EYE-MOVEMENTS IN RECOVERING SUBSTANCE-ABUSERS - A PROSPECTIVE-STUDY

Smooth-pursuit (SPEM) and saccadic (SEM) eye movements were studied in 11 cocaine-dependent and 4 alcohol-dependent patients after 1, 3, and 12 weeks of verified abstinence. Sixteen non-drug-dependent controls were studied after comparable intervals. SPEM tracking accuracy, estimated by the Ln (S/N) statistic, was higher among cocaine-dependent patients than among alcohol-dependent patients and normal controls. A microanalysis of SPEM tracking revealed that the superior accuracy of the cocaine-dependent group was due to a small increase in eye movements at the target frequency (0.4 Hz) and a small compensatory decrease in higher frequency eye movements (i.e., saccades). In contrast to the findings of the SPEM study, the findings of the SEM study revealed that alcohol-dependent patients constituted the only abnormal group. Alcohol-dependent patients exhibited slower saccade onset latencies than the other groups. There were no significant differences among the groups with respect to saccade velocity, amplitude, or duration.