Zhongxing Zhang1,2, Ramin Khatami1,2,3. 1. Center for Sleep Medicine and Sleep Research, Clinic Barmelweid, Barmelweid, Switzerland. 2. Department of Neurology, University Hospital Bern, Bern, Switzerland. 3. ZIHP, Zurich Center for Integrative Human Physiology, Zürich, Switzerland.
Abstract
STUDY OBJECTIVES: Current knowledge on hemodynamics in sleep is limited because available techniques do not allow continuous recordings and mainly focus on cerebral blood flow while neglecting other important parameters, such as blood volume (BV) and vasomotor activity. DESIGN: Observational study. PARTICIPANTS AND SETTINGS: Continuous measures of hemodynamics over the left forehead and biceps were performed using near-infrared spectroscopy (NIRS) during nocturnal polysomnography in 16 healthy participants in sleep laboratory. MEASUREMENTS AND RESULTS: Temporal dynamics and mean values of cerebral and muscular oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (HHb), and BV during different sleep stages were compared. A biphasic change of cerebral BV was observed which contrasted a monotonic increase of muscular BV during non-rapid eye movement sleep. A significant decrement in cerebral HbO2 and BV accompanied by an increase of HHb was recorded at sleep onset (Phase I). Prior to slow wave sleep (SWS) HbO2 and BV turned to increase whereas HHb began to decrease in subsequent Phase II suggested increased brain perfusion during SWS. The cerebral HbO2 slope correlated to BV slope in Phase I and II, but it only correlated to HHb slope in Phase II. The occurrence time of inflection points correlated to SWS latencies. CONCLUSION: Initial decrease of brain perfusion with decreased blood volume (BV) and oxygenated hemoglobin (HbO2) together with increasing muscular BV fit thermoregulation process at sleep onset. The uncorrelated and correlated slopes of HbO2 and deoxygenated hemoglobin indicate different mechanisms underlying the biphasic hemodynamic process in light sleep and slow wave sleep (SWS). In SWS, changes in vasomotor activity (i.e., increased vasodilatation) may mediate increasing cerebral and muscular BV.
STUDY OBJECTIVES: Current knowledge on hemodynamics in sleep is limited because available techniques do not allow continuous recordings and mainly focus on cerebral blood flow while neglecting other important parameters, such as blood volume (BV) and vasomotor activity. DESIGN: Observational study. PARTICIPANTS AND SETTINGS: Continuous measures of hemodynamics over the left forehead and biceps were performed using near-infrared spectroscopy (NIRS) during nocturnal polysomnography in 16 healthy participants in sleep laboratory. MEASUREMENTS AND RESULTS: Temporal dynamics and mean values of cerebral and muscular oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (HHb), and BV during different sleep stages were compared. A biphasic change of cerebral BV was observed which contrasted a monotonic increase of muscular BV during non-rapid eye movement sleep. A significant decrement in cerebral HbO2 and BV accompanied by an increase of HHb was recorded at sleep onset (Phase I). Prior to slow wave sleep (SWS) HbO2 and BV turned to increase whereas HHb began to decrease in subsequent Phase II suggested increased brain perfusion during SWS. The cerebral HbO2 slope correlated to BV slope in Phase I and II, but it only correlated to HHb slope in Phase II. The occurrence time of inflection points correlated to SWS latencies. CONCLUSION: Initial decrease of brain perfusion with decreased blood volume (BV) and oxygenated hemoglobin (HbO2) together with increasing muscular BV fit thermoregulation process at sleep onset. The uncorrelated and correlated slopes of HbO2 and deoxygenated hemoglobin indicate different mechanisms underlying the biphasic hemodynamic process in light sleep and slow wave sleep (SWS). In SWS, changes in vasomotor activity (i.e., increased vasodilatation) may mediate increasing cerebral and muscular BV.
Authors: Felix Scholkmann; Stefan Kleiser; Andreas Jaakko Metz; Raphael Zimmermann; Juan Mata Pavia; Ursula Wolf; Martin Wolf Journal: Neuroimage Date: 2013-05-16 Impact factor: 6.556
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Authors: Meryem A Yücel; Alexander V Lühmann; Felix Scholkmann; Judit Gervain; Ippeita Dan; Hasan Ayaz; David Boas; Robert J Cooper; Joseph Culver; Clare E Elwell; Adam Eggebrecht; Maria A Franceschini; Christophe Grova; Fumitaka Homae; Frédéric Lesage; Hellmuth Obrig; Ilias Tachtsidis; Sungho Tak; Yunjie Tong; Alessandro Torricelli; Heidrun Wabnitz; Martin Wolf Journal: Neurophotonics Date: 2021-01-07 Impact factor: 3.593