Sleep apnoea and cognitive impairment: myth or reality?

A growing number of studies in animal models have highlighted the link between sleep disorders and Alzheimer's disease (AD). In the absence of curative treatment, it is therefore important to consider any comorbidities that may influence the course of AD such as obstructive sleep apnoea-hypnoea (OSAH) and its syndrome (OSAHS), which appear to be potentially interesting because it occurs frequently, it is treatable and it is often associated with cognitive impairment. The association between OSAH/OSAHS and cognition is variable across studies, but OSAH/OSAHS is more common in older patients with AD than in cognitively normal individuals. OSAH/OSAHS is often associated with the subsequent development of mild cognitive impairment and AD. Although there is no evidence that treatment of OSAH/OSAHS in AD would have a major impact on the course of the disease, treatment would appear to improve cognition in AD patients with OSAH/OSAHS. Finally, the literature suggests a link between OSAH/OSAHS and AD biomarkers. Taken together, these data highlight the importance of detecting and treating OSAHS in this population.