Psychomotor performance tests using a microcomputer: evaluation of effects of caffeine and chlorpheniramine in healthy human subjects.

We have developed two kinds of microcomputer programs for evaluation of psychomotor function in man. In one (simple test), two single-digit random numbers are displayed, and the subject inputs the last figure of their sum from the keyboard. The performance during two sequential trial periods of 5 min with a rest interval of 1 min is evaluated. In the other (complicated test), four single-digit random numbers are displayed and the test is performed in the same manner. With the latter we intended to decrease the efficacy of performance by about 50% as compared with the former. A validation study of these programs was conducted in 20 healthy volunteers (14 males and 6 females) with caffeine as a central nervous stimulant. The study was a double-blind, placebo controlled and cross-over one. The subjects performed both of the above tests prior to and 1 h after an oral administration of a capsule containing either placebo or caffeine (230 mg) at an interval of 24 h. The numbers of correct answers during 10 min of trial were used for the evaluation of performance. The relationship between the performance of the simple test and that of the complicated test was linear and, as expected, the efficacy of the latter was about a half (48%) of the former in the total 40 performances of control. The concentration of caffeine in plasma was measured with and HPLC technique to be 4.4 +/- 1.7 micrograms/ml (mean +/- SD) 40 min after administration. Caffeine significantly (P less than 0.05) increased the performances of both tests 1 h after the administration.(ABSTRACT TRUNCATED AT 250 WORDS)