Effects of rest-duration, time-of-day and their interaction on periodic leg movements while awake in restless legs syndrome.

BACKGROUND AND PURPOSE: The diagnostic criteria for restless legs syndrome (RLS) indicate that both time-of-day and rest effects induce or aggravate symptoms. Periodic limb movements while awake (PLMW) provide an objective motor sign of RLS that can be measured during an awake suggested immobilization test (SIT). This study uses the SIT at different times of the day and analyzes time-of-day and duration-of-rest effects and their interaction on the PLMW.

PATIENTS AND

METHODS

Twenty-eight RLS patients who were not on medications had SIT tests at 10 pm, 8 am and 4 pm on two consecutive days. PLMW for each 20-min period were analyzed for time-of-day and rest effects and their interaction. PLMW increase from the first to last 20-min SIT period assessed the rest-effects.

RESULTS

Significant effects were found for rest, time-of-day and rest-time-of-day interaction. The rest-effect increased most from morning to afternoon while total PLMW increased more from afternoon to night. Males compared to females had significantly more PLMW and a larger rest-effect change with time-of-day.

CONCLUSIONS

Rest and time-of-day effects and their interaction all increase RLS symptoms. PLMW increase with rest may provide a sensitive measure of symptom severity.