System and Method for Cognition and Oculomotor Impairment Diagnosis Using Binocular Coordination Analysis

Abstract

A method of testing a subject for impairment includes presenting the subject with a display of a smoothly moving object, repeatedly moving over a tracking path and, while presenting the display to the subject, measuring the subject's right eye positions and measuring the subject's left eye positions. The method further includes generating a disconjugacy metric by comparing the measured right eye positions with the measured left eye positions, comparing the disconjugacy metric with a predetermined baseline to determine whether the disconjugacy metric is indicative of an impairment, and generating a report based on the disconjugacy metric.

What is claimed is: 
     
         1 . A method of testing a subject for impairment, comprising:
 at a system having a computer system, a display, and a measurement apparatus to measure the subject's right eye positions and the subject's left eye positions, the computer system having one or more processors and memory storing one or more programs for execution by the one or more processors, performing a set of operations including:   presenting to the subject, on the display, a smoothly moving object, repeatedly moving over a tracking path;   while presenting to the subject the smoothly moving object on the display:
 measuring the subject's right eye positions, using the measurement apparatus; and 
 measuring the subject's left eye positions, using the measurement apparatus; 
   using the computer system:
 generating a disconjugacy metric by comparing the measured right eye positions with the measured left eye positions; 
 comparing the disconjugacy metric with a predetermined baseline to determine whether the disconjugacy metric is indicative of an impairment; and 
 generating a report based on the disconjugacy metric. 
   
     
     
         2 . The method of  claim 1 , wherein the disconjugacy metric corresponds to a standard deviation of differences between the subject's right eye position and the subject's left eye position over a duration of the presentation. 
     
     
         3 . The method of  claim 1 , wherein the predetermined baseline is based on at least one of:
 a disconjugacy range associated with a preselected group of control subjects, wherein the preselected group of control subjects have normal conjugate gaze; and   a disconjugacy metric for the subject generated from a previous test.   
     
     
         4 . The method of  claim 1 , further comprising:
 presenting a distraction to the subject while presenting the subject with the smoothly moving object;   generating a metric of distractibility, wherein the metric of distractibility is indicative of the subject's susceptibility to distraction; and   wherein the generated report is further based on the metric of distractibility.   
     
     
         5 . The method of  claim 1 , including presenting the smoothly moving object with a plurality of pseudorandom gaps, wherein, during a respective pseudorandom gap in the plurality of pseudorandom gaps, the object is not displayed;
 the method further includes generating a stressed disconjugacy metric, wherein the stressed disconjugacy metric is indicative of whether the subject has a stress-sensitive impairment; and   wherein the generated report is further based on the stressed disconjugacy metric.   
     
     
         6 . The method of  claim 5 , wherein a respective pseudorandom gap comprises a pseudorandom starting point on the tracking path and a pseudorandom duration. 
     
     
         7 . The method of  claim 5 , including comparing the stressed disconjugacy metric with the disconjugacy metric to determine whether the subject has a stress-sensitive impairment. 
     
     
         8 . The method of  claim 1 , including:
 while presenting the subject with a display of a smoothly moving object, measuring the subject's eye movements;   comparing the measured eye movements with movements of the smoothly moving object to generate a tracking metric, wherein the tracking metric corresponds to how accurately and how consistently the subject visually tracks movement of the object; and   wherein the generated report is further based on the tracking metric.   
     
     
         9 . The method of  claim 8 , wherein the tracking metric is generated based on at least one of:
 a variability of eye position error metric;   a variability of eye velocity gain metric;   an eye position error metric;   a rate or number of saccades metric; and   a visual feedback delay metric.   
     
     
         10 . The method of  claim 1 , wherein the impairment is a cognitive impairment. 
     
     
         11 . The method of  claim 1 , wherein the impairment is an oculomotor impairment. 
     
     
         12 . The method of  claim 1 , wherein measuring the subject's eye positions is accomplished using one or more video cameras. 
     
     
         13 . The method of  claim 1 , including repeating the presenting, generating, and comparing operations multiple times so as to generate a sequence of subject feedback signals, thereby enabling the subject to adjust their response to the stimuli in accordance with the subject feedback signals. 
     
     
         14 . A system of testing a subject for impairment, comprising:
 a measurement apparatus to measure the subject's right eye positions and the subject's left eye positions;   a display;   one or more processors;   memory, the memory storing one or more programs, the one or more programs comprising instructions to:
 present to the subject, on the display, a smoothly moving object, repeatedly moving over a tracking path; 
 while presenting to the subject the smoothly moving object on the display:
 measure the subject's right eye positions; and 
 measure the subject's left eye positions; 
 
 generate a disconjugacy metric by comparing the measured right eye positions with the measured left eye positions; 
 compare the disconjugacy metric with a predetermined baseline to determine whether the disconjugacy metric is indicative of an impairment; and 
 generate a report based on the disconjugacy metric. 
   
     
     
         15 . The system of  claim 14 , wherein the disconjugacy metric corresponds to a standard deviation of differences between the subject's right eye position and the subject's left eye position over a duration of the presentation. 
     
     
         16 . The system of  claim 14 , wherein the predetermined baseline is based on at least one of:
 a disconjugacy range associated with a preselected group of control subjects, wherein the preselected group of control subjects have normal conjugate gaze; and   a disconjugacy metric for the subject generated from a previous test.   
     
     
         17 . The system of  claim 14 , the one or more programs including instructions to:
 present a distraction to the subject while presenting to the subject the smoothly moving object;   generate a metric of distractibility, wherein the metric of distractibility is indicative of the subject's susceptibility to distraction; and   wherein the generated report is further based on the metric of distractibility.   
     
     
         18 . The system of  claim 14 , wherein the presentation of the smoothly moving object includes a plurality of pseudorandom gaps, wherein, during a respective pseudorandom gap in the plurality of pseudorandom gaps, the object is not displayed;
 the one or more programs further comprise instructions to generate a stressed disconjugacy metric, wherein the stressed disconjugacy metric is indicative of whether the subject has a stress-sensitive impairment; and   wherein the generated report is further based on the stressed disconjugacy metric.   
     
     
         19 . The system of  claim 18 , wherein a respective pseudorandom gap comprises a pseudorandom starting point on the tracking path and a pseudorandom duration. 
     
     
         20 . The system of  claim 18 , the one or more programs include instructions to compare the stressed disconjugacy metric with the disconjugacy metric to determine whether the subject has a stress-sensitive impairment. 
     
     
         21 . The system of  claim 14 , the one or more programs including instructions to:
 while presenting to the subject a display of a smoothly moving object, measure the subject's eye movements;   compare the measured eye movements with movements of the smoothly moving object to generate a tracking metric, wherein the tracking metric corresponds to how accurately and how consistently the subject visually tracks movement of the object; and   wherein the generated report is further based on the tracking metric.   
     
     
         22 . The system of  claim 14 , wherein the measurement apparatus includes one or more video cameras. 
     
     
         23 . A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions to:
 present to the subject, on a display device, a display of a smoothly moving object, repeatedly moving over a tracking path;   while presenting the display of the smoothly moving object to the subject:
 measure the subject's right eye positions, using a measurement apparatus; and 
 measure the subject's left eye positions, using the measurement apparatus; 
   generate a disconjugacy metric by comparing the measured right eye positions with the measured left eye positions;   compare the disconjugacy metric with a predetermined baseline to determine whether the disconjugacy metric is indicative of an impairment; and   generate a report based on the disconjugacy metric.   
     
     
         24 . The computer readable storage medium of  claim 23 , wherein the disconjugacy metric corresponds to a standard deviation of differences between the subject's right eye position and the subject's left eye position over a duration of the presentation.