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Daytime sleepiness, fatigue may be clinical markers of brain aging

Researchers reported that sleepiness and fatigue were associated with brain atrophy in elderly patients who were cognitively normal, according to findings presented at the SLEEP 2016 annual meeting.

Diego Z. Carvalho, MD, a resident physician of neurology at the Mayo Clinic in Rochester, Minnesota, and colleagues evaluated 1,258 patients who were at least 50 years old and were deemed cognitively normal.

Patients all had a baseline structural MRI and completed fatigue and sleepiness surveys. The researchers also measured regional cortical thickness and hippocampal volume.

Carvalho and colleagues reported that 178 participants had excessive daytime sleepiness, 25 had clinically significant fatigue and nine had both.

Results showed that excessive daytime sleepiness was associated with lower global cortical thickness (–27 µm; 95% CI, –42.9 to –11; P = .001). The association was greatest in the temporal lobes, which "were equivalent to more than 3 years of aging."

In addition, fatigue was associated with lower temporal thickness (–83.7 µm; 95% CI, –138.4 to –28.9; P = .003) and lower hippocampal volume (–419.2 mm³; 95% CI, –729.3 to –109; P = .008). These decreases were equivalent to 6 and 8.5 years of aging, respectively.

"Symptoms of [excessive daytime sleepiness] and fatigue were associated with reduced cognitive performance and altered brain structure, especially in regions implicated in mild cognitive impairment," the researchers concluded. "We hypothesize that [excessive daytime sleepiness] and fatigue symptoms are clinical markers of accelerated brain aging, which may be associated with sleep and medical comorbidities."

"Our results may help to identify healthy individuals at higher susceptibility or risk for dementia prior to symptom onset so that appropriate interventions can be undertaken early to prevent progression to dementia," Carvalho said in a press release. – by Chelsea Frajerman Pardes

Reference:

Carvalho DZ, et al. Sleepiness and fatigue associated with brain atrophy in cognitively normal elderly: Mayo Clinic study of aging. Presented at: SLEEP Annual Meeting 2016; June 11-15; Denver.

Disclosures: The study was supported by the National Institute on Aging.