A novel, wearable, in-ear EEG technology to assess sleep and daytime sleepiness
Source: PubMed Central Open Access, NCBI / U.S. National Library of Medicine
In-ear electroencephalography (EEG) has emerged as a promising alternative to traditional in-laboratory sleep studies, offering greater comfort and practicality. Here we present a novel in-ear EEG system, comparing in-ear recordings against scalp EEG channels acquired concurrently as part of polysomnography (PSG). The study enrolled 16 healthy control participants in a single-visit overnight-plus-daytime design, and 8 participants with central disorders of hypersomnolence (CDH) in a randomized crossover daytime design (medication vs. medication-holiday). For overnight sleep recordings, ear-EEG and scalp EEG sleep staging showed substantial agreement (Cohen’s). For daytime MWT trials, agreement was moderate (Cohen’s), reflecting the predominance of wake epochs in this paradigm. For the primary Maintenance of Wakefulness Test (MWT) endpoint of sleep onset latency (SOL), at the per-subject level ()—averaging across trials as in standard clinical practice—agreement was good (ICC = 0.71,, MAD = 5.1 min). Among the 37 of 126 trials where both devices detected sleep (approximately 30% of trials), agreement was strong (ICC = 0.82, MAD = 1.9 min), with excellent agreement in healthy controls (ICC = 0.95, MAD = 1.2 min). Overall trial-level agreement across all 126 trials was moderate (ICC = 0.55), reflecting 22 discordant trials in which scalp EEG detected sleep but in-ear EEG did not—predominantly brief, subtle N1 transitions, concentrated in a subset of CDH participants. For overnig
Abstract
In-ear electroencephalography (EEG) has emerged as a promising alternative to traditional in-laboratory sleep studies, offering greater comfort and practicality. Here we present a novel in-ear EEG system, comparing in-ear recordings against scalp EEG channels acquired concurrently as part of polysomnography (PSG). The study enrolled 16 healthy control participants in a single-visit overnight-plus-daytime design, and 8 participants with central disorders of hypersomnolence (CDH) in a randomized crossover daytime design (medication vs. medication-holiday). For overnight sleep recordings, ear-EEG and scalp EEG sleep staging showed substantial agreement (Cohen’s). For daytime MWT trials, agreement was moderate (Cohen’s), reflecting the predominance of wake epochs in this paradigm. For the primary Maintenance of Wakefulness Test (MWT) endpoint of sleep onset latency (SOL), at the per-subject level ()—averaging across trials as in standard clinical practice—agreement was good (ICC = 0.71,, MAD = 5.1 min). Among the 37 of 126 trials where both devices detected sleep (approximately 30% of trials), agreement was strong (ICC = 0.82, MAD = 1.9 min), with excellent agreement in healthy controls (ICC = 0.95, MAD = 1.2 min). Overall trial-level agreement across all 126 trials was moderate (ICC = 0.55), reflecting 22 discordant trials in which scalp EEG detected sleep but in-ear EEG did not—predominantly brief, subtle N1 transitions, concentrated in a subset of CDH participants. For overnight sleep architecture (healthy controls), total sleep time (, ICC = 0.85), sleep efficiency (), and wake after sleep onset () showed strong agreement, with small systematic biases consistent with reduced N1 detection sensitivity. These findings support the feasibility of in-ear EEG for sleep staging and daytime sleepiness assessment in laboratory settings, and motivate larger confirmatory studies—including home-based longitudinal monitoring—to establish clinical utility, particularly in populations with altered sleep architecture. Abs1