Studies on the Visual Neural Information Flow Alterations in Parkinson's disease with visual hallucinations

Abstract

Visual hallucinations are a common non-motor symptom in Parkinson's disease (PD) patients, and the mechanism of their occurrence is still unclear. Damage of visual neural pathway is one of the main explanations for Parkinson's hallucination which will cause changes in the Visual Neural Information Flow, resulting in patients processing visual information differently than healthy people. This study aimed at investigating the abnormalities of bottom-up and top-down visual information flow in patients with PD. Eight patients with PD with hallucinations and eight healthy controls were selected. EEG data in the resting state were collected and analyzed for abnormalities in visual information flow in combination with spectral and brain network analysis. Compared with healthy controls, EEG data from PD patients showed enhanced activity in theta ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\theta$</tex> ) and alpha ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\alpha$</tex> ) bands associated with top-down information flow and reduced activity in gamma ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\gamma$</tex> ) band associated with bottom-up information flow, generating the accumulation and dissemination of disorderly information flow. The imbalance of visual information flow may be one of the main causes of visual hallucinations in PD patients.