Neurophysiological Parameters Influencing Sleep-Wake Discrepancy in Insomnia Disorder: A Preliminary Analysis on Alpha Rhythm during Sleep Onset.

Sleep state misperception (SSM) is a common issue in insomnia disorder (ID), causing a discrepancy between objective and subjective sleep/wake time estimation and increased daytime impairments. In this context, the hyperarousal theory assumes that sustained central nervous system activation contributes to the SSM. This study investigates factors influencing SSM during sleep latency (SL) and total sleep time (TST). Objective polysomnographic sleep variables (the alpha density index, latency-to-sleep stages and the first K-complex, and Rapid Eye Movement (REM) arousal density) and subjective sleep indices, taken from sleep diaries, were analyzed in 16 ID patients. Correlation analyses revealed a positive association between the degree of SL misperception (SLm) and the percentage of epochs that contained a visually scored stereotyped alpha rhythm during objective SL. A regression analysis showed that the REM arousal density and alpha density index significantly predicted TST misperception (TSTm). Furthermore, the degree of SLm was associated with an increased probability of transitioning from stage 1 of non-REM sleep to wakefulness during subjective SL. These findings support the role of hyperarousal in SSM and highlight the importance of alpha activity in unravelling the heterogeneous underpinnings of SSM.

Non-pharmacological and melatonin interventions for pediatric sleep initiation and maintenance problems: A systematic review and network meta-analysis.

Sleep initiation and maintenance problems are common in the pediatric population and while behavioral interventions are recommended, their efficacy remains to be evaluated in clinical trials. We conducted a systematic review and network meta-analysis to assess the efficacy of non-pharmacological treatments and melatonin for sleep initiation and maintenance problems in healthy pediatric populations. We included 30 studies in the systematic review and 15 in the meta-analysis. Three network meta-analyses were conducted for sleep onset latency (SOL), wake after sleep onset (WASO), and total sleep time (TST). For SOL variable, the results support greater effectiveness of light therapy and melatonin than evidence-based psychological interventions, whether implemented in combination with light therapy or not. Regarding WASO variable, evidence-based psychological interventions and a combination of those techniques plus light treatment were the most efficacious. Finally, for TST variable, a larger effect was shown for the combined treatment of evidence-based psychological intervention with light therapy in comparison to other interventions. In conclusion, we found a high variability between study protocols likely impacting the results of the meta-analysis. Future randomized control trials studies, stratified by pediatric age classes, are needed in order to provide clear suggestions in clinical settings.

Cognitive Reserve in Isolated Rapid Eye-Movement Sleep Behavior Disorder.

Isolated rapid-eye-movement sleep behaviour disorder (RBD) is considered the prodromal stage of α-synucleinopathies (e.g., Parkinson's disease and dementia with Lewy bodies); however, iRBD patients show a wide variety in the progression timing (5-15 years). The model of cognitive reserve (CR) might contribute to explaining this phenomenon. Our exploratory study aimed to evaluate, for the first time, the impact of CR level on cognitive performance in polysomnography-confirmed iRBD patients. Fifty-five iRBD patients (mean age ± SD: 66.38 ± 7.51; M/F 44/11) underwent clinical and neuropsychological evaluations at the time of diagnosis. The CR Index questionnaire was part of the clinical assessment. We found that iRBD patients with high levels of CR showed: (i) the lowest percentage of mild cognitive impairment (10%), and (ii) the best performance in visuo-constructive and verbal memory functions (i.e., the recall of the Rey-Osterrieth complex figure test). Our results suggest that CR might help iRBD patients better cope with the cognitive decline related to the neurodegenerative process, providing the first preliminary findings supporting CR as a possible protective factor in this condition. This might pave the way for future longitudinal studies to evaluate the role of CR as a modulating factor in the timing of iRBD conversion and cognitive deterioration development.