Discriminant Analysis Between Schizophrenics and Nonschizophrenics Using Exploratory Eye Movements

Abstract

To extract a common feature from schizophrenics, we discriminated schizophrenics from nonschizophrenics using exploratory eye movements. Eye movements while viewing a stationary figure were recorded using an eye-mark recorder. Subjects were 60 schizophrenics and 140 nonschizophrenics, consisting of six patient groups with various psychiatric diseases and normal controls. Of five indicators of eye movements available, the responsive search score (RSS), which is eye movements in response to repeated questions in a comparison task and number of eye fixations (NEF) in memory tasks, were selected by stepwise selection. The schizophrenics were discriminated from nonschizophrenics with a sensitivity of 73.3%–76.7% and a specificity of 81.4%–84.3%. The obtained discriminated function in this study was applied to the data of a WHO collaborative project including 167 schizophrenics, 144 depressed patients, and 154 normal subjects in six countries. In total, the sensitivity was 88% and specificity was 83.9%. It was found that we could extract a common feature from many schizophrenics using the RSS and NEF of exploratory eye movements.