Visual hallucinations in PD and Lewy body dementias: old and new hypotheses.
Marco Onofrj, J P Taylor, D Monaco, R Franciotti, F Anzellotti, Laura Bonanni, V Onofrj, A Thomas
Behavioural Neurology 2013 DOI: 10.3233/ben-129022 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Review Peer reviewed |
|---|---|
| Topics | Default mode network |
| Keywords | Neural pathways Humans Lewy body disease Parkinson disease Attention Sleep wake disorders Parkinson's disease Visual hallucinations Lewy body dementias |
| Key findings | Argues that the origin of visual hallucinations in Parkinson's disease and Lewy body dementias remains debated, with proposed mechanisms including visual disorders, REM sleep intrusions, top-down or bottom-up visual pathway dysfunction, and neurotransmitter imbalance. Presents a newer hypothesis in which persistent Default Mode Network activity during active tasks, together with dysfunctional imbalance of dorsal and ventral attention networks, contributes to visual hallucinations. |
Abstract
Visual Hallucinations (VH) are a common non-motor symptom of Parkinson's Disease (PD) and the Lewy body dementias (LBD) of Parkinson's disease with dementia (PDD) and Dementia with Lewy Bodies (DLB). The origin of VH in PD and LBD is debated: earlier studies considered a number of different possible mechanisms underlying VH including visual disorders, Rapid Eye Movement (REM) Sleep Intrusions, dysfunctions of top down or bottom up visual pathways, and neurotransmitter imbalance. More recently newer hypotheses introduce, among the possible mechanisms of VH, the role of attention networks (ventral and dorsal) and of the Default Mode Network (DMN) a network that is inhibited during attentional tasks and becomes active during rest and self referential imagery. Persistent DMN activity during active tasks with dysfunctional imbalance of dorsal and ventral attentional networks represents a new hypothesis on the mechanism of VH. We review the different methods used to classify VH and discuss reports supporting or challenging the different hypothetical mechanisms of VH.