Nerve conduction and creatinine clearance in aged subjects with periodic movements in sleep.

Periodic leg movements during sleep (PLMs) are non-epileptiform, repetitive limb movements that are highly prevalent among the geriatric population. The mechanisms underlying these movements are poorly understood. In this study we evaluated PLMs of 24 aged volunteers. We hypothesized that the high prevalence of PLMs seen in the aged would be related to (a) lower creatinine clearance and (b) slowed velocities/delayed latencies in the nerve conduction studies of such individuals. Results did not support hypothesis (a) but offered some equivocal support for hypothesis (b), inasmuch as aged subjects with higher levels of PLMs had delayed motor and sensory latencies in the upper limbs (median n., ulnar n.). Results are discussed in terms of central vs peripheral mechanisms involved in the generation of PLMs in elderly persons.