The interaction of age, performance and hypnotics in the sleep of insomniacs.

Scant attention has been paid to the objective evaluation of insomnia as a function of age, particularly with reference to increased drug sensitivity and resulting loss in balance performance. Therefore, the electroencephalographic sleep and the balance-board performance of 10 young and 12 geriatric insomniacs were studied under baseline and hypnotic drug (ketazolam) conditions. In terms of objectively measured sleep, the geriatric insomniacs had worse sleep on every dimension except sleep latency and percentage of stage-2 sleep. These differences between aged and young insomniacs, however, were no greater than might be expected as a function of normal aging. Drug-age interactions indicated that ketazolam differentially increased sleep efficiency, decreased the percentage of REM sleep, and eliminated any learning improvement on the balance board in geriatric versus young insomniacs. The findings indicate that the geriatric subjects were more sensitive to the hypnotic drug, in that their sleep improved to a greater extent. However, an important loss in balance performance was also observed.