Smooth pursuit eye movements and functional psychoses; a review

Abstract

This brief review has presented evidence that disorders of SPEM are associated with schizophrenia, and quite likely with other functional psychoses as well as with some central nervous system disorders. The effects are not drug related in the psychiatric population the authors studied. A large proportion of first-degree family members also show similar SPEM dysfunctions, and there is a significant concordance among MZ twins who are discordant for schizophrenia. The dysfunction does not appear to be a reflection of the psychosis or its treatment. Nor is it likely to reflect motivational factors or a failure of voluntary attention. It is not a predictor of later psychosis, nor can it be used as a specific diagnostic sign of schizophrenia. Rather it represents an association with a predisposition to some functional psychosis; the predisposition shows itself in a dysfunction of nonvoluntary attention, a disorder of cognitive centering, which has a neurophysiological substrate not only in the form of eye pursuit dysfunctions, but in hitherto unspecified neural noise.