Distal Upper Limb Tremor during Walking in Parkinson's Disease

Background: Distal upper limb tremor during walking (TW) is frequently observed in Parkinson's disease (PD) but its clinical features are unknown. Objective: To characterize the occurrence and the clinical features of TW in comparison to the other types of tremors in PD. Methods: Fifty-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. Results: TW 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. Conclusions: TW is a frequent motor sign in PD and is likely a clinical variant of rest tremor.