Sleep spindle density in narcolepsy

TY - JOUR

T1 - Sleep spindle density in narcolepsy

AU - Christensen, Julie Anja Engelhard

AU - Nikolic, Miki

AU - Hvidtfelt, Mathias

AU - Kornum, Birgitte Rahbek

AU - Jennum, Poul

N1 - Copyright © 2017 Elsevier B.V. All rights reserved.

PY - 2017/6/1

Y1 - 2017/6/1

N2 - BACKGROUND: Patients with narcolepsy type 1 (NT1) show alterations in sleep stage transitions, rapid-eye-movement (REM) and non-REM sleep due to the loss of hypocretinergic signaling. However, the sleep microstructure has not yet been evaluated in these patients. We aimed to evaluate whether the sleep spindle (SS) density is altered in patients with NT1 compared to controls and patients with narcolepsy type 2 (NT2).METHODS: All-night polysomnographic recordings from 28 NT1 patients, 19 NT2 patients, 20 controls (C) with narcolepsy-like symptoms, but with normal cerebrospinal fluid hypocretin levels and multiple sleep latency tests, and 18 healthy controls (HC) were included. Unspecified, slow, and fast SS were automatically detected, and SS densities were defined as number per minute and were computed across sleep stages and sleep cycles. The between-cycle trends of SS densities in N2 and NREM sleep were evaluated within and between groups.RESULTS: Between-group comparisons in sleep stages revealed no significant differences in any type of SS. Within-group analyses of the SS trends revealed significant decreasing trends for NT1, HC, and C between first and last sleep cycle. Between-group analyses of SS trends between first and last sleep cycle revealed that NT2 differ from NT1 patients in the unspecified SS density in NREM sleep, and from HC in the slow SS density in N2 sleep.CONCLUSIONS: SS activity is preserved in NT1, suggesting that the ascending neurons to thalamic activation of SS are not significantly affected by the hypocretinergic system. NT2 patients show an abnormal pattern of SS distribution.

AB - BACKGROUND: Patients with narcolepsy type 1 (NT1) show alterations in sleep stage transitions, rapid-eye-movement (REM) and non-REM sleep due to the loss of hypocretinergic signaling. However, the sleep microstructure has not yet been evaluated in these patients. We aimed to evaluate whether the sleep spindle (SS) density is altered in patients with NT1 compared to controls and patients with narcolepsy type 2 (NT2).METHODS: All-night polysomnographic recordings from 28 NT1 patients, 19 NT2 patients, 20 controls (C) with narcolepsy-like symptoms, but with normal cerebrospinal fluid hypocretin levels and multiple sleep latency tests, and 18 healthy controls (HC) were included. Unspecified, slow, and fast SS were automatically detected, and SS densities were defined as number per minute and were computed across sleep stages and sleep cycles. The between-cycle trends of SS densities in N2 and NREM sleep were evaluated within and between groups.RESULTS: Between-group comparisons in sleep stages revealed no significant differences in any type of SS. Within-group analyses of the SS trends revealed significant decreasing trends for NT1, HC, and C between first and last sleep cycle. Between-group analyses of SS trends between first and last sleep cycle revealed that NT2 differ from NT1 patients in the unspecified SS density in NREM sleep, and from HC in the slow SS density in N2 sleep.CONCLUSIONS: SS activity is preserved in NT1, suggesting that the ascending neurons to thalamic activation of SS are not significantly affected by the hypocretinergic system. NT2 patients show an abnormal pattern of SS distribution.

KW - Adult

KW - Brain/physiopathology

KW - Electroencephalography

KW - Female

KW - Humans

KW - Male

KW - Narcolepsy/chemically induced

KW - Pattern Recognition, Automated

KW - Polysomnography

KW - Sleep Stages/physiology

U2 - 10.1016/j.sleep.2017.02.022

DO - 10.1016/j.sleep.2017.02.022

M3 - Journal article

C2 - 28522097

SN - 1389-9457

VL - 34

SP - 40

EP - 49

JO - Sleep Medicine

JF - Sleep Medicine

ER -