Perception and hallucinations

5. Hallucinations in people with dementia

A hallucination is an experience of something that is not really there. They can occur for all the senses, though visual hallucinations (seeing things that are not really there) are the most common type experienced by people with dementia.

Visual hallucinations can be simple (eg seeing flashing lights) or complex (eg seeing animals, people or strange situations). Less often in people with dementia, hallucinations can involve hearing, smelling, tasting or feeling things that do not really exist.

Hallucinations and dementia

People with dementia are often thought to be hallucinating when in fact they are making a mistake about what they have seen (see ‘Visuoperceptual mistakes’). In some specific forms of dementia, hallucinations are more common. These include dementia with Lewy bodies and Parkinson’s disease dementia. People with Alzheimer’s disease can also experience hallucinations.

Hallucinations in people with dementia with Lewy bodies usually take the form of brightly coloured people or animals. They often last for several minutes and can occur on a daily basis. Some people with dementia with Lewy bodies can also experience hallucinations in other senses – for example, hearing things that aren’t there (auditory hallucinations) or smelling things that aren’t there (olfactory hallucinations). People with other types of dementia may also experience these types of hallucinations, as well as tactile hallucinations (sensing things that aren’t there).

Supporting the person

If you suspect that a person is hallucinating, try to calmly explain what is happening. If they cannot retain this information, repeat it when they are more relaxed. If this is still not possible, don’t argue with them – it will not help. Trying to convince someone that they are mistaken can lead to more distress for both you and them. Stay with the person and try to reassure them. Explain that even though you can’t sense what they do, you want to know what they are experiencing. Listen carefully to what they describe. There may be some language difficulties that may explain what the person is reporting. For example, referring to green cushions as ‘cabbages’.

Hallucinations may be limited to a particular setting. Gently leading someone away from where they are having the hallucinations can help make the hallucinations disappear.

It may help to distract the person, and see if this stops the hallucinations. For visual hallucinations, consider making changes to the environment, such as improving lighting levels and reducing visual clutter. In addition, make sure that the person has regular eye checks, wears the correct glasses (if needed) and that they are clean.

For auditory hallucinations, arrange to have their hearing checked. If the person wears a hearing aid, check that it is working properly and encourage them to wear it. People are less likely to hear voices that are not there when they are talking to someone real, so having company around may help.