P141 High prevalence of obstructive sleep apnoea in patients with mild cognitive impairment or mild dementia

AIMS: Obstructive sleep apnoea (OSA) occurs with greater frequency in advancing age. The resulting sleep fragmentation and oxygen desaturations may induce or contribute to neurodegeneration. As such, OSA may be an important modifiable risk factor for the development of dementia. However, the prevalence of OSA within the population with cognitive impairment remains uncharacterised. This study aims to assess the prevalence of OSA in patients attending a specialist memory clinic with either mild cognitive impairment (MCI) or mild stages of dementia (Mini-Mental State Examination (MMSE) > 20). METHODS: Eligible and consenting participants were asked to wear an ApneaLink™ (ResMed) device overnight that measured nasal airflow and oximetry to generate a Respiratory Disturbance Index (RDI). The Epworth Sleepiness Scale (ESS) was used to evaluate subjective symptoms. RESULTS: 64 participants completed the study. Mean(±SD) age=76.1±9.2 years, MMSE=25.6±2.8, RDI=15.5±12.0. The distribution of normal, mild, moderate and severe OSA was 16%, 44%, 26% and 14% respectively. 84% of participants had an abnormal RDI (>5), with 40% being moderate to severe (RDI >15) where CPAP may be the recommended treatment. Mean ESS was 7.08±4.45 and not correlated with OSA severity. CONCLUSION: The prevalence of OSA in MCI or early stages of dementia is high and represents a potential target for therapeutic intervention. Further research studies are required to determine whether treatment of OSA alters dementia progression.