Obstructive sleep apnea patients had reductions of gray-matter volume at baseline but showed significant gray-matter volume increase after 3 months of CPAP therapy, according to a research abstract at SLEEP 2010.

Results indicate that obstructive sleep apnea patients showed focal reductions of gray-matter volume at baseline in the left hippocampus, posterior parietal cortex, and right superior frontal gyrus. Significant gray-matter volume increases were observed after 3 months of CPAP therapy in hippocampal and frontal structures. No further improvement in gray-matter volume was observed after 1 year of CPAP therapy.

"OSA patients showed cognitive impairment associated with neurostructural damage affecting specific cerebral regions," said principal investigator Vincenza Castronovo, PhD, clinical psychologist and psychotherapist and sleep laboratory coordinator at the University Vita-Salute San Raffaele and San Raffaele Scientific Institute in Milan, Italy. "In addition, we show that most of the neuropsychological deficits are reversed after three months of treatment with CPAP and, for the first time, that such cognitive improvements parallel an increase of grey-matter volume in specific hippocampal and frontal brain regions. The increase of grey-matter volume in these regions is significantly correlated with the improvement at neuropsychological tests of executive functioning and short-term memory."