Comparison of 17 people with severe obstructive sleep apnea (OSA) with 15 age-matched controls has revealed that those with OSA had reduced gray matter in several brain regions, most particularly in the left parahippocampal gyrus and the left posterior parietal cortex, as well as the entorhinal cortex and the right superior frontal gyrus. These areas were associated with deficits in abstract reasoning and executive function. Deficits in the left posterior parietal cortex were also associated with daytime sleepiness.
Happily, however, three months of treatment with continuous positive airway pressure (CPAP), produced a significant increase in gray matter in these regions, which was associated with significant improvement in cognitive function. The researchers suggest that the hippocampus, being especially sensitive to hypoxia and innervation of small vessels, is the region most strongly and quickly affected by hypoxic episodes.
The findings point to the importance of diagnosing and treating OSA.
(2010). Obstructive Sleep Apnea: Brain Structural Changes and Neurocognitive Function Before and After Treatment.
Am. J. Respir. Crit. Care Med.. 201005-0693OC - 201005-0693OC.