Quantifying effects of upper motor neuron degeneration on the wrist in amyotrophic lateral sclerosis

Quantifying effects of upper motor neuron degeneration on the wrist in amyotrophic lateral sclerosis

Plouvier, just (TU Delft Mechanical, Maritime and Materials Engineering)

van der Helm, F.C.T. (mentor)

Delft University of Technology

Biomedical Engineering

2022-09-30

Background: Amyotrophic lateral sclerosis (ALS) is a motor neuron disease that is characterized by the degeneration of upper and lower motor neuron (UMN, LMN). A defining feature of ALS is its heterogeneous presentation, with varying sites of disease onset and progression rate. Diagnosing ALS requires the observation of both UMN and LMN degeneration in multiple regions of the body. Signs of UMN degeneration are difficult to observe in ALS. The goal of this study was to determine if reflexive parameters were related to UMN dysfunction in ALS patients.

Methods: A robot applied continuous torque perturbations to the right wrist of the subjects. Subject were asked to perform 4 different tasks, each provoking different control strategies. Closed-loop system identification was used to estimate the joint dynamics. A neuromuscular model was then fitted to the estimated joint dynamics to express the contribution of intrinsic and reflexive pathways in physiologically relevant parameters.

Results: We show that patients are able to alter their joint dynamics in order to comply with the tasks. During the relax task patients had visibly higher admittance than controls, in the active tasks the patients were able to lower their admittance similar as controls. Patients with pathologically increased reflexes had significantly increased reflexive feedback during the force tasks compared to controls.

Conclusion: In this study we have demonstrated the ability of neuromechanical parameters to detect hyperreflexia in patients diagnosed in ALS. Therefore the proposed method of closed-loop system identification and parameters estimation could be used to monitor the progression of ALS.

http://resolver.tudelft.nl/uuid:f1093df3-1db4-4277-8ec5-c4fe0f480364

Student theses

master thesis

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