O050 Associations between sleep-wake state discrepancy and clinical characteristics in older adults with chronic insomnia before and after Cognitive Behaviour Therapy (CBTi)

INTRODUCTION: Individuals with chronic insomnia often self-report more wakefulness and less sleep than is derived from objective measures, which is called sleep-wake state discrepancy (SWSD). This study investigated associations between SWSD and clinical characteristics in older adults with sleep maintenance insomnia before and after Cognitive Behaviour Therapy (CBTi). METHOD: Seventy-three adults (female=53%, mean age=63.2, SD=6.3) were recruited. Participants completed sleep diaries and wore actigraphy for one week, as well as questionnaires related to sleep quality and daytime functioning immediately before and after CBTi. SWSD was calculated as the difference between subjective (sleep diary reported) and objective (actigraphy derived) total sleep time (TST) at pre- and post-treatment. RESULTS: Before treatment, SWSD was not associated with age or any clinical variables, ps > .05. Following treatment, SWSD significantly reduced (p<.001), despite no improvement in objective TST, and was significantly associated with improvements in insomnia severity (r=-.57), fatigue (r=-.26), sleep self-efficacy (r=.33), and beliefs about sleep (r=-.38), ps < .05. DISCUSSION: These findings suggest SWSD does not correlate with any other routinely-measured clinical characteristic prior to treatment. Given the associations with treatment outcomes, the need to incorporate objective measures, in conjunction with sleep diary assessments, to determine the degree of discrepancy and therapeutically address using CBTi is warranted. Following treatment, the reduction in discrepancy was driven by sleep diary reported TST that more closely matched objective TST, which remained relatively unchanged from pre-treatment. This has important implications for CBTi and suggests improvements in the accuracy of perceived sleep is a major therapeutic mechanism.