AUTHOR=Simpson Benjamin K. , Rangwani Rohit , Abbasi Aamir , Chung Jeffrey M. , Reed Chrystal M. , Gulati Tanuj 

TITLE=Disturbed laterality of non-rapid eye movement sleep oscillations in post-stroke human sleep: a pilot study

JOURNAL=Frontiers in Neurology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1243575

DOI=10.3389/fneur.2023.1243575

ISSN=1664-2295

ABSTRACT=<p>Sleep is known to promote recovery post-stroke. However, there is a paucity of data profiling sleep oscillations in the post-stroke human brain. Recent rodent work showed that resurgence of physiologic spindles coupled to sleep slow oscillations (SOs) and concomitant decrease in pathological delta (<italic>δ</italic>) waves is associated with sustained motor performance gains during stroke recovery. The goal of this study was to evaluate bilaterality of non-rapid eye movement (NREM) sleep-oscillations (namely SOs, <italic>δ</italic>-waves, spindles, and their nesting) in post-stroke patients vs. healthy control subjects. We analyzed NREM-marked electroencephalography (EEG) data in hospitalized stroke-patients (<italic>n</italic> = 5) and healthy subjects (<italic>n</italic> = 3). We used a laterality index to evaluate symmetry of NREM oscillations across hemispheres. We found that stroke subjects had pronounced asymmetry in the oscillations, with a predominance of SOs, <italic>δ</italic>-waves, spindles, and nested spindles in affected hemisphere, when compared to the healthy subjects. Recent preclinical work classified SO-nested spindles as restorative post-stroke and <italic>δ</italic>-wave-nested spindles as pathological. We found that the ratio of SO-nested spindles laterality index to <italic>δ</italic>-wave-nested spindles laterality index was lower in stroke subjects. Using linear mixed models (which included random effects of concurrent pharmacologic drugs), we found large and medium effect size for <italic>δ</italic>-wave nested spindle and SO-nested spindle, respectively. Our results in this pilot study indicate that considering laterality index of NREM oscillations might be a useful metric for assessing recovery post-stroke and that factoring in pharmacologic drugs may be important when targeting sleep modulation for neurorehabilitation post-stroke.</p>