SOF Analysis Plan #573 Restless Legs Syndrome, Periodic Limb Movements, and Cognitive Impairment in Older Women

Restless legs syndrome (RLS) and periodic limb movements in sleep (PLMS) are related conditions that often are comorbid. A diagnosis of RLS is made on the basis of patient complaints, and PLMS is diagnosed by polysomnography (PSG). Both RLS and PLMS are common in older adults, affecting 19% and 66% of elders, respectively. Although numerous studies have investigated other sleep disturbances (e.g., sleep apnea, insomnia) as risk factors for cognitive impairment and decline, we are aware of only two studies that have investigated whether RLS is associated with cognitive performance. One study found that a mixed-age sample of RLS patients exhibited lower performance on tests of attention and executive function compared to age-matched controls. Another study of the same RLS patients found that they performed better on cognitive tests than a mixed-age sample of sleep-restricted controls. However, both studies failed to control for baseline differences in cognitive performance between RLS patients and controls, complicating interpretation of results. Currently, there are no published studies of the association between RLS and cognition in large samples of elders--a population at elevated risk for cognitive impairment. In addition, there are no published studies of the association between PLMS and cognition in older adults.