The Regional EEG Pattern of the Sleep Onset Process in Older Adults.

Maurizio Gorgoni,Michele Ferrara,Luigi De Gennaro,Aurora D’Atri,Serena Scarpelli,Ludovica Annarumma,Valentina Alfonsi

doi:10.3390/brainsci11101261

Abstract

Healthy aging is characterized by macrostructural sleep changes and alterations of regional electroencephalographic (EEG) sleep features. However, the spatiotemporal EEG pattern of the wake-sleep transition has never been described in the elderly. The present study aimed to assess the topographical and temporal features of the EEG during the sleep onset (SO) in a group of 36 older participants (59–81 years). The topography of the 1 Hz bins’ EEG power and the time course of the EEG frequency bands were assessed. Moreover, we compared the delta activity and delta/beta ratio between the older participants and a group of young adults. The results point to several peculiarities in the elderly: (a) the generalized post-SO power increase in the slowest frequencies did not include the 7 Hz bin; (b) the alpha power revealed a frequency-specific pattern of post-SO modifications; (c) the sigma activity exhibited only a slight post-SO increase, and its highest bins showed a frontotemporal power decrease. Older adults showed a generalized reduction of delta power and delta/beta ratio in both pre- and post-SO intervals compared to young adults. From a clinical standpoint, the regional EEG activity may represent a target for brain stimulation techniques to reduce SO latency and sleep fragmentation.

Highlights

Published: 24 September 2021In the last decades, research has questioned the “classic” view of sleep and wakefulness as discrete and mutually exclusive states, describing the co-existence of regional electrophysiological markers of sleep and wakefulness in different cerebral areas [1,2]
Healthy physiological aging is characterized by relevant modifications of the sleep pattern, mainly characterized by longer sleep onset (SO) latency, decreased sleep duration, greater sleep fragmentation and time spent awake after the beginning of sleep, and reduced slow wave sleep (SWS)
PSG measures are reported in Table 1, describing in older adults a normal night of sleep expressed by substantially similar values compared with our previous studies [19,46,47,48,49]

Summary

Introduction

Research has questioned the “classic” view of sleep and wakefulness as discrete and mutually exclusive states, describing the co-existence of regional electrophysiological markers of sleep and wakefulness in different cerebral areas [1,2]. In this view, sleep should be considered as a locally regulated process [3,4]. The reductions of slow wave (0.5–4.5 Hz) and spindle (12–16 Hz) activity represent the greatest age-related modifications, mainly observable in the frontal region [6,7,8,9,10,11,12,13].

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