Evaluation of sleep using ambulatory skin potential recording: differences between morning and evening type.

In order to validate the evaluation of sleep using cassette type ambulatory skin potential measurement system (C-SPA), sleep duration variables extracted from 24 h recordings were compared between two groups (16 of the intermediate type and 16 of the evening type) with different sleep-wake habits rated by Morningness and Eveningness Questionnaires (MEQ). Compared with the intermediate type, the evening type subjects go to bed and get up later, have difficulty in falling asleep and more frequently awaken during sleep. Thus, the sleep variables by C-SPA provide valuable information about duration of sleep and differentiate the sleep-wake habits.