Distal Upper Limb Tremor during Walking in Parkinson's Disease

BackgroundDistal upper limb tremor during walking (TW) is frequently observed in Parkinson's disease (PD) but its clinical features are unknown. ObjectiveTo characterize the occurrence and the clinical features of TW in comparison to the other types of tremors in PD. MethodsFifty-one PD patients with rest tremor were evaluated off- and on-treatment. Occurrence, body distribution, severity and latency of TW and of other tremor types were assessed. ResultsTW was present in 78% of the PD patients examined. TW body distribution and severity were similar to those of rest and re-emergent tremor but different from the postural tremor presented by the same patients. TW latency, observed in 85% of patients, was on average 5.8 s. Dopaminergic treatment significantly improved TW, rest, and re-emergent tremor severity but left TW latency unaffected. ConclusionsTW is a frequent motor sign in PD and is likely a clinical variant of rest tremor.