{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T18:40:52Z","timestamp":1792435252948,"version":"4.5.0"},"reference-count":42,"publisher":"Oxford University Press (OUP)","license":[{"start":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T00:00:00Z","timestamp":1789776000000},"content-version":"am","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Study Objectives<\/jats:title>\n                    <jats:p>Conventional electroencephalographic (EEG) slowing in isolated REM sleep behavior disorder (iRBD) may be confounded by disease-related shifts in the aperiodic background. We separated periodic and aperiodic EEG components to clarify oscillatory slowing and examine associations with phenoconversion and clinical measures.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and Methods<\/jats:title>\n                    <jats:p>Resting-state EEG was recorded from 134 patients with iRBD and 51 healthy controls (HCs). During follow-up, 26 converted to Parkinson\u2019s disease or dementia with Lewy bodies. Power spectra (2\u201350\u00a0Hz) were parameterized using fitting oscillations and one-over-f to extract aperiodic offset, low-frequency slope (2\u201330\u00a0Hz), and high-frequency slope (30\u201350\u00a0Hz), and to derive the periodic spectrum after aperiodic removal. Group differences, spatial distributions, survival associations, and clinical correlations were analyzed.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>After removing the aperiodic component, iRBD showed higher band-averaged periodic 4\u20138\u00a0Hz power than HC (p\u2009=\u2009.042), consistent with slowing of the dominant alpha rhythm. In aperiodic analyses, iRBD exhibited higher offset than HC (p\u2009&amp;lt;\u2009.001). Converters (CVs) showed more pronounced oscillatory slowing (p\u2009=\u2009.008). Topographically, CVs showed higher offset in the occipital region. Survival analyses showed that higher posterior periodic 4\u20138\u00a0Hz power (hazard ratio\u2009=\u20091.342, 95% confidence interval\u2009=\u20091.1\u20131.6) and offset (hazard ratio\u2009=\u20097.457, 95% confidence interval\u2009=\u20092.6\u201321.3) were associated with phenoconversion risk. Among CVs, MoCA-K correlated with low-frequency slope (r\u2009=\u2009\u22120.613), whereas MDS-UPDRS-III correlated with offset (r\u2009=\u20090.605).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Separating periodic from aperiodic EEG activity revealed distinct RBD- and phenoconversion-related oscillatory slowing and aperiodic alterations. These findings suggest that aperiodic components may provide additional prognostic and clinical information beyond conventional band power.<\/jats:p>\n                    <jats:p>Statement of Significance Predicting phenoconversion in isolated REM sleep behavior disorder remains a major challenge in prodromal \u03b1-synucleinopathies. Conventional EEG analyses based on band power may obscure disease-related alterations in the aperiodic background. By separating periodic oscillations from aperiodic components, we demonstrate more distinct EEG oscillatory slowing and identify aperiodic features associated with phenoconversion risk and clinical measures. These findings suggest that aperiodic components may provide prognostic and clinical information beyond conventional band power.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/sleep\/zsag248","type":"journal-article","created":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T14:36:45Z","timestamp":1789569405000},"source":"Crossref","is-referenced-by-count":0,"title":["Periodic oscillatory slowing and aperiodic broadband shifts in isolated REM sleep behavior disorder are associated with phenoconversion"],"prefix":"10.1093","author":[{"given":"Eung-Gyu","family":"Lee","sequence":"first","affiliation":[{"name":"Department of Translational Medicine, Seoul National University College of Medicine , Seoul ,","place":["Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tae-Gon","family":"Noh","sequence":"additional","affiliation":[{"name":"Interdisciplinary Program in Neuroscience, College of Natural Sciences, Seoul National University , Seoul 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