Visual Evoked Potentials as a Biomarker for Visual Hallucination Pathway Integrity in Late-Stage Alzheimer's Disease

Abstract

Objective

Alzheimer's disease (AD) often presents visual hallucinations (VH) in late stages. Visual evoked potentials (VEPs) are noninvasive electrophysiological measures that reflect the functional integrity of the visual conduction pathway. This study uses visual evoked potentials (VEP) to assess visual pathway dysfunction and evaluates VEP as a biomarker for disease progression.

Methods

A retrospective study of 112 AD patients (2016-2024) was conducted, categorizing individuals into VH and non-VH groups based on the presence of visual hallucinations. VEP testing assessed P100 latency and amplitude. Baseline characteristics and VEP parameters were compared between groups, and correlations with disease duration were analyzed.

Results

No significant differences were observed between the two groups in terms of age, sex, years of education, homocysteine (HCY) levels, or Mini-Mental State Examination (MMSE) scores (p > 0.05). However, disease duration was significantly longer in the VH group than in the non-VH group (p = 0.00). VEP findings revealed a significantly prolonged P100 latency (p = 0.01) and reduced P100 amplitude (p = 0.00) in the VH group. Correlation analysis indicated a positive correlation between P100 latency and disease duration (r = 0.21, p = 0.03) and a negative correlation between P100 amplitude and disease duration (r = −0.34, p = 0.00), suggesting progressive impairment of the visual conduction pathway over the course of the disease.

Conclusion

AD patients with visual hallucinations exhibit more severe impairments in the integrity of the visual conduction pathway than those without hallucinations, as evidenced by prolonged P100 latency and decreased amplitude. These changes are closely associated with disease duration.