Visual evoked potential abnormalities in dementia with Lewy bodies

Area of Science:

• Neuroscience
• Ophthalmology
• Neurology

Background:

• Dementia with Lewy bodies (DLB) and Parkinson's disease (PD) share visuo-perceptual deficits and visual hallucinations (VHs).
• Visual evoked potential (VEP) delays, reversed by l-dopa, are noted in PD, linked to retinal dopaminergic amacrine cell dysfunction.
• VEP abnormalities and their correlation with clinical symptoms in DLB remain under-investigated.

Purpose of the Study:

• To compare VEP abnormalities between DLB and PD patients.
• To assess correlations between VEP measures and visuospatial deficits or VHs in DLB patients.

Main Methods:

• Fifteen DLB patients and fifteen matched PD patients were recruited.
• Pattern reversal VEPs were recorded before and after l-dopa administration.
• A brief neuropsychological assessment was conducted.

Main Results:

• DLB patients showed delayed P100 latency to foveal stimuli in both eyes compared to normative data.
• DLB patients exhibited significantly longer P100 latency for right-eye foveal stimulation pre-l-dopa compared to PD patients (p=0.018).
• No significant correlations were found between VEP alterations and visuospatial deficits or VHs.

Conclusions:

• DLB patients demonstrate longer P100 VEP delays than PD patients, particularly affecting the right visual pathway.
• Findings suggest mechanisms beyond pre-geniculate dopaminergic pathways, potentially involving thalamic dysfunction, contribute to VEP abnormalities in DLB.
• Further research is needed to elucidate the specific neurophysiological underpinnings of visual disturbances in DLB.