Slow wave activity is linked to memory improvement following Cognitive-Behavioral Therapy for Insomnia in older adults

Study Objectives: 1. To investigate the effect of Cognitive-behavioral therapy for insomnia (CBT-I) on memory performance and slow-wave activity (SWA) in older adults with insomnia disorder. 2. To determine whether changes in SWA are linked to improvements in memory performance. 3. To assess how the individual therapies of CBT-I treatment contribute to these effects. Methods: A secondary analysis was conducted using data from 104 older adults with insomnia disorder enrolled in a clinical trial examining the impact of CBT-I, Behavioral Therapy (BT), and Cognitive Therapy (CT) on insomnia severity. Participants were randomized to six sessions of BT, CT, or CBT-I (combined BT and CT). They underwent polysomnography and RBANS memory testing ––assessing immediate (List Learning and Story Memory) and delayed memory (List Recall, Story Recall, Figure Recall, and List Recognition)–– at baseline and at 6-month follow-up. Linear-mixed effects models examined the impact of treatment on memory and SWA. Regression analyses examined relationships between changes in SWA and memory following the treatment. Results: Improvements were identified in immediate memory (List Learning and Story Memory) and delayed memory (List Recall, Story Recall, and Figure Recall). The analysis did not reveal significant changes in SWA following treatment. However, there was a significant positive association between improvements in List Learning and increases in SWA. There were no differences in outcomes among the treatments. Conclusions: These findings suggest that BT, CT and CBT-I may enhance memory performance in older adults with insomnia disorder, with a potential link between SWA and immediate memory performance.