title: Hypoxemia, Sleep Disturbances, and Depression Correlated with Fatigue in Neuromyelitis Optica Spectrum Disorder.
abstract: OBJECTIVE
  Among patients with neuromyelitis optica spectrum disorder (NMOSD), fatigue is commonly complained about and is one of the most debilitating symptoms. This study aimed to investigate the incidence of fatigue and explore impacting factors attributed to fatigue in NMOSD.
  
  
  METHODS
  Thirty-three patients with NMOSD and twenty matched healthy controls were enrolled. A battery of self-reported questionnaires was conducted to assess quality of sleep, daytime sleepiness, fatigue, depression, and level of activity of daily life. The structure of sleep was assessed by polysomnography with blood oxygen saturation monitored by noninvasive pulse oximeter. Brain and spinal cord lesions were evaluated by MRIs.
  
  
  RESULTS
  Fatigue was more severe and more prevalent among the patients with NMOSD compared with controls (fatigue score which ranges from 0 to 11 with higher scores indicating more severe fatigue: 6.4 ± 0.6 vs. 3.8 ± 0.4, P = 0.002; incidence, 64% vs. 35%, P = 0.043), and it was negatively associated with daily activity level (r = 0.455, P = 0.008). The patients with fatigue had higher Pittsburgh Sleep Quality Index score, higher Epworth Sleepiness Scale score, lower blood oxygen state, and higher depression score than patients without fatigue; blood oxygen was especially negatively correlated with fatigue (nadir SpO2 , r = -0.558, P = 0.001; mean SpO2 , r = -0.457, P = 0.007); depression was also positively correlated with fatigue (r = 0.599, P < 0.001).
  
  
  CONCLUSIONS
  Patients with NMOSD experienced significant fatigue, which had an obvious impact on their daily activity. Fatigue in these patients was related to hypoxemia, sleep disturbances, and depression.
authors.affiliation: Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Pan
authors.affiliation: Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.affiliation: Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Cai
authors.affiliation: Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Su
authors.affiliation: Department of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA.
authors.forename: Kristofer
authors.initials: K
authors.lastname: Wood
authors.affiliation: Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China.|Department of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA.
authors.forename: Fu-Dong
authors.initials: FD
authors.lastname: Shi
authors.affiliation: Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Fu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000378:metabolism; D051401:Aquaporin 4 / Q000276:immunology; D003430:Cross-Sectional Studies; D005221:Fatigue / Q000150:complications / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000150:complications / Q000175:diagnosis / Q000209:etiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009471:Neuromyelitis Optica / Q000150:complications*; D010865:Pilot Projects; D017286:Polysomnography; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D012893:Sleep Wake Disorders / Q000150:complications / Q000209:etiology*; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D000906:Antibodies; D051401:Aquaporin 4
keywords: Fatigue; Imaging feature; Neuromyelitis optica; Sleep