Rigidity and bradykinesia reduce interlimb coordination in Parkinsonian gait

Objective: To assess the influence of rigidity and bradykinesia and the extent of dopaminergic degeneration on interlimb coordination during walking in early, drug-naive patients with Parkinson's disease (PD). Design: The interlimb coordination was examined during a systematic manipulation of walking speed on a treadmill. The phase relations between arm and leg movements were related to the clinical measures of rigidity and bradykinesia as well as to the extent of dopaminergic degeneration. Setting: Movement disorders outpatient clinic (including motion analysis laboratory) and a nuclear medicine department of a university hospital. Participants: Twenty-nine early and drug-naive PD patients. Interventions: Not applicable. Main Outcome Measures: The interlimb coordination during walking was evaluated by studying the (continuous) relative phase relations between movements of arms and legs. The clinical assessment of rigidity and bradykinesia was performed by using the Unified Parkinson Disease Rating Scale. The dopaminergic degeneration was expressed as striatal 2beta-carboxymethoxy-3beta-(4-iodophenyl) tropane (beta-CIT) single-photon emission computed tomography (SPECT) binding. Results: The mean relative phase between arm and leg movements increased significantly with walking speed in all patients. Significant correlations were found between the rigidity and bradykinesia and the coordination measures (Pless than or equal to.007), as well as contralateral striatal [I-123]beta-CIT SPECT binding and coordination measures (P<.001), in terms of asymmetry indices. Conclusions: Early, drug-naive PD patients in this sample were able to adapt their coordination patterns when walking speed was systematically manipulated. However, bradykinesia and rigidity as well as the extent of degeneration of the dopaminergic system were associated with a limited adaptive ability (flexibility) in movement coordination. The combination of a drug treatment that controls bradykinesia and rigidity and a physical therapy exercise programs possibly using external cues mechanisms are required to obtain relevant effects on gait in PD patients.