Smooth pursuit eye movements and functional psychoses; a review.

In 1908 Diefendorf and Dodge reported an association between schizophrenia and impaired smooth pursuit eye movements. Using a pendulum as a stimulus and photographing corneal reflection of light, they monitored eye movements in chronic schizophrenics, manic-depressives, epileptics, and mentally retarded patients. Deviant pursuit movements characterized the performance of most of the schizophrenic patients, but of only a small proportion of other patients unless their clinical condition was markedly deteriorated. The authors interpreted their findings as evidence of a central nervous system defect in processing perceptual data. They explicitly discounted poor motivation or inattention as the cause of the group differences. Couch and Fox in 1934 repeated that experiment on a sample of 117 patients that included, in addition to schizophrenics, neurotics, psychopaths, manic-depressives, cases of dementia paralytica, mental deficiency, epilepsy, and alcoholism. These authors, too, reported disordered pursuit movements in their most severely ill patients, but the dysfunctions were not limited to the schizophrenic patients. Couch and Fox believed that inattention was principally involved in producing the deviant pursuit in their patients. The two issues of specificity and origin of the deviant pursuit movements remained unresolved. Both studies, however, were rarely cited and they seemed to have been all but forgotten. Forty years elapsed before renewed interest in this phenomenon occurred. In a series of papers (Holzman 1975, Holzman, Proctor, and Hughes 1973, and Holzman et al. 1974) we described a significant association between impairments in smooth pursuit