The Accuracy, Night-to-Night Variability, and Stability of Frontopolar Sleep Electroencephalography Biomarkers

Daniel J. Levendowski, MBA1; Luigi Ferini-Strambi, MD2; Charlene Gamaldo, MD3; Mindy Cetel, MD4; Robert Rosenberg, DO5; Philip R. Westbrook, MD1
1Advanced Brain Monitoring, Carlsbad, California; 2Department of Clinical Neurosciences, San Raffaele Scientific Institute, Sleep Disorders Center, Università Vita-Salute San Raffaele, Milan, Italy; 3Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland; 4Integrative Insomnia and Sleep Health Center, San Diego, California; 5Sleep Disorders Center of Prescott Valley, Prescott Valley, Arizona

Study Objectives

To assess the validity of sleep architecture and sleep continuity biomarkers obtained from a portable, multichannel forehead electroencephalography (EEG) recorder.


Forty-seven subjects simultaneously underwent polysomnography (PSG) while wearing a multichannel frontopolar EEG recording device (Sleep Profiler). The PSG recordings independently staged by 5 registered polysomnographic technologists were compared for agreement with the autoscored sleep EEG before and after expert review. To assess the night-to-night variability and first night bias, 2 nights of self-applied, in-home EEG recordings obtained from a clinical cohort of 63 patients were used (41% with a diagnosis of insomnia/depression, 35% with insomnia/obstructive sleep apnea, and 17.5% with all three). The between-night stability of abnormal sleep biomarkers was determined by comparing each night’s data to normative reference values.


The mean overall interscorer agreements between the 5 technologists were 75.9%, and the mean kappa score was 0.70. After visual review, the mean kappa score between the autostaging and five raters was 0.67, and staging agreed with a majority of scorers in at least 80% of the epochs for all stages except stage N1. Sleep spindles, autonomic activation, and stage N3 exhibited the least between-night variability (P < .0001) and strongest between-night stability. Antihypertensive medications were found to have a significant effect on sleep quality biomarkers (P < .02).


A strong agreement was observed between the automated sleep staging and human-scored PSG. One night’s recording appeared sufficient to characterize abnormal slow wave sleep, sleep spindle activity, and heart rate variability in patients, but a 2-night average improved the assessment of all other sleep biomarkers.


Two commentaries on this article appear in this issue on pages 771 and 773.


Levendowski DJ, Ferini-Strambi L, Gamaldo C, Cetel M, Rosenberg R, Westbrook PR. The accuracy, night-to-night variability, and stability of frontopolar sleep electroencephalography biomarkers. J Clin Sleep Med. 2017;13(6):791–803.

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