Please can you give an introduction to the different types of dementia?
Dementia is the umbrella term used to describe a number of neurodegenerative brain disorders that cause progressive changes in thinking abilities and behaviour. The kind of deficits experienced by individuals diagnosed with dementia depends on the location and severity of the pathology in the brain.
For example, Alzheimer’s disease, which is the most common type of dementia, is characterised by a decline in memory function and a difficulty in learning and remembering novel information. In contrast, frontotemporal dementia presents with marked disturbance in social behaviour and social conduct or with disturbance of language and communication.
Other common types of dementia include dementia with Lewy bodies, which is related to Parkinson’s disease, and vascular dementia, which is caused by ‘mini strokes’ in the brain.
Please can you describe the type of dementia that attacks language and memory for words?
This type of dementia is called semantic dementia. It is a younger-onset dementia syndrome in that people are often diagnosed when they are in their 50s or 60s. Patients with semantic dementia have relatively good memory and attention, but experience significant problems with thinking of and understanding words. Even the simplest of words around the house can be difficult for these patients to recall. For example, a person with this semantic dementia might know what a kettle does, but may not know what to call it or may not recognise the word “kettle” when someone else says it.
What causes this type of dementia?
In this type of dementia, the causes are unknown with no identified triggers. On brain imaging, patients with semantic dementia show severe atrophy of the temporal lobes compared to the rest of the brain. This atrophy tends to be asymmetric and generally more severe on the left than on the right.
In recent years, this brain region has been found to be the centre or ‘hub’ where our knowledge about the world converges and is being processed. Under the microscope, there is an abnormal accumulation of a protein called TDP-43, leading to cell death.
Please can you outline the simple word-training program that has been found to restore key words in people with this type of dementia?
The program is based on a very simple type of practice, pairing pictures with words. Patients review photographs of everyday objects, one at a time, on the computer. After seeing the picture, they click to see and hear the word which matches. Patients are encouraged to repeat the word out aloud, before moving on to the next picture. The pictures are presented twice in each session, but in a different order each time.
For some participants we also included additional information about the object, presented along with the picture and the word (such as a short description of the item and how it relates to the person), or asked participants to write a sentence each day which included the word, as another form of practice. However, while these additional activities might also be helpful, we actually found that patients’ ability to recall the names of the pictures could be improved just by linking the picture and word alone.
How was this word-training program developed?
Each training program was tailor made for the individual person, selecting words which are meaningful and relevant to their everyday lives. We worked with the patients and family members to identify the most suitable words – sometimes related to household appliances, favourite foods, or other interests such as gardening tools. Photographs were then collected, for example the kettle or heater. These were the images that were then used in the training program.
How often did patients have to undergo this training program in order to start receiving benefits?
Patients were encouraged to practice once a day throughout the training period for up to an hour. We were delighted that within only 3 weeks, clear improvements could be seen in these patients’ ability to remember the trained words. In some instances, quite substantial improvements were made even after one week.
What do you think was the underlying mechanism behind the patients’ improvements?
The training aims to help people with their words in a very functional, everyday way. Unfortunately the disease still continues, however, by engaging in practice we hope to lessen the impact of it by boosting up those words that are important in activities of everyday life.
How the brain works to re-learn these words though is a very interesting question and one which we are exploring using functional brain imaging. It would be very exciting to find that through completing these word exercises, a positive effect could be achieved in the brain. This is an area of further investigation.
Are there plans in place for this simple word-training program to be made available to dementia patients worldwide?
The approach taken is simple and given the technology available these days with various apps and software, our hope is that families could develop their own programs, under the guidance of a speech pathologist or neuropsychologist. In this way we would hope the program could be made available to everyone who is interested.
How do you think the future of dementia therapy will develop?
At this stage, there is still no cure for dementia, so it becomes very important to try to help people using these sorts of interventions. Sometimes there can be the tendency for people to think that nothing can be done. It’s exciting to see from our study that there is still the opportunity for dementia patients to improve aspects of their everyday lives. We hope that research continues to provide examples of this.
Would you like to make any further comments?
With the ageing of the general population, the number of individuals affected by dementia will increase dramatically over the next 20-30 years with the number expected to treble by 2050.
No cure currently exists for dementia. The only treatments currently available are symptomatic and do not alter the progression of the disease. While a number of drug trials are currently under way, some of which look promising, a lot of work remains before an effective treatment or cure becomes available.
Current research, such as that conducted at NeuRA (Neuroscience Research Australia), will contribute to our understanding of the presentation of dementia syndromes, their progression over time and their impact on family members. Our research is important in that it will ensure that we are better equipped to identify individuals that will benefit from retraining programmes such as the one we developed and those that are likely to benefit from the few drugs currently available on the market.
This research would not be possible without the support of a number of funding bodies including the National Health and Medical Research Council of Australia and the Australian Research Council.
Where can readers find more information?
About Assoc Prof Olivier Piguet and Sharon Savage
Assoc Prof Olivier Piguet is a clinical neuropsychologist at NeuRA with over 15 years experience in dementia research. He obtained his PhD from the University of Sydney and completed his postdoctoral training at MIT in the USA.
Assoc Prof Piguet leads his research group at NeuRA investigating early presentations of frontotemporal dementia and related disorders, with a particular interest in social cognition, memory and behaviour and has published over 50 scientific papers on the topic.
He is also the co-director of FRONTIER, the only clinical research group dedicated to frontotemporal dementia in Australia.
Assoc Prof Piguet is supported by a National Health and Medical Research Council (NHMRC) Career Development Fellowship. His research is funded in part by grants from the NHMRC and by the Australian Research Council Centre of Excellence in Cognition and its Disorders.
Sharon Savage is a clinically trained neuropsychologist at NeuRA currently undertaking her PhD studies at the University of New South Wales. She is supported by an Australia Postgraduate Award, NeuRA scholarship and is part of the Australian Research Council Centre of Excellence in Cognition and its Disorders.
She has presented on her retraining work with Semantic Dementia patients at international meetings including the recent Frontotemporal Dementia conference in Manchester, UK.
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