Living with Dementia November 2008

By Caroline Bradley

New research suggests that not answering questions does not always mean that people with dementia have lost the ability to understand

We often link an ability to use language with a person's ability to understand. Perhaps the best example of this is the stereotype of the frustrated Brit abroad slowly and loudly repeating words in a desperate bid to be understood.

We know that dementia has a dramatic affect on people's language skills and ability to communicate, but what is less clear is the effect this loss of skills has on their knowledge and ability to understand.

Researchers in Scotland have used a new approach to analyse this problem. Focusing on the skills we need to use language, their tests revealed that people with Alzheimer's disease may retain more knowledge and understanding than they tend to express.

Defining loss
Professor Trevor Harley, a member of the research team from the University of Dundee, said,

'A lot of research into dementia investigates the skills and abilities that are lost rather than what is preserved.'

If people with Alzheimer's disease find it difficult to define words and objects, it might seem reasonable to assume that they no longer understand the meaning of the word in question. However, as Professor Harley explains,

'Defining a word requires a lot more knowledge and understanding than simply knowing what the word means.

If you try to define the word 'apple' you need to talk about trees and fruit and shape and colour and taste. It's a complicated notion that requires different abilities.'

It is perfectly possible for a person with dementia to know what an apple is, but be unable to define it. Professor Harley and colleagues decided to investigate whether Alzheimer's disease affects our ability to use language in this way.

Testing for skills
Two groups of seven older people of similar ages were presented with 30 individual words, including names of animals, insects and general household objects, and asked to describe their meaning. Members of one group had a diagnosis of Alzheimer's disease, while people in the control group had no Alzheimer's.

The words were spoken one at a time to each individual in private. Once the participant had offered a definition they were asked six further questions about the word. Three of the questions were open, and three required the individual to make a definite choice. Two independent judges then assessed the definitions that had been given.

How did people do?
The people with Alzheimer's disease were much less able to provide meaningful spontaneous definitions compared to members of the control group. However, they did provide a great deal of relevant information when they were asked the six supplementary questions, showing that they had an understanding of the meaning of the words in question.
Professsor Harley said,

'The assumption has been that Alzheimer's disease causes this knowledge to be destroyed. However, we found that if you ask appropriate questions, people with Alzheimer's can often generate detailed information about a specific subject. Knowledge has been lost, but not as much as we thought. To get such striking results from a small group suggests we are dealing with a strong effect.'

Autobiographical information
Interestingly, the definitions offered by the seven people with Alzheimer's disease tended to contain a lot of autobiographical information. People would refer to their personal experiences when explaining meanings, which in many ways is how young children tend to describe things.

Professor Harley said,

'Returning to early patterns of language use is not that surprising as these were the skills we learned first; the robust building blocks on which we placed the more sophisticated skills we developed later.'

This use of personal experiences adds weight to the argument that the professionals caring for people with Alzheimer's disease need to know about their life stories and events.
 
Professor Harley says,

'There's a danger of being over-optimistic about these results, but they do provide evidence that it is important not to assume that people with Alzheimer's disease have lost understanding or knowledge. It is too easy to think that they do not know simply because they do not communciate. We need to take on the challenge of finding ways to communicate successfully, to try different routes to find common ground.'

The research was carried out by Dundee, Abertay and St Andrews universities.

Reference:
Harley, Trevor A., Jessiman, Lesley J., MacAndrew, Siobhan B. G. and Astell, Arlene 'I don't know what I know: Evidence of preserved semantic knowledge but impaired metalinguistic knowledge in adults with probable Alzheimer's disease ', Aphasiology, 22:3, 321 - 335

A small US study has found that when adults with Alzheimer's disease are spoken to like children they are more resistant to care. The research showed that speaking to people with dementia in an adult manner enhances their quality of life and improves the entire care experience.