{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T05:03:31Z","timestamp":1777352611924,"version":"3.51.4"},"reference-count":62,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2021,7,30]],"date-time":"2021-07-30T00:00:00Z","timestamp":1627603200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003243","name":"Ministerstvo Zdravotnictv\u00ed Cesk\u00e9 Republiky","doi-asserted-by":"publisher","award":["NV18-07-00272"],"award-info":[{"award-number":["NV18-07-00272"]}],"id":[{"id":"10.13039\/501100003243","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100007655","name":"\u010cesk\u00e9 Vysok\u00e9 U\u010den\u00ed Technick\u00e9 v Praze","doi-asserted-by":"publisher","award":["SGS21\/140\/OHK4\/2T\/17"],"award-info":[{"award-number":["SGS21\/140\/OHK4\/2T\/17"]}],"id":[{"id":"10.13039\/100007655","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000025","name":"National Institute of Mental Health","doi-asserted-by":"publisher","award":["LO1611"],"award-info":[{"award-number":["LO1611"]}],"id":[{"id":"10.13039\/100000025","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Slow-wave synchronous acoustic stimulation is a promising research and therapeutic tool. It is essential to clearly understand the principles of the synchronization methods, to know their performances and limitations, and, most importantly, to have a clear picture of the effect of stimulation on slow-wave activity (SWA). This paper covers the mentioned and currently missing parts of knowledge that are essential for the appropriate development of the method itself and future applications. Artificially streamed real sleep EEG data were used to quantitatively compare the two currently used real-time methods: the phase-locking loop (PLL) and the fixed-step stimulus in our own implementation. The fixed-step stimulation method was concluded to be more reliable and practically applicable compared to the PLL method. The sleep experiment with chronic insomnia patients in our sleep laboratory was analyzed in order to precisely characterize the effect of sound stimulation during deep sleep. We found that there is a significant phase synchronization of delta waves, which were shown to be the most sensitive metric of the effect of acoustic stimulation compared to commonly used averaged signal and power analyses. This finding may change the understanding of the effect and function of the SWA stimulation described in the literature.<\/jats:p>","DOI":"10.3390\/s21155169","type":"journal-article","created":{"date-parts":[[2021,8,1]],"date-time":"2021-08-01T21:44:32Z","timestamp":1627854272000},"page":"5169","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Real-Time Excitation of Slow Oscillations during Deep Sleep Using Acoustic Stimulation"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8157-6447","authenticated-orcid":false,"given":"Marek","family":"Piorecky","sequence":"first","affiliation":[{"name":"National Institute of Mental Health, 250 67 Klecany, Czech Republic"},{"name":"Faculty of Biomedical Engineering, Czech Technical University in Prague, 272 01 Kladno, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7553-7529","authenticated-orcid":false,"given":"Vlastimil","family":"Koudelka","sequence":"additional","affiliation":[{"name":"National Institute of Mental Health, 250 67 Klecany, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7661-0660","authenticated-orcid":false,"given":"Vaclava","family":"Piorecka","sequence":"additional","affiliation":[{"name":"National Institute of Mental Health, 250 67 Klecany, Czech Republic"},{"name":"Faculty of Biomedical Engineering, Czech Technical University in Prague, 272 01 Kladno, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2835-4391","authenticated-orcid":false,"given":"Jan","family":"Strobl","sequence":"additional","affiliation":[{"name":"National Institute of Mental Health, 250 67 Klecany, Czech Republic"},{"name":"Faculty of Biomedical Engineering, Czech Technical University in Prague, 272 01 Kladno, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6500-7578","authenticated-orcid":false,"given":"Daniela","family":"Dudysova","sequence":"additional","affiliation":[{"name":"National Institute of Mental Health, 250 67 Klecany, Czech Republic"},{"name":"Third Faculty of Medicine, Charles University, Rusk\u00e1 87, 100 00 Prague, Czech Republic"}]},{"given":"Jana","family":"Koprivova","sequence":"additional","affiliation":[{"name":"National Institute of Mental Health, 250 67 Klecany, Czech Republic"},{"name":"Third Faculty of Medicine, Charles University, Rusk\u00e1 87, 100 00 Prague, Czech Republic"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"105116","DOI":"10.1016\/j.cmpb.2019.105116","article-title":"EEG sleep stages identification based on weighted undirected complex networks","volume":"184","author":"Diykh","year":"2020","journal-title":"Comput. 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