정상인，정신분열증 및 우울증환자에서 한글의 시각적인식과 관련된 대뇌반구의 비대칭성

Hemispheric Asymmetry in Visual Recognition o f Hangul Words in Normal Subjects, Schizophrenic and Depressive Patients

Hemispheric asymmetry in recognition of Hangul words was investigated in 33 normal subjects and 33 schizophrenic and 33 depressive patients who were physically healthy. Using a computer program and a computer monitor with very short decay time, Hangul words were presented to the right or left visual field at 3° from the central fixation point for 150 msec. Each subject was instructed to respond with his right or left hand respectively immediately upon the recognition of the tachistoscopically presented word as either the same as or different from the word presented just later the middle of visual field. Each subject had 48 practices and 48 examined trials. The procedures were randomized and counterbalanced. The reaction time and the rates of correct response were measured. The means of medial value of reaction time and the means of correct response in each of 4 units of 2 visual field conditions x 2 association value conditions were statistically compared. 1) the reaction time was significantly faster in the normal group than in the schizophrenic and depressive group. There as no difference between the two visual fields but there was a tendency of slower reaction time in the right visual field in the schizophrenic group and in the left visual field in the depressive group. The reaction time in the right ipsilateral conditionOeft hemisphere) was significantly slower in the schizophrenic group, and in the left ipsilateral condition(right hemisphere), it was significantly slower in the depressive group. 2) The correct response rate was significantly higher in the normal group than in the schizophrenic and depressive group. There was a significantly interaction between the two visual fields; higher rate was observed in the right visual field. There was a strong tendency of right visual field superiority in the normal group but right visual field inferiority in the schizophrenic group. In conclusion, the results suggest that the left hemisphere was superior to right hemisphere in recognition of Hangul words and that schizophrenia is related with dysfunction of the left hemisphere and depression is related with dysfunction of the right hemisphere