Cognitive dysfunctions in obstructive sleep apnea patients

OBJECTIVE: The main objective of the presented narrative review is to assess the contemporary literature regarding cognitive functions and their deterioration in obstructive sleep apnea patients. METHOD: Articles were acquired via PubMed database via computerized search applying selected keywords in combinations from January 1953 to December 2022. Papers were nominated using including criteria: studies in humans, published in peer-reviewed journals; reviews; English language. The criteria for exclusion were: abstracts from conferences, commentaries, and subjects younger than 18 years. According to the inclusion and exclusion criteria, 80 articles were chosen. Relevant documents from the references of primarily chosen papers were investigated, evaluated and relevant papers were added to the initial list of documents. Review team then assessed full texts and selected and included 110 papers in total in the review. RESULTS: Studies included in the review documented the dysfunctions in the attention, selected domains of memory, and executive functions in OSA. Verbal functions mostly remain intact, and tests of psychomotor speed show mixed findings. Repeated desaturations caused by airway closure accompanied by hypoxemia and hypercapnia at night and frequent arousals associated with excessive sympathetic activation and sleep fragmentation are presumed to be etiological factors in these cognitive dysfunctions. CONCLUSIONS: Areas of cognitive function most affected by untreated OSA include attention, memory and executive functions. Studies show that untreated OSA prolongs reaction time and impairs intentional attention and the ability to divide attention between multiple stimuli. Cognition partially improves after CPAP treatment. However there is not enough evidence in the long-term effects of CPAP on cognition and the long-term effect of untreated OSA on cognitive functions.