Protein aggregation or other abnormalities are a feature of several dementias. Alzheimer’s is characterised by two types of abnormal protein deposits in the brain, involving amyloid beta proteins and tau proteins.²²

TAR DNA-binding protein 43 (TDP-43) is another protein associated with Alzheimer’s as well as frontotemporal dementia. TDP-43 is a nuclear RNA/DNA-binding protein linked to regulating RNA processing.^23,24

TDP-43 aggregations in the CNS are also found in amyotrophic lateral sclerosis (ALS) and limbic predominant age-related TDP-43 encephalopathy (LATE). LATE dementia symptoms resemble Alzheimer’s but there is a different pattern of brain changes and symptoms tend to appear in older people, over the age of 80.

Lewy bodies are the build-up in the brain of the protein alpha-synuclein. They are a key feature of dementia with Lewy bodies, but they also occur in Parkinson’s disease dementia. Differential diagnosis looks at whether motor symptoms such as tremor or rigidity were occurring before dementia or if there are any impaired motor symptoms.^23,25

Vascular dementia arises mainly from damage to arteries in the brain, which may affect memory. Different types of vascular damage can occur, such as transient ischaemic attacks (TIAs) and stroke (with rapid appearance of dementia symptoms) or small vessel disease of the brain. This can be a result of long-term hypertension, but also due to amyloid protein build-up.^2,3