Changes in brain morphology associated with obstructive sleep apnea.

Obstructive sleep apnea (OSA) causes hypoxemia and fragmented sleep, which lead to neurocognitive deficits. We hypothesised that focal loss of cortical gray matter generally within areas associated with memory processing and learning and specifically within the hippocampus would occur in OSA. Voxel-based morphometry, an automated processing technique for magnetic resonance images, was used to characterise structural changes in gray matter in seven right handed, male patients with newly diagnosed OSA and seven non-apneic, male controls matched for handedness and age. The analysis revealed a significantly lower gray matter concentration within the left hippocampus (p=0.004) in the apneic patients. No further significant focal gray matter differences were seen in the right hippocampus and in other brain regions. There was no difference in total gray matter volume between apneics and controls. This preliminary report indicates changes in brain morphology in OSA, in the hippocampus, a key area for cognitive processing.