JP2008509762A - Aptitude test - Google Patents

Abstract

(I) presenting a group of cognitive tasks to a subject; (ii) detecting a brain response signal from the subject during presentation of the group of cognitive tasks; (iii) an SSVEP amplitude, phase from the brain response signal; And / or calculating a coherence response; and (iv) a known SSVEP response obtained from an individual with high and / or low suitability for the default task to assess the subject's suitability for the default task. A method for assessing a subject's cognitive suitability for a given task, including a step of comparing with.

Description

The present invention relates generally to the field of aptitude testing, including devices and methods for testing a subject's suitability for mental tasks and assessing subject thinking style.

BACKGROUND OF THE INVENTION Existing commonly used aptitude tests attempt to measure a subject's current ability using standard tests appropriate to the subject's age, language, culture, and educational background. Tests do not necessarily identify potential aptitudes in subjects who do not meet the basic requirements of the test, such as a particular educational background, or where standard tests do not exist or are not appropriate. For example, because existing tests require a minimum level of knowledge before suitability can be assessed, subjects with innate abilities that do not meet the minimum requirements will generally not be identified as potential candidates. Conceivable. In addition, ethnic minorities may consider certain tests unfair and discriminatory. There is a need for new tests that can be used to assess potential fitness as well as current fitness levels.

  Aptitude and thought style are closely related, so a test that can identify aptitude may be used to identify a subject's thought style. Knowledge of the subject's thinking style may be used to identify the optimal teaching and training approach for the subject.

  US Pat. Nos. 4,955,938 and 5,331,969, the contents of which are hereby incorporated by reference, acquire steady state visual evoked potentials (SSVEP) from subjects. Techniques for disclosing are disclosed. These patents disclose the use of Fourier analysis to quickly acquire SSVEP and changes to it.

U.S. Pat.No. 4,955,938 U.S. Pat.No. 5,331,969

Summary of the Invention It is highly appreciated that these techniques can be utilized to measure brain activity and assess an individual's suitability.

More specifically, the present invention
(I) presenting a group of cognitive tasks to the subject;
(Ii) detecting a brain response signal from the subject during presentation of the group of cognitive tasks;
(Iii) calculating an amplitude, phase, and / or coherence SSVEP response from the brain response signal; and (iv) to assess the subject's suitability for the predetermined task, the SSVEP response is increased to the predetermined task. A method is provided for assessing a subject's cognitive aptitude for a predetermined task, comprising comparing to a known SSVEP response obtained from an individual with and / or low aptitude.

The present invention
(I) means for presenting a group of cognitive tasks to a subject;
(Ii) means for detecting a brain response signal from the subject during presentation of the group of cognitive tasks;
(Iii) means for calculating an amplitude, phase and / or coherence SSVEP response from the brain response signal; and (iv) to assess the subject's suitability for the predetermined task, the SSVEP response Means to compare with known SSVEP responses obtained from individuals with high and / or low suitability for
A device for assessing a subject's cognitive suitability for a predetermined task is also provided.

  The present invention provides a steady state probe topology (Steady), a brain imaging technique based on the brain's response to continuous sinusoidal visual flicker, to examine changes in activity in various brain regions while an individual performs many cognitive tasks. State Probe Topology) (SSPT) or SSVEP may be used. Cognitive aptitude seems to be indicated by specific changes in SSVEP amplitude, phase, and coherence during a given cognitive task. Changes in SSVEP amplitude, phase, and coherence may also indicate different thinking styles associated with different patterns of brain activity. A subject who obtains a high score in the examination of analytical thinking shows a greater left hemispheric phase advance and is interpreted as a greater activation of this range during the analytical task. In contrast, subjects who get low scores in analytical thinking tests do not show this pattern. In addition, subjects who obtain a high score in the holistic thinking test show greater SSVEP phase advance in the right hemisphere region. These results are consistent with neuropsychological studies showing a special role for the left hemisphere in analytical thinking and the right hemisphere for holistic thinking.

  More generally, SSVEP can be used to identify aptitudes in specific cognitive domains known to be associated with performance and training aptitude. For example, aircraft pilot trainees need aptitude in drawing their environment in three dimensions. Testing for this ability could be involved in SSVEP measurements while subjects perform Mental Rotation Tasks where they are required to rotate 3D shaped images. Certain changes in SSVEP amplitude, phase, and coherence are associated with high suitability for this task, and these changes can be used to identify individuals with high ability to manipulate 3D images. Investigations conducted by the inventors have shown that individuals with high aptitude for manipulation of 3D images have greater phase advance in the left prefrontal cortex and reduced coherence between the central and parietal cortex. Clarify what to show. In contrast, subjects with high ability show increased SSVEP coherence between the right prefrontal region and the central region during the time that the image was retained in short-term memory without manipulation.

More particularly, the techniques of the present invention can be used in many different areas including:
(I) identifying cognitive aptitude in a particular domain;
(Ii) identify the personal thinking style and hence the optimal teaching / training approach;
(Iii) identifying an individual's suitability for a particular training; and (iv) identifying an individual's suitability for a particular employment.

  Changes in SSVEP amplitude, phase, and / or coherence can be increased or decreased. In addition, the magnitude of the change may change depending on circumstances. One way to determine if there is a significant change in SSVEP amplitude, phase, and / or coherence is by reference to statistical analysis, and at the p <0.05 level, the change is considered significant, p indicates the probability of a first-class statistical error (ie, erroneously rejecting the null hypothesis). Statistical significance can be tested using a number of methods, including Student's t-test, Hotellig's T2, and multivariate permutation test. For discussion of these methods used to analyze SSVEP, Silberstein RB, Danieli F., Nunez PL (2003) Frontoparietal evoked potential synchronization is increased during mental rotation. Neuroreport, 14: 67-71, Silberstein RB , Farrow MA, Levy F. Pipingas A., Hay DA, Jarman FC (1998). Functional brain electrical; activity mapping in boys with attention deficit hyperactivity disorder. Archives of General Psychiatry 1998; 55: 1105-12.

  The invention will now be further described with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 schematically illustrates a system 20 for determining a subject's 6 response to a cognitive task that can be presented to the subject 6 on the video screen 1 and loudspeaker 11. The system includes a computer 2 that controls various parts of the hardware and also performs calculations on signals derived from the brain activity of subject 6, as will be described below. The computer 2 also maintains a cognitive task that can be presented to the subject 6 on the screen 1 and / or via the loudspeaker 11.

  A subject 6 to be examined is fitted with a helmet 7 that includes a plurality of electrodes for acquiring brain electrical activity from various sites on the scalp of subject 6. The helmet includes a visor 8 that includes semi-transparent mirrors 17 and 18 and LED arrays 19 and 21, as shown in FIG. The semi-transparent mirror is positioned to direct light from the LED arrays 19 and 21 toward the subject's eyes. The LED arrays 19 and 21 are controlled such that the light intensity therefrom changes sinusoidally under the control of the control circuit 5. The control circuit 5 includes a waveform generator for generating a sine function signal. The circuit 5 also includes an amplifier, a filter, an analog to digital converter, and a USB interface for coupling various electrode signals to the computer 2.

  The system also includes a microphone 9 for recording audio signals from the subject 6. The microphone 9 is connected to the computer 2 via the microphone interface circuit 10. The system also includes a switch 4 that can be manually moved by the subject as part of the response to the cognitive task. The switch 4 is connected to the computer 2 via the switch interface circuit 3.

  The computer 2 includes software that calculates the SSVEP amplitude, phase, and / or coherence from each of the electrodes in the helmet 7.

  The details of the hardware and software required to generate SSVEP are well known and need not be described in detail. In this regard, reference is made to the aforementioned US patent specification disclosing details of hardware and technology for the calculation of SSVEP. Briefly, subject 6 views video screen 1 through a visor 8 that delivers continuous background flicker to the peripheral vision. The frequency of the background flicker is typically 13 Hz, but can be selected to be between 3 Hz and 50 Hz. Brain electrical activity appears to be recorded using special electronic hardware that filters and amplifies the signal and digitizes it in circuit 5, which is then sent to computer 2 for storage and analysis And transferred. SSPT is used to determine local brain activity at the scalp site using SSPT analysis software.

  Cognitive tasks are presented on the video screen 1 and / or via the loudspeaker 11. Subject 6 is required to make a response that may include a button press on switch 4 and / or a verbal response detected by microphone 9. The topographic distribution of SSVEP amplitude, SSVEP phase, and SSVEP coherence during cognitive task performance may correlate with subject aptitude and thought style. The microphone 9 generates an audio signal, is amplified via the interface 10, filtered and digitized, and stored as a sound file on the computer 2. This allows the timing of the language response to be determined within an accuracy of, for example, 10 microseconds. Alternatively, the subject may respond to the cognitive task via a motor response such as a button press via switch 4. In all cases, the exact timing of all events presented to subject 6 is preferably determined with an accuracy of 10 microseconds or greater.

  As mentioned above, the visor 8 includes LED arrays 19 and 21. In one embodiment, the light therefrom varies sinusoidally. An alternative approach utilizes pulse width adjustment, where the light emitting source is driven by 1-10 Khz pulses, and the pulse interval is proportional to the brightness of the light emitting source. In this embodiment, the control circuit 5 receives a digital input stream from the computer 2 and outputs a pulse width adjustment pulse at a frequency of 1 to 10 Khz. The time of each positive zero crossing from the sinusoidal stimulus waveform is determined with an accuracy of 10 microseconds and stored in the computer 2 memory.

  Brain electrical activity is recorded using a multipolar electrode on helmet 7 or another commercially available multielectrode system such as Electro-cap (ECI Inc., Eaton, Ohio USA). The number of electrodes is usually 16 or more and usually 256 or less, typically 64.

  Brain activity at each of the electrodes is directed to the control circuit 5. Circuit 5 includes multi-stage fixed gain amplification, bandpass filtering, and sample and hold circuits for each channel associated with the helmet electrode. The amplified / filtered brain activity is digitized to 16-bit accuracy at a rate of 300 Hz or higher and transferred to the computer 2 for storage on the hard disk. Along with the time of presentation of the different components of the cognitive task, the timing of each brain electrical sample is also registered and stored with an accuracy of 10 microseconds.

SSVEP amplitude, phase, and coherence Digitized brain electrical activity (EEG) with timing of stimulus zero crossing is independent component analysis to remove recorded EEG or artifacts and increase signal-to-noise ratio Allows the calculation of SSVEP from pre-processed EEG data. [Bell AJ and Sejnowski TJ 1995. An Information Maximization Approach to Blind Separation and Blind Deconvolution, Neural Computation, 7, 6, 1129-1159; TP. Jung, S. Makeig, M. Westerfield, J. Townsend, E. Courchesne and TJ Sejnowskik, Independent Component Analysis of Single-Trial Event-Related Potential Human Brain Mapping, 14 (3): 168-85, 2001.]

Calculation of SSVEP amplitude and phase for each stimulation cycle can be accomplished using Fourier techniques using the following equations 1.0 and 1.1:

a _n and b _n are cosine and sine Fourier coefficients, respectively. n denotes the nth stimulation cycle, S is the number of samples per stimulation cycle (16), Δτ is the time interval between samples, T is the duration of one cycle, and f ( nT + iΔτ) is the EEG signal (pretreated using raw or ICA).

  Amplitude and phase components can be calculated using either single cycle Fourier coefficients or coefficients calculated by integrating multiple cycles.

  Two types of coherence functions are calculated from the SSVEP sine and cosine Fourier coefficients while the subject performs a cognitive task. One is called SSVEP Coherence (“SSVEPC”), and the other is called Event Related SSVEP Coherence (“ER-SSVEPC”).

SSVEPC
SSVEP sine and cosine coefficients can be expressed as complex numbers,
C _n = (a _n , b _n )
a _n and b _n are already defined.

Nomenclature is generalized to allow for multiple tasks and multipolar electrodes.
C _{g, e, n} = (a _{g, e, n} , b _{g, e, n} )
g = number of tasks
e = electrode
n = point in time

C^*は、Cの複素共役である
かつ

次いで、SSVEPCは、

によって与えられる。
かつ、SSVEPCの位相は、ER-SSVEPCによって与えられる。

The following functions are defined:

C ^* is the complex conjugate of C and

Next, SSVEPC

Given by.
And the phase of SSVEPC is given by ER-SSVEPC.

In this case, coherence across trials in a particular task can be calculated. This provides coherence as a function of time. The nomenclature can be generalized to account for multiple tasks and multipolar electrodes.
C _{g, d, e, n} = (a _{g, d, e, n} , b _{g, d, e, n} )
g = number of tasks
d = trial within a specific task, for example a specific response
e = electrode
n = point in time

かつ

次いで、SSVEPCは、

によって与えられる。
かつSSVEPCの位相は、

によって与えられる。 The following functions are defined:

And

Next, SSVEPC

Given by.
And the phase of SSVEPC is

Given by.

  The above equation applies to scalp recording data and brain electrical activity inferred deeper, such as the cortical surface adjacent to the skull and the anterior cingulate cortex. Activity in deeper regions of the brain, such as the anterior cingulate or ventrolateral cortex, is BESA (Scherg M, Ebersole JS., Brain Source Imaging of Focal and Multifocal Epileptiform EEG Activity. Neurophysiol Clin. 1994 Jan; 24 (1): 51 LORETA (Pascual-Marqui RD, Esslen M, Kochi K, Lehmann D. Functional Imaging with Low-Resolution Brain Electromagnetic Tomography (LORETA): Overview. Methods Find Exp Clin Pharmacol. 2002; 24 Suppl C: 91-5 ); Or many available inverse mapping techniques such as EMSE Information (Source Signal Imaging Inc. 2323 Broadway, Suite 102, San Diego, Ca. 92102).

  While subject 6 is performing cognitive and emotional tasks, visual flicker is switched on in visor 8 and brain activity is continuously recorded on computer 2.

  At the end of the examination, the SSVEP responses associated with the various tasks are calculated and averaged separately. For a particular task, SSVEP amplitude, phase, and coherence can be compared to a database of results for a group of subjects with high aptitude and a specific thinking style. The comparison appears to identify an individual's specific thinking style and aptitude. For example, individuals with suitability for computer software development may experience increased SSVEP phase lag in the prefrontal region and reduced left frontal area while performing Raven's Progressive Matrices (tasks used in IQ testing). SSVEP coherence can be demonstrated. In contrast, individuals suitable for aircraft pilots may demonstrate reduced left temporal SSVEP coherence when performing mental rotation tasks. For security purposes, the database may be located on a remote computer (not shown) that is accessed via the Internet via modem 12.

Example 1
The system illustrated in FIGS. 1-3 was used to test a subject using an analytical test known as the Hidden Figures Test. Data from the electrode sites were analyzed using SSPT technology based on the computer algorithm listed in Equation 1.1, and the SSVEP phase distribution was displayed graphically.

  FIG. 4 illustrates the SSVEP phase from subjects with high analytical aptitude. In this figure, the brighter areas indicate areas of SSVEP phase advance or increased brain processing speed. In this diagram, the darker shades indicate areas of SSVEP phase lag or reduced brain processing speed. The bright area 50 drawn with a dashed line demonstrates a greater range of activity. This range is located in the posterior left hemisphere in the temporal and parietal cortex areas. This indicates that the subject has a high analytical aptitude.

  FIG. 5 graphically illustrates the SSVEP phase distribution for a subject performing the same test. It will be pointed out that there is no bright range in the distribution, and this distribution is interpreted as demonstrating that the subject has low analytical suitability.

Example 2
The same equipment as in Example 1 above was used, but the subject underwent a Gestalt Completion Test. The gestalt completion inspection puts demands on holistic thinking. The electrical activity from the electrode site was analyzed using SSPT technology based on the computer algorithm described in Equation 1.1 and the results displayed graphically.

  FIG. 6 schematically shows the SSVEP phase distribution. The result includes a bright area 52 bounded by a dashed line. This bright range demonstrates increased activity in the right and right frontal ranges, consistent with the importance of right hemisphere activity in holistic perception. This is taken to indicate that the subject has a high holistic thinking ability.

  In contrast, FIG. 7 shows the results of a subject performing the same test against a subject with low holistic thinking ability. The SSVEP phase distribution shows reduced left temporal activity and enhanced left parietal, left posterior activity as shown by the bright area 54 bounded by the dashed line.

Example 3
The system shown in FIGS. 1-3 was used to test subjects performing a computerized version of the Raven Progressive Matrix Test. The electrical activity was again processed using SSPT technology based on the computer algorithm described in Equation 1.8. The results are displayed graphically in FIGS. 8 and 9.

  The graph of FIG. 8 shows event-related SSVEP coherence between activity recording sites 56. The display includes a plurality of lines 58 between the frontal regions. This result was generated from statistically significant differences in event-related SSVEP coherence recorded from participants with high language IQ scores.

  FIG. 9 illustrates statistically significant differences in event-related SSVEP coherence recorded from participants with high conceptual and visualization skills (performance IQ). The results illustrated in FIG. 9 include a line 60 that demonstrates increased event-related SSVEP coherence between the right parietotemporal region and other scalp sites. The activity was recorded while the subject was preparing to make a decision while performing a computerized version of the Raven Progressive Matrix Test.

  The technique of the present invention examines the SSVEP phase and amplitude during various thinking tasks and the scalp distribution of SSVEP event-related coherence and compares these distributions to a database of known SSVEP amplitude, phase, and coherence patterns. By doing so, it is possible to infer the suitability of a particular participant for various tasks.

  Many modifications will be apparent to those skilled in the art without departing from the spirit and scope of the invention.

It is a wiring diagram of the system of the present invention. It is a schematic plan view which shows in more detail the manner in which the visual flicker signal is presented to the subject. It is the schematic which shows one half mirror and LED array. Fig. 4 schematically illustrates the SSVEP phase distribution for subjects with high analytical aptitude. Fig. 3 schematically illustrates the SSVEP phase distribution where the subject has low analytical aptitude. Schematic illustration of the SSVEP phase distribution for subjects with high holistic thinking ability. Schematic illustration of the SSVEP phase distribution for subjects with low holistic thinking ability. Figure 3 schematically illustrates SSVEP coherence at the frontal site for subjects with high language IQ. Schematic illustration of SSVEP coherence in subjects with high conceptual and visualization skills.

Claims (12)

(I) presenting a group of cognitive tasks to a subject;
(Ii) detecting a brain response signal from the subject during presentation of the group of cognitive tasks;
(Iii) calculating an SSVEP amplitude, phase, and / or coherence response from the brain response signal;
(Iv) comparing the SSVEP response to a known SSVEP response obtained from an individual with high and / or low suitability for the predetermined task to assess the subject's suitability for the predetermined task ,
A method for assessing the subject's cognitive suitability for a predetermined task.   The method of claim 1, comprising presenting a group of cognitive tasks to an individual to obtain a known SSVEP response.   The method of claim 1 or 2, wherein the cognitive task is selected such that the cognitive task imposes a request on the subject that is similar to that experienced when performing the default task.   The cognitive task selects the cognitive task to impose one or more of the following requirements: attention, analytical thinking, holistic thinking, language thinking, visuospatial thinking, working memory, recognition memory, and discriminative emotional expression 4. The method of claim 3, wherein: Repeating the presentation of cognitive tasks to calculate multiple SSVEP responses;
Statistically analyzing the SSVEP response to determine a statistically significant change in SSVEP amplitude, phase, and / or coherence;
Comparing the statistically significant change to a known SSVEP response to assess the subject's suitability for a predetermined task.
The method according to any one of claims 1 to 4.   6. The method of any one of claims 1-5, wherein comparing the SSVEP response to a known SSVEP response comprises assessing the subject's thinking style.   The method according to any one of claims 1 to 6, wherein steps (i), (ii) and (iii) are performed at a local site and step (iv) is performed at a remote site.   8. The method of claim 7, comprising maintaining a database of known SSVEP responses at a remote site.   9. The method of claim 8, comprising communicating amplitude, phase, and / or coherence SSVEP responses from a local site to a remote site via the Internet. (I) means for presenting a group of cognitive tasks to a subject;
(Ii) means for detecting a brain response signal from the subject during presentation of the group of cognitive tasks;
(Iii) means for calculating an SSVEP amplitude, phase, and / or coherence response from the brain response signal;
(Iv) means for comparing the SSVEP response with a known SSVEP response obtained from an individual with high and / or low suitability for the predetermined task to assess the subject's suitability for the predetermined task; Including,
A device for assessing the subject's cognitive suitability for a predetermined task.   The means for presenting, the means for detecting, and the means for calculating are located at the local site, the means for comparing is located at the remote site, and means for calculating the SSVEP via the network 11. Apparatus according to claim 10, comprising coupling means for coupling to a communication network for transmitting amplitude, phase and / or coherence response to said means for comparing.   12. The apparatus of claim 11, wherein the coupling means includes a modem and the network is the Internet.

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