Diagnosing and Training the Gaze Stabilization System

• US 20070121066A1
• Filed: 02/12/2007
• Published: 05/31/2007
• Est. Priority Date: 04/28/2004
• Status: Active Grant

• Current Assignee: Natus Medical Incorporated
• Original Assignee: Neurocom International Inc. (Natus Medical Incorporated)
• Inventors: Nashner, Lewis
• Granted Patent: US 7,500,752 B2
• Time in Patent Office: Days
• US Class Current: 351/210
• CPC Class Codes: A61B 3/0091 Fixation targets for viewing direction
• CPC Class Codes: A61B 3/028 for testing visual acuity; for determination of refraction, e.g. phoropters
• CPC Class Codes: A61B 3/032 Devices for presenting test symbols or characters, e.g. test chart projectors A61B3/036 takes precedence
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721

Abstract

A method for diagnosing impairments of a subject'"'"'s gaze stabilization system is provided. The method includes measuring the subject'"'"'s static visual acuity to obtain an assessment, setting at least one test parameter based on the assessment, measuring the subject'"'"'s dynamic visual acuity using the test parameters to obtain a first dynamic measurement and a second dynamic measurement, and determining an impairment of the subject'"'"'s gaze stabilization system using the assessment and the first and second dynamic measurements.

Claims

1. A method for diagnosing impairments of a subject'"'"'s gaze stabilization system, the method comprising:

measuring the subject'"'"'s static visual acuity to obtain an assessment;

setting at least one test parameter based on the assessment;

measuring the subject'"'"'s dynamic visual acuity using the test parameters to obtain a first-dynamic measurement and a second dynamic measurement; and

determining an impairment of the subject'"'"'s gaze stabilization system using the assessment and the first and second dynamic measurements.

2. A method according to claim 1, wherein the subject'"'"'s dynamic visual acuity is measured when a subject'"'"'s head is fixed and a display object is continuously moving, when the subject'"'"'s head is fixed and the display object is discontinuously moving, when the subject'"'"'s head is fixed and the display object is continuously moving and is displayed in a patterned large field background, when the subject'"'"'s head is moving and the display object is fixed, when a subject'"'"'s head is moving and a display object is continuously moving, when a subject'"'"'s head is moving and a display object is discontinuously moving, when the subject'"'"'s head is moving and the display object is continuously moving and is displayed in a patterned large field background, or any combination thereof.

3. A method according to claim 2, wherein measuring the subject'"'"'s dynamic visual acuity includes displaying a preliminary form and displaying a test form of the display object.

4. A method according to claim 3, wherein the assessment includes a minimum interval for the subject to correctly identify a visual object, the test parameters include a display interval that is greater than or equal to the minimum interval, and the test form is displayed for the display interval.

5. A method according to claim 2, wherein measuring the subject'"'"'s visual acuity when the subject'"'"'s head is fixed and the display object is continuously moving and is displayed in a patterned large field background includes when the patterned large field background is moving in relation to the moving display object, when the patterned large field background is fixed in relation to the moving display object, or a combination thereof.

6. A method according to claim 2, further comprising:

determining a first maximum velocity of a visual object that the subject correctly perceives using the subject'"'"'s smooth pursuit system, wherein measuring the subject'"'"'s dynamic visual acuity includes displaying the display object moving at a velocity equal to or less than the first maximum velocity.

7. A method according to claim 6, wherein measuring the subject'"'"'s dynamic visual acuity further includes displaying the display object moving at a velocity equal to or greater than the first maximum velocity.

8. A method according to claim 6, further comprising:

determining a second maximum velocity of the visual object that the subject correctly perceives using the subject'"'"'s optokinetic system.

9. A method according to claim 2, wherein the assessment includes a minimum size of a visual object that the subject correctly identifies, the test parameters include a display size that is greater than or equal to the minimum size, and the display object is displayed at the display size.

10. A method according to claim 2, wherein measuring the subject'"'"'s visual acuity when the subject'"'"'s head is fixed and the display object is discontinuously moving includes:

displaying a central marker in a first location;

displaying the display object at a second location; and

determining a minimum display time that the subject correctly identifies the display object over a plurality of trials.

11. A method according to claim 10, wherein the second location is in various directions relative to the first location.

12. A method according to claim 1, further comprising:

measuring the subject'"'"'s dynamic visual acuity to obtain a third dynamic measurement, wherein determining an impairment of the subject'"'"'s gaze stabilization system includes using the assessment and the first, second and third dynamic measurements.

13. A method according to claim 12, further comprising:

measuring the subject'"'"'s dynamic visual acuity to obtain a fourth dynamic measurement, wherein determining an impairment of the subject'"'"'s gaze stabilization system includes using the assessment and the first, second, third and fourth dynamic measurements.

14. A method according to claim 13, further comprising:

measuring the subject'"'"'s dynamic visual acuity to obtain a fifth dynamic measurement, wherein determining an impairment of the subject'"'"'s gaze stabilization system includes using the assessment and the first, second, third, fourth and fifth dynamic measurements.

15. A method according to claim 1, further comprising:

having the subject perform at least one free standing balance task while measuring the subject'"'"'s dynamic visual acuity.

16. A method according to claim 15, wherein having the subject perform at least one free standing balance task includes having the subject stand on at least one surface which moves in relation to a display of the display object.

17. A method according to claim 16, wherein the surface is a force plate, a treadmill, or a combination thereof.

18. A method according to claim 15, wherein having the subject perform at least one free standing balance task includes surrounding the subject with a visual surround.

19. A method according to claim 1, wherein measuring the subject'"'"'s dynamic visual acuity includes the subject'"'"'s dynamic visual acuity related to the subject'"'"'s vestibule-ocular reflex system, the subject'"'"'s smooth pursuit eye movement system, the subject'"'"'s optokinetic eye movement system, the subject'"'"'s saccadic movement system, the subject'"'"'s vergence eye movement system, or any combination thereof.

20. A method for diagnosing impairments of a subject'"'"'s gaze stabilization system, the method comprising:

measuring the subject'"'"'s static visual acuity to obtain an assessment;

measuring the subject'"'"'s dynamic visual acuity to obtain a first dynamic measurement and a second dynamic measurement,

wherein the subject'"'"'s dynamic visual acuity is measured when a subject'"'"'s head is fixed and a display object is continuously moving, when the subject'"'"'s head is fixed and the display object is discontinuously moving, when the subject'"'"'s head is fixed and the display object is continuously moving and is displayed in a patterned large field background, when the subject'"'"'s head is moving and the display object is fixed, when a subject'"'"'s head is moving and a display object is continuously moving, when a subject'"'"'s head is moving and a display object is discontinuously moving, when the subject'"'"'s head is moving and the display object is continuously moving and is displayed in a patterned large field background, or any combination thereof, and

wherein the display object is displayed in a preliminary form and a test form; and

determining an impairment of the subject'"'"'s gaze stabilization system using the assessment and the first and second dynamic measurements.

21. A method according to claim 20, wherein the assessment includes a minimum interval for the subject to correctly identify a visual object, and the test form is displayed for a display interval that is greater than or equal to the minimum interval.

22. A method according to claim 20, wherein the assessment includes a minimum size of a visual object that the subject correctly identifies, and the display object is displayed at a display size that is greater than or equal to the minimum size.

23. A method according to claim 20, further comprising:

determining a first maximum velocity of a visual object that the subject correctly perceives using the subject'"'"'s smooth pursuit system, wherein measuring the subject'"'"'s dynamic visual acuity includes displaying the display object moving at a velocity equal to or less than the first maximum velocity.

24. A method according to claim 23, wherein measuring the subject'"'"'s dynamic visual acuity further includes displaying the display object moving at a velocity equal to or greater than the first maximum velocity.

25. A method according to claim 23, further comprising:

determining a second maximum velocity of the visual object that the subject correctly perceives using the subject'"'"'s optokinetic system.

26. A method for training a subject'"'"'s gaze stabilization system, the method comprising:

measuring the subject'"'"'s static visual acuity to obtain an assessment;

displaying a display object to the subject, the display object having at least one parameter based on the assessment;

having the subject maintain gaze on the display object when the subject is moving, when the display object is moving or both and while executing a gaze control task;

determining a quantity related to proficiency of the subject'"'"'s gaze performance at selected times during execution of the gaze control task; and

displaying the one or more quantities to the subject.

27. A method according to claim 26, wherein having the subject maintain gaze on the display object occurs when a subject'"'"'s head is fixed and the display object is continuously moving, when the subject'"'"'s head is fixed and the display object is discontinuously moving, when the subject'"'"'s head is fixed and the display object is continuously moving and is displayed in a patterned large field background, when the subject'"'"'s head is moving and the display object is fixed, when a subject'"'"'s head is moving and a display object is continuously moving, when a subject'"'"'s head is moving and a display object is discontinuously moving, when the subject'"'"'s head is moving and the display object is continuously moving and is displayed in a patterned large field background, or any combination thereof.

28. A method according to claim 26, further comprising:

moving the display object according to a protocol.

29. A method according to claim 28, further comprising:

having the subject move according to a second protocol.

30. A method according to claim 26, further comprising:

having the subject move according to a protocol.

31. A method according to claim 26, wherein displaying a display object includes displaying a preliminary form and displaying a test form of the display object.

32. A method according to claim 31, wherein the assessment includes a minimum interval for the subject to correctly identify a visual object and displaying the test form includes displaying the test form for a display interval that is greater than or equal to the minimum interval.

33. A method according to claim 26, further comprising:

determining a first maximum velocity of a visual object that the subject correctly perceives using the subject'"'"'s smooth pursuit system, wherein displaying a display object includes moving the display object at a velocity equal to or less than the first maximum velocity.

34. A method according to claim 33, wherein displaying a display object further includes moving the display object at a velocity equal to or greater than the first maximum velocity.

35. A method according to claim 33, further comprising:

determining a second maximum velocity of the visual object that the subject correctly perceives using the subject'"'"'s optokinetic system.

36. A method according to claim 26, wherein the assessment includes a minimum size of a visual object that the subject correctly identifies and displaying a display object includes displaying the display object at a display size that is greater than or equal to the minimum size.

37. A method according to claim 26, further comprising:

having the subject perform at least one free standing balance task while executing the gaze control task.

38. A method according to claim 37, wherein having the subject perform at least one free standing balance task includes having the subject stand on at least one surface which moves in relation to a display of the display object.

39. A method according to claim 38, wherein the surface is a force plate, a treadmill, or a combination thereof.

40. A method according to claim 37, wherein having the subject perform at least one free standing balance task includes surrounding the subject with a visual surround.

41. A method according to claim 26, wherein determining a quantity related to proficiency of the subject'"'"'s gaze performance includes the subject'"'"'s gaze performance related to the subject'"'"'s vestibule-ocular reflex system, the subject'"'"'s smooth pursuit eye movement system, the subject'"'"'s optokinetic eye movement system, the subject'"'"'s saccadic movement system, the subject'"'"'s vergence eye movement system, or any combination thereof.