Studies on exploratory eye movement

Abstract 

This paper describes the pioneering studies on eye movements by Prof. Takuya Kojima, which clarified the scarcity of adjustability of alertness level in schizophrenia. Shimazono first thought that closed-eye eye movement may provide objective and physiological indicator for brain activities during awake state. Prof. Kojima thought that depressive patients may also have latent inner tension and was also intrigued by the contrast of the scarcity of exploratory eye movement in schizophrenic patients. He found out that depressive patients are tense at rest but that accustomization takes place in them, while accustomization does not take place in schizophrenic patients. Isse researched on closed-eye eye movements in relation with alertness and disturbance of consciousness. Prof. Kojima invented eye camera to measure the exploratory eye movement and created Responsive Search Score (RSS), an indicator of the parts which the subject covers during the responsive search. Prof. Kojima's research on differentiation of schizophrenic patients was carried out as WHO and the result was replicated in different ethnicities. Clinical molecular genetic studies suggest that RSS reflects the disposition of susceptibility for schizophrenia and possible linkage between RSS and chromosome 22q. Brain imaging studies showed correlation between RSS and the volume of the right parietal eye field, right frontal eye field including the right supplementary eye field and the right inferior frontal gyrus. Based on these findings Prof. Kojima invented an apparatus which can monitor eye movements and show diagnostic sensitivity 75% and specificity 80% for schizophrenia. The apparatus is expected to be applied clinically in the future.

Keywords: Closed-eye eye movement, Exploratory eye movement, Responsive Search Score, Accustomization, Susceptibility for schizophrenia