Vestibular and visual influence on postural stability and egomotion perception in persistent postural-perceptual...

Area of Science:

• Neuroscience
• Vestibular System Research
• Human Postural Control

Background:

• Persistent postural-perceptual dizziness (PPPD) is characterized by postural instability exacerbated by visual motion.
• Understanding the interplay between visual stimuli, vestibular input, and postural control in PPPD is crucial.

Purpose of the Study:

• To investigate the effects of various visual and vestibular motion stimuli on postural sway and perceived egomotion in PPPD patients.
• To compare responses between PPPD patients and healthy controls (HC).

Main Methods:

• Posturography was performed on firm and foam surfaces with galvanic vestibular stimulation (GVS) and diverse visual stimuli (VS).
• Participants included 28 PPPD patients and 26 healthy controls.
• Outcome measures were postural sway speed (PSS) and self-rated perceived egomotion.

Main Results:

• PPPD patients exhibited higher PSS than HC on a firm surface with vestibular or combined visual-vestibular stimulation, but not with visual stimulation alone.
• Group differences in PSS diminished on foam surfaces, except under baseline conditions.
• PPPD participants consistently reported higher egomotion perception across all conditions, with a non-linear relationship to postural sway.

Conclusions:

• The study challenges the notion of universally increased visual sensitivity in PPPD, as visual motion stimuli alone did not significantly increase postural sway differences.
• Multisensory stimulation appears to mitigate visual sensitivity and correct postural misperceptions in PPPD.
• The non-linear egomotion perception in PPPD patients suggests a distinct perceptual-postural scaling mechanism compared to healthy individuals.