Smooth pursuit eye movements in subjects reporting physical anhedonia and perceptual aberrations.

Two studies were conducted to evaluate the ability of schizotypic subjects to track the horizontal movement of a light source across the face of an oscilloscope. In the first experiment, subjects were selected based on their scores on the Physical Anhedonia Scale (Chapman et al., 1976). The high anhedonic group was found to be significantly more variable than the low anhedonic group and contained three subjects with particularly deviant smooth pursuit eye movements (SPEM). In the second study, an additional group of schizotypic subjects who scored high on the Perceptual Aberration Scale (Chapman et al., 1978) was selected. In this study, eye-tracking records produced by both the anhedonic and perceptual aberration subjects were more variable than those recorded from control subjects, and once again, the most deviant records were produced by a small subgroup (n = 10) of the schizotypic subjects. These questionnaire-identified schizotypes with poor tracking ability might comprise a group of subjects especially vulnerable to a future schizophrenia-like disorder.