Don’t Sleep on It: The Prognostic Value of Electroencephalography (EEG) Spindles in the Critically ill

Sleep Spindles as a Predictor of Cognitive Motor Dissociation and Recovery of Consciousness After Acute Brain Injury Carroll EE, Shen Q, Kansara V, Casson N, Michalak A, Niesvizky-Kogan I, Lim J, Postelnik A, Viereck MJ, Egawa S, Kahan J, Carmona JC, Kruger L, Song YL, Velazquez A, Schevon CA, Connolly ES, Ghoshal S, Agarwal S, Roh D, Park S, Kent P, Claassen J. Nat Med . 2025 May;31(5):1578–1585. doi: 10.1038/s41591-025-03578-x. Epub 2025 Mar 3. PMID: 40033114. Cognitive motor dissociation (CMD) can improve the accuracy to predict recovery of behaviorally unresponsive patients with acute brain injury, but acquisition and analysis of task-based electroencephalography (EEG) are technically challenging. N2 sleep patterns, such as sleep spindles on EEG, have been associated with good outcomes, rely on similar thalamocortical networks as consciousness and could provide less technically challenging complementary outcome predictors. In this prospective observational cohort study of 226 acutely brain injured patients, well-formed sleep spindles (WFSS) were more likely present in those with CMD than in those without CMD, often preceding the detection of CMD. WFSS were associated with a shorter time to recovery of consciousness, and both CMD and WFSS independently predicted recovery of independence, controlling for age, admission neurological status and injury type. WFSS are seen in approximately every third behaviorally unresponsive patient after acute brain injury, frequently precede detection of CMD and are a promising complementary predictor for recovery of consciousness and functional independence.