Changes in brain morphology in patients with obstructive sleep apnoea

Abstract

Background Obstructive sleep apnoea (OSA) is a common disease that leads to daytime sleepiness and cognitive impairment. Attempts to investigate changes in brain morphology that may underlie these impairments have led to conflicting conclusions. This study was undertaken to aim to resolve this confusion, and determine whether OSA is associated with changes in brain morphology in a large group of patients with OSA, using improved voxel-based morphometry analysis, an automated unbiased method of detecting local changes in brain structure. Methods 60 patients with OSA (mean apnoea hypopnoea index 55 (95% CI 48 to 62) events/h, 3 women) and 60 non-apnoeic controls (mean apnoea hypopnoea index 4 (95% CI 3 to 5) events/h, 5 women) were studied. Subjects were imaged using T1-weighted 3-D structural MRI (69 subjects at 1.5 T, 51 subjects at 3 T). 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. Results Patients with OSA had a reduction in grey matter volume in the right middle temporal gyrus compared with non-apnoeic controls (p<0.05, corrected for topological false discovery rate across the entire brain). A reduction in grey matter was also seen within the cerebellum, maximal in the left lobe VIIIb close to XI, extending across the midline into the right lobe. Conclusion These data show that OSA is associated with focal loss of grey matter 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.

A multicentre randomised controlled trial and economic evaluation of continuous positive airway pressure for the treatment of obstructive sleep apnoea syndrome in older people: PREDICT

“…Cognitive dysfunction is well recognised in middle-aged OSAS patients 14,157 and is potentially linked to changes in brain morphology. 158 However, the impact of OSAS on cognitive function, separate from its effects on sleepiness and vigilance, is debated. 159,160 In older people with OSAS, the benefits of CPAP could be reduced because the capacity for neuronal recovery is less, owing to a combination of neurodegeneration associated with ageing and the life-long effects of OSAS.…”

Sleep Abnormalities in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: A Review

“…These techniques have also applied to clinical populations, including primary insomnia, 90 OSA, 91,92 and depression. 93 Particularly in primary insomnia, functional neuroimaging studies during sleep have helped understand the neurophysiological underpinnings of sleep dysregulation in these patients.…”

Modest Changes in Cerebral Glucose Metabolism in Patients with Sleep Apnea Syndrome after Continuous Positive Airway Pressure Treatment

“…Recent evidence suggests that SAS may lead to structural brain abnormalities [6,7], and studies using functional neuroimaging techniques observe subtle cerebral changes associated with SAS. With regard to 18 F-fluoro-2-deoxy- D -glucose-positron emission tomography (FDG-PET) studies, two preliminary, small-sample reports have been published [8,9].…”