{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,15]],"date-time":"2025-11-15T17:07:11Z","timestamp":1763226431640,"version":"build-2065373602"},"reference-count":65,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2017,3,25]],"date-time":"2017-03-25T00:00:00Z","timestamp":1490400000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>The characterisation of healthy ageing of the brain could help create a fingerprint of normal ageing that might assist in the early diagnosis of neurodegenerative conditions. This study examined changes in resting state magnetoencephalogram (MEG) permutation entropy due to age and gender in a sample of 220 healthy participants (98 males and 122 females, ages ranging between 7 and 84). Entropy was quantified using normalised permutation entropy and modified permutation entropy, with an embedding dimension of 5 and a lag of 1 as the input parameters for both algorithms. Effects of age were observed over the five regions of the brain, i.e., anterior, central, posterior, and left and right lateral, with the anterior and central regions containing the highest permutation entropy. Statistically significant differences due to age were observed in the different brain regions for both genders, with the evolutions described using the fitting of polynomial regressions. Nevertheless, no significant differences between the genders were observed across all ages. These results suggest that the evolution of entropy in the background brain activity, quantified with permutation entropy algorithms, might be considered an alternative illustration of a \u2018nominal\u2019 physiological rhythm.<\/jats:p>","DOI":"10.3390\/e19040141","type":"journal-article","created":{"date-parts":[[2017,3,27]],"date-time":"2017-03-27T10:49:10Z","timestamp":1490611750000},"page":"141","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Permutation Entropy for the Characterisation of Brain Activity Recorded with Magnetoencephalograms in Healthy Ageing"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0351-2063","authenticated-orcid":false,"given":"Elizabeth","family":"Shumbayawonda","sequence":"first","affiliation":[{"name":"Centre for Biomedical Engineering, Department of Mechanical Engineering Sciences, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alberto","family":"Fern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Laboratorio Universidad Polit\u00e9cnica de Madrid-Universidad Complutense de Madrid (UPM-UCM) de Neurociencia Cognitiva y Computacional, Departamento de Psiquiatr\u00eda y Psicolog\u00eda M\u00e9dica, Universidad Complutense de Madrid, Madrid 28040, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael","family":"Hughes","sequence":"additional","affiliation":[{"name":"Centre for Biomedical Engineering, Department of Mechanical Engineering Sciences, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4268-2885","authenticated-orcid":false,"given":"Daniel","family":"Ab\u00e1solo","sequence":"additional","affiliation":[{"name":"Centre for Biomedical Engineering, Department of Mechanical Engineering Sciences, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,3,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/0921-884X(96)95573-3","article-title":"Age increases brain complexity","volume":"99","author":"Anokhin","year":"1996","journal-title":"Electroencephalogr. 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