Poster presentations

Impairments in cognition are frequently observed in untreated patients with obstructive sleep apnoea (OSA), including defi -cits in memory, executive functioning, attention, and processing speed. The precise nature and causes of these defi cits remains controversial. The present study aimed to characterise the magnitude of cognitive defi cits in a sleep clinic sample of OSA patients. Specifi cally, we sought to defi ne the dose response relationship between cognition and disease severity. Methods: Ninety patients with moderate to severe OSA were recruited for cognitive testing following their diagnostic overnight sleep study and prior to starting any treatment. Cognitive testing included comput-erised and pencil & paper tasks assessing short and long term verbal and visual memory, visuoconstructional ability, verbal fl uency, cogni-tive set shifting, verbal and visuospatial working memory, reaction time, vigilance, and nonverbal reasoning.Results: Participants were aged 32–77 years (M 53.8 ± 11.3), 50% male with mean AHI 44.6 ± 23.7, range 15.5–108.7. After controlling for the effect of age, the severity of OSA (using AHI) was signifi cantly related to the quality of working memory (r = −.35) and the accuracy of attention (r = −.54), but not to an individual’s ability to learn new information (quality of secondary memory) or to executive function (planning and visuoconstructional problem solving).Discussion: The more severe an individual’s OSA, the worse their ability to hold information in short term memory whilst working with it (both visuospatial and verbal), and the more errors they make on attentional tasks. Working memory and attention abilities are likely to impact on the capacity of patients with OSA to work efficiently and safely