Idiopathic Hypersomnia Severity Scale to better quantify symptoms severity and their consequences in idiopathic hypersomnia.

Abstract

STUDY OBJECTIVES:

To assess the responsiveness of the Idiopathic Hypersomnia Severity Scale (IHSS) to medications and estimate the minimum clinically important difference, to report clinically relevant score ranges, and to confirm its psychometric properties and whether items need to be weighted in drug-free and treated patients with idiopathic hypersomnia (IH).

METHODS:

Two-hundred twenty-six (166 drug-free and 60 treated) patients with IH (cross-sectional sample) completed the 14-item IHSS to quantify the severity of the 3 major IH symptoms (excessive daytime sleepiness, prolonged nighttime sleep, and sleep inertia) and consequences; 77 untreated patients were evaluated again after treatment (longitudinal sample). Patients filled in the Epworth Sleepiness Scale, Beck Depression Inventory II, and European Quality of Life questionnaires.

RESULTS:

The IHSS confirmed adequate psychometric properties with a factor analysis indicating a 3-component solution. IHSS total score was lower in treated than untreated patients, with a mean difference of 4-5 points in the cross-sectional and longitudinal samples. Distribution-based methods were used to estimate that 4 points represented the minimum clinically important difference. Four severity levels were defined with between-group differences related to treatment. The probability of having severe sleepiness, depressive symptoms, and low quality of life increased with the severity level. Our results showed that IHSS item-weighting was not necessary.

CONCLUSIONS:

The IHSS is a valid and reliable tool to quantify IH symptoms, with 4 severity score levels of clinical importance. The IHSS has adequate psychometric properties and can detect symptom changes after treatment. These findings should stimulate its use in clinical settings and in research studies.

CITATION:

Rassu AL, Evangelista E, Barateau L, et al. Idiopathic Hypersomnia Severity Scale to better quantify symptoms severity and their consequences in idiopathic hypersomnia. J Clin Sleep Med. 2022;18(2):617-629.

• Authors: Anna Laura Rassu, Elisa Evangelista, Lucie Barateau, Sofiene Chenini, Régis Lopez, Isabelle Jaussent, Yves Dauvilliers
• Journal: Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine (J Clin Sleep Med) Vol. 18 Issue 2 Pg. 617-629 (Feb 01 2022) ISSN: 1550-9397 [Electronic] United States
• PMID: 34596041 (Publication Type: Journal Article)
• Copyright: © 2022 American Academy of Sleep Medicine.

Topics

• Cross-Sectional Studies
• Disorders of Excessive Somnolence (diagnosis)
• Humans
• Idiopathic Hypersomnia (diagnosis)
• Narcolepsy (diagnosis)
• Quality of Life