title: Cognition and biomarkers of oxidative stress in obstructive sleep apnea.
abstract: OBJECTIVE
  The aim of this study was to investigate neuropsychological performance and biomarkers of oxidative stress in patients with obstructive sleep apnea and the relationships between these factors.
  
  
  METHODS
  This was an observational, cross-sectional study of 14 patients (36.0±6.5 years old) with obstructive sleep apnea and 13 controls (37.3±6.9 years old). All of the participants were clinically evaluated and underwent full-night polysomnography as well as neuropsychological tests. Blood samples were used to assay superoxide dismutase, catalase, glutathione and homocysteine, as well as vitamins E, C, B11 and B12.
  
  
  RESULTS
  The patients performed poorly relative to the controls on several neuropsychological tests, such as the attention test and tests of long-term memory and working memory/executive function. They also had lower levels of vitamin E (p<0.006), superoxide dismutase (p<0.001) and vitamin B11 (p<0.001), as well as higher concentrations of homocysteine (p<0.02). Serum concentrations of vitamin C, catalase, glutathione and vitamin B12 were unaltered. Vitamin E levels were related to performance in the backward digit span task (F = 15.9; p = 0.002) and this correlation remained after controlling for age and body mass index (F = 6.3, p = 0.01). A relationship between superoxide dismutase concentrations and executive non-perseveration errors in the Wisconsin Card Sorting Test (F = 7.9; p = 0.01) was also observed.
  
  
  CONCLUSIONS
  Decreased levels of antioxidants and lower performance on the neuropsychological tasks were observed in patients with obstructive sleep apnea. This study suggests that an imbalance between antioxidants and pro-oxidants may contribute to neuropsychological alterations in this patient population.
authors.affiliation: Departamento de Psicobiologia, Universidade Federal de São Paulo (UNIFESP), São Paulo/SP, Brazil.
authors.forename: Leticia Viana
authors.initials: LV
authors.lastname: Sales
authors.forename: Veralice Meireles Sales de
authors.initials: VM
authors.lastname: Bruin
authors.forename: Vania
authors.initials: V
authors.lastname: D'Almeida
authors.forename: Sabine
authors.initials: S
authors.lastname: Pompéia
authors.forename: Orlando Francisco Amodeo
authors.initials: OF
authors.lastname: Bueno
authors.forename: Sérgio
authors.initials: S
authors.lastname: Tufik
authors.forename: Lia
authors.initials: L
authors.lastname: Bittencourt
mesh_terms: D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000032:analysis; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D003071:Cognition / Q000502:physiology*; D045422:Continuous Positive Airway Pressure; D003430:Cross-Sectional Studies; D005260:Female; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008297:Male; D008570:Memory, Short-Term; D008875:Middle Aged; D009483:Neuropsychological Tests; D018384:Oxidative Stress; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000503:physiopathology* / Q000523:psychology; D013482:Superoxide Dismutase / Q000097:blood; D014803:Vitamin B Complex / Q000097:blood; D014810:Vitamin E / Q000097:blood
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D006710:Homocysteine; D014803:Vitamin B Complex; D014810:Vitamin E; D013482:Superoxide Dismutase