DementiaRoadmap Wales

Promoting living well with dementia across Wales

Sight, perception and hallucinations in dementia

October 20 2012

This Alzheimer’s Society factsheet considers some specific difficulties that people with dementia can have with sight, perception and hallucinations, and suggests ways to support them.

Download Sight, perception and hallucinations in dementia

Specific types of dementia can also damage the visual system and cause visuoperceptual difficulties. These include Alzheimer’s disease, Parkinson’s disease dementia, dementia with Lewy bodies and vascular dementia. Rarer forms of dementia, such as posterior cortical atrophy (PCA), can also cause visuoperceptual difficulties.

The specific difficulties a person experiences will depend on the type of dementia they have. This is because each type of dementia can damage the visual system in a different way.

There are some specific forms of dementia, however, where hallucinations are more common. These include dementia with Lewy bodies and Parkinson’s disease dementia. Hallucinations can also occur in Alzheimer’s disease.

For people with a Lewy Body type dementia it is common to experience vivid hallucinations which are not the result of mis-perceiving the environment but are being created as a feature of internal changes to the brain.

It is important to ensure that the person actually is hallucinating and not just misperceiving information as this can lead to inappropriate use of medications. People with a Lewy Body type dementia are at particular risk of severe adverse reactions to antipsychotic medication.

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