Attention modulates step initiation postural adjustments in Parkinson freezers

Area of Science:

• Neuroscience
• Motor Control
• Parkinson's Disease Research

Background:

• Freezing of gait (FOG) in Parkinson's disease (PD) is linked to attentional resource involvement in step initiation.
• Anticipatory postural adjustments (APAs) are critical for unloading the stepping leg and enabling gait progression.

Purpose of the Study:

• To investigate if altered attentional load during step initiation differentially affects APAs in PD patients with and without FOG.
• To understand the role of attention in modulating APAs and its impact on gait initiation.

Main Methods:

• Three groups (n=15 each): elderly controls, PD patients with FOG, and PD patients without FOG.
• Auditory oddball task used to modulate attention before step execution, with event-related potential recording.
• Primary endpoint: occurrence of inappropriate APAs not followed by a step after an intercurrent auditory stimulus.

Main Results:

• Inappropriate APAs occurred more frequently in PD patients with FOG (63%) compared to those without FOG (51%) and controls (48%).
• Inappropriate APAs were longer and more substantial in PD patients with FOG.
• Postural preparation was generally impaired in PD patients.

Conclusions:

• Attentional resource allocation during step preparation differentially influences APA release in PD patients with and without FOG.
• Modulating attentional load can trigger inappropriate motor programs, contributing to gait initiation failure in PD freezers.
• Difficulties in focusing attention or resisting interference may underlie FOG in Parkinson's disease.