Advances In the Treatment of Visual Hallucinations In Neurodegenerative Diseases

Abstract

Treatment of visual hallucinations in neurodegenerative disorders is not well advanced. The complexity of underlying mechanisms presents a number of potential avenues for developing treatments, but also suggests that any single one may be of limited efficacy. Reducing medication, with the careful introduction of antidementia medication if needed, is the mainstay of current management. Antipsychotic medication leads to excessive morbidity and mortality and should only be used in cases of high distress that do not otherwise respond. Education, reduction of risk factors and psychological treatments have limited evidence of efficacy, but are unlikely to cause harm.

Cognitive phenotype of psychotic symptoms in Alzheimer's disease: evidence for impaired visuoperceptual function in the misidentification subtype

“…Our findings are also consistent with integrative theories regarding the origins of visual hallucinations within the context of neurodegenerative disease (reviewed by Collerton and Taylor, 2013), which suggest that deficits in attentional control and perceptual processing are necessary for visual misperceptions and hallucinations to occur (Collerton et al ., 2005; Diederich et al ., 2009; Shine et al ., 2011). On the basis of the present findings, it is tempting to speculate that psychotic symptoms in AD are underpinned by disruption of the cholinergic/dopaminergic axis within frontostriatal circuits, with additional pathology in the ventral visual pathway in patients with the misidentification subtype.…”

“…Contemporary models (Coltheart, 2010;Corlett et al, 2010) that integrate neuropsychological and associative learning theories have emphasised the importance of perceptual expectations in the pathophysiology of delusions and propose that visuoperceptual deficits, combined with disruption of corticostriatal networks, play an integral role in misidentification delusions. Our findings are also consistent with integrative theories regarding the origins of visual hallucinations within the context of neurodegenerative disease (reviewed by Collerton and Taylor, 2013), which suggest that deficits in attentional control and perceptual processing are necessary for visual misperceptions and hallucinations to occur (Collerton et al, 2005;Diederich et al, 2009;Shine et al, 2011). On the basis of the present findings, it is tempting to speculate that psychotic symptoms in AD are underpinned by disruption of the cholinergic/dopaminergic axis within frontostriatal circuits, with additional pathology in the ventral visual pathway in patients with the misidentification subtype.…”

Visual hallucinations in neurological and ophthalmological disease: pathophysiology and management

“…76 Around 50% of patients are significantly distressed by their experiences, with fear and anger being the most common responses. 77 As core defining features of DLB, they are likely to be present at the point of diagnosis, contrasting with AD where VH occur in later stages of cognitive decline, 5 to 6 years after the onset of dementia. 78 VH are associated with increased likelihood of nursing home placement.…”

Management of visual hallucinations in dementia and Parkinson’s disease

“…Whilst this approach is widely recommended, it is important to note that it is expert, rather than evidence, based. Other reviewers have recommended increased socialization, as well as improving lighting and reducing visual triggers, but admit this because they are useful and inexpensive rather than based on trial evidence ( Collerton and Taylor, 2013). Correcting visual defects could be considered, as the phenomenology of VH in PD and DLB can be similar to that seen in the Charles Bonnet syndrome (CBS), where visual hallucinations occur in the context of visual impairment, with retained insight.…”