A New Computerized Test Battery to Evaluate Drug Effects on Psychomotor Performance. Lorazepam-induced Impaired Performance in Healthy Volunteers.

Abstract

Objective: This study was performed to evaluate the sensitivity of a new computerized test battery which we developed for the detection of drug-induced impaired psychomotor performance.Methods: Twelve healthy male volunteers participated in this study. Lorazepam (0.5 or 1.0 mg oral), an antianxiety drug, or placebo was administered in a double-blind fashion with a Latin square design, with an interval of more than one week. The psychomotor performance tests were done before, and at 1 and 3 hours after drug administration. The test battery consisted of four different tasks ; a simple number copying test (SNCT), a continuous number addition test (CNAT), a number comparison test (NCT) and two types of reaction time tests (RTT). In SNCT, CNAT and NCT, percent changes in the number of keyed-in figures and the number of correctly keyed-in figures were automatically measured, and in RTT, the latency to respond was automatically recorded. To measurelorazepam-induced subjective sedative actions, visual analogue scales (VAS) were used.Results: The performance was impaired in SNCT and CNAT 1 hour after administration of 1.0 mg lorazepam, and in NCT 1 hour after administration of 0.5 and 1.0 mg lorazepam. There was no significant difference between lorazepam and placebo in RTT. The impaired psychomotor performance was observed irrespective of the absence of lorazepam-induced subjective sedative effects.Conclusion: The lorazepam-induced impaired psychomotor performance was objectively and sensitively detected in healthy volunteers by a new computerized test battery which we developed. This new objective method can be applied to sensitively detect minimal sedative effects of drugs in a situation similar to daily life.