Comparison of the cognitive effects of premedication with hyoscine and atropine.

An investigation was carried out comparing the nature and duration of the cognitive effects of atropine and hyoscine. Thirty patients undergoing a minor gynaecological operation were randomly assigned to one of three groups to receive hyoscine, atropine or placebo as premedication. A battery of psychological tests was administered before premedication, 30 min after premedication, and 1 and 3 h following operation. The tests included orientation questions, simple tasks such as reciting the alphabet, memory tests, a reaction-time test and two tests of visuo-motor co-ordination. The results showed that hyoscine had detrimental effects on memory and on motor tasks compared with placebo, while atropine did not. In addition, the effects on motor performance had not disappeared 3 h after operation.