Visual hallucinations are common in older people and are especially associated with ophthalmological and neurological disorders, including dementia and Parkinson’s disease. Uncertainties remain whether there is a single underlying mechanism for visual hallucinations or they have different disease-dependent causes. However, irrespective of mechanism, visual hallucinations are difficult to treat. The National Institute for Health Research (NIHR) funded a research programme to investigate visual hallucinations in the key and high burden areas of eye disease, dementia and Parkinson’s disease, culminating in a workshop to develop a unified framework for their clinical management. Here we summarise the evidence base, current practice and consensus guidelines that emerged from the workshop.Irrespective of clinical condition, case ascertainment strategies are required to overcome reporting stigma. Once hallucinations are identified, physical, cognitive and ophthalmological health should be reviewed, with education and self-help techniques provided. Not all hallucinations require intervention but for those that are clinically significant, current evidence supports pharmacological modification of cholinergic, GABAergic, serotonergic or dopaminergic systems, or reduction of cortical excitability. A broad treatment perspective is needed, including carer support. Despite their frequency and clinical significance, there is a paucity of randomised, placebo-controlled clinical trial evidence where the primary outcome is an improvement in visual hallucinations. Key areas for future research include the development of valid and reliable assessment tools for use in mechanistic studies and clinical trials, transdiagnostic studies of shared and distinct mechanisms and when and how to treat visual hallucinations.

Background Background: Levodopa and dopamine agonists (dopamine replacement therapy [DRT]) are implicated in Parkinson's disease psychosis (PDP), but the relationship between DRT and neurotransmitter dysfunction inherent to PD remains unclear. Objectives Objectives: To examine the relationship between baseline striatal dopamine transporter (DAT) binding in drugnaïve idiopathic PD, introduction of DRT, or dose change and incident early-onset PDP. Methods Methods: Baseline DAT binding was compared between patients with and without incident psychosis (defined here as hallucinations or delusions), controlling for age, sex, baseline cognition, and prospective DRT in the Parkinson's Progression Markers Initiative cohort. Incident illusions were not considered psychosis symptoms. ResultsResults: Of 386 patients, 30 (8%) developed PDP (predominantly hallucinations, mean onset 42 months) and 355 (92%) had either no PDP symptoms (mean follow-up 64 months) or reported illusions only (111/355, 31%). Incident PDP was associated with reduced baseline striatal DAT binding, controlling for confounders (F 1,377 = 10.9; P = 0.001), but not with a specific DRT regime. A total of 6 patients developed PDP when DRT free. There was no suggestion that PDP onset was coincident with starting levodopa or levodopa dose increase. Incident illusions were not associated with reduced DAT binding. Conclusion Conclusion: The findings highlight the role of disease-related dopamine mechanisms in the pathophysiology of hallucinations in Parkinson's disease alongside medication. It remains to be determined how dopamine mechanisms, medication, and other neurotransmitter systems implicated in PDP interact.

There is currently no treatment for early/intermediate Age-related Macular Degeneration (AMD) but Eye Care Professionals (ECPs) are recommended to advise patients about modifiable lifestyle factors, including dietary changes, that can slow disease progression. The aim of this review was to understand advice currently given to patients with AMD by ECPs and to evaluate evidence regarding patient compliance. A systematic review was conducted of literature published in electronic databases: CINAHL, MEDLINE, PsycINFO, PyscARTICLES, EMBASE, AMED. Methods followed PRISMA guidelines (PROSPERO registration number: CRD42020223724). Twenty-four reports were eligible for inclusion, 12 focused on ECP experience, 7 on patient experience, and 6 on impact of advice (one paper reported on the ECP and patient experience). Studies reported that a substantial proportion of patients did not recall receiving lifestyle modification advice from their ECP (57.95%, range 2–95% across patient based studies). Practitioners were most likely to provide advice about nutritional supplements (80%, range 67–93% across ECP studies), and least likely about smoking (44%, range 28–71% across ECP studies), however supplements advised did not always comply with evidence-based guidelines. The main reason for patients not following lifestyle advice was lack of provision by the ECP (54.5%, range 21–94% across studies on the impact of advice). The review highlighted a need for more studies to understand patient preferences for receiving advice and research on ECP perceived barriers to advice provision.

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