Cognition and biomarkers of oxidative stress in obstructive sleep apnea

• Main Authors: Leticia Viana Sales, Veralice Meireles Sales de Bruin, Vania D'Almeida, Sabine Pompéia, Orlando Francisco Amodeo Bueno, Sérgio Tufik, Lia Bittencourt
• Format: Article
• Language: English
• Published: Faculdade de Medicina / USP 2013-04-01
• Series: Clinics
• Subjects: Sleep Apnea; Neuropsychological Tests; Oxidative Stress; Vitamin E; Superoxide Dismutase
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1807-59322013000400449
• ISSN: 1807-5932; 1980-5322

OBJECTIVES: 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&#177;6.5 years old) with obstructive sleep apnea and 13 controls (37.3&#177;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&#8202;=&#8202;15.9; p&#8202;=&#8202;0.002) and this correlation remained after controlling for age and body mass index (F&#8202;=&#8202;6.3, p&#8202;=&#8202;0.01). A relationship between superoxide dismutase concentrations and executive non-perseveration errors in the Wisconsin Card Sorting Test (F&#8202;=&#8202;7.9; p&#8202;=&#8202;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.