right eye), in which the x-axis is the Cartesian coordinate of the eye position and the y-axis is time. The eyes are not as conjugate as the subject in Figure 2.
• Figure 4 demonstrates the binocular eye movement tracking of a subject with a mild Ilird nerve palsy recruited from the ophthalmology clinic. The subject reported increased lacrimation but no diplopia.
• Figures 4A and 4B represent eye-box trajectories (Figure 4A, left eye; Figure 4B right eye).
• Figures 4C and 4D are time-course representations (Figure 4C, left eye; Figure 4D right eye), in which the x-axis is the Cartesian coordinate of the eye position and the y-axis is time.
• the eyes are not as conjugate as the subject in Figure 2 in the x-plane but are completely disconjugate in the y-plane.
• the eye tracking anomaly appears contralateral to the ocular pathology.
• Figure 5 demonstrates the binocular tracking of a subject with concussion.
• the subject experienced a witnessed fall with blunt head trauma while attending a clinic in the hospital.
• Figures 5A and 5B represent eye-box trajectories (Figure 5A, left eye; Figure 5B right eye).
• Figures 5C and 5D are time-course representations (Figure 5C, left eye; Figure 5D right eye), in which the x-axis is the Cartesian coordinate of the eye position and the y-axis is time.
• the subject was unable to watch much of the video, but for the little that he did watch, his y, more so than his x, was disconjugate. His head computed tomography scan did not show any evidence of acute structural injury.
• the eye tracking is thus showing concussion (radiographically silent) brain injury.
• Figure 6 demonstrates that binocular eye movement tracking may be useful to quantitate the extent of physiologic brain injury.
• the eye box trajectory from a normal subject shows highly conjugate gaze (Figure 6A, x-plane; Figure 6B y-plane).
• a subject with third nerve palsy shows only diconjugacy in the y-plane ( Figure 6E, x-plane; Figure 6F y-plane).
• a subject with structural brain injury has disconjugacy in both x and y planes ( Figure 6G, x-plane; Figure 6H y- plane), as does a concussion subject (Figure 6C, x-plane; Figure 6D y-plane).
• Figure 7 represents total conjugacy versus age. Normal subjects demonstrated conjugate eye movement that was not impacted by age. A linear regression t-test was used to determine whether the slope of the relationship between total variance and age yielded a regression line statistically significantly different from 0. The test resulted in a t-statistic of -0.523 and a p-value of 0.6017 showing that the slope of the regression line was not statistically significantly different from 0. Thus in our subject population ranging in age from 7 to 75, there was no change in conjugacy of eye movements with age. [0105] Figure 8 represents male versus female conjugacy of eye movements. Normal subjects demonstrated conjugate eye movement that was not impacted by gender. A Welch Two Sample t-test with 68.49 degrees of freedom resulted in a t-statistic of 0.6734 and a p-value of 0.5029 showing that the difference in the means was not statistically significantly different from 0.
• Figure 9 represents X (horizontal) versus Y (vertical) conjugacy. Normal subjects demonstrated horizontal eye movement that was statistically highly significantly more conjugate than vertical eye movement. A paired t-test was used to determine if the mean of the subject- paired differences between the total x- variance and total y- variance was statistically significantly different from 0. With 124 degrees of freedom, the test resulted in a t-statistic of -3.0263 and a p- value of 0.003011 showing that the mean of the subject-paired differences was statistically highly significantly different from 0. Specifically, it was shown that for a particular subject, x- variance is statistically significantly less than y-variance.
• Figure 11 demonstrates the test retest reliability of a stationary to portable tracker.
• Subjects (n 24) demonstrated high test-retest reliability between separate eyetracking sessions on the stationary tracker and the portable tracker ( Figure 10).
• a paired t-test with 23 degrees of freedom (n 24), resulted in a t-statistic of 1.3661 and a p-value of 0.1851 showing that the mean of the subject-paired differences was not statistically significantly different from 0.
• Figure 12 provides the eye movement tracking trajectories of subjects with cranial nerve IV, III and VI palsies.
• Figure 13 is a block diagram of a computer system in accordance with an illustrative implementation.
• Figure 14 is a schematic diagram showing a configuration of how a subject's eye movements are measured, analyzed and displayed by such a computer system.
• Figure 15 provides a representation of the binocular eye movement tracking of a normal subject.
• A, B provide box plots of eye movement in response to a moving stimulus. The aspect ratio for each eye is provided.
• C, D provide graphic representation of the eye movement tracking for each eye over time.
• E, F provide graphical representation of the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye. Total variance of x and y coordinates of eye movement over time is provided.
• Figure 16 provides a representation of the eye movement of a patient with conjunctivitis due to a blocked lacrimal duct.
• A, B provide box plots of eye movement. The aspect ratio for each eye is provided.
• C, D provide graphic representation of the eye movement tracking for each eye over time.
• E, F provide graphical representation of the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye. Total variance of x and y coordinates of eye movement over time is provided. The same information is provided after resolution of symptoms.
• G, H provide box plots of eye movement. The aspect ratio for each eye is provided.
• I, J provide graphic representation of the eye movement tracking for each eye over time.
• K, L provide graphical representation of the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye.
• Total variance of x and y coordinates of eye movement over time is provided.
• Total variance (disconjugacy) is markedly improved after resolution of symptoms.
• Figure 17 provides a representation of the eye movement of a 9 year old patient with a history of lymphoma and exotrophic strabismus.
• A, B provide box plots of eye movement. The aspect ratio for each eye is provided.
• C, D provide graphic representation of the eye movement tracking for each eye over time.
• E, F provide graphical representation of the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye. Total variance of x and y coordinates of eye movement over time is provided.
• Figure 18 provides a representation of the eye movement of subjects with cranial nerve palsies.
• A, B provide box plots of eye movement in a patient having a cranial nerve IV palsy.
• the aspect ratio for each eye is provided.
• C, D provide graphical representation of the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye. Total variance of x and y coordinates of eye movement over time is provided.
• E, F provide box plots of eye movement in a patient having a diabetic cranial nerve III palsy.
• the aspect ratio for each eye is provided.
• G, H provide graphical representation of variance over time.
• I, J provide box plots of eye movement in a patient having a post-surgical cranial nerve VI palsy.
• the aspect ratio for each eye is provided.
• K, L provide graphical representation of variance over time.
• Figure 19 provides a representation of the eye movement of a 35 year old patient with a ruptured cerebral aneurysm resulting in subarachnoid hemorrhage.
• A, B provide box plots of eye movement. The aspect ratio for each eye is provided.
• C, D provide graphic representation of the eye movement tracking for each eye over time.
• E, F provide graphical representation of variance over time. The total variance of x and y coordinates is provided.
• G, H provide box plots of eye movement in the patient 6 days later, after embolization of the aneurysm. The aspect ratio for each eye is provided.
• I, J provide graphic representation of the eye movement tracking for each eye over time.
• K, L provide graphical representation of the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye. Total variance of x and y coordinates of eye movement over time is provided.
• Figure 20 provides a representation of the eye movement of a brain injured subject.
• A, B provide box plots of eye movement. The aspect ratio for each eye is provided.
• C, D provide graphic representation of the eye movement tracking for each eye over time.
• E, F provide graphical representation of the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye. Total variance of x and y coordinates of eye movement over time is provided.
• Figure 21 provides a representation of the eye movement of a subject suffering a concussion.
• A, B provide box plots of eye movement. The aspect ratio for each eye is provided.
• C, D provide graphic representation of the eye movement tracking for each eye over time.
• E, F provide graphical representation of variance over time. The total variance of x and y coordinates is provided.
• Figure 22 provides a representation of the eye movement of a subject suffering a concussion.
• A, B provide box plots of eye movement on the day of the fall resulting in the concussion.
• the aspect ratio for each eye is provided.
• C, D provide graphic representation of the eye movement tracking for each eye over time.
• Disconjugacy is calculated or quantified.
• E, F provide box plots of eye movement ten days after the fall resulting in the concussion.
• the aspect ratio for each eye is provided.
• G, H provide graphical representation of the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye. Total variance of x and y coordinates of eye movement over time is provided.
• Disconjugacy is calculated or quantified.
• I, J provide box plots of eye movement three weeks after the fall resulting in the concussion.
• the aspect ratio for each eye is provided.
• K, L provide graphic representation of the eye movement tracking for
• Figure 23 provides a representation of the disconjugate gaze in a subject suffering a severed cranial nerve III.
• A-N provide box plots of eye movement tracking (left and right eyes). The aspect ratio for each eye is provided.
• O, P, Q provide graphic representation of the eye movement tracking for each eye over time demonstrating the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye.
• Figure 24 provides a representation of the conjugate gaze in a normal subject while watching television.
• A-N provide box plots of eye movement tracking (left and right eyes). The aspect ratio for each eye is provided.
• O, P, Q provide graphic representation of the eye movement tracking for each eye over time demonstrating the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye.
• Conjugacy is calculated or quantified at 0.0169.
• Figure 25 provides a representation of the disconjugate gaze in a subject with a surgically severed cranial nerve III.
• A-N provide box plots of eye movement tracking (left and right eyes). The aspect ratio for each eye is provided.
• O, P, Q provide graphic representation of the eye movement tracking for each eye over time demonstrating the variance in x-axis movement between the left and right eye and the variance in y-axis movement between the left and right eye.
• Disconjugacy is calculated or quantified at 2.2711.
• Figure 26 represents findings from a 38 year old right-handed male recruited from the emergency room after being hit by a car while riding his bicycle. The patient was brought in with a backboard and C-collar, intoxicated with reported loss of consciousness and normal vitals but intermittent confusion with retrograde amnesia. On physical examination he was alert and oriented x3, had a right eye hematoma and a posterior vertex soft tissue hematoma. He had active bleeding over a 5cm vertical laceration overlying the left maxilla.
• Head CT findings include bilateral parafalcine posterior vertex subdural hematomas measuring up to 8mm in thickness. There were multiple punctuate-subcentimeter bifrontal contusions, right greater than left. There was a 4mm left parafalcine subdural hematoma. He had no significant ophthalmic history following his last optometric visit 10 years prior. No other major body injuries.
• Quantitative serum alcohol level was 130 mg/dl.
• Medications administered up to 24 hours prior to recruitment included acetaminophen 325mg, bacitracin, moxifloxacin hydrochloride.
• B. Represents eye movement tracking box plots 2 days after triage. The patient was positive for 12/22 symptoms according to SCAT3 with a severity score of 45/132 and GCS score of 13/15. Total SAC score of 17/30.
• C. Represent eye movement tracking box plots 13 days after triage. The patient was positive for 10/22 symptoms according to SCAT3 with a severity score of 27/132 and GCS score of 15/15. Total SAC score of 24/30.
• Medications administered up to 24 hours prior to eye tracking included ibuprofen.
• Figure 27 represents findings from a 37 year old right-handed female. The patient fell 2 weeks prior to seeking medical care. She denied loss of consciousness at the time. After taking aspirin, she developed word finding difficulty 4 days prior to admission. She presented to the emergency room where her examination was otherwise non-focal. A. The head CT showed a mixed attenuation predominantly hyperdense subdural fluid collection over the left cerebral convexity measuring up to 1.7 cm in thickness with associated mass effect upon the left lateral ventricle and 7mm left to right midline shift of the septum pellucidum. The patient underwent craniotomy and was recruited for the study from NSICU on the third postoperative day.
• B. Represents eye movement tracking box plots 3 days post operatively and 17 days post injury patient. The patient was positive for 6/22 symptoms according to SCAT3 with a severity score of 17/132 and GCS score of 15/15. Total SAC score of 18/30.
• C. Represents eye movement tracking box plots at 35 days post surgery and 49 days post injury. The patient was positive for 13/22 symptoms according to SCAT3 with a severity score of 32/132 and GCS score of 15/15. Total SAC score of 27/30. No medications, drugs or alcohol 24 hours prior.
• Figure 28 represents findings from a 22 year old right-handed male recruited from the emergency room who was participating in a skateboard competition and experienced a fall from 10-15 feet landing on his unhelmeted head. He lost consciousness for approximately 30 minutes and then was agitated, confused and amnestic for the event. His trauma bay GCS was 15 and he had a moderate sized left scalp hematoma on physical examination. A. His head CT findings included a comminuted minimally displaced fracture of the left occipitoparietal bone with extension to the anterior aspect of the left temporal bone. There was also a small underlying left subdural hematoma with pneumocephalus.
• B. Represents eye movement tracking box plots 1 day after injury. The patient was positive for 13/22 SCAT3 symptoms with a severity score of 62/132 and GCS score of 14/15. The total SAC score was 19/30.
• C. Represents eye movement tracking box plots 12 days after injury. The patient was positive for 19/22 SCAT3 symptoms with a severity score of 81/132 and GCS score of 15/15. The total SAC score was 17/30.
• D. Represents eye movement tracking box plots 66 days after injury. The patient was positive for 19/22 SCAT3 symptoms with a severity score of 69/132 and GCS score of 15/15. The total SAC score was 24/30. No medications, drugs or alcohol were consumed in the 24 hours prior to tracking on any occasion.
• Figure 29 represents the findings from a 23 year old right-handed male who fell from height of 30 feet.
• the Patient was awake, alert and hypotensive in the field, GCS 14. He reported diffuse pain including in head, no vomiting.
• the neurological examination was non- focal, but the patient was intubated for chest and pelvis injuries. He had no ophthalmic history other than an optometric visit 6 months prior. He wears corrective lenses for astigmatism and reports a learning disability.
• Medications administered within 24hours prior to eye tracking included albuterol, vancomycin hydrochloride, piperacilin tazobactam, aztreonam, pentacel.
• A. Represents eye movement tracking box plots 8 days after injury. No SCAT was performed initially.
• C. Represents eye movement tracking box plots 34 days after injury. The patient was positive for 10/22 SCAT3 symptoms with a severity score of 27/132 and GCS of 15/15. Total SAC score of 22/30.
• D. Represents eye movement tracking box plots 75 days after injury. The patient was positive for 13/22 SCAT3 symptoms with a severity score of 39/132 and GCS of 15/15. Total SAC score of 26/30.
• Figure 30 represents the findings from a 47 year old right-handed male recruited from the emergency room. The patient was inebriated and crashed his bicycle into a parked truck. He was unhelmeted. He vomited and then became unresponsive. Upon arrival, he was intubated, GCS 3T. Radiograph revealed a broken clavicle. Quantitative serum alcohol level was 284 mg/dl. He had no ophthalmic history following an optometric visit many years ago. Upon recruitment 24 hours later the patient was extubated, alert and oriented x3. Medications administered up to 24 hours prior to recruitment included claritin and hydrocodone-acetaminophen, lidocaine, etomidate, and succinylcholine. A.
• Figure 31 represents the findings from a 53 year old right-handed female recruited from the ER after falling on the street down bus steps, impacting her face. She denied loss of conscious or amnesia and presented immobilized with cervical collar. On examination she had a lip laceration. She had a medical history significant for migraines and bitemporal hemianopsia due to benign pituitary adenoma. Head CT showed moderate multifocal white matter disease to right putamen, posteriorly in the right caudate head and left frontal corona radiate, maybe ischemic in origin, and bilateral proptosis. Her last optometric visit was one month prior to recruitment, and she wears corrective lenses and bifocal contact in right eye.
• Medications administered up to 24hours prior to recruitment included diovan, lidocaine, hydrochloide 600mg, acetaminphen 650mg, vitamins, and tylenol.
• A. Represents eye movement tracking box plots a few hours after triage. The patient was positive for 16/22 SCAT3 symptoms with a severity score of 40/132 and GCS score of 15/15. The total SAC score was 23/30.
• B. Represents eye movement tracking box plots at 10 days post injury. The patient was positive for 4/22 SCAT3 symptoms with a severity score of 17/132 and GCS score of 15/15. The total SAC score was 20/30.
• C. Represents eye movement tracking box plots 17 days post injury.
• D. Represents eye movement tracking box plots at 113 days post injury. The patient was positive for 16/22 SCAT3 symptoms with a severity score of 48/132 and GCS score of 15/15. The total SAC score was 27/30.
• Figure 32 represents graphically that while MRI and CT can detect structural traumatic brain injury (TBI), eye tracking can detect physiologic disruption of cerebral function.
• TBI structural traumatic brain injury
• Subject or “patient” refers to a mammal, preferably a human, in need of or undergoing treatment or screening for a condition, disorder or disease such as, for instance, increased intracranial pressure.
• assessing central nervous system integrity is meant identifying one or more symptoms that may indicate a pathology of or affecting the central nervous system, or identifying, assessing, quantifying or diagnosing a pathology of the central nervous system.
• the pathology may be, for instance, one or more of increased intracranial pressure, hydrocephalus, concussion, dementia, schizophrenia, amyotrophic lateral sclerosis, muscular sclerosis, autism and Fragile X disease.
• a central nervous system lesion in some instances determining information that may predict a likely position of a lesion, for instance, determining the side of the body, for instance, left or right, where a lesion may likely be located within the central nervous system. In other instances, “localizing a central nervous system lesion” may mean determining a particular fossa or compartment, such as, for instance, a fascia compartment or brain ventricle in which a lesion is likely located within the central nervous system.
• having eye movement of a first eye that is significantly different from eye movement of a second eye is meant displaying eye movement in a first eye over 5, 10, 25, 50, 100, 1,000, 5,000, 10,000 or more observations, tracked with at least x, y coordinate positions, that is at least 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 75%, or 100% or more variant compared to the corresponding eye movement observations tracked from the second eye.
• the 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 75%, or 100% or more variant may be calculated or observed either numerically or graphically.
• "having eye movement of a first eye that is significantly different from eye movement of a second eye” is meant displaying eye movement in a first eye over 5, 10, 25, 50, 100, 1,000, 5,000, 10,000 or more observations, tracked with at least x, y coordinate positions, that, when graphically displayed in a scatterplot as described herein, is at least 5°, 10°, 15°, 20°, 25°, 30°, 40°, 50°, 60°, 75° or 90° or more variant compared to the corresponding eye movement observations tracked and graphically displayed on a scatterplot as described herein from the second eye.
• vergence or “vergence disorders” refers generally to convergence, when the eyes rotate inward as an object moves closer, and to divergence, when the eyes rotate outward as an object moves farther away. Both convergence and divergence are tested to some extent as an object moves around, effectively assessing sustained vergence. Most vergence disorders are due to the pathologies and causes described herein, for instance, trauma. Some vergence disorders may be congenital. The methods and algorithms described herein facilitate screening for such vergence and vergence disorders.
• the methods described herein are distinct from conventional methods. As applied to determining intracranial pressure, a conventional ICP monitor determines the brain's pressure number in one spot, an 0 2 monitor determines an oxygenation number in one spot, imaging reveals what the brain looks like, but the methods described herein provide methods for testing for physiologic function of the cranial nerves that may reflect factors that may delay axoplasmic transport such as elevated intracranial pressure.
• the methods described herein may be used to detect elevated intracranial pressure and assess or determine the severity of the same. Similarly, the methods described herein may be used to localize the intracranial cause of such intracranial pressure and to monitor progression of lesions or diffuse processes within the cranium. Likewise, the methods described herein may be used to detect concussion and assess or determine the severity of the same.
• the methods described herein provide high sensitivity. No patient yet evaluated with an abnormal physical exam or films consistent with elevated ICP has had normal eye movement tracking.
• the methods described herein may be used to reduce the need for CT scans among potential shunt malfunction patients, patients with lesions causing elevated intracranial pressure, and may be used to screen patient populations such as emergency room ER populations, sports participants, soldiers or other combatants, nursing home residents or other populations at risk for falling for elevated intracranial pressure or concussion.
• High resolution automated eye movement tracking occurring over, for instance, about 220 seconds, is a powerful tool for detecting subclinically apparent ocular motility dysfunction, and thus aid in the rapid diagnosis of elevated intracranial pressure or concussion.
• the IVth nerve would be most vulnerable (median length 33 mm (Hanson et al, Neurology 2004; 62(l):33-36)), the Illrd nerve would be second most vulnerable (26 mm (Adler et al., Journal of Neurosurgery 2002; 96(6): 1103-1112)) and Ilnd and Vlth would be approximately equally least vulnerable (5 to 16 mm for II (Murali, R. Injuries of the Cranial Nerves. In: Golfinos PCaJ, ed. Head Injury. 4th ed. New York: McGraw Hill; 2000), and 11 mm median length for VI (Hanson et al., Neurology 2004; 62(l):33-36)).
• the abducens nerve (VI) exits the brainstem from its tethering at the medullopontine junction and courses intracranially before entering Dorello's canal, where it is again tethered by fibrous and osseous structures. Elevation of supratentorial ICP forces the parahippocampal gyri down past the free edge of the tentorium while the brainstem with the tethered Vlth nerve moves caudally toward the foramen magnum, stretching the nerve where it enters Dorello's canal (Hanson et al, Neurology 2004; 62(l):33-36).
• Vlth nerve palsies may directly compress the Vlth nerve against the clivus (Hanson et al, Neurology 2004; 62(l):33-36). It is also possible that the increased reporting of Vlth nerve palsies may be due to their easier detection on clinical examination than III and IVth nerve palsies.
• the data presented herein does not feature a calibration step in eye movement tracking. Thus patients need not reliably follow instructions, and the data does not filter out the possible effects of cranial neuropathy. Unlike other studies (Contreras et al, Brain research 2011 ; 1398:55-63; Maruta et al, The Journal of Head Trauma Rehabilitation 2010; 25(4):293-305; Contreras et al., Journal of Biological Physics 2008; 34(3-4):381-392 and Trojano et al., J Neurol 2012;(published online; ahead of print)) the data presented herein does not use saccade count or spatial accuracy as the measure. In addition to results based on the moving aperture's periodic envelope presented in this paper, the methodology also affords a very fine-scale data showing eye movements in response to the successive frames of the movie itself.
• the present methods feature diagnosing specific clinical conditions related to vision and ocular motility reflecting the function of cranial nerves II, III, IV, VI and associated nuclei rather than measuring cognitive impairment due to primarily cortical mild to moderate traumatic brain injury.
• the present methods use more fine-scale information, using, for instance, about 100,000 measurements to pull out subtle differences that can be lost through the somewhat arbitrary thresholding of velocity measures into saccades.
• the present methods do not use measurements of spatial accuracy, which requires transforming the raw data by a series of scaling and rotating processes whose effectiveness depends on the ability of their subjects to follow precise commands reliably. In such methods previously used, it is necessary to exclude the vast majority of neurologically compromised patients. Further, such methods previously used lose any information related to the function of cranial nerves II, III, IV and VI, because the spatial distortions expected to result from damage to these nerves is reversed in the process of spatial calibration.
• Trojano et al J Neurol 2012;(published online; ahead of print) recently described uncalibrated eye movement measurements in a population of minimally conscious and persistently vegetative patients.
• the methods described herein differ in several ways.
• First, Trojano et al. report data from 11 rather than 25 healthy control subjects.
• Second, Trojano et al. evaluate chronic disorders of consciousness rather than acute changes in intracranial pressure.
• Third, Trojano et al. sample eye movements at 60 Hz rather than 500 Hz, effectively reducing the power of the data 100-fold.
• Trojano et al. report differences in on-target and off-target fixations between the groups, despite not having spatially calibrated the data, making these values noisy.
• Finally, Trojano et al. use static stimuli moving in a quasi-periodic way.
• the methods described herein use moving images shown within an aperture that moves periodically and allows assessing both coarse and fine eye movement characteristics in both controls and patients.
• the methods described herein provide a useful adjunct for diagnosis of elevated ICP and the prospective monitoring of such patients at risk for its development.
• No patients with elevated ICP by history, physical examination and radiology have demonstrated normal ocular motility, demonstrating that the methods described herein are sensitive.
• the data presented herein demonstrate that patients with grossly intact extraocular movements on physical exam, and relatively minimal changes in pathology, may have profound disruption on high resolution tracking.
• the methods described herein provide a useful adjunct for diagnosis of concussion and prospective monitoring of such patients at risk for developing the same.
• the data presented herein demonstrate that patients with grossly intact extraocular movements on physical exam, and relatively minimal changes in pathology, may have profound disruption on high resolution tracking.
• the data presented herein demonstrates in part that it is possible to diagnose elevated intracranial pressure and concussion by analysis of eye movements during watching of a video.
• the methods described herein are significantly different from other technologies since imaging studies enable one to see the brain and invasive techniques enable determination of an arbitrary pressure or oxygenation number.
• the methods described herein actually assess physiologic functioning.
• the methods described herein have many clinical applications including, for instance, i) assessing function of cranial nerves II, III, IV and VI, and perhaps even VII, VIII, and/or X; ii) detecting and quantitatively monitoring any process impeding or improving the function of the above (e.g. demonstrating elevated ICP or increased brain mass effect, that may be applied to such things as aneurysms, multiple sclerosis, sarcoidosis, tumors, aging, alcohol abuse, intoxicants/narcotics, etc.), iii) localizing pathology and identifying the nature of that pathology within the brain (e.g.
• the methods described herein may provide means for in-person screening such as to, for example, assess vision, assess ocular motility, and assess cognitive dysfunction all relatively simultaneously (e.g. for a driver's or pilot's license, employment etc.). Further, the methods described herein may be used to assess variance, which appears to increase with cognitive decay. This could be used, for instance, to target advertising by stratification of intelligence. Further, the methods described herein may be used to assess disconjugate gaze that apparently increases with cognitive decay. Still further, the methods described herein may be used for intelligence or neurologic function testing.
• the present invention features a novel eye movement tracking method that is useful for quantitating gaze conjugacy, and thus disconjugacy, during naturalistic viewing. Similarly, the method assesses vergence, or the ability of the eyes to focus on a single point. When the point moves closer the eyes converge and if it moves further away they diverge. Watching a moving stimulus on a monitor thus requires sustained vergence. It may be performed while a subject watches television or a video moving inside an aperture with a set trajectory for about 220 seconds at a fixed distance from a viewing monitor. It may also be performed as the subject views natural stimuli over time.
• the position of each pupil may be recorded over time elapsed as the video travels on its time course, enabling detection of impaired ability to move the pupils relative to time and therefore relative to each other.
• This method has high test-retest reliability in control subjects without significant neurologic or ophthalmic impairments using both a stationary and portable eye tracking device.
• Eye movement tracking for neuropsychiatric and brain injury research has been performed for nearly 30 years and can evaluate smooth pursuit, saccades, fixation, pupil size and other aspects of gaze.
• Spatial calibration of the eye tracker is generally performed for each individual being tracked. With calibration, the eye-tracker measures the relative position of pupil and corneal reflection for a period of about 400-800 ms while the subject looks at a target or targets of known position to generate meaningful spatial coordinates during subsequent pupil movement.
• the process of spatial calibration implies relatively preserved neurologic function because it requires that the subject is able to follow commands and look at specific points.
• the process of spatial calibration may mask deficits in ocular motility. If there is a persistent and replicable weakness in movement of an eye, the camera may interpret the eye's ability to move in the direction of that weakness as the full potential range of motion in that direction due to the calibration process. In other words if the subject is directed to look at a position but consistently only moves halfway there, the calibration process may account for that when tracking subsequent eye movements and interpret movements to the halfway point as occurring at the full range of normal motion. If during calibration one eye only makes it halfway to the target, but the other eye is fully there, the camera may interpret both eyes as being together when one performs half the eye movement as the other. Thus binocular spatial calibration may preclude detection of disconjugate gaze unless each eye is calibrated separately using a dichoptic apparatus (Schotter, et al, PLoS One, 2012; 7: e35608).
• the present invention provides a novel technique for non-spatially calibrated tracking performed while subjects watch a music video moving inside an aperture on a computer monitor.
• the aperture moves around the monitor periphery at a known rate so that the position of the pupil can be predicted at any given time based on the time elapsed since the start of the video.
• the method detects impaired ability to move one pupil relative to the other.
• Uncalibrated tracking not only does not compensate for impaired motility, but also can be used in patients who do not follow commands such as aphasics, foreign- language speakers, persistently vegetative individuals and small children. It can also be used on animals.
• the method and associated algorithm elicits pupil movement in a maximum range of about 15° in any direction from midposition, or approximately 30° total from top to bottom or side to side.
• the method and associated algorithm may not require or assess the full range of ocular motility, nor the entire visual field. Use of a larger monitor, or one positioned closer to the subject would enable assessment of these.
• the observed and measured conjugacy was significantly higher in the horizontal plane than vertical. This may reflect any of multiple factors: (1) the shape of the monitor was not a perfect square but rather a 17" diameter rectangle. Each side was traversed in 10 seconds so the eyes had a greater distance to travel horizontally than vertically. Because the eyes were moving faster horizontally they may possibly be more conjugate. (2) Humans have stronger event related desynchronization on electroencephalogram with horizontal versus vertical eye movements (Kaiser, et al, Clin NeurophysioL, 2009; 120: 1988-1993). Humans may have evolved to have higher conjugacy in the horizontal plane than in the vertical because more prey and predators are likely to be at near the same altitude rather than above or below. Other species have
• the technique described herein differs from uncalibrated tracking using static stimuli for on-target and off-target fixations in a population of minimally conscious and persistently vegetative patients that have open eyes (Trojano, et al, J Neurol, 2012 (published online; ahead of print)).
• the moving images shown within an aperture that moves periodically allow assessing both coarse and fine eye movement characteristics in both controls and neurologically impaired subjects.
• the present methods do not use saccade count or spatial accuracy which requires transformation of raw data by a series of scaling and rotating processes whose effectiveness depends on the ability of their subjects to follow precise commands reliably.
• the present methods also differ from gaze estimation, which requires either a fixed head position or multiple light sources and cameras to localize the pupil (Guestrin, et al, IEEE Trans Biomed Eng., 2006; 53 : 1124-1133).
• Video oculography is a relatively newer technique that uses infrared cameras mounted in goggles to track the center of the pupil's position as the eye moves. It has been demonstrated to be useful in screening for neurovestibular and labyrinthine dysfunction and most recently in distinguishing these from vertebrobasilar stroke (Newman-Toker, et al, Stroke, 2013; 44: 1158- 1161). Video oculography generally relies on spatial calibration (Hong, et al, Behav Res Methods, 2005; 37: 133-138; Schreiber, et al, IEEE Trans Biomed Eng., 2004; 51 : 676-679). The use of our non-calibrated stimulus algorithm with video oculography rather than a sole eye tracking camera might be an interesting subject for future study.
• the methods described herein provide both sensitivity and specificity. Because so many different cortical functions are required for watching a video, any process impeding global cranial function or specific cranial nerve function will likely be revealed by the present methods. Tracking may be confounded in patients with a history of prior brain insult, who are intoxicated, or are under the influence of pharmacologic agents. Patients' cognitive abilities, attention span and distractibility will impact the quality of ocular motility data.
• A-pattern strabismus was associated with a greater prevalence of neurological impairment, hydrocephalus and meningomyelocele, while those with V-pattern exhibited a greater prevalence of
• disconjugacy and vergence disorders may be due to neurologic causes including trauma, hydrocephalus, demyelination, inflammation, infection, degenerative disease,
• Disconjugacy may also be due to ophthalmologic causes such as conjunctivitis, ophthalmoplegia, ocular injury or other diseases.
• the methods described herein are useful for screening for strabismus or congenital disconjugate gaze, screening for acquired disconjugate gaze due to neurologic causes including trauma, hydrocephalus, demyelination, inflammation, infection, degenerative disease, neoplasm/paraneoplastic syndrome, metabolic disease including diabetes, or vascular disruption such as stroke, hemorrhage or aneurysm formation.
• Disconjugacy may also be due to ophthalmologic causes such as conjunctivitis, ophthalmoplegia, ocular injury or other diseases, and assessing reading/learning disorders.
• Binocular tracking may be used to compare the non-spatially calibrated trajectory of one eye to the other. Subtle differences between the trajectories of the two eyes may be detected. These differences provide valuable information regarding the physiologic function or dysfunction of the movement of one eye relative to the other. In the absence of known structural ocular injury, such differences reflect physiologic differences in the function of the two sides of the brain. Since brain lesions due to stroke, trauma or concussion, tumors, demyelinating disease, hydrocephalus, degenerative disease, etc.
• comparing the eye movement of one eye to the eye movement of the other eye may be used to either confirm the presence of a lesion, to differentiate the existence of a lesion from other more global factors that may affect a person's ability to participate in an eye tracking task, such as fatigue, intoxication, medications, drug abuse, malingering, or lack of willingness to participate in an eye tracking task.
• binocular tracking and directly comparing the trajectories obtained over time, rather than with spatial calibration may be used to diagnose pathology and to distinguish between these diagnoses and global factors that may impact eye tracking.
• a video oculography device such as goggles may be used to evaluate eye movements over time rather than with spatial calibration.
• the eye tracking device may also be located remotely and function via the internet or other visualization mechanism.
• the computer system or computing device 1000 can be used to implement a device that includes the processor 106 and the display 108, the eye movement/gaze tracker component 104, etc.
• the computing system 1000 includes a bus 1005 or other communication component for communicating information and a processor 1010 or processing circuit coupled to the bus 1005 for processing information.
• the computing system 1000 can also include one or more processors 1010 or processing circuits coupled to the bus for processing information.
• the computing system 1000 also includes main memory 1015, such as a random access memory (RAM) or other dynamic storage device, coupled to the bus 1005 for storing information, and instructions to be executed by the processor 1010.
• Main memory 1015 can also be used for storing position information, temporary variables, or other intermediate information during execution of instructions by the processor 1010.
• the computing system 1000 may further include a read only memory (ROM) 1010 or other static storage device coupled to the bus 1005 for storing static information and instructions for the processor 1010.
• ROM read only memory
• a storage device 1025 such as a solid state device, magnetic disk or optical disk, is coupled to the bus 1005 for persistently storing information and instructions.
• the computing system 1000 may be coupled via the bus 1005 to a display 1035, such as a liquid crystal display, or active matrix display, for displaying information to a user.
• a display 1035 such as a liquid crystal display, or active matrix display
• An input device 1030 such as a keyboard including alphanumeric and other keys, may be coupled to the bus 1005 for communicating information and command selections to the processor 1010.
• the input device 1030 has a touch screen display 1035.
• the input device 1030 can include a cursor control, such as a mouse, a trackball, or cursor direction keys, for communicating direction information and command selections to the processor 1010 and for controlling cursor movement on the display 1035.
• main memory 1015 implemented by the computing system 1000 in response to the processor 1010 executing an arrangement of instructions contained in main memory 1015. Such instructions can be read into main memory 1015 from another computer-readable medium, such as the storage device 1025. Execution of the arrangement of instructions contained in main memory 1015 causes the computing system 1000 to perform the illustrative processes described herein. One or more processors in a multi-processing arrangement may also be employed to execute the instructions contained in main memory 1015. In alternative implementations, hard-wired circuitry may be used in place of or in combination with software instructions to effect illustrative
• implementations are not limited to any specific combination of hardware circuitry and software.
• Implementations of the observer matter and the operations described herein can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them.
• the observer matter described herein can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on one or more computer storage media for execution by, or to control the operation of, data processing apparatus.
• the program instructions can be encoded on an artificially-generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus.
• a computer storage medium can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them.
• a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially-generated propagated signal.
• the computer storage medium can also be, or be included in, one or more separate components or media (e.g., multiple CDs, disks, or other storage devices). Accordingly, the computer storage medium is both tangible and non-transitory.
• data processing apparatus or “computing device” encompasses all kinds of apparatus, devices, and machines for processing data, including by way of example a
• the apparatus can include special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).
• the apparatus can also include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more of them.
• the apparatus and execution environment can realize various different computing model infrastructures, such as web services, distributed computing and grid computing infrastructures.
• a computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment.
• a computer program may, but need not, correspond to a file in a file system.
• a program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub-programs, or portions of code).
• a computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.
• processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer.
• a processor will receive instructions and data from a read-only memory or a random access memory or both.
• the essential elements of a computer are a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data.
• a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks.
• mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks.
• a computer need not have such devices.
• a computer can be embedded in another device, e.g., a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, or a portable storage device (e.g., a universal serial bus (USB) flash drive), to name just a few.
• Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.
• the processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.
• implementations of the observer matter described in this specification can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer.
• a display device e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor
• keyboard and a pointing device e.g., a mouse or a trackball
• Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.
• feedback provided to the user can be any form of sensory feedback, e.g., visual feedback,
• the raw data is preprocessed as follows: for the x (horizontal) and y (vertical) vectors independently, the mean is subtracted and divided by the standard deviation (which is the square root of the variance). This puts all the data in the same relative frame (zero-mean, max and min about 1 and -1). This is the reason the boxes look square (even if the stimulus presentation monitor is not square).
• the methods described herein provide means for assessing or quantifying disconjugate gaze or disconjugate eye movement. These means feature receiving an array of pupil x and y coordinates that may be generated or obtained according to the methods described herein. These coordinates may be be averaged across, for instance, five eyebox trajectory cycles. Formulaically this can be represented as as follows: where Xy k refers to the x-coordinate of the pupil, and k refers to the left or right eye of a subject. The difference in the x and y position, for the left and right eye, may then be computed. This vector of difference may then be plotted graphically for purposes of assessment and
• a variance of the data may be computed with respect to an expected mean of zero. This is significant because the code assumes that a healthy subject has zero lateral or longitudinal pupil position difference between each eye.
• the variance may be computed as follows:
• the total variance may be computed as follows:
• the variance in X, Y, and the total variance may be plotted in order to assess the amount of disconjugation (i.e. disconjugate gaze) present in a subject.
• the methods described herein may identify strabismus.
• A-pattern was associated with a greater prevalence of neurological impairment, hydrocephalus and meningomyelocele, while those with V-pattern exhibited a greater prevalence of cranio synostosis and malformative syndromes (Dickmann, et al, Ophthalmic Epidemiol, 2012; 19: 302-305).
• disconjugacy may be due to neurologic causes including trauma, hydrocephalus, demyelination, inflammation, infection, degenerative disease, neoplasm/paraneoplastic syndrome, metabolic disease including diabetes, or vascular disruption such as stroke, hemorrhage or aneurysm formation.
• Disconjugacy may also be due to ophthalmologic causes such as conjunctivitis, ophthalmoplegia, ocular injury or other diseases.
• the methods described herein may feature assessing conjugacy or disconjugacy of eye movement in correlation with structural and non- structural traumatic brain injury, including concussion or blast injury.
• a purpose of the prospective observational study described herein was to quantitate differences in eye tracking of structurally and non- structurally brain injured subjects relative to non-brain but bodily injured and healthy non-injured controls to identify the eye tracking parameters associated with structural and non- structural injury. Another purpose was to identify a correlation between impaired eye tracking and clinical neurologic functioning. Eye tracking and clinical concussion assessments were performed on 44 injured subjects, and eye tracking was performed only on 31 healthy normal controls. 51 eye tracking parameters were assessed in each patient. 10 parameters showed statistically significant differences between negative controls (healthy normal people and corporally injured trauma patients) and both positive controls (patients with structural brain injury) and patients with non- structural brain injury.
• the data presented herein quantitates differences in eye tracking of structurally and non- structurally brain injured subjects relative to non-brain but bodily injured and healthy non-injured controls to identify the parameters associated with structural and non- structural injury.
• the data presented herein further establish a correlation between impaired eye tracking and clinical neurologic functioning.
• Index i corresponds to an individual data point.
• the size of i depends on the eye tracking hardware capture frequency and the time of tracking.
• x represents the left normalized raw x pupil position minus the right normalized raw x pupil position.
• / corresponds to the top, right, bottom and left segments of the box.
• the variance here does not follow the traditional form of statistical variance.
• the average of the data points is subtracted from the sum of individual data points. In this case, the average is forced to zero, thus inferring that the hypothetical control patient has perfect conjugacy (left and right eye move precisely together).
• Eye movements contain clinically important information about neurological integrity.
• Clinical devices may take advantage of the relative ease of automated eye-movement tracking, for applications such as assessing recovery following clinical intervention.
• a technique was designed that can reliably measure eye movements with precision, without initial spatial calibration.
• Temporal features of the data were measured, rather than traditional spatial measures such as accuracy or speed.
• Eye movements have long been known to contain clinically relevant information about neurological integrity. Assessment of ocular motility is a standard part of any neurological exam, because it is easy and informative. However, there are some problems with the standard clinical exam including that it is normally administered by an expert, and generally is only qualitative, not quantitative.
• the calibration process itself may reduce the sensitivity of the eye tracking test. For example, consider a patient with impaired vertical ocular motility. Because the calibration process assumes that the eyes cover the full range of locations mapped out by the calibration points, it assigns the maximum pupil angle up and down incorrectly to the 'top' and 'bottom' of the monitor, respectively. In such instances, all future measurements for that observer are adjusted to conform to that incorrect assignment. Thus, impaired ocular motility may be undetected in tests that begin with a spatial calibration of the eye tracker.
• Eye movement measurements may reflect severity of damage to the brain, as well as recovery following clinical intervention.
• the methods described herein were used to test patients from neurosurgery, emergency department and ophthalmology clinics as well as a control set of healthy volunteers. The success of the method involves two features. First, the methods described herein do not use spatial measures of accuracy as a variable of interest. By looking at eye movement trajectories in the time domain rather than the spatial domain, it is possible to quantify measures that do not rely on spatial calibration. Second, the measures are easily visualized and evaluated, making them immediately useful to the clinician or researcher.
• Eye Movement Tracking Observers' eye movements were recorded using an Eyelink 1000 binocular eye tracker (500 Hz sampling, SR Research). All observers were seated approximately 55 cm from the screen. Some test patients were tracked on multiple visits at different stages of diagnosis, surgery, and recovery.
• Visual Stimulus The visual stimulus provided as a music video that played continuously while it moved clockwise along the outer edges of a computer monitor. Observers were instructed to watch the video. The stimulus was expected to evoke smooth pursuit eye
• the video was presented in a square aperture with an area approximately 1/8 of the size of the screen (about 16° of visual angle). This square aperture started at the upper left hand corner of the screen and moved at a constant speed, taking 10 seconds to traverse each edge of the monitor. A full cycle took 40 seconds, and five full cycles were played, for a total of 200 seconds. A countdown video played in the starting position for 10 seconds before the music video began, to give observers time to orient to the stimulus. Only the 200 seconds of the music video were used for analyses.
• the eye tracker sampled eye position at 500 Hz, yielding 100,000 samples of eye position over 200 seconds.
• Phase was calculated as phase of the sine function that best fit the data.
• the 8 following complementary procedures were used to assess the statistical significance of any differences in these two measures (phase difference and model fit) as compared between the neurologically intact control observers and the test patient observers.
• (i) Statistical Analysis 1 hypothesis testing. For each measure, a statistical test was performed to determine whether the data from the test patient population could have come from the same underlying distributions as the data from the neurologically intact control population. For the phase measure, an unpaired t-test was used. For the sinusoidal fit measure, the Kruskal- Wallis analysis of variance (ANOVA) was used which is more appropriate for data that are not normally distributed.
• ANOVA Kruskal- Wallis analysis of variance
• Uncalibrated tracking may provide a quantitative measure of the ability to fixate, attend, and follow a stimulus. These date demonstrate that it is possible to collect reliable high- frequency eye movement data without first completing a spatial calibration for each observer. Many patients are not capable of calibrated eye tracking. The ability to track eye movements in these populations provides new insights about a variety of disorders that disturb the ocular-motor system, including but not limited to brain injury, stroke, and psychiatric disorders. Possible applications include clinical screening, diagnosis, monitoring the efficacy of treatment, and tracking progression of impairment and recovery.
• Eye Movement Tracking The subjects' eye movements were recorded using an Eyelink 1000 binocular eye tracker (500 Hz sampling, SR Research). Healthy volunteers were seated 55 cm from the screen with their head stabilized using a chinrest. Stimulus was presented on average 55 cm from patient eyes, with the presentation monitor adjusted to match gaze direction. Subjects used a chinrest.
• Units The units of relative variance are related to size in degree of visual angle, but are not exactly identical to degrees of visual angle, because there was no spatial calibration. These may be referred to as time-degrees units.
• Control subjects were employees, volunteers, visitors and patients at the Bellevue Hospital Center recruited in accordance with Institutional Review Board policy. Inclusion criteria for normal control subjects were: age 7 to 100 years, vision correctable to within 20/500 bilaterally, intact ocular motility, and ability to provide a complete
• ophthalmologic, medical and neurologic history as well as medications/drugs/alcohol consumed within the 24 hours prior to tracking.
• Parents were asked to corroborate details of the above for children aged 7-17. Exclusion criteria were history of: strabismus, diplopia, palsy of cranial nerves III, IV or VI, papilledema, optic neuritis or other known disorder affecting cranial nerve II, macular edema, retinal degeneration, dementia or cognitive impairment, hydrocephalus, sarcoidosis, myasthenia gravis, multiple sclerosis or other demyelinating disease, and active or acute epilepsy, stroke/hemorrhage or brain injury sufficiently significant to result in
• the video was played continuously in a square aperture with an area approximately 1/8 the screen size while moving clockwise along the outer edges of the monitor for five complete cycles of 40 seconds each.
• the first and last 10 seconds of each data set were discarded to yield 200 seconds of data.
• the afferent stimulus was presented binocularly and eye tracking was performed binocularly.
• subjects were assessed for gaze conjugacy using a naturalistic viewing stimulus. This consisted of watching television as eye movements were tracked over time. Subjects were not seated at a fixed distance from the monitor but were able to move their heads during viewing.
• the variance in X, Y, and the total variance may be plotted in order to assess the amount of disconjugation present in a subject.
• Test-retest on the stationary tracker and from the stationary to the portable tracker A paired t-test was used to determine if the mean of the subject-paired differences between the total variances for two separate eyetracking sessions was statistically significantly different from 0.
• Subjects (n 27) demonstrated high test-retest reliability between two separate eyetracking sessions on the stationary tracker ( Figure 10).
• a paired t-test was used to determine if the mean of the subject-paired differences between the total variances for two separate eyetracking sessions was statistically significantly different from 0. With 26 degrees of freedom, the test resulted in a t-statistic of 1.2778 and a p-value of 0.2126 showing that the mean of the subject- paired differences was not statistically significantly different from 0.
• non-structural TBI subjects meaning they show no signs of structural injury on imaging; however, they complain of usual brain injury symptoms such as headache, dizziness, cognitive impairment, etc.
• a subject with mild traumatic brain injury is a person who has had a traumatically induced physiological disruption of brain function, as manifested by at least one of the following:
• Focal neurological deficit(s) that may or may not be transient, but where the severity of the injury does not exceed the following:
• PTA Posttraumatic amnesia
• non-brain injured subjects that have suffered some type of injury such as to the extremities or other parts of the body.
• the subjects have sustained a blunt or penetrating trauma such as, to the corpus or extremities (i.e. car accident, falling, violent act excluding interpersonal violence).
• Healthy non injured control subjects were employees, volunteers, visitors and patients with intact ocular motility, and ability to provide a complete ophthalmologic, medical and neurologic history as well as medications/drugs/alcohol consumed within the 24 hours prior to tracking. Exclusion criteria included any minor brain injury regardless of loss of consciousness within the previous month.
• a portable binocular eye movement tracker was constructed by attaching an adjustable arm to a rolling cart.
• a computer monitor was attached to the proximal portion of the arm, and a chinrest was attached to the distal aspect of the arm such that the chinrest centered the subject's eyes 55 cm away from the monitor.
• Metrics 51 eye-tracking parameters were measured per subject, looking at movement in each individual eye and conjugate movement between eyes. All data were analyzed using XL STAT version 2012.6.02 (Addinsoft SARL, Paris, France) and MedCalc version 12.6.1 (MedCalc Software, Ostend, Belgium). A p-value of ⁇ 0.05 was deemed as statistically significant.
• the sports concussion assessment tool (SCAT) was administered, and standardized assessment of concussion (SAC) scores were obtained on thirty-seven subjects. Stepwise multiple regression analysis was performed to evaluate the impact of each eye-tracking parameter on the SCAT and SAC scores. Parameters with p-values > 0.1 were removed from the model.
• Table 4 provides group means for each of the 51 measured parameters.
• Table 5 provides p-values. Ten of the 51 measured parameters demonstrated statistically significant differences between negative controls (either normal healthy people, or corporally injured but not brain injured controls) and both positive controls (structurally brain injured) and non- structurally brain injured people. 8 additional parameters showed statistically significant differences between negative controls (healthy normal people and corporally injured trauma patients) and patients with either structural or non- structural brain injury. 10 of the eye tracking measures showed statistically significant correlation between SCAT or SAC scores, suggesting that these eye tracking parameters correlated with a validated clinical outcome measure. Table 5

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