Eye movements, verbal material recall and negative symptoms in chronic schizophrenia

Eye movements in response to verbal stimuli (Japanese cursive syllabary from the Standard Language test of Aphasia) were examined in 20 chronic schizophrenics diagnosed by DSM III and 15 normal controls. In chronic schizophrenics, the number of correct recalls in the test were lower than those in the normal controls, both the deviation indices and maximum deviation indices (the degree of fixation-time deviation) of chronic schizophrenics were higher than those of controls. Thus in chronic schizophrenics the fixation time for each character had greater deviation than in controls, and fixation on a single character was longer than in controls. In chronic schizophrenics there were significant negative correlations between syllables correctly recalled and both the deviation indices and the maximum deviation indices, while there were no significant correlations in controls. There were significant positive correlations between the four fixation time parameters; average fixation time on one character, deviation indices, maximum and minimum deviation indices and the severity of schizophrenia, especially that of negative symptoms. The results showed that chronic schizophrenics had distinct fixation time differences when presented with verbal stimuli, suggesting a mnemonic strategy deficit. The degree of fixation time deviation depended on the severity of negative symptoms.