Visuoperceptual disturbances in Parkinson's disease
Kazuya Kawabata1, Reiko Ohdake2, Hirohisa Watanabe2,3
1Department of Neurology, Nagoya University Graduate School of Medicine, Japan.
Clinical Parkinsonism & Related Disorders
|July 28, 2021
Summary
Parkinson's disease (PD) often involves visual disturbances. This study found that the "incomplete letters" test is sensitive for detecting these visuoperceptual deficits in PD patients, linked to altered brain connectivity.
Area of Science:
- Neuroscience
- Ophthalmology
- Medical Imaging
Background:
- Parkinson's disease (PD) is associated with various visual deficits, but their underlying neural mechanisms are not fully understood.
- Visuoperceptual disturbances are common in PD, impacting daily functioning.
Purpose of the Study:
- To investigate the clinical and neural characteristics of visuoperceptual disturbances in Parkinson's disease.
- To identify specific tests sensitive to these deficits and explore their neural correlates.
Main Methods:
- Ninety-six participants (48 PD patients, 48 controls) underwent visual-perceptual testing, including the Visual Object and Space Perception (VOSP) battery.
- Resting-state fMRI was used to analyze functional connectivity differences between PD patients with varying performance on the 'incomplete letters' task.
- Spectral dynamic causal modeling examined causal relationships in brain networks.
Main Results:
- PD patients showed deficits in VOSP subtests, particularly the 'incomplete letters' and 'position discrimination' tasks.
- Lower 'incomplete letters' scores correlated with poorer 'position discrimination'.
- Patients with lower 'incomplete letters' scores exhibited decreased functional connectivity in the primary visual network, specifically around the calcarine sulcus, with altered connectivity to the lingual gyrus, cuneus, and thalamus.
Conclusions:
- The 'incomplete letters' test is a sensitive tool for detecting visuoperceptual disturbances in Parkinson's disease.
- Reduced connectivity within the ventral visual feedback pathway may underlie these observed visual deficits in PD.
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