# Sleep State Misperception in Insomnia: The Role of Sleep Instability and Emotional Dysregulation

## TL;DR

People with insomnia often misjudge their sleep, and this misperception is linked to unstable sleep patterns and trouble regulating emotions.

## Contribution

The study identifies specific PSG features and emotional traits that predict sleep state misperception in insomnia patients.

## Key findings

- Underestimators of sleep time showed higher cortical arousal density and more sleep stage 1 compared to normoestimators.
- Regression analyses identified sleep fragmentation and emotional dysregulation as key predictors of sleep misperception.
- Healthy controls did not reach thresholds for sleep underestimation, highlighting a unique pattern in insomnia patients.

## Abstract

Background/Objectives: Sleep state misperception (SSM) is a common phenomenon in insomnia disorder (ID), characterized by a discrepancy between subjective and objective sleep metrics. Recent studies have revealed microstructural EEG alterations specifically in misperceiving ID patients, yet clinically accessible SSM markers remain limited. This study aimed to characterize SSM within ID by integrating standard polysomnography (PSG) features and cognitive-affective traits, focusing on accessible clinical tools. Methods: Twenty patients with ID and twenty healthy controls (HC) underwent a night of PSG recording and completed both sleep diaries and a comprehensive psychological assessment. SSM was quantified using the Total Sleep Time misperception index (TSTm), analyzed both dimensionally and categorically Results: IDs reported significantly altered sleep parameters compared to HCs, both subjectively and objectively. Within the ID sample, although underestimators and normoestimators had similar objective TST, underestimators showed significantly more cortical arousal density (CAd), a higher percentage of sleep stage 1 and higher non-acceptance of emotions. Notably, none of the HC reached the threshold for being classified as underestimators. Regression analyses identified CAd, latency to sleep stage 3 and to REM, percentage of REM sleep and lack of emotional clarity, as key predictors of TSTm. Conclusions: SSM in insomnia reflects a dimensional vulnerability grounded in subtle sleep fragmentation and emotional dysregulation. Recognizing SSM as a clinically meaningful phenomenon may guide more targeted, emotion-focused, interventions for insomnia.