Grey matters; Reason to have a sleep study

Snoring/choking, snorting or gasping during sleep? Long pauses in breathing and daytime sleepiness, no matter how much time you spend in bed? If we were having any of these symptoms, saw the doctor and they recommended a sleep study test… would it be important that we did the test? Why would we bother?

It's very important to follow through with this test as obstructive sleep apnoea increases the risk of cardiovascular disease, type II diabetes and accidents but recent studies have also indicate osa has an adverse effect on our grey matter.

A recent study in the UK by Morell et al ("Changes in brain morphology in patients with obstructive sleep apnoea") published in Thorax 2010;65:908-914, looked at determining whether Obstructive Sleep Apnoea (OSA) is associated with changes in brain morphology. They looked at a large group of patients with OSA, and used improved voxel-based morphometry analysis, an automated unbiased method of detecting local changes in brain structure. [Obstructive sleep apnoea occurs when the soft tissue in the back of your throat relaxes during sleep, causing a blockage of the airway (as well as loud snoring)].

The study involved 60 patients with OSA and 60 non-apnoeic controls. The subjects were imaged using T1-weighted 3-D structural MRI and the differences in grey matter were investigated in the two groups, controlling for age, sex, site and intracranial volume. Dedicated cerebellar analysis was performed on a subset of 108 scans using a spatially unbiased infratentorial template.

The researchers found that the patients with OSA had a reduction in grey matter volume in the right middle temporal gyrus compared with non-apnoeic controls. A reduction in grey matter was also seen within the cerebellum, maximally in the left lobe and extending across the mid line into the right lobe.

This study shows that OSA is associated with focal loss of grey matter in the brain that could contribute to cognitive decline. Specifically, lesions in the cerebellum may result in both motor dysfunction and working memory deficits, with downstream negative consequences on tasks such as driving.

Heather