Spatial and temporal memories are affected by sleep fragmentation in obstructive sleep apnea syndrome.

This study evaluated episodic memory, with an emphasis on the recollection of spatial and temporal contexts, in 28 patients suffering from obstructive sleep apnea syndrome and 29 healthy controls. Recollection was assessed by means of the R/K paradigm and the process-dissociation procedure. Attentional abilities were also evaluated. A polysomnographic assessment, including nocturnal oxygen saturation and daytime sleepiness, was conducted. Recollection was strongly disturbed in patients, the number of microarousals being the best predictor of the memory deficit. Attention was only slightly disturbed. Results suggest a link between episodic memory deficit and those areas of the brain that are particularly sensitive to sleep fragmentation, in particular the hippocampus.