VIGILANCE IN RECOVERING COCAINE-DEPENDENT AND ALCOHOL-DEPENDENT PATIENTS - A PROSPECTIVE-STUDY

Electroencephalographic activity and psychomotor performance were eval uated in 11 cocaine-dependent and 4 alcohol-dependent patients, after 1, 3, and 12 weeks of verified abstinence, and 15 non-drug-dependent a ge-matched controls, while they performed a 30-min signal-detection ta sk. The task consisted of lower and higher pitched tones, 100 msec in duration, occurring in randomized order at a rate of 1 every 2 seconds . Subjects were asked to press a response key whenever they detected t he less frequent (p = 0.3), higher pitched tone. Over the course of th e 30 min task, subjects responded less frequently and more slowly to t he higher pitched tone. Also, the amount of slow wave (i.e., alpha) ac tivity in their EEGs increased. There were no differences among the gr oups with respect to the rate or magnitude of these time-related decre ments in performance and electroencephalographic arousal. The only dep endent variable which differentiated groups was reaction time, average d across the duration of the task. Overall, the cocaine dependent grou p responded 80-100 msec slower than the other groups. In the context o f other findings, this finding of increased reaction time among recove ring cocaine dependent patients is interpreted as reflecting an effect of previous cocaine use on neural processes involved in the programmi ng and/or execution of motor responses.