[Visual hallucinations in Parkinson's disease].

Area of Science:

• Neuroscience
• Ophthalmology
• Sleep Medicine

Background:

• Visual hallucinations (VH) significantly impact Parkinson's disease (PD) patients and caregivers.
• Understanding the pathogenesis of VH in PD is crucial for effective management.

Purpose of the Study:

• To elucidate the underlying theories and pathogenetic mechanisms of VH in PD.
• To explore the role of the retina-hypothalamus pathway and circadian system in VH development.
• To identify novel therapeutic targets for VH in PD.

Main Methods:

• Review of existing theories on VH in PD.
• Analysis of visual processing disruptions, including retinal input and central processing.
• Examination of ponto-geniculo-occipital system function, REM sleep intrusion, and brainstem filtering.
• Investigation of the retino-hypothalamic tract and its role in circadian rhythm regulation.

Main Results:

• VH in PD involve impaired visual processing, disrupted internal image suppression, REM sleep intrusion, and altered brainstem filtering.
• Dysfunction in the retina-hypothalamus system and its impact on circadian rhythms are implicated in VH timing and severity.
• Drug-induced mesolimbic system overactivation may contribute to VH.

Conclusions:

• VH in PD are multifactorial, involving visual pathway, sleep regulation, and neurotransmitter systems.
• The retina-hypothalamus-circadian system axis presents a promising target for novel VH treatments in PD.
• Further research into circadian system modulation could alleviate VH burden in Parkinson's patients.