Saccadic reaction times in acute and remitted schizophrenics

Abstract

Schizophrenics are known to have various disturbances of the visuomotor system. Whereas smooth pursuit eye movement disorders have been repeatedly confirmed, there are relatively few reports regarding possible disturbances of the saccadic system. In this study, the saccadic reaction times of 47 schizophrenic inpatients were investigated upon admission and later in the remitted state; 28 age- and sex-matched normal volunteers were tested as controls. Psychopathology and outcome were evaluated according to the Brief Psychiatric Rating Scale and the Prognostic Scale. Light stimuli were presented at random direction, location (ranging from 0 degrees to 20 degrees) and duration (800, 1000, and 1200 ms). The eye movements were recorded by electro-oculography. Compared with the control group, schizophrenics revealed prolonged saccadic reaction times, which correlated with pronounced negative symptoms and an unfavourable course of the illness. The saccadic reaction times remained prolonged in schizophrenic patients. These findings suggest attentional deficits in schizophrenics.

Adverse Effects of Risperidone on Eye Movement Activity: A Comparison of Risperidone and Haloperidol in Antipsychotic-Naive Schizophrenic Patients

“…One study has reported a pattern of normal latency, but hypometric saccades, in schizophrenic patients who had been untreated for at least 6 months (Crawford et al 1995a). An increased latency of visually guided saccades also has been reported in some studies of schizophrenic patients (Yee et al 1987), and one group has shown this to be particularly pronounced in chronically ill patients with prominent negative symptoms (Mackert and Flechtner 1989). On the basis of the results of the present study, which indicate intact reflexive saccadic eye movements in schizophrenic patients prior to treatment initiation, previous reports of saccade abnormalities might represent adverse medication effects or pathophysiological changes associated with the course of illness.…”

“…This pattern of generalized deficits in the saccade system is one associated with multiple CNS-active medications that reduce alertness or cause sedation, and thus it is possible that some reductions in alertness may be associated with risperidone treatment. Mackert and Flechtner (1989), in the only published study of which we are aware investigating treatment effects on saccades in initially untreated schizophrenic patients, studied saccade latencies and reported no change after an average of 11.5 weeks of treatment with various typical neuroleptic medications. The results of the present study in haloperidol-treated patients replicate this effect in saccade latency and extend it by demonstrating that other parameters of saccade function, including peak velocity and accuracy, also appear not to be affected by the typical antipsychotic haloperidol.…”

The tell-tale tasks: A review of saccadic research in psychiatric patient populations

“…Schizophrenia patients may display significantly prolonged saccadic response latencies under conditions of considerable task complexity (Done & Frith, 1984; Mackert & Flechtner, 1989; Schmidt-Burghk et al, 1982). For example, in a complicated choice paradigm in which subjects were required to move their eyes either left or right as directed by an imperative signal and report upon the characteristics of a peripheral stimulus, Done and Frith (1984) observed that schizophrenia patients had significantly longer saccadic latencies.…”

“…For example, in a complicated choice paradigm in which subjects were required to move their eyes either left or right as directed by an imperative signal and report upon the characteristics of a peripheral stimulus, Done and Frith (1984) observed that schizophrenia patients had significantly longer saccadic latencies. The Mackert and Flechtner (1989) task was similarly complex; fast-changing saccadic stimuli were presented in varying positions for varying durations (800 to 1200 msec.) randomly chosen and led to prolonged saccade latencies.…”

Smooth pursuit deficits in schizophrenia, affective disorder and obsessive–compulsive disorder

“…Saccades are reflexively triggered by a suddenly appearing visual target and are also under volitional control. With respect to reflexive saccades ambiguous results have been reported for schizophrenia : some authors found prolonged latency and/or reduced spatial accuracy, suggesting a dysfunction within posterior parietal areas (Schmid-Burgk et al 1983 ;Mackert & Flechtner, 1989 ;Gaymard et al 1998) but others were not able to confirm these results (Fukushima et al 1988;Crawford et al 1998 ;Karoumi et al 1998). In OCD reflexive saccades were normal, whereas in the antisaccade paradigm error rates were increased in OCD as well as in schizophrenia (Gambini et al 1993 ;Rosenberg et al 1997;Crawford et al 1998 ;Karoumi et al 1998 ;McDowell et al 1999).…”