Eye tracking headset and system for neuropsychological testing including the detection of brain damage

• US 20130308099A1
• Filed: 05/18/2012
• Published: 11/21/2013
• Est. Priority Date: 05/18/2012
• Status: Active Grant

• Current Assignee: Sync Think, Inc.
• Original Assignee: Halcyon Bigamma
• Inventors: Stack, Matthew E.
• Granted Patent: US 9,004,687 B2
• Time in Patent Office: Days
• US Class Current: 351/209
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: A61B 5/162 Testing reaction times
• CPC Class Codes: A61B 5/163 by tracking eye movement, gaze, or pupil change
• CPC Class Codes: A61B 5/6803 Head-worn items, e.g. helmets, masks, headphones or goggles

Abstract

A universal headset-mounted Neuropsychological Testing System utilizes eye tracking, with a single screen fixed with respect to the face and a dot on the screen driven to present an object that both eyes are focused on using a set of prisms, with the prisms eliminating interocular distance considerations. Ultrathin optics cast a virtual image at 40 centimeters and a universal mask against which the test taker'"'"'s face is placed fixes the single screen with respect to the face so that head movement is not a factor. Additionally, miniature cameras are located in the headset housing beneath the eyes, and a quick release tensioning unit provides easy headset mounting and removal. Moreover, all elements are located in the headset hood to eliminate the effects of head movement as well as environmental distractions.

Claims

1. In a neuropsychological testing system involving smooth pursuit eye tracking, apparatus for measuring gaze direction without calibration while at the same time eliminating environmental effects, comprising:

A headset adapted to fit over the face of a test subject, the headset locating a single screen spaced a predetermined distance from the eyes of said test subject.

2. The apparatus of claim 1, and further including a pair of prisms adapted to be positioned between the eyes of said test subject and said screen such that the prisms bend the lines of sight from the eyes of said test subject to converge on a single spot on said screen.

3. The apparatus of claim 1, wherein said headset includes a hood carrying said screen at one end thereof and having side panels adapted to block outside light from entering the hood when said headset is in place on said test subject, whereby environmental conditions surrounding the test subject are eliminated.

4. The apparatus of claim 1, wherein said neuropsychological testing system using smooth pursuit eye tracking includes a light source for providing a glint on the eye of said test subject and a camera trained on an eye of said test subject for detecting said glint and the extent of the dark iris of the eye of said test subject.

5. The apparatus of claim 4, wherein said headset includes a hood and wherein said light source and camera are located in said hood.

8. The apparatus of claim 1, and further including a drive for presenting a moving dot along a path on said screen and wherein said headset includes a processor for calculating gaze direction.

9. The apparatus of claim 8 wherein said processor measures anticipatory timing of the movement of the eye of said test subject as it tracks said moving dot from said calculated gaze direction.

10. The apparatus of claim 9, wherein said processor calculates variability in anticipatory timing as the eye of said test subject tracks the dot from one position to the next on said screen.

11. The apparatus of claim 10, wherein said dot moves on a path in equal timed increments.

12. The apparatus of claim 9, wherein the measured anticipatory timing is compared with anticipatory timing of a normal test subject and wherein the difference between the measured anticipatory timing and the anticipatory timing associated with a normal test subject indicates cognitive impairment.

13. The apparatus of claim 9, and further including measuring the variability in the anticipatory timing as the dot moves from one position to the next on said path in terms of time it takes for the eye of the test subject to direct gaze to the dot.

14. The apparatus of claim 13, wherein said time is lead time or lag time.

6. In a neuropsychological testing system involving smooth pursuit eye tracking, apparatus useful in the measuring of gaze direction without calibration while at the same time eliminating environmental effects, comprising:

A headset adapted to fit over the face of a test subject, the headset locating a single screen spaced a predetermined distance from the eyes of said test subject, said headset including a hood having a mask at the end opposite that carrying said screen, said mask adapted to fit about the face of said test subject and having apertures therethrough so that the test subject can look through the mask to said screen.

7. The apparatus of claim 6, wherein said mask is made of firm but compliant material and has a nose aperture of sufficient size to permit the mask to be held tight to the face of said test subject without interference from the nose of said test subject.

15. In a neuropsychological testing system involving smooth pursuit eye tracking,

a headset having a hood adapted to cover the face of a test subject, the headset locating a screen spaced from the eyes of a test subject,

a flexible spine coupled to said headset with one end of said hood attached to a forward end of said spine, said spine having an occipital lobe pad at a distal end adapted to contact the occipital lobe of said test subject when said headset is in place,

a pair of strands running from the end of said spine adjacent said occipital lobe pad to said hood;

and,

a ratchet for tightening said strands to draw said hood towards said occipital lobe pad, with said spine flexing during the tightening of said strands.

16. A universal headset mounted neuropsychological testing system utilizing eye tracking comprising:

a headset adapted to fit over the face of a test subject said headset including a hood adapted to be attached to the front face of the test subject and including a single screen;

a driver for providing a dot on said single screen that moves along a path;

a mask fixed to said headset and adapted to contact the face of said test subject around the periphery thereof, the mask having apertures therein adapted to be positioned adjacent the eyes of said test subject;

a pair or prisms between the apertures in said mask and said single screen so as to bend the lines of sight from the eyes of said test subject to converge at a single spot on said screen;

a camera located within said hood and adapted to be trained on an eye of said test subject, said camera having a focal plane array and optics to project the iris of the associated eye of said test subject onto said focal plane array;

a light emitting device and optics adapted to focus the light therefrom onto a portion of the iris of said subject to form a glint thereon; and

,

a smooth pursuit processor coupled to said focal plane array for measuring the centroid of said iris and the position of the associated glint and for calculating the direction of gaze of the eye of said test subject based on a vector between said centroid position and said glint position and for calculating anticipatory timing of said eye as it tracks said dot on said screen in response to said gaze calculation, said hood and mask filtering out environmental factors while locating said screen and said light emitting device at a predetermined distance from the eye of said test subject.

17. The apparatus of claim 16, and wherein said device moves the dot on said screen in equal increments along said path and further including time stamping each of the successive positions of said dot on said path.

18. The apparatus of claim 17, wherein said processor includes calculating the difference in pixels between the gaze direction at different time stamps and for turning the differences into values correlated with anticipatory timing including the lead time or lag time that it takes the eye to track the moving dot, said processor converting the lead time or lag time into a score;

and

a comparator for comparing the variability of said anticipatory timing with the variability of the anticipatory timing of a normal person such that the departure of the sensed variability in anticipatory timing from that of a normal person indicates cognitive impairment.

19. The apparatus of claim 16, and further including a camera and a light emitting device for the other eye of the test subject and wherein the anticipatory timing measurement is taken for the dominant eye.

20. The apparatus of claim 19, wherein the dominant eye is determined by determining the longer length of continuous good data from the eyes of said test subject.