There are various types or causes of dementia, and it is possible for someone to have a combination of these - this can make an accurate diagnosis more difficult.

BRACE funds research into the most common types of dementia which are as follows:

Alzheimer's disease 
  • Alzheimer’s disease is the most common form of dementia, responsible for about 62% of cases.
  • The first sign is short term memory loss. This develops to further symptoms including more severe memory problems, confusion, disorientation, personality changes and problems with language and speech.
  • Alzheimer’s disease affects the brain physically. Proteins build up in an abnormal way in the brains of those with Alzheimer’s disease. Amyloid-β deposits known as ‘plaques’ build up around brain cells, and tau ‘tangles’ form inside brain cells.
  • The result is damage to brain cells and a loss of connections between them. The brain becomes smaller than normal.
  • Alzheimer’s disease is progressive, meaning it gets worse over time. Because it develops slowly, it can often be difficult to recognise.
Vascular dementia (VaD)
  • Vascular dementia is the second most common type of dementia, responsible for 17% of cases.
  • Diseased blood vessels mean that the blood supply to parts of the brain is reduced. This causes death of brain cells, leading to problems with memory, thinking and reasoning.
  • At least 10% of people with dementia are diagnosed with mixed dementia, where both Alzheimer’s disease and vascular disease are causes of dementia.
Dementia with Lewy bodies (DLB)
  • DLB accounts for about 4% of dementia cases.
  • DLB shares symptoms with both Alzheimer’s disease and Parkinson’s disease.
  • Lewy bodies are deposits of a protein called α-synuclein in nerve cells, and are associated with cell damage. They are the underlying cause of several progressive diseases affecting the brain and nervous system, including dementia with Lewy bodies and Parkinson’s disease.
  • Symptoms of DLB depend upon where the Lewy bodies are in the brain. If they are in the outer layers of the brain, this is usually associated with problems in mental abilities.
  • About one third of Parkinson’s disease patients eventually develop dementia.
Frontotemporal dementia (FTD)
  • FTD is less common (2% of dementia cases), but is a significant cause of dementia in those under 65 years of age.
  • Nerve cells in the frontal and/or temporal lobes of the brain die and the pathways that connect them change. This leads to symptoms including changes in personality and behaviour, and difficulties with language.
  • Autopsy studies show that the death of nerve cells in the frontal and temporal lobes is linked to clumps of abnormal proteins inside cells, including tau. Tau may take the form of Pick bodies, giving frontotemporal dementia its original name of Pick’s disease.