OSAS-Related Cognitive Impairment after First-Ever Stroke: Study Design and Methodology

Abstract: Introduction: Obstructive Sleep Apnea Syndrome (OSAS) is considered an emerging risk factor for cerebrovascular disease. Both the two conditions could share the same neurocognitive impairment, which, in the early phase of OSAS, are reversible and mediated by the excessive daytime sleepiness. Treatment with continuous positive air pressure (CPAP) device could improve the neurocognitive functions, and therefore, it could be considered as a valid treatment option in stroke patients affected by OSAS and neurocognitive impairment. Materials and Methods: Patients affected by unilateral ischemic stroke will be subdivided into two groups, according to the presence or absence of OSAS. All participants will be evaluated by using a specific neuropsychological battery exploring attention, memory, praxic abilities and executive functions. Patients presented with a moderate to severe OSAS will be treated with CPAP and followed for at least 1 year. Results: The data analysis requires a sample size of 550 to provide adequate power of the study. The outcome variable is the score of specific neuropsychological and quality of life tests at baseline, after 6 months and at 1 year follow-up. Discussion and Conclusion: This study design presents three specific analysis limitations. First, several other sleep disorders can produce drowsiness beyond OSAS. Second, the neurocognitive impairment in stroke patients is difficult to assess. Third, OSAS patients are often intolerant to diagnostic tests requiring an excessive length. However, the findings coming from the protocol may have important implications about the effect of sleep disorders on cognitive function in stroke patients. Moreover, the easy employed procedures could be translated into clinical practice to improve the quality of life of patients affected by both OSAS and stroke.