0526 Objective Total Sleep Duration Do Not Predicting the Effectiveness of Cognitive-Behavioral Therapy for Insomnia (CBT-I)

Abstract Introduction Several studies investigated the role of objective sleep markers, in particular of Total Sleep Time (TST) in identifying different subtypes of Insomnia Disorder (ID) and in evaluating the efficacy of treatments. Based on objective TST two phenotypes of ID are usually distinguished in the literature: normal sleepers (objective sleep duration ≥ 6 hours) and short sleepers (objective sleep duration < 6 hours). Aim of our study was to evaluate in normal and short sleepers (objective sleep duration was assessed by both Polysomnography and Actigraphy) possible different response to Cognitive-Behavioral Therapy for Insomnia (CBT-I). Methods 53 ID patients (females = 50.9%; mean age = 56.53±11.43) were divided into “Short Sleep duration” and “Normal Sleep duration” groups. All patients underwent 7-sessions group CBT-I. Main clinical outcome was Insomnia Severity Index questionnaire (ISI); secondary outcomes were Sleep Efficacy (SE), Sleep Latency (SL), Wake After Sleep Onset (WASO), Number of Awakenings (N°awk) according to sleep diaries. Results All ID patients showed significant improvements after treatment for all clinical outcomes. Non-significant effects of CBT-I between “Short Sleep duration” and “Normal Sleep duration” measured by patients were found in terms of ISI, SE, SL, WASO and N°awk, neither using Polysomnography nor Actigraphy. Furthermore, no accordance between these two objective measurements was found for the identification of the two subgroups. Conclusion Our findings suggest that the use of objective TST (both by Actigraphy and Polysomnography) is not a consistent predictor for CBT-I effectiveness. Moreover, only a small percentage of patients were classified as short or normal sleepers according both to Polysomnography and Actigraphy. These findings underline the instability and poor reliability of using objective TST in subtyping insomniacs. Support No