Sleep Apnea Appears to Age Brain Faster

By Jonathan Springston, Editor, Relias Media

Investigators recently observed a possible connection between poor sleep quality and bad brain health.

Researchers studied data on participants from the Mayo Clinic Study of Aging who had not been diagnosed with dementia and who had undergone at least one brain MRI and polysomnographic test (i.e., an overnight sleep study in a lab). They narrowed their focus to 140 patients (60% men, average age = 73 years). Investigators noted 34% of patients had been diagnosed with mild sleep apnea, 32% with moderate apnea, and 34% with severe apnea.

The authors were watching for how long patients spent in deep sleep (known as slow-wave sleep or non-REM stage 3 sleep), a good indicator of whether a person is resting adequately. Researchers also measured two cerebrovascular disease brain biomarkers: white matter hyperintensities and fractional anisotropy of the genu of the corpus callosum.

Investigators observed patients with severe sleep apnea recorded higher levels of hyperintensities than those living with mild or moderate apnea. More specifically, the authors noted for every 10-point decrease in the percentage of slow-wave sleep, there was an increase in the amount of hyperintensities, similar to the effect of being 2.3 years older. These biomarkers are red flag indicators suggesting a patient might be at higher risk of cognitive decline, stroke, and Alzheimer’s disease.

However, in addition to its observational nature, there were limitations to this work. When patients participated in their sleep studies, those researchers observed the patients only two or three hours until they met the criteria for sleep apnea. Then, those patients received a positive airway pressure machine for the rest of the night. This means the data on a full night of sleep for these patients are incomplete. The authors called for more longitudinal studies to learn specifics about these possible connections and how treatments for improving sleep quality might affect these biomarker levels.

For more on this and related subjects, be sure to read the latest issues of Neurology Alert.