Abstract
Eye movement diagnosis for cerebral nerve have been researched by many medical agency to assess a psychotic disorder, such as schizophrenia and post traumatic stress disorder (PTSD) [1]–[3]. As well as checking the symptomatic state, diagnosis of eye movement is expected to find an indication at the earlier stage of mental disorder. Especially, by means of measuring an abnormal reaction of eye movement, we challenge to develop the novel method for early detection of mental disorder.
It is well-known that eye movement involves a head movement as well as extraocular muscles movement [4]. Since only a behavior of eye is believed to be influenced by the state of cerebral activity, a conventional measurement of eye movement was performed by using an instrument of head fixation to separate each movement. However, we assume that a slight change caused by mental disorder is hard to detect with only the behavior of eye which consists of powerful extraocular muscles.
Therefore, we focus on a relative change of velocity in both eye and head movement, which have different muscular system and neural control. In our proposed method, we compare the change of each velocity in antisaccade examination before and after stress task, which is continuous mental arithmetic [5]. To separate the movement between eye and head, we adopted two measurement instruments; one is eye tracking system and the other is image processing system with digital camera and laser maker. As the results for healthy 10 subjects mentally, the speed of head movement with most subject becomes slow after stress task, even though the speed of eye movement is almost equivalent before and after. Since this compensation between eye and head movement is stable without the influence of individual variation, the proposed method has a possibility to be useful for early detection of mental disorder.
Supported by Japan Grant-in-Aid for Scientific Research No. 15K00415, and Tokyo Metropolitan University and College Joint Grant.