Abstract
BACKGROUND: Coordination between the upper and lower extremities is important to providing dynamic stability during human gait. Though limited, previous research has suggested that interlimb coordination may be impaired in persons with Parkinson's disease. We extend this previous work using continuous analytical techniques to enhance our understanding of interlimb coordination during gait in persons with Parkinson's disease. METHODS: Eighteen adults with Parkinson's disease and fifteen healthy older adults walked overground while undergoing three-dimensional motion capture. Ipsilateral and contralateral interlimb coordination between the sagittal shoulder and hip angles was assessed using cross-covariance techniques. Independent samples and paired samples t-tests compared measures of interlimb coordination between groups and between sides within the participants with Parkinson's disease, respectively. Pearson's correlations were applied to investigate associations between interlimb coordination measures and subscores of gait, posture, and bradykinesia on the Unified Parkinson's Disease Rating Scale. FINDINGS: Ipsilateral and contralateral interlimb coordination was reduced in persons with Parkinson's disease compared to the healthy older adults. Ipsilateral coordination between the upper and lower extremities more affected by disease was found to be negatively associated with clinical scores of gait and posture. Interlimb coordination was not significantly associated with clinical measures of bradykinesia. INTERPRETATION: Persons with Parkinson's disease exhibit reduced interlimb coordination during gait when compared to healthy older adults. These reductions in coordination are related to clinically-meaningful worsening of gait and posture in persons with PD and coordination of arm and leg movements should be considered in future research on gait therapy in this population.