Effects of sleep loss on waking actigraphy

STUDY OBJECTIVES: To assess the effect of sleep loss and the effect of a sedating drug on waking actigraphy DESIGN: N/A SETTING: N/A PARTICIPANTS: Seventeen healthy volunteers, aged 19-35 yrs Interventions: Four night-day treatments presented in a Latin Square Design: placebo-8 hr time-in-bed (TIB), placebo-4 hr TIB, placebo-0 hr TIB, and diphenhydramine 50 mg-8 hr TIB. MEASUREMENTS AND RESULTS: After the appropriate TIB, medication was administered at 09:00 hr, the Multiple Sleep Latency Test at 09:30, 11:30, 13:30, 15:30, and 17:30 hr, and a 45 min performance battery at 10:30, 14:30, and 16:30 hr. Each day the volunteers wore actigraphs from 0700-1800 hrs. Decreasing TIB was associated with decreased daily mean sleep latency on the MSLT with 4 and 0 hrs differing from 8 hrs and each other. Daytime activity also was reduced by the reduced prior TIB. Increased inactivity relative to the 8 hr TIB developed between the 4 hr and 0 hr TIBs, with 4 hrs differing from 0 hrs, but not 8 hrs. Diphenhydramine 50 mg reduced mean daily sleep latency and increased percent inactive time relative to placebo. On the MSLT diphenhydramine was intermediate to 4 hr and 0 hr TIB and on actigraphy it was similar to 0 hr TIB. CONCLUSIONS: The difference in the effect of diphenhydramine on these actigraphy and MSLT may reflect the different sensitivities of the measures.