Method and apparatus for reducing errors in screening-test administration

1. A system for detecting errors in balance related screening tests, the system comprising:

a force-plate for measuring forces applied by a subject to determine a quantity related to a balance task performed by the subject in trials under a plurality of distinct sensory conditions; and

a computation device in communication with the force-plate, the computational device

(i) receiving the quantity related to the balance task for each trial,

(ii) determining a rank order for the quantities, each quantity for each trial being associated with a rank, and

(iii) determining if any of the ranks associated with a given one of the trials has fallen outside a reference range associated with the given trial performed under error-free conditions.

2. A system according to claim 1 , further comprising a display device in communication with the computational device for indicating an instance wherein any of the ranks associated with a given one of the trials has fallen outside a reference range associated with the given trial.

3. A system according to claim 2 , wherein the display device displays a number corresponding to the number of times a performance of the balance task by the subject has fallen outside the reference range.

4. A method, for detecting a screening-test error, the method comprising:

measuring at least one performance parameter related to at least one screening-test task performed by a subject; and

calculating at least one performance statistical quantity characterizing the measured performance parameter; and

comparing the at least one performance statistical quantity to at least one reference statistical quantity associated with an error-free screening test to derive error information; and displaying the error information on a display device or in a report, wherein:

(i) the screening-test task is a balance task;

(ii) the at least one performance parameter is a quantity related to vertical force applied to a force plate;

(iii) the at least one performance statistical quantity corresponds to an average of a mathematical derivative of the total vertical force applied to the force plate; and

(iv) comparing the at least one performance statistical quantity to the at least one reference statistical quantity includes determining whether the average deviates from zero by a predetermined threshold value,

wherein the statistical quantity represents a value associated with a root mean square.

5. A method for detecting a screening-test error, the method comprising:

measuring at least one performance parameter related to at least one balance task performed by a subject; and

calculating at least one performance statistical quantity characterizing the measured performance parameter; and

comparing the at least one performance statistical quantity to at least one reference statistical quantity associated with an error-free screening test to derive error information; and displaying the error information on a display device or in a report, wherein:

(i) the at least one performance parameter is a quantity related to vertical force applied to a force plate by the subject;

(ii) the at least one performance statistical quantity corresponds to a moving window average value for total vertical force applied to the force plate; and

(iii) comparing the at least one performance statistical quantity to the at least one reference statistical quantity includes determining whether the moving window average value deviates from a constant value by a predetermined threshold value.

6. A method according to claim 5 , wherein the balance task is walking, standing, turning quickly, sitting, stepping, squatting, rhythmic weight shifting or lunging.

7. A method for detecting a screening-test error, the method comprising:

measuring at least one performance parameter related to at least one balance task performed by a subject; and

calculating at least one performance statistical quantity characterizing the measured performance parameter; and

comparing the at least one performance statistical quantity to at least one reference statistical quantity associated with an error-free screening test to derive error information; and displaying the error information on a display device or in a report, wherein:

(i) the at least one performance parameter is a quantity related to vertical force applied to a force plate by the subject;

(ii) the at least one performance statistical quantity corresponds to an average of a mathematical derivative of the total vertical force applied to the force plate; and

(iii) comparing the at least one performance statistical quantity to the at least one reference statistical quantity includes determining whether the average deviates from zero by a predetermined threshold value.

8. A method according to claim 7 , wherein the statistical quantity represents a value associated with an average.

9. A method according to claim 7 , wherein the statistical quantity represents a value associated with a standard deviation.

10. A method according to claim 7 , wherein the statistical quantity represents a value associated with a standard error.

11. A method according to claim 7 , wherein the statistical quantity represents a value associated with a power spectrum.

12. A method according to claim 7 , wherein the statistical quantity represents a value associated with a frequency histogram.

13. A method according to claim 7 , further comprising displaying the extent to which the at least one performance statistical quantity differs from the at least one reference statistical quantity on a display device.

14. A method according to claim 7 , wherein the balance task is walking, standing, turning quickly, sitting, stepping, squatting, rhythmic weight shifting or lunging.

15. A method for detecting a screening-test error, the method comprising:

measuring at least one performance parameter related to at least one balance task performed by a subject; and

calculating at least one performance statistical quantity characterizing the measured performance parameter; and

comparing the at least one performance statistical quantity to at least one reference statistical quantity associated with an error-free screening test to derive error information; and displaying the error information on a display device or in a report, wherein:

(i) the at least one performance parameter is a quantity related to horizontal force applied to a force plate by the subject;

(ii) the at least one performance statistical quantity corresponds to an average of a mathematical derivative of the total horizontal force applied to the force plate; and

(iii) comparing the at least one performance statistical quantity to the at least one reference statistical quantity includes determining whether the average deviates from zero by a predetermined threshold value.

16. A method according to claim 15 , wherein the balance task is walking, standing, turning quickly, sitting, stepping, squatting, rhythmic weight shifting or lunging.

17. A system for detecting errors in balance related screening tests, the system comprising:

a force-plate for measuring forces to determine a quantity related to a stability factor of a balance task performed in trials by a subject under a plurality of distinct sensory conditions; and

a computation device in communication with the force-plate, the computational device

(i) receiving the quantity related to the stability factor for each trial,

(ii) determining a rank order for the quantities, each quantity for each trial being associated with a rank, and

(iii) determining if any of the ranks associated with a given one of the trials has fallen outside a reference range associated with the given trial performed under error-free conditions,

wherein measuring the quantity related to a stability factor includes following a modified CTSIB protocol.

18. A system for detecting errors in balance related screening tests, the system comprising:

a force-plate for measuring forces to determine a quantity related to a stability factor of a balance task performed in trials by a subject under a plurality of distinct sensory conditions; and

a computation device in communication with the force-plate, the computational device

(i) receiving the quantity related to the stability factor for each trial,

(ii) determining a rank order for the quantities, each quantity for each trial being associated with a rank, and

(iii) determining if any of the ranks associated with a given one of the trials has fallen outside a reference range associated with the given trial performed under error-free conditions,

wherein determining a rank order for the performance of the plurality of distinct tasks includes determining a rank order according to the level of difficulty of the balance tasks.