Optimal Control Perspective on Parkinson's Disease: Increased Delay Between State Estimator and Controller Produces...

Area of Science:

• Neuroscience
• Systems Biology
• Biomedical Engineering

Background:

• Parkinson's disease (PD) causes tremor, but its underlying pathophysiology remains unclear.
• Existing models often focus on neural activity, while control system approaches offer insights into motor control.
• Excessive basal ganglia inhibition in PD suggests potential delays in central nervous system processing.

Purpose of the Study:

• To investigate the hypothesis that increased central nervous system delay, uncompensated, causes parkinsonian tremor.
• To explore how optimal control principles can model tremor generation in PD.
• To correlate model parameters with clinical features of PD tremor.

Main Methods:

• Utilized an optimal control framework to model the human motor system.
• Simulated tremor generation in a neuromuscular wrist model.
• Investigated the impact of increased neural pathway delays and altered effort sensitivity.

Main Results:

• Simulations successfully generated realistic tremor patterns in the wrist model.
• Model modifications, including increased delay and altered effort sensitivity, replicated key tremor characteristics.
• The model accounts for re-emergent tremor and time-varying amplitude and frequency.

Conclusions:

• Increased central nervous system delay is a plausible mechanism for parkinsonian tremor.
• Optimal control models provide valuable insights into PD tremor pathophysiology.
• Findings suggest the basal ganglia and cerebello-thalamo-cortical circuit's role in tremor and potential treatment mechanisms.