1 SLEEPJ, 2022, 1–15 https://doi.org/10.1093/sleep/zsac017 Advance Access Publication Date: 17 January 2022 Original Article Submitted: 7 July, 2021; Revised: 17 December, 2021 © The Author(s) 2022. Published by Oxford University Press on behalf of Sleep Research Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com Original Article The diagnostic value of sleep and vigilance tests in central disorders of hypersomnolence Johannes Mathis 1,2, * ,†, , Daniel Andres 1,†, , Wolfgang J. Schmitt 3, , Claudio L. Bassetti 1, , Christian W. Hess 1 and David R. Schreier 1 1 Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland, 2 Sleep Medicine, Neurozentrum Bern, Bern, Switzerland and 3 University Hospital of Psychiatry, University of Bern, Bern, Switzerland *Corresponding author: Johannes Mathis, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland. Email: johannes.mathis@belponline.ch. † These authors contributed equally to this work. Abstract Study Objectives: This retrospective cross-sectional observational study explored the diagnostic value of selected sleep and vigilance tests (SVT) beyond the multiple sleep latency test to differentiate between various central disorders of hypersomnolence (CDH) and fatigue syndromes. Methods: Data from patients who underwent the multiple sleep latency test and at least one additional SVT were extracted from the Bern sleep database (1997–2018). One thousand three hundred ffty-two patients with a CDH (106 narcolepsy type 1, 90 narcolepsy type 2, 119 idiopathic hypersomnia, 192 nonorganic hypersomnia, 205 insuffcient sleep syndrome), fatigue syndromes (n = 183), and a subgroup of patients with sleep apnea (n = 457) were analyzed. Classifcation based on SVT parameters was compared with the fnal clinical diagnosis serving as a reference. Results: An overall model predicted the fnal diagnosis in 49.5% of patients. However, for the pairwise differentiation of two clinically suspected diagnoses, many SVT parameters showed a sensitivity and specifcity above 70%. While the overall discrimination power of the multiple sleep latency test was slightly better than the one of the maintenance of wakefulness test, the latter differentiated best between narcolepsy and idiopathic hypersomnia with prolonged sleep need. Disproportionally poor results in reaction tests (e.g. steer clear test), despite comparable or lower sleepiness levels (SLAT, WLAT), were valuable for differentiating nonorganic hypersomnia from idiopathic hypersomnia/sleep insuffciency syndrome. Conclusion: This study demonstrates how the combination of a careful clinical assessment and a selection of SVTs can improve the differentiation of CDH, whereas it was not possible to establish an overall prediction model based on SVTs alone. Key words: narcolepsy; idiopathic hypersomnia; nonorganic hypersomnia; maintenance of wakefulness test; multiple sleep latency test; vigilance tests; hypersomnolence Statement of signifcance The differential diagnosis of central disorders of hypersomnolence is challenging but of great importance for patient care. Unlike the multiple sleep latency test, vigilance tests have not been routinely applied so far for diagnostic purposes. This is the frst large-scale retrospective cross-sectional observational study analyzing the diagnostic value of many different sleep and vigilance tests. The results suggest that selected vigilance tests can improve the identifcation of the fnal diagnosis out of the clinically determined suspected diag- noses. Particularly for the diffcult differentiation of narcolepsy without cataplexy and idiopathic hypersomnia with prolonged sleep need, the maintenance of wakefulness test seems to be of great additive value. Furthermore, performance tests help to separate nonorganic hypersomnia from organic disorders of hypersomnolence. Downloaded from https://academic.oup.com/sleep/article/45/3/zsac017/6509928 by guest on 30 May 2023