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Sleep misestimation among older adults suffering from insomnia with short and normal objective sleep duration and the effects of Cognitive Behaviour Therapy.

STUDY OBJECTIVES
Compare the degree of sleep misestimation in older adults with insomnia presenting with objectively short relative to normal sleep duration, and investigate the differential therapeutic response on sleep misestimation between the proposed sleep duration phenotypes to Cognitive Behaviour Therapy for insomnia (CBTi).


METHOD
Ninety-one adults (male=43, mean age=63.34, SD=6.41) with sleep maintenance insomnia were classified as short sleepers (SS;<6hrs total sleep time [TST]) or normal sleepers (NS;≥6hrs TST) based on one night of home-based polysomnography. Participants were randomly allocated to CBTi (N=30 SS, N=33 NS) or to a wait-list control condition (N=9 SS, N=19 NS). Sleep misestimation was calculated as the difference scores of subjective (sleep diary reported) and objective (derived from actigraphy) sleep onset latency (SOL), wake after sleep onset (WASO), and TST at pre and post-treatment, and 3-month follow-up.


RESULTS
Prior to treatment, perception of SOL, WASO, and TST did not differ between patients with objectively short sleep duration relative to those with objectively normal sleep duration. Patients' perception of WASO, and TST, improved immediately following treatment and at 3-month follow-up relative to the waitlist group. These improvements did not differ significantly between those with short or normal objective sleep duration prior to treatment.


CONCLUSIONS
The degree of sleep misestimation is similar for older adults suffering from chronic insomnia with short or normal objective sleep duration. Irrespective of objective sleep duration prior to treatment, CBTi produces significant improvements in sleep perception.