Research

Agreed terms

An international project has laid out the consensus on how to describe different types of vascular dementia, allowing better communication between research groups.

One of the great strengths of science is that researchers across the world share their findings and learn from each other. In this way, each small addition to shared knowledge brings us closer to the next breakthrough.

For this collaboration to work well, researchers need a common language and an agreed understanding of the topic. With vascular dementia, there have been recent advances in our knowledge of how the brain can be affected and of its symptoms and diagnosis. This has resulted in different groups using different terminology.

The lack of well-established definitions makes it difficult to compare findings and build on each other’s work. A consensus is needed to bring shared understanding and make research comparable, regardless of where it takes place.

Alzheimer’s Society gave funding to Professor Patrick Kehoe and Dr Olivia Skrobot to lead an international project to agree how vascular dementia should be classified and described. The Vascular Impairment of Cognition Classification Consensus Study involved over 100 scientists and clinicians from 27 countries. Participants completed questionnaires looking at existing guidelines and suggested improvements. In a number of rounds, they refined guidelines and moved towards a new agreed description.

Through this process, the study clarified what is meant by the terms ‘vascular cognitive impairment’ and ‘vascular dementia’, which are sometimes used interchangeably. According to this new consensus, vascular cognitive impairment is an overall term that encompasses the earliest stages of the condition – mild vascular cognitive impairment – and the moderate and severe stages described as vascular dementia.

The researchers settled on four sub-types of vascular dementia:

• Post-stroke dementia is the term used when cognitive decline begins within six months after a stroke.
• Subcortical ischaemic vascular dementia is caused by restriction in blood supply to brain tissue, mainly caused by disease of the small blood vessels.
• Multi-infarct dementia describes cases where multiple large areas of brain tissue are damaged due to changes in the blood supply.
• Mixed dementia is a term used for people who have signs of vascular damage, but also another cause of dementia such as Alzheimer’s disease.

These guidelines have now been published in the journal Alzheimer’s & Dementia. They will be used widely and will make it easier for different researchers to compare their findings and work together in collaborative ways to advance vascular dementia research.

Find out more

• Scientific summary of the original research