Evaluation of the Impact of Sleep Apnea on Cerebral Volumetry According to Age

Sleep apnea is a common disease in the general population and more particularly in elderly subjects in whom prevalence can reach 30 % after 70 years old. In adults (\<55 years old) cardiovascular consequences are well known and make sleep apnea treatment necessary. However elderly (\>70 years old) apneic subjects are less symptomatic in terms of sleepiness, they usually present a lower index of respiratory events and cardiovascular consequences in this population are still discussed, driving some authors to consider sleep apnea in the elderly as a specific disease and making the need for a treatment questionable. In this study the investigators will focus on the comparison between adult and elderly apneic subjects in terms of cognitive and cardiovascular consequences. Adult apneic patients suffer from a decrease of cognitive performance as well as grey matter local atrophy, particularly in the hippocampus and in the frontal lobes. According to fewer studies, white matter can also be affected by a demyelinisation process. These structural modifications are sometimes associated with disorders of executive and memory functions. In the elderly, no clear association can be drawn between cognitive decline and sleep apnea. Moreover, to our knowledge, the cerebral state of elderly symptomatic apneic subjects has mostly not be investigated.