Cognitive deficits in insomnia patients.

This study investigates performance in insomnia patients, comparing it with performance in normals matched not only on age and sex but also on education and occupation. There were 26 pairs of insomniacs and normals; and the computer-driven performance battery, lasting about one hour, was administered three times over the course of a day. In addition, an auditory vigilance test was also administered twice. Insomniacs performed worse than normals on reaction time (they were both slower and more variable), they swayed more on the balance test, and they forgot more numbers on the Digit Span Test. There were no significant differences in Digit Symbol Substitution, Divided Attention, and Auditory Verbal Learning Tests, suggesting that the pattern of deficiencies in insomnia is different than that in sleep-deprived subjects. When insomniacs were administered the performance batteries after spontaneously occurring good or poor nights, little differences in performance were observed.