New Delhi, Oct 5 : Alzheimer's disease patients' brains do not shrink uniformly, the pattern varies between individuals with the neurodegenerative disease, finds a study.

Alzheimer's disease is the most common type of dementia and is responsible for 60-70 per cent of dementia cases in people over 65 years of age.

The study by researchers at University College London, UK, and Radboud University in the Netherlands, is the first to analyse patterns of brain shrinkage over time in people with mild memory problems or Alzheimer's disease, and then compare it against a healthy benchmark.

The results, published in the journal Alzheimer's and Dementia, are based on brain scans of 3,233 MRI brain scans from 1,181 people with Alzheimer's disease or mild memory issues and compared with benchmark brain scan data collected from 58,836 healthy people.

The team searched for the "fingerprints" of disease.

They found that people with mild memory problems whose brains shrunk more than normal quickly were increasingly at risk of developing Alzheimer's. No uniformity was found in the way the brain shrank in people with Alzheimer's, the team said.

Notably, the analysis showed that although most participants, in the beginning, had similar-sized brains, different patterns (progression/regions affected) of brain shrinkage were seen between individuals over time.

According to researchers, the individual variability may also stem from the fact that many people with Alzheimer's have more than one cause of cognitive illness, such as vascular dementia or frontotemporal dementia.

Genetic and environmental factors, such as brain injuries, alcohol consumption, or smoking habits, are also thought to play a part, the team said.

The findings may enable the development of more personalised medicines, which targets the specific range of brain areas affected in an individual.

/IANS