Smooth pursuit deficits in schizophrenia, affective disorder and obsessive - Compulsive disorder

Background. In schizophrenia, affective disorders, and obsessive-compulsive disorder (OCD) dysfunction of frontal neuronal circuits has been suggested. Such impairments imply corresponding oculomotor deficits. Method. Eye movement response to foveofugal and foveopetal step-ramp stimuli was recorded within the same study design in patients with schizophrenia (N= 16), affective disorder (N = 15), and OCD (N = 18) and compared with controls (N = 23) using infra-red reflection oculography. Results. In the foveofugal task steady-state velocity was lower in all patient groups compared with controls. Post-saccadic eye velocity was also decreased in patients with schizophrenia and affective disorder. In the foveopetal stimulus steady-state velocity was reduced in schizophrenic patients, only. Changes of saccadic latencies or position errors were not found in any of the patient groups. Also, pursuit latency was unchanged and initial eye acceleration was not decreased. Conclusions. Unaltered saccadic parameters indicate intact motion perception in cortical visual area V5. Therefore, the observed deficit of pursuit maintenance implies a dysfunction of frontal networks in all patient groups including the pursuit region of the frontal eye field (FEF). In patients with schizophrenia and affective disorder reduced post-saccadic pursuit initiation may indicate an impaired interaction between the pursuit and the saccadic system.