Obstructive sleep apnea syndrome (OSAS) and swallowing function-a systematic review

The purpose of this systematic review was to summarize and qualitatively analyze published evidence elucidating the prevalence of dysphagia and detail alterations in swallowing function in patients with OSAS. Computerized literature searches were performed from four search engines. The studies were selected based on the inclusion and exclusion criteria. The studies were screened using Covidence (Cochrane tool) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement standards (PRISMA-2009). A total 2645 studies were initially retrieved, of which a total of 17 studies met inclusion criteria. Two reviewers, blinded to each other, evaluated level and strength of evidence using the Oxford Centre for Evidence-based Medicine Levels of Evidence and QualSyst, respectively. Dysphagia prevalence ranged from 16 to 78% among the eligible studies. Studies varied in operational definitions defining swallowing dysfunction (dysphagia) and method used to assess swallowing function. Approximately 70% of eligible studies demonstrated strong methodological quality. The majority of studies (n = 11; 65%) reported pharyngeal swallowing impairments in patients with OSAS, including delayed initiation of pharyngeal swallow and penetration/aspiration. This systematic review describes swallowing function in patients with OSAS. However, due to the variability in defining OSAS and dysphagia, in the assessment method used to determine dysphagia, and heterogeneity of study designs, true prevalence is difficult to determine. Clinicians involved in the management of OSAS patients should employ validated assessment measures to determine if swallow dysfunction is present.