SMOOTH-PURSUIT EYE-MOVEMENTS IN SCHIZOPHRENIA IN NEW-ZEALAND

Objective: The objective of this study was to answer the following que stions: what is the frequency of smooth pursuit dysfunction in schizop hrenia in New Zealand; is it comparable to that observed in other popu lations; is it specific to schizophrenia; and is it represented in maj or ethnic groups present in New Zealand? Method: Patients with schizop hrenia (n = 26) were recruited at five clinical facilities in the Auck land region. Diagnoses were taken from clinical records. Patients' smo oth pursuit eye movements while following sinusoidal and triangular wa ve targets were recorded and their performance compared to a control p opulation (n = 34). Eye movements were scored using the In(s/n), pursu it gain, and saccadic frequency measures. Results: Patients with schiz ophrenia scored significantly worse than controls using the In(s/n) me asure and had significantly higher saccadic frequencies for both targe ts. Percentile equivalents allow the estimation that about 50% of pati ents with schizophrenia have smooth pursuit dysfunction (SPD). There w as no difference between groups for pursuit gain score, although low g ain pursuit was significantly correlated with higher medication in the schizophrenia patient group. There were no differences associated wit h age, sex or ethnicity. The SPD marker was found in European-and Poly nesian-derived New Zealanders. Conclusions: The results of the present study are consistent with results of previous studies performed elsew here. Differences are at least partly ascribable to variations in meth ods. Smooth pursuit dysfunction is a robust marker for schizophrenia. Its application would be particularly useful in the New Zealand contex t as part of a first admission study looking at the effects of ethnici ty on schizophrenia prognosis and on the stability of psychiatric diag noses.