Altered Visual and Proprioceptive Spatial Perception in Individuals with Parkinson's Disease

Area of Science:

• Neuroscience
• Human Perception
• Movement Disorders

Background:

• Parkinson's disease (PD) is characterized by difficulties integrating sensory information, potentially affecting spatial orientation.
• Perception of verticality relies on visual, vestibular, and somatosensory systems, which may be compromised in PD.

Purpose of the Study:

• To investigate alterations in subjective visual vertical (SVV) and subjective haptic vertical (SHV) perception in individuals with Parkinson's disease.
• To compare these perceptions between PD patients and healthy controls and assess clinical relevance.

Main Methods:

• A cross-sectional study involving 13 PD patients and 14 healthy controls.
• SVV assessed using the bucket test; SHV assessed using rod rotations (clockwise and counterclockwise).
• Statistical analysis included t-tests, Cohen's d for clinical relevance, and Pearson correlations.

Main Results:

• Individuals with PD showed greater variability in right SHV supination compared to controls (p=.002).
• Clinically relevant differences were observed in right SVV, right SHV pronation, and left SHV pronation.
• A higher proportion of PD patients exhibited E-effect (overestimation of body tilt) and significant alterations in SHV compared to previous literature.

Conclusions:

• Subjective visual and proprioceptive perception of verticality is significantly altered in patients with Parkinson's disease.
• These findings highlight sensory integration deficits impacting spatial orientation in PD.
• Further research may explore therapeutic strategies targeting sensory-motor integration in PD.