Neck rigidity: a pitfall for video head-impulse tests in Parkinson's disease

Area of Science:

• Neurology
• Vestibular System
• Movement Disorders

Background:

• Video head impulse tests (video-HITs) are crucial for vestibular evaluation but susceptible to artifacts.
• Neck rigidity, a common symptom in Parkinson's disease (PD), has not been systematically studied for its impact on video-HITs.

Purpose of the Study:

• To investigate the effect of neck rigidity on video-HIT results in patients with Parkinson's disease.
• To determine if neck rigidity is a confounder in vestibular function assessment using video-HITs in PD.

Main Methods:

• Prospective recruitment of 140 Parkinson's disease patients and 19 healthy controls.
• Assessment of video-HITs and stratification of neck rigidity using the MDS-UPDRS-III.
• Comparison of vestibulo-ocular reflex (VOR) gain and head velocities between groups.

Main Results:

• 41% of PD patients showed overestimation of VOR gain, primarily in the anterior canal.
• VOR gain overestimation occurred even in patients with subtle or mild neck rigidity.
• Neck rigidity was positively associated with VOR gain overestimation (OR=1.51, p=0.043) and reduced head velocities.

Conclusions:

• Neck rigidity is a significant confounder that can contaminate video-HIT results in Parkinson's disease patients.
• Video-HIT results, especially for the anterior canal, require careful interpretation considering neck rigidity and head velocity.
• Future vestibular assessments in PD should account for neck rigidity to ensure accurate diagnosis and management.