Attention, eye tracking and schizophrenia

Two experiments are reported. The first experiment successfully replicated the finding that Smooth Pursuit Eye-Tracking(SPET) performance recorded using electronsystagmographic techniques statistically differentiates between groups of clinically diagnosed shizophrenic patients and normal controls. Ratings taken of spontaneous patient behaviour during testing indicated that behaviour which on a priori grounds was thought to preclude optimum attention to eye tracking was related to greater impairment of schizophrenic performance. The second experiment investigated the effect of experimentally induced distraction on SPET performance by normal controls. It was found that competing tasks of increasing levels of difficulty produced increasing degrees of impairment in SPET performance. The results of the two experiments were interpreted as evidence that SPET performance is sensitive to superficial inattention, and that deficits in schizophrenic SPET performance are best explained by attentional deficits in the schizophrenics.