The effect of distraction on acute schizophrenics' visual tracking.
To examine the nature of impaired smooth pursuit eye movement (SPEM) in schizophrenia, 16 hospitalized schizophrenics in the acute phase and 16 hospitalized nonpsychotic patients were studied. The experiment consisted of five 30-sec visual tracking phases: (i) base line (no distraction); (ii) auditory-visual distraction; (iii) middle base line; (iv) dichotic listening; and (v) final base line. Schizophrenics were characterized by significantly more velocity arrests throughout all phases of the experiment. Auditory-visual distraction did not impair either group's SPEM relative to base line performance. In contrast, dichotic listening significantly increased both groups' velocity arrests. This form of distraction also tended to produce greater impairment among schizophrenics. The failure of apparently intense auditory-visual distraction to significantly disrupt schizophrenics' SPEM suggests that inattentiveness alone does not account for schizophrenics' tracking impairment. This notion is supported by the finding that only the more intense distraction by dichotic listening produced a (trend toward) greater impairment in schizophrenics.