WO1997039677A1

WO1997039677A1 - Portable motor symptoms assessment device

Info

Publication number: WO1997039677A1
Application number: PCT/US1997/007616
Authority: WO
Inventors: Kelvin O. Lim
Original assignee: The Board Of Trustees Of The Leland Stanford Junior University
Priority date: 1996-04-25
Filing date: 1997-04-21
Publication date: 1997-10-30

Abstract

This invention is a portable device (10) for assessing motor symptoms of a patient, including a bradykinesia testing system for measuring reaction and movement times of the patient, a tremor testing system for measuring tremors in extremities of the patient, and a rigidity testing system for measuring rigidity in the hand of a patient. The rigidity testing system includes a digital shaft encoder (44) with a rotatable shaft (24) that is actuated by the patient's fingers. A microprocessor (46) is connected to the bradykinesia, tremor, and rigidity testing systems for computing test results which are stored along with test instructions in an electronic memory (48), which is connected to the microprocessor (46). A user interface (16) is connected to the microprocessor (46) for programming in test parameters. The device is compactly housed to enable hand carried portability, and an input/output port (20) and printer port (22) are provided for transmitting test results to a host computer or printer.

Description

PORTABLE MOTOR SYMPTOMS ASSESSMENT DEVICE

RELATED APPLICATION INFORMATION

This application claims priority from copending U.S. application Ser. No. 08/641,143 filed April 25, 1996, which is hereby incorporated by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of motor symptoms assessment, and in particular to a portable electronic device for assessing three key motor symptoms of a patient.

BACKGROUND OF THE INVENTION

Many neurological diseases, such as Parkinson's Disease, have three key motor symptoms: bradykinesia (slowed voluntary- movement) , rigidity, and tremor. Assessment of these three motor symptoms is necessary to determine the progression of the disease and to document the patient's response to drug administrations and other therapies. These three motor symptoms are also associated with alcohol and drug withdrawal and must be assessed to document the progress of a recovering addict. Further, in studies of new drugs, researchers must determine what affects the new drugs have on a patient's motor symptoms.

Thus, the assessment of these three motor symptoms must be performed for a variety of medical applications. The assessment should be performed as often as necessary, in some cases several times per week, for precise and accurate tracking of a patient's progress. Further, the assessment should objectively quantify the patient's motor symptoms in a uniform and easily reproducible manner. Unfortunately, most of the conventional methods for assessing these motor symptoms are not performed objectively. Instead, the assessments are performed subjectively by a trained clinician. A subjective assessment makes quantifying small changes in the clinical state of a patient extremely difficult. A subjective assessment also prevents an effective comparison of test results when the results are produced by two different clinicians.

Some progress has been made in developing systems which provide an objective assessment of a patient's tremor. U.S. Patent 4,306,291 issued to Zilm et al. on December 15, 1981, U.S. Patent 4,817,628 issued to Zealear et al . on April 4, 1989, U.S. Patent 5,265,619 issued to Colmby et al. on November 30, 1993, and U.S. Patent 5,293,879 issued to Vonk et al . on March 15, 1994 all disclose systems for measuring tremor in a patient. Each system includes an accelerometer which is strapped to an extremity of the patient. The accelerometer produces signals representative of the patient's tremor and these signals are then analyzed by a computer to produce an objective assessment of the tremor.

Although these systems are effective for objectively measuring one key motor symptom, tremor, none of these systems has a mechanism for measuring the other two motor symptoms, bradykinesia and rigidity. They are therefore inadequate for assessing all three key motor symptoms of a patient. Each of these systems suffers from the added disadvantage of requiring a trained clinician to administer the tremor test. Consequently, the patient must visit the trained clinician each time a tremor measurement is required. As a result, these conventional systems for measuring tremor place a large travel burden on the patient and consume both the patient's and clinician's time for each tremor assessment.

A system for quantitatively assessing all three key motor symptoms of a patient is described by Ghika et al. "Portable System for Quantifying Motor Abnormalities in Parkinson's Disease", IEEE Transactions in Biomedical Engineering, Vol. 40, No. 3, March 1993. In Ghika' s system, three separate test apparatuses are required for measuring the three key motor symptoms. Each of the three _test apparatuses is connected to a desktop computer equipped with an analog in_terface board. The first test apparatus measures tremor and includes two solid state accelerometers attached to two lucite boards. The patient's hand is then sandwiched between the two lucite boards so that tremor measurements may be taken.

The second test apparatus is for measuring bradykinesia. The second test apparatus includes three light bulbs with three corresponding buttons placed below the bulbs. The bulbs are sequentially lit under the control of a computer program and the patient moves as quickly as possible to press the corresponding button under a newly lit bulb. Reaction times and movement times of the patient are measured and stored in the computer.

The third test apparatus measures rigidity at the patient's elbow. The third test apparatus includes a lucite cradle for holding the patient's forearm. The lucite cradle is mounted on a metal plate with low friction ball bearings so that the clinician may move the patient's forearm back and forth. While moving the arm back and forth, the clinician uses a metronome to try to maintain a constant frequency of 0.67 Hz. As the clinician moves the cradle, a goniometer measures the angular displacement of the patient's forearm and a load cell records the amount of torque applied by the clinician to move the cradle. The angular displacements and applied torques are recorded in the computer for further analysis.

The system described by Ghika has several disadvantages that prevent its widespread use. First, the system requires a trained clinician co administer the three tests to the patient, so that the patient must still visit the clinician's office each time a motor symptoms assessment is required. Second, the system requires three separate test apparatuses and a desktop computer for measuring the three key motor symptoms, so that the system is not easily portable.

Thus, all of the prior art systems for measuring the motor symptoms of a patient require a trained clinician to administer the tests. This requirement severely limits the possible frequency of testing and places a large travel burden on the patient to continually visit the clinician's office each time a motor symptoms assessment is required. Further, none of the prior art systems provide a device that combines all three motor symptoms tests in one compact and portable unit.

OBJECTS AND ADVANTAGES OF THE INVENTION

In view of the above, it is an object of the present invention to provide a device for objectively and quantitatively measuring three key motor symptoms of a patient. It is another object of the invention to provide a motor symptoms assessment device which may be operated by a patient with minimal training. It is a further object of the invention to package the device in one integral unit that is sufficiently compact to enable the device to be hand-carried to the home or bed of a patient.

These and other objects and advantages will become more apparent after consideration of the ensuing description and the accompanying drawings.

SUMMARY OF THE INVENTION

The invention presents a portable device for assessing three key motor symptoms of a patient. The portable device includes a bradykinesia testing system for measuring reaction times and movement times of the patient. The bradykinesia testing system produces first electrical signals representative of the reaction times and second electrical signals representative of the movement times. The device also includes a tremor testing system for measuring a tremor in an extremity of the patient, such as the patient's wrist, hand, or foot. The tremor testing system produces third electrical signals representative of the tremor.

The device further includes a rigidity testing system for measuring rigidity in a hand of the patient. The rigidity testing system includes a digital shaft encoder having a rotatable shaft so that when the patient rotates the shaft with their hand, the digital shaft encoder counts a number of rotations of the shaft. The digital shaft encoder produces fourth electrical signals representative of the number of rotations .

A microprocessor is connected to the bradykinesia, tremor, and rigidity testing systems for receiving and computing test results from the first electrical signals, second electrical signals, third electrical signals, and fourth electrical signals. An electronic memory is connected to the microprocessor for storing test instructions and for recording the test results. The device also has a display for displaying the test instructions and the test results .

In the preferred embodiment, a user interface is connected to the microprocessor for programming the microprocessor with test parameters relating to the bradykinesia, tremor, and rigidity testing systems. Also in the preferred embodiment, the device has an input/output port and a printer port for transmitting the test results to a host computer and a printer, respectively. The entire device is packaged in a housing sufficiently compact to allow the device to be hand-carried.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portable device according to the invention. FIG. 2 is a top plan view of a user interface of the portable device of FIG. 1. FIG. 3 is a perspective view of an accelerometer strapped to a hand of a patient according to the invention. FIG. 4 is a perspective view of a portion of the portable device of FIG. 1 connected to a host computer and a printer. FIG. 5 is a schematic block diagram of the portable device of FIG. 1. FIG. 6 is a schematic view of a display of the portable device of FIG. 1 displaying user programmable test parameters. FIGS. 7 - 8 are schematic views of the display of FIG. 6 displaying bradykinesia test instructions.

FIGS. 9 - 10 are schematic views of the display of FIG. 6 displaying bradykinesia test results. FIGS. 11 - 13 are schematic views of the display of FIG. 6 displaying rigidity test instructions. FIGS. 14 - 16 are schematic views of the display of FIG. 6 displaying rigidity test results. FIG. 17 is a schematic view of the display of FIG. 6 displaying tremor test instructions. FIG. 18 is a schematic view of the display of FIG. 6 displaying tremor test results .

DESCRIPTION

A preferred embodiment of the invention is shown in FIGS. 1 - 18. FIG. 1 shows a perspective view of a portable device 10 for assessing three motor symptoms of a patient. Device 10 has a rectangular housing 12 sufficiently compact to enable device 10 to be hand-carried. Typically, housing 12 has a length in the range of 20 to 30 cm, a width in the range of 10 to 20 cm, and a height in the range of 5 to 15 cm. In the presently preferred embodiment, housing 12 has a length of 24 cm, a width of 15 cm, and a height of 8 cm.

A display 14 for displaying test instructions and test results is recessed in the top surface of housing 12. In the preferred embodiment, display 14 is a liquid crystal display capable of displaying two lines of text having up to twenty characters per line. In alternative embodiments, other types and sizes of displays may be used. Adjacent display 14 is a user interface 16 for programming device 10 with various test parameters, as will be described in the operation section below. A top plan view of user interface 16 is illustrated in FIG. 2. In the preferred embodiment, interface 16 is a keypad having twelve function keys for programming device 10. The twelve function keys are a menu key 28, an item key 30, a field key 32. an up key 34 , a down key 36, a help key 38, a left reaction time key 29, a right reaction time key 31, a left finger key 33, a right finger key 35, a both fingers key 37, and a tremor key 39 The user interface 16 of the preferred embodiment is ηust one example of a suitable interface for programming device 10 In alternative embodiments, other types of user interfaces may be used for programming device 10, such as switches or buttons. The assembly and use of such user interfaces are well known in the art.

Referring again to FIG 1, a right rotatable shaft 24B of a right digital shaft encoder is located on the right side surface of housing 12 A left rotatable shaft 24A (not shown m FIG. 1) of a left digital shaft encoder is located on the left side surface of housing 12 Shafts 24A and 24B are for the patient to rotate during a rigidity test, as will be described in the operation section below.

A left button 26A, a middle button 26B, and a right button 26C are located below interface 16 on the top surface of housing 12. Buttons 26A, 26B, and 26C are for the patient to press during a bradykinesia test, as will be described in detail in the operation section below In the preferred embodiment, buttons 26A, 26B, and 26C are LED buttons arranged in a straight line along the top surface of housing 12 Both left button 26A and right button 26C are spaced an equal distance from middle button 26B. In the preferred embodiment, left button 26A and right button 26C are spaced 8 to 12 cm from middle button 26C, with a preferred spacing of 10 cm.

An input/output port 20 and a printer port 22 are located on the right side surface of housing 12. Ports 20 and 22 are for connecting device 10 to a host computer 54 and a printer 56, respectively, as shown in FIG. 4. Also located on the side of housing 12 is an accelerometer port 18 for connecting device 10 to an accelerometer 60 through an accelerometer connection cord 62, as shown in FIG. 3. In a particularly advantageous embodiment, housing 12 has a compartment (not shown) for storing accelerometer 60 and cord 62.

A schematic block diagram of device 10 and its connections to host computer 54 and printer 56 is shown in FIG. 5 Device 10 includes a bradykinesia testing system for measuring reaction times and movement times of the patient The bradykinesia testing system includes buttons 26A, 26B, and 26C, as well as a buzzer 50 for producing an audible monotone buzzing sound. Buttons 26A, 26B, and 26C and buzzer 50 are connected to a microprocessor 46.

Each button 26A, 26B, and 26C includes a switch (not shown) for indicating when each button is depressed by tne patient and when each button is released by the patient Each button 26A, 26B, and 26C further includes an LED for lighting buttons 26A, 26B, and 26C under the control of microprocessor 46. Buttons 26A, 26B, and 26C and their included switches are configured such that the pressing and releasing of buttons 26A, 26B, and 26C by the patient produces reaction time digital signals representative of the patient's reaction times and produces movement time digital signals representative of the patient's movement times Suitable buttons for performing these functions are commercially available from DigiKey Corporation of Thief River Falls, Minnesota, orderable as DigiKey part number EG17151-ND Specific techniques for configuring buttons 26A, 26B, and 26C and their included switches m this manner are well known in the art.

Device 10 further includes a tremor testing system for measuring a tremor m an extremity of the patient Referring to FIG. 3, the tremor testing system includes accelerometer 60 which is strapped to a wrist 58 of the patient with a strap 64. Accelerometer 60 is preferably a light weight, three axis accelerometer capable of measuring tremor at wrist 58 and producing analog signals representative of the tremor Such an accelerometer is commercially available from Analog Devices of Norwood, Massachusetts, model number ADXL-05-EM-3. Accelerometer 60 is connected to accelerometer port 18 through connection cord 62 such that the analog signals produced by accelerometer 60 are transmitted to port 18 through cord 62.

Referring again to FIG. 5, port 18 is connected to a high speed analog to digital converter 52 for converting the analog signals received from accelerometer 60 to tremor digital signals representative of the patient's tremor. High speed analog to digital converters are commercially available from many electronic component suppliers, such as Z World Engineering of Davis,

California. Converter 52 is connected to microprocessor 46 such that microprocessor 46 receives the tremor digital signals from converter 52.

Device 10 further includes a rigidity testing system for measuring rigidity in both the left hand and right hand of the patient. The rigidity testing system includes left shaft 24A of a left digital shaft encoder 44A and right shaft 24B of a right digital shaft encoder 44B. Shafts 24A and 24B are configured such that when shafts 24A and 24B are rotated by the patient, left encoder 44A counts a first number of rotations of left shaft 24A and right encoder 44B counts a second number of rotations of right shaft 24B. In the preferred embodiment, encoders 44A and 44B are Miniature Panel Mount Optical Encoders model number HRPG-A commercially available from Hewlett Packard Corporation of Palo Alto, California.

Shafts 24A and 24B have a size and shape such that they may be easily grasped and rotated by a hand of the patient. In the preferred embodiment, both shaft 24A and 24B are cylinders having a length in the range of 2 to 4 cm and a diameter in the range of 1 to 2 cm. In alternative embodiments, shafts of different shapes and dimensions may be used. Shafts 24A and 24B have a rotational resistance sufficiently small such that they may be freely rotated by an applied rotational force, such as a force applied by the patient's hand. However, the rotational resistance is sufficiently large to quickly dampen the rotational motion of shafts 24A and 24B when the rotational force is removed. Encoders 44A and 44B are capable of counting the first number of rotations and the second number of rotations, respectively, in fractional increments. In the preferred embodiment, encoders 44A and 44B count shaft rotations with a precision of one sixteenth of one rotation. Encoder 44A is capable of producing left encoder digital signals representative of the first number of rotations and encoder 44B is capable of producing right encoder digital signals representative of the second number of rotations. Encoders 44A and 44B are connected to microprocessor 46 such that microprocessor 46 receives the left encoder digital signals and the right encoder digital signals.

Microprocessor 46 is programmed to perform various control functions related to the operation of the bradykinesia testing system, tremor testing system, and rigidity testing system, as will be described in the operation section below. For controlling the function of the bradykinesia testing system, microprocessor 46 is programmed to light up either left button 26A or right button 26C and simultaneously sound buzzer 50 based on the output of a random number generation algorithm.

The random number generation algorithm programmed in microprocessor 46 produces a first random number corresponding to the delay time from the start of a bradykinesia test trial to the time that either left button 26A or right button 26C is lit and buzzer 50 simultaneously sounded. In the preferred embodiment, the random number generating algorithm produces delay times in the range of 1 to 3 seconds. In alternative embodiments, the range of the delay time may be increased. The random number generation algorithm also produces a second random number used by microprocessor 46 to determine which button 26A or 26C to light for each bradykinesia test trial. Microprocessor 46 is further capable of timing the pressing and releasing of buttons 26A, 26B, and 26C with milliseconds precision.

In controlling the functions of the rigidity testing system and tremor testing system, microprocessor 46 is capable of timing a rigidity testing period and a tremor testing period. Microprocessor 46 is further capable of sounding buzzer 50 and lighting middle button 26B at the start and the end of both the rigidity testing period and the tremor testing period. A microprocessor capable of performing the control functions described is the Little Star model number 101-0092 commercially available from Z World Engineering of Davis, California. In the preferred embodiment, microprocessor 46 is programmed to perform the described control functions using C programming language. Specific techniques of programming a microprocessor to perform these control functions for the bradykinesia testing system, tremor testing system, and rigidity testing system are well known in the art.

Microprocessor 46 is connected to user interface 16 such that microprocessor 46 can be further programmed with test parameters relating to the bradykinesia testing system, tremor testing system, and rigidity testing system. In the preferred embodiment, the bradykinesia test parameters correspond to a desired number of practice trials and a desired number of test trials. The rigidity and tremor test parameters correspond to a desired rigidity test period and a desired tremor test period, respectively. Microprocessor 46 is further connected to an electronic memory 48 such that electronic memory 48 records test results computed by microprocessor 46, as will be described in detail in the operation section below.

Test instructions relating to the bradykinesia testing system, tremor testing system, and rigidity testing system are stored in memory 48. Memory 48 is connected to display 14 through microprocessor 46 such that the test instructions and test results are displayed on display 14. Input/output port 20 and printer port 22 are connected to microprocessor 46 such that the test results computed by microprocessor 46 are transmitted through ports 20 and 22 to host computer 54 and printer 56, respectively. In the preferred embodiment, device 10 is powered by a DC battery (not shown) . In an alternative embodiment, device 10 receives power from a conventional electrical wall outlet (not shown) . Specific techniques for supplying power to a portable electronic device are well known in the art.

The operation of the preferred embodiment is illustrated in FIGS. 1 - 18. To program microprocessor 46 with test parameters related to the bradykinesia, rigidity, and tremor testing systems, a user pushes menu key 28 of interface 16, as shown in FIG. 2. When menu key 28 is pushed, a parameter menu is displayed on display 14, as shown schematically in FIG. 6. For simplicity of understanding, all of the test parameters of the preferred embodiment are shown in FIG. 6. However, because display 14 shows only two lines of text at one time, the user scrolls through the test parameters shown in FIG. 6 by pressing item key 30 of interface 16.

The first test parameter displayed is a number of test trials 70 desired for the bradykinesia test. In the preferred embodiment, number of trials 70 entered by the user is ten, as ten trials is a sufficiently large sample size to adequately assess the patient's reaction time and movement time. In alternative embodiments, the user may enter a different number of trials 70 based on a different desired sample size. To enter the number of test trials 70, the user presses field key 32 to move the display cursor to numeric field 71.

The user then presses either up key 34 or down key 36 until numeric field 71 contains the desired value of ten. Each time the user presses up key 34, the value of numeric field 71 is increased by one. Each time the user presses down key 36, the value of numeric field 71 is decreased by one. Once the user has set numeric field 71 to the desired value of ten, he presses item key 30 to scroll to the next test parameter, a number of practice trials 72.

The user programs number of practice trials 72 and each remaining test parameter in an manner analogous to the programming of number of test trials 70. In the preferred embodiment, the users enters two practice trials 72 in numeric field 73. The user then presses item key 30 to scroll to the next test parameter, a rigidity test period 74, abbreviated on display 14 as "ROTATE ⁽SEC⁾". After entering rigidity test period 74 as 15 seconds in numeric field 75, the user scrolls to the next test parameter, a tremor test period 76, abbreviated on display 14 as "TREMOR (SEC)". In the preferred embodiment, the user sets numeric field 77 corresponding to tremor test period 76 equal to 20 seconds.

The next test parameter is an end pause 78 which corresponds to a desired pause between the end of one bradykinesia test trial and the start of a subsequent test trial. In the preferred embodiment, the users sets numeric field 79 corresponding to end pause 78 equal to 1000 milliseconds. The user then scrolls to the last test parameter of the preferred embodiment, an instruction time 80. Instruction time 80 corresponds to the period of time that each two lines of test instructions are displayed on display 14 before the next two lines of test instructions are displayed. In the preferred embodiment, the user sets numeric field 81 corresponding to instruction time 80 equal to 3000 milliseconds. After programming each of the test parameters, the user presses menu key 28 to exit the parameter menu.

It is to be understood that the preferred values of the test parameters described above only illustrate one of many possible embodiments. The user may program different values for the test parameters that are specifically tailored to the patient's needs. Further, the test parameters are stored in memory 48 so that the user need not program all of the test parameters before every motor symptoms assessment. The user only needs to program the test parameters when he or she desires to change one or more of the test parameters.

To perform the bradykinesia test on the patient's left hand, the user presses left reaction time key 29. When key 29 is pressed, left hand bradykinesia test instructions 82 are displayed, as shown in FIG. 7. In the example of the preferred embodiment, instruction time 80 is set to three seconds so that each two lines of text is displayed for three seconds before the next two lines of text are displayed. Test instructions 82 instruct the patient to use his left index finger to hold down the lit button. The patient is then instructed to press the newly lit button upon hearing buzzer 50. The patient is then informed that the first two buzzes are for practice and that the next ten buzzes are for the bradykinesia test. Finally, the patient is reminded to use his left index finger.

In the preferred embodiment, the lit button at the start of each bradykinesia practice trial and test trial is middle button 26B. When the patient holds down middle button 26B to start the first practice trial, the random number generation algorithm of microprocessor 46 produces the first random number corresponding to the delay time and the second random number corresponding to which button 26A or 26B to light at the end of the delay time. For example, according to one possible outcome of the random number generation algorithm, microprocessor 46 delays 2.6 seconds and then lights left button 26A and simultaneously sounds buzzer 50. Upon seeing left button 26A lit and hearing buzzer 50, the patient moves his left index finger aε quickly as possible to release middle button 26B and press left button 26A.

As the patient releases middle button 26B, the switch corresponding to middle button 26B is moved from a closed position to an open position, producing left hand reaction time digital signals representative of the patient's left hand reaction time. As the patient presses left button 26A, the switch corresponding to left button 26A moves from an open position to a closed position, producing left hand movement time digital signals representative of the patient's left hand movement time. Microprocessor 46 receives the left hand reaction time digital signals and left hand movement time digital signals. This completes a first practice trial of the bradykinesia test. The second practice trial and ten test trials are performed in an analogous manner.

To perform the bradykinesia test for the patient's right hand, the user presses right hand reaction time key 31. When key 31 is pressed, display 14 displays right hand bradykinesia test instructions 84, as shown in FIG. 8. The right hand bradykinesia test is performed in a manner analogous to the left hand bradykinesia test, except for the patient using his right index finger rather than his left index finger to perform the right hand bradykinesia test.

After the left hand bradykinesia test has been completed, microprocessor 46 computes left hand bradykinesia test results 86 from the received left hand movement time digital signals and left hand reaction time digital signals. Test results 86 are recorded in memory 48 and displayed on display 14, as shown in FIG. 9. Test results 86 include a left mean reaction time 88, a left reaction time standard deviation 90, a left mean movement time 92. and a left movement time standard deviation 94.

Similarly, after the right hand bradykinesia test has been completed, microprocessor 46 computes right hand bradykinesia test results 96 from the received right hand movement time digital signals and right hand reaction time digital signals. Test results 96 are recorded in memory 48 and displayed on display 14, as shown in FIG. 10. Test results 96 include a right mean reaction time 98, a right reaction time standard deviation 100, a right mean movement time 102, and a right movement time standard deviation 104.

The rigidity testing system may be used to perform a rigidity test on the fingers of the patient's left hand, right hand, or both hands simultaneously. To select the rigidity test for the fingers of the left hand, the user pushes left finger key 33 on interface 16, as shown in FIG. 2. When the user pushes key 33, display 14 displays a set of left hand rigidity test instructions 106, as shown in FIG. 11. Test instructions 106 instruct the patient to turn left shaft 24A away from himself. Next, test instructions 106 ask the patient if he is ready and issue a "GO!" command.

After the "GO!" command is issued, microprocessor 46 begins to time the 15 second rigidity test period 74. Meanwhile, the patient rotates left shaft 24A with the fingers of his left hand as many times as he can during rigidity test period 74. Left digital shaft encoder 44A counts the first number of rotations of left shaft 24A and produces left encoder digital signals representative of the first number of rotations. The left encoder digital signals are received by microprocessor 46. At the end of rigidity test period 74, microprocessor 46 sounds buzzer 50, indicating the end of the left hand rigidity test.

To select the rigidity test for the fingers of the right hand, the user pushes right finger key 35 on interface 16, as shown in FIG. 2. When the user pushes key 35, display 14 displays a set of right hand rigidity test instructions 108, as shown in FIG. 11. Test instructions 108 instruct the patient to turn right shaft 24B away from himself. Next, test instructions 108 ask the patient if he is ready and issue a "GO!" command.

After the "GO! " command is issued, microprocessor 46 begins to time the 15 second rigidity test period 74. Meanwhile, the patient rotates right shaft 24B with the fingers of his right hand as many times as he can during rigidity test period 74. Right digital shaft encoder 44B counts the second number of rotations of right shaft 24B and produces right encoder digital signals representative of the second number of rotations. The right encoder digital signals are received by microprocessor 46. At the end of rigidity test period 74, microprocessor 46 sounds buzzer 50, indicating the end of the right hand rigidity test.

Similarly, to select the rigidity test for the fingers of both hands, the user pushes both finger key 37 on interface 16, as shown in FIG. 2. When the user pushes key 37, display 14 displays a set of both hand rigidity test instructions 110, as shown in FIG. 13. Test instructions 110 instruct the patient to turn both shafts 24A and 24B away from himself. Next, test instructions 110 ask the patient if he is ready and issue a "GO!" command.

After the "GO!" command is issued, microprocessor 46 begins to time the 15 second rigidity test period 74. Meanwhile, the patient rotates left shaft 24A with the fingers of his left hand and right shaft 24B with the fingers of his right hand as many times as he can during rigidity test period 74. Left digital shaft encoder 44A counts the first number of rotations of left shaft 24A and produces left encoder digital signals representative l of the first number of rotations. Similarly, right digital shaft encoder 44B counts the second number of rotations of right shaft 24B and produces right encoder digital signals representative of the second number of rotations. The left encoder digital signals and right encoder digital signals are received by microprocessor 0 46. At the end of rigidity test period 74, microprocessor 46 sounds buzzer 50, indicating the end of the both hands rigidity test.

After the left hand rigidity test has been completed, 5 microprocessor 46 computes test results 112 from the received left encoder digital signals. Test results 112 are recorded in memory 48 and displayed on display 14, as illustrated in FIG. 14. Test results 112 include a number of left hand rotations 114 made by the patient with the fingers of his left hand.

After the right hand rigidity test has been completed, microprocessor 46 computes test results 116 from the received right encoder digital signals. Test results 116 are recorded in memory 48 and displayed on display 14, as illustrated in FIG. 15. Test results 116 include a number of right hand rotations 118 made by the patient with the fingers of his right hand. Similarly, after the both hands rigidity test has been completed, microprocessor 46 computes test results 120 from the received left encoder digital signals and right encoder digital signals. Test results 120 are recorded in memory 48 and displayed on display 14, as illustrated in FIG. 16. Test results 112 include both number of left hand rotations 114 and number of right hand rotations 118.

To select the tremor test, the user pushes tremor test key 39 on interface 16, as shown in FIG. 2. When the user pushes key 39, display 14 displays tremor test instructions 122, as shown in FIG. 17. Tremor test instructions 122 instruct the user to attach accelerometer 60 to nand 58 using strap 64, as shown in FIG. 3 Once accelerometer 60 is strapped to hand 58, the user is instructed to press the lit button, middle button 26B in the preferred embodiment to start the tremor test

After middle button 26B is pressed, microprocessor 46 begins to time tremor test period 76 During tremor test period 76, accelerometer 60 senses tremor in hand 58 and produces analog signals representative of the tremor. The analog signals are received by converter 52 through cord 62 and port 18. Converter 52 converts the analog signals to tremor digital signals representative of the patient's tremor, and microprocessor 46 receives the tremor digital signals.

Microprocessor 46 computes tremor test results 124 from the received tremor digital signals Test results 124 are recorded in memory 48 and displayed on display 14, as shown in FIG. 18. Test results 124 include a maximum power 128 of the patient's tremor, a frequency 126 of maximum power 128, and a total power 130 of the patient's tremor Maximum power 128 and total power 130 are computed by microprocessor 46 using a power spectral analysis. Specific techniques of performing such a power spectral analysis are well known m the art

Test results 86, 96, 112, 116, 120, and 124 recorded in memory 48 are then transmitted through input/output port 20 to host computer 54, as shown in FIG 4. Test results 86, 96, 112, 116, 120, and 124 are also transmitted through printer port 22 to printer 56. The transmission of the test results to computer 54 and printer 56 may be performed immediately following each motor symptoms assessment. Alternatively, a series of test results for multiple assessments may be recorded in memory 48 and transmitted at any point in time desired by the user.

One advantage of the motor symptoms assessment device of the present invention is that it can be operated by a minimally trained user to objectively measure all three key motor symptoms of a patient. A further advantage is that the device is extremely

IB portable, so that it can be easily carried to the home or bedside of a patient. Because of these two advantages, the portable assessment device of the invention allows for the first time objective testing of motor symptoms without requiring the presence of a trained clinician to perform the assessment. Effective assessments of the patient ' s motor symptoms may be carried out at home as frequently as needed to monitor the progression of the patient's disease.

SUMMARY, RAMIFICATIONS, AND SCOPE

Although the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but merely as illustrations of the presently preferred embodiment. Many other embodiments of the invention are possible. For example, the device may include more than one accelerometer and accelerometer port for measuring tremor in an extremity of the patient. Multiple accelerometers may provide greater sensitivity for measuring tremor. Also, the accelerometer need not be strapped to a wrist of the patient. Other extremities, such as a hand, finger, or foot, are also effective for measuring tremor. Further, the device need not have two shafts for measuring rigidity in the patient's hands. A single shaft could be employed to measure fine finger movements of the left and right hand separately.

Additionally, the device is described with three buttons for measuring reaction times and movement times of the patient. The number three is used for illustrative purposes only. It is obvious that any number of buttons greater than one could also be used to measure reaction times and movement times. Similarly, the test results described are examples of useful summary test results of the motor symptoms assessment. Many other test results can be easily computed from the digital signals received by the microprocessor. Further, the microprocessor may be programmed to receive many other test parameters for controlling the functions of the bradykinesia, rigidity, and tremor testing systems. Therefore, the scope of the invention should be determined, not by examples given, but by the appended claims and their legal equivalents.

Claims

What is claimed is:

l l. A portable device for assessing motor symptoms of a patient,

2 said device comprising:

3 a) a bradykinesia testing means for measuring reaction

4 times and movement times of said patient and for

5 producing first electrical signals representative of

6 said reaction times and second electrical signals

7 representative of said movement times;

8 b) a tremor testing means for measuring a tremor in an

9 extremity of said patient and for producing third o electrical signals representative of said tremor; 1 c) a rigidity testing means for measuring rigidity in a 2 hand of said patient, said rigidity testing means 3 comprising at least one digital shaft encoder having a 4 rotatable shaft such that when said patient rotates said 5 shaft with said hand, said digital shaft encoder counts 6 a number of rotations of said shaft and produces fourth electrical signals representative of said number of 8 rotations; 9 d) a microprocessor means connected to said bradykinesia 0 testing means, said tremor testing means, and said rigidity testing means for receiving and computing test results from said first electrical signals, said second electrical signals, said third electrical signals, and said fourth electrical signals; e) a memory means connected to said microprocessor means for storing test instructions and for recording said test results; and f) a display means connected to said microprocessor means for displaying said test instructions and said test results.

2. The device of claim 1, further comprising a housing sufficiently compact to enable said device to be hand- carried.

3. The device of claim 1, further comprising a user interface connected to said microprocessor means for programming said microprocessor means with test parameters relating to said bradykinesia testing means, said tremor testing means, and said rigidity testing means.

4. The device of claim 3, wherein said user interface comprises a keypad having function keys for entering said test parameters.

5. The device of claim 1, further comprising an input/output port connected to said microprocessor means for transmitting said test results to a host computer.

6. The device of claim 1, further comprising a printer port connected to said microprocessor means for transmitting said test results to a printer.

7. The device of claim 1, wherein said test results comprise a mean reaction time, a reaction time standard deviation, a mean movement time, and a movement time standard deviation.

8. The device of claim 1, wherein said test results comprise a maximum power of said tremor, a frequency of said maximum power, and a total power of said tremor.

A method for assessing motor symptoms of a patient, said method comprising the following steps: a) providing a digital shaft encoder having a rotatable shaft; b) counting a number of rotations of said rotatable shaft during a rigidity test period using said digital shaft encoder, said shaft being rotated by a hand of said patient, and said digital shaft encoder producing digital signals representative of said number of rotations; c) computing first test results from said digital signals using a microprocessor; and d) storing said first test results in an electronic memory.

10. The method of claim 9, further comprising the steps of: a) measuring reaction times and movement times of said patient; b) producing first electrical signals representative of said reaction times and second electrical signals representative of said movement times; c) measuring a tremor in an extremity of said patient; d) producing third electrical signals representative of said tremor; e) computing second test results from said first electrical signals, said second electrical signals, and said third electrical signals using said microprocessor; and f) recording said second test results in said electronic memory.

11. The method of claim 10, further comprising the steps of storing test instructions in said electronic memory and displaying said test instructions, said first test results, and said second test results on a display.

12. The method of claim 10, further comprising the step of transmitting said first test results and said second test results to a host computer through an input/output port connected to said microprocessor.

13. The method of claim 10, further comprising the step of transmitting said first test results and said second test results to a printer through a printer port connected to said microprocessor.