The symptoms each person experiences depends on the parts of the brain that are affected. However, the most common dementia symptoms include changes in memory, thinking, behaviour, personality and emotions. These changes affect a person’s ability to perform everyday tasks and interfere with their everyday lives.

Dementia is progressive, which means that for most people the changes gradually spread through the brain and lead to the symptoms getting worse. Dementia is different for everyone – what people experience, and how quickly they are affected is unique to them. What they can do, remember and understand may change from day to day.


No one single factor has been determined as the cause of dementia. It is likely that a combination of factors, including age, genetic inheritance and environmental factors, are responsible. Some of the most common forms are:

Alzheimer's disease

This is the most common form of dementia - around two-thirds of people with dementia have Alzheimer's disease. Although we are still learning about the causes, there are typical changes seen in the brain - shrinkage and a build-up of abnormal proteins (plaques and tangles).

Alzheimer’s disease is progressive, starting as forgetfulness and mild confusion, progressing to memory loss, disorientation and changes in personality and behaviour. The specific symptoms can vary, depending on the part of the brain that is affected.

Vascular dementia

This is the second most common form of dementia. This group of conditions is caused by poor blood supply to the brain as a result of a stroke or several mini-strokes, or by the slow accumulation of blood vessel disease in the brain. Vascular dementia symptoms can begin suddenly after a stroke or gradually as disease in the blood vessels worsen. Some people will have both vascular dementia and Alzheimer’s disease.

Lewy Body disease

This condition is characterised by the presence of ‘Lewy Bodies’, which are abnormal clumps of protein in the brain. These cause changes in movement, thinking, behaviour and alertness. People with Lewy Body disease can fluctuate between almost normal functioning and severe confusion within short periods, and may also have hallucinations, seeing things that aren't really there.

Frontotemporal Dementia

Fronto-temporal dementia is a group of conditions which affect the frontal and/or temporal lobes of the brain. If a person has affected frontal lobes they will have increasing difficulty with motivation, planning and organising, controlling emotions and maintaining socially appropriate behaviour. If temporal lobes are affected the person will have difficulty with speaking and/or understanding language. Symptoms often begin in a person's 50s or 60s.




Dementia is one of New Zealand’s most significant and growing healthcare challenges. Almost 70,000 Kiwis have dementia & that number is expected to almost triple by 2050. 

Dementia also has a significant impact on the family/whan?u and friends of people with the condition. A survey we conducted in 2017 indicated that 4 out of every 5 New Zealanders knows or has known someone with dementia.

The total financial cost of dementia on the health system in 2011 was estimated as $954.8 million.

Informally, the value of those who were fully or partially removed from the workforce to care for someone with dementia was estimated at $37.7 million.




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