Lateralized Subthalamic Stimulation for Axial Dysfunction in Parkinson's Disease: A Randomized Trial

Area of Science:

• Neurology
• Neurosurgery
• Movement Disorders

Background:

• Parkinson's disease (PD) patients can develop treatment-resistant axial dysfunction after bilateral subthalamic nucleus (STN) stimulation.
• Axial dysfunction significantly impacts quality of life in PD patients.

Purpose of the Study:

• To investigate if lateralized STN stimulation (50% amplitude reduction) improves gait velocity in PD patients with treatment-resistant axial dysfunction.
• To assess the effects of lateralized stimulation on motor and axial function, gait, speech, quality of life, and cognition.

Main Methods:

• Randomized, double-blinded, double-crossover trial.
• 22 PD patients (51-79 years) with bilateral STN stimulation and axial dysfunction participated.
• Evaluated gait velocity, motor/axial function (MDS-UPDRS), freezing of gait (FoG), speech, cognition, and quality of life.

Main Results:

• No significant improvements in gait velocity, quality of life, cognitive, or speech measures were observed.
• Reducing left-sided STN stimulation amplitude by 50% for ≥21 days led to a significant improvement in axial motor function (MDS-UPDRS score) and reduced freezing of gait.
• The improvements were statistically significant but may not be clinically meaningful.

Conclusions:

• Lateralized STN stimulation does not provide meaningful gait velocity improvement in PD patients with treatment-resistant axial dysfunction.
• Left-sided STN overstimulation might exacerbate axial deterioration in these patients.
• Further research is needed to optimize STN stimulation parameters for axial symptoms in PD.