Periodic leg movements during sleep and sleep disturbances in elders.

Background: Periodic limb movements in sleep (PLMS) are an increasingly pervasive disturbance for aging adults. The aims of this experiment were: (a) to describe the index of periodic limb movements in sleep (myoclonus index [MI] in elderly subjects with complaints of poor sleep or depression (N = 22; 68 +/- 5.5 SD years); and (b) to correlate MI with sleep history, depression scores, and objective and subjective indices of sleep.

Method: Sleep and leg movements were assessed for 5 consecutive nights. Between-subjects, nonparametric correlations were examined between mean MI and sleep history, depression scores, and objective and subjective sleep characteristics. Associations among within-subject night-to-night variabilities of MI, objective, and subjective variables were examined with repeated measures ANCOVA, entering MI as a covariate.

Results: A remarkably high level of MI was found (median 25.8 events per hour; 86% of subjects > 5). Nevertheless, no associations were found between MI and sleep disturbance measures.

Conclusion: These results extend previous reports that PLMS are remarkably persuasive in elderly volunteers and support other reports questioning whether there is a distinct PLMS syndrome.