Dataset Information

Impaired tilt perception in Parkinson's disease: a central vestibular integration failure.

ABSTRACT:

Introduction

Impaired balance control is a hallmark symptom in Parkinson's disease (PD). Altered sensory-motor integration contributes to the deficiency. We aimed to determine whether impaired vestibular signal processing added to the disorder. We exposed patients (N = 11; 68±6y) and age-matched healthy subjects (hS: N = 19; 65±11y) on a motion platform in complete darkness to two consecutive forward tilt movements (12 series; N = 24; overall 288 trials) and asked them to indicate which tilt was perceived larger. By combing tilt movements with translations we manipulated vestibular sensory input in order to investigate whether putative impairment resulted from a deficiency of the sensory organs (semicircular canals in 'single-SCC-cue-condition', otoliths in 'single-OT-cue-condition') themselves or to a sensory integration failure ('multi-cue-condition').

Results

Tilt discrimination in the multi-cue-condition was inferior in patients compared to hS (p = 0.02). No significant differences between the two groups were found for both single-cue-conditions. Comparison of multi-cue-condition with a prediction resulting from the combination of both single-cue-conditions by optimal observer theory revealed that patients (p = 0.04), in contrast to hS, failed to efficiently combine SCC and OT information to improve tilt perception.

Conclusion

We found that PD patients distinguished forward tilts less precise than hS, suggesting impaired vestibular perception. Tilt discrimination in patients, moreover, did not improve as much as in hS in conditions where both SCC and OT information was available compared to conditions where only SCC or OT cues were activated. The latter provides evidence that tilt misperception in PD most likely results from an integration failure of vestibular signals.

SUBMITTER: Bertolini G

PROVIDER: S-EPMC4398395 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Publications

Impaired tilt perception in Parkinson's disease: a central vestibular integration failure.

Bertolini Giovanni G Wicki Andrea A Baumann Christian R CR Straumann Dominik D Palla Antonella A

PloS one 20150415 4

<h4>Introduction</h4>Impaired balance control is a hallmark symptom in Parkinson's disease (PD). Altered sensory-motor integration contributes to the deficiency. We aimed to determine whether impaired vestibular signal processing added to the disorder. We exposed patients (N = 11; 68±6y) and age-matched healthy subjects (hS: N = 19; 65±11y) on a motion platform in complete darkness to two consecutive forward tilt movements (12 series; N = 24; overall 288 trials) and asked them to indicate which ...[more]

PMID: 25874868

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Project description:Parkinson's disease is prototypically a movement disorder. Although perceptual and motor functions are highly interdependent, much less is known about perceptual deficits in Parkinson's disease, which are less observable by nature, and might go unnoticed if not tested directly. It is therefore imperative to seek and identify these, to fully understand the challenges facing patients with Parkinson's disease. Also, perceptual deficits may be related to motor symptoms. Posture, gait and balance, affected in Parkinson's disease, rely on veridical perception of one's own motion (self-motion) in space. Yet it is not known whether self-motion perception is impaired in Parkinson's disease. Using a well-established multisensory paradigm of heading discrimination (that has not been previously applied to Parkinson's disease), we tested unisensory visual and vestibular self-motion perception, as well as multisensory integration of visual and vestibular cues, in 19 Parkinson's disease, 23 healthy age-matched and 20 healthy young-adult participants. After experiencing vestibular (on a motion platform), visual (optic flow) or multisensory (combined visual-vestibular) self-motion stimuli at various headings, participants reported whether their perceived heading was to the right or left of straight ahead. Parkinson's disease participants and age-matched controls were tested twice (Parkinson's disease participants on and off medication). Parkinson's disease participants demonstrated significantly impaired visual self-motion perception compared with age-matched controls on both visits, irrespective of medication status. Young controls performed slightly (but not significantly) better than age-matched controls and significantly better than the Parkinson's disease group. The visual self-motion perception impairment in Parkinson's disease correlated significantly with clinical disease severity. By contrast, vestibular performance was unimpaired in Parkinson's disease. Remarkably, despite impaired visual self-motion perception, Parkinson's disease participants significantly overweighted the visual cues during multisensory (visual-vestibular ) integration (compared with Bayesian predictions of optimal integration) and significantly more than controls. These findings indicate that self-motion perception in Parkinson's disease is affected by impaired visual cues and by suboptimal visual-vestibular integration (overweighting of visual cues). Notably, vestibular self-motion perception was unimpaired. Thus, visual self-motion perception is specifically impaired in early-stage Parkinson's disease. This can impact Parkinson's disease diagnosis and subtyping. Overweighting of visual cues could reflect a general multisensory integration deficit in Parkinson's disease, or specific overestimation of visual cue reliability. Finally, impaired self-motion perception in Parkinson's disease may contribute to impaired balance and gait control. Future investigation into this connection might open up new avenues of alternative therapies to better treat these difficult symptoms.

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Dataset Information

Impaired tilt perception in Parkinson's disease: a central vestibular integration failure.

Introduction

Results

Conclusion

Publications

Impaired tilt perception in Parkinson's disease: a central vestibular integration failure.

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