Muscle forces and activations in Parkinson’s disease: a model-based approach

Parkinson’s disease (PD) is a progressive pathological condition caused by a dopamine deficiency. Although gait alterations are well-known in PD patients, changes in neural strategies have recently been explored. The presented study aims to address the advantages of adopting a neuromusculoskeletal modelling approach, in order to detect alterations in PD’s motor control and report differences in knee and ankle muscle forces with respect to the healthy individuals. The adopted electromyography (EMG)-informed computational model was fed by EMG signal coupled with 3D marker trajectories and ground reaction forces. Ten PD subject-specific models were developed and compared with a control group of 13 subjects matched for age and BMI. Results showed significant differences in the neuromuscular control strategy of the PD group both in terms of muscle forces and co-contraction index. The estimated variables can become a measurable outcome in order to assess the effect of physical therapy interventions thus allowing to track the disease progression. Furthermore, this technology might be adopted to plan interventions through exoskeletons, by providing an estimate of the degree of muscle forces required by the specific subject to restore a physiological gait profile.