Dementia: Risk factors may include ‘erratic’ sleep warns new study

In the latest body of research, however, sleep duration did not appear to be the issue.

Sleep variability, however, where a person’s sleep behaviours change from one night to the next, was found to correlate with cognitive impairment.

“Seep variability over time and not median sleep duration was associated with cognitive impairment,” noted the authors.

Samantha Keil, PhD, a postdoctoral fellow at the University of Washington, Seattle added: “What we were a little surprised to find in this model was that sleep duration, whether short, long or average, was not significant, but the sleep variability – the change in sleep across those time measurements – was significantly impacting the incidence of cognitive impairment.”