Inactograms and objective sleep measures as means to capture subjective sleep problems in patients with a bipolar disorder.

BACKGROUND: Sleep problems are common in bipolar disorders (BDs). To objectively characterize these problems in BDs, further methodological development is needed to capture subjective insomnia. AIM: To test psychometric properties of the Athens Insomnia Scale (AIS), and associations with actigraphy-derived measures, applying modifications in actigraphy data processing to capture features of perturbed sleep in patients with a BD. METHODS: Seventy-four patients completed the AIS and the Quick Inventory of Depressive Symptomatology, self-report (QIDS-SR-16). Locomotor activity was continuously recorded by wrist-actigraphy for >/=10 consecutive days. We computed the sleep onset/offset, the center of daily inactivity (CenDI), as a proxy for chronotype, and the degree of consolidation of daily inactivity (ConDI), as a proxy for sleep-wake rhythm strength. RESULTS: AIS showed good psychometric properties (Cronbach's alpha=0.84; test-retest correlation=0.84, p<.001). Subjective sleep problems correlated moderately with a later sleep phase (CenDI with AIS rho=0.34, p=.003), lower consolidation (ConDI with AIS rho=-0.22, p=.05; with QIDS-SR-16 rho=-0.27, p=.019), later timing of sleep offset (with AIS rho=0.49, p=