Dementia is a term used for a range of conditions that affect the brain. Each of these conditions prevents the brain cells - or neurons - from functioning properly, which will affect their memory, thoughts and speech.
The most common types of dementia are Alzheimer's disease, vascular dementia, frontotemporal dementia and Lewy body dementia.
The typical symptoms of dementia include memory loss, confusion, and problems with speech and understanding, and these get progressively worse over time.
According to Dementia UK, some patients will experience a phenomenon known as "sundowning". This refers to a change in behaviour in the evening.
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