Is earlier detection of dementia possible?
By Dr Ashok Jansari, Goldsmiths, University of London
Memory is one of our most important abilities that allows us to feel connected to our own past and to those around us, allowing us to reminisce about shared experiences such as a holiday or a meal out, as well as to plan things that we want or need to do today, tomorrow or next month. Not being able to remember something, otherwise known as forgetting, is natural and in fact, research has demonstrated that having exceptional memory can have negative side effects – after all, who wants to remember an awful incident with crystal clarity ten years later?! However, while forgetting is natural, it is obvious that as we get older, particularly past the age of 60, we tend to forget more easily; this is known as ‘normal age-related memory loss’ and is a simple consequence of an ageing brain. However, some (usually older) people who are suffering from one of a family of disorders that come under the dementia label, start showing worrying levels of forgetting which gets progressively worse to the point where unfortunately, some of them need to be taken into residential care. Unfortunately, the standard tests of memory that clinicians use are not able to reliably detect dementia until the disease has progressed significantly. Given the increased rates of dementia diagnoses globally (which are becoming much higher in low and middle-income countries) and the huge financial burden to society (estimates suggest that by 2030, the annual cost globally will be 2 trillion US dollars) one of the ‘holy grails’ of current research is to develop methods of earlier detection of this debilitating disorder. Our research published on our new memory test (1) is the culmination of work that started 20 years ago and we hope that it may provide a possible pre-clinical detector.
In our paper, we present a test that we have been developing for a number of years. We had developed the VALMT (Verbal Associative Learning & Memory Test) while working with a patient who had a severe form of forgetting known as ‘Accelerated Long-Term Forgetting’ or ALF; patients with ALF tend to perform normally on clinical tests and yet their families say that they forget things within a few weeks of them happening. In our patient’s case, a few months after going around the world for their 25th wedding anniversary, while his wife was talking about their time in Hawaii, he claimed never to have been there…. Despite forgetting such a significant life event, formal clinical testing showed no obvious brain abnormalities and performance on memory assessments were fully within the ‘normal’ range. However, using a new experimental method (2), we demonstrated that while the patient remembered things very well for half an hour (the usual delay used in clinical testing), within one day of learning something, he was showing significant forgetting and within four weeks, he was ‘functionally amnesic’ meaning that he had forgotten everything that he had learnt in our paradigm. Since clinicians rarely have the resources to see a patient more than once for an appointment that might last at most two hours, our original paradigm was useful from a research perspective but of no clinical utility since the patient’s forgetting was only detectable after a day. We therefore developed VALMT (3) to try to detect the patient’s obvious forgetting within ‘a clinical hour’; the task involves learning pairs of unrelated words (e.g. TROOP-SHAWL) and then being tested at different intervals by presenting the first word and requiring the participant to provide its pair (e.g. TROOP-?). With VALMT we were able to detect the patient’s ALF within an hour of learning which had never been demonstrated before with this class of patients.
In the next phase of our research, we applied VALMT to look at ageing in elderly people by comparing a group of younger people in their 20s with a group in their 60s. It wasn’t surprising that the older group showed more forgetting than the younger group since that is what is already known. However, thanks to the acute eye of the research student who was running that particular project, we saw that in fact, our elderly group were not one homogenous group but in fact, some of our 60-year olds were performing much like our 20-year olds only forgetting very slightly (which as stated above is normal) whereas others were showing catastrophic forgetting which mirrored that of our original ALF patient! As we started exploring this, we saw that these individuals had learnt our word pairs to the same level as their age-matched peers who performed like the 20-year olds but that it took them much longer both in terms of time and number of attempts to learn the whole list sufficiently. Further, our ‘Slow Older’ participants also gave much higher ratings for subjective everyday memory problems than their ‘Fast Older’ counterparts; importantly, on a standard that clinicians around the world use, these two groups showed no significant difference. Given that longitudinal epidemiological studies show that older individuals who subjectively complain of memory problems are twice as likely to develop dementia in the next five years than those who do not show these subjective difficulties, our results suggest that VALMT is detecting a pre-clinical signature of dementia.
If the findings that we present in this paper can be replicated and extended, the implications could be substantial. Since currently there are no reliable biomarkers for early detection of dementia, the best bet is for behavioural and cognitive tests to help clinicians identify those at a higher risk of developing this disorder. If this is possible, then psychoeducation for both the individual and their family members will help in understanding what may happen in the next few years which will allow them to cope with the difficulties. In addition, rehabilitation techniques are being developed such as using smart technology to help the sufferer externalise their memory and to use that to ‘remember’ things that the biological processes ravaging their brains don’t currently allow.
In addition to the work with ageing, we are also using VALMT in two other unrelated arenas. Memory problems and possible early onset dementia through repeated head injuries that may be a form of brain damage known as Chronic Traumatic Encephalopathy (CTE) has started to become documented in the last two decades. For even longer, while women have been complaining of a range of cognitive difficulties (sometimes known as ‘brain fog’) during the perimenopause, maybe because of societal issues, this issue has not received the attention that it merits. We are therefore investigating whether the greater sensitivity of VALMT may help to understand fluctuations in memory in these two areas.
In summary, through a number of parallel projects (which includes collecting data with translated versions around the world), we are exploring how our test VALMT can help in the scientific study of memory and forgetting, aid in earlier diagnosis and therefore management of individuals at risk of dementia, provide an understanding of the potential negative impacts of contact sports and finally help to understand the difficulties experienced by women during a huge biological change that they will all experience.
1. McGibbon, T., Jansari, A., Demirjian, J., Nemes, A., & Opre, A. (2022). Accelerated forgetting in healthy older samples: implications for methodology, future ageing studies and early identification of risk of dementia. Quarterly Journal of Experimental Psychology
2. Jansari, A., Davis, K., McGibbon, T. Firminger, S. & Kapur, N. (2010). When “long-term memory” no longer means “forever”: Analysis of accelerated long-term forgetting in a patient with temporal lobe epilepsy. Neuropsychologia, 48, 1707-1715
3. McGibbon, T. & Jansari, A. (2013). Detecting the onset of accelerated long-term forgetting: evidence from temporal lobe epilepsy. Neuropsychologia. 51(1), 114-122.
Ashok Jansari is the author of SAGE Publishing’s soon to be published textbook A Student’s Guide to Neuropsychology (Sept 2022). Find out more and request an inspection copy.
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