Comparison of actigraphy and polysomnography to assess effects of zolpidem in a clinical research unit

ObjectiveThis study sought to compare devices that use actigraphy for measuring sleep endpoints in the clinical research unit (CRU) and home environment. The abilities of polysomnography (PSG) and actigraphy monitors to detect drug effects in a CRU were also investigated.MethodsEleven healthy subjects were recruited and monitored with PSG for four consecutive nights in a CRU after receiving no treatment (night 1, N1), and then placebo or 5 mg day−1 or 10 mg day−1 zolpidem in a randomised, cross-over design. Subjects wore two devices that use actigraphy (a Respironics® Actiwatch® on the wrist and a BodyMedia® Sensewear® Armband on the upper-arm) on the non-dominant arm for five nights at home and four nights in the CRU during PSG.ResultsWake after sleep onset (WASO) and total sleep time (TST) measured by PSG and estimates of WASO by the Actiwatch decreased significantly with 5 mg but not 10 mg of zolpidem versus placebo. Direct activity (counts/min) with the Actiwatch decreased in response to zolpidem (both 5 and 10 mg day−1) versus placebo. Armband recordings of direct activity were similar to the Actiwatch but not significantly different versus placebo. Both actigraphy device estimates of TST were approximately 1 h longer in CRU versus home. Agreement between actigraphy estimates of TST and WASO and PSG values of TST and WASO were closer during nights with zolpidem treatment.ConclusionsPSG can detect the effects of zolpidem on sleep in a CRU setting. Actigraphy can provide useful assessment of sleep, but direct activity endpoints may be more effective than estimates of TST and WASO.