Can identifying problems with short-term memory help to diagnose Alzheimer's disease?
Research project: Short-term memory binding: A sensitive cognitive marker for Alzheimer's disease
Lead researcher: Dr Mario Parra
Institution: University of Edinburgh/Heriot-Watt University
Grant type: Fellowship
Duration: 3 years
Amount funded: £187,116
Start Date: September 2012
End Date: September 2016
What was the project, and what did the researchers do?
There has been much work in the past focusing on a specific type of long-term memory, and investigating how it is affected in Alzheimer's disease. However these effects are also found in normal ageing, as well as other types of dementia, and so changes in this are not specific to Alzheimer's disease.
Changes in short-term memory in Alzheimer's disease have been less well investigated. Dr Parra and his team at the University of Edinburgh had shown that a particular test -called 'short-term memory binding'- can identify changes that are specific to Alzheimer's disease, as it is not affected during normal ageing or other conditions.
This test explores the ability of a person to temporarily hold combinations of features (for example both shapes and colours within coloured shapes) in their memory. This declines in Alzheimer's disease, maybe even before other symptoms start to show. It is not seen in healthy ageing, chronic depression or other forms of dementia.
In this project the researchers investigated loss of this short-term memory binding further. They looked at:
- Whether problems with short-term memory binding a specific to, and an early indicator of, Alzheimer's disease
- The biological basis of this decline
- Whether these problems are responsible for people with Alzheimer's disease often struggling with daily tasks
What were the key results and how will this benefit people with dementia?
Memory loss at different stages of disease
For the first time the researchers have been able to document problems with short term memory binding in people at all stages of Alzheimer's disease development. This included people who had no other symptoms. The researchers confirmed the hypothesis that problems with short-term memory binding are present and detectable in individuals who will develop dementia due to Alzheimer's disease.
Clearer and earlier diagnosis will both allow people to be better informed, and also help research into dementia and possible treatments.
The biological basis of short term memory loss
The researchers found that the short term memory loss results from damage to brain structures different to those traditionally targeted by standard memory tests. This suggests that these simple memory tests can show early changes associated to the development of Alzheimer's disease. This information means that researchers may want to refocus on these unexplored areas.
Effect on daily living
Mario and his team developed several tools for studying the effect of short term memory loss on everyday life of people. Using these they found that problems with short-term memory binding are indeed associated to impairments in activities of daily living, such as remembering where things are.
The researchers are developing tools that combine of Virtual Reality and Cognitive Assessment, to enhance memory abilities and promote independent living in people who are experiencing cognitive decline.
What happened next? Future work and additional grants
Dr Parra was awarded a Senior Fellowship by Alzheimer's Society to continue this work, which was which was converted to a Project Grant after he was appointed as Assistant Professor at Heriot-Watt University.
How were people told about the results?
Parra, M.A. Memory binding in Alzheimer's Disease. Sixth book of the series "Research Progress in Alzheimer's Disease and Dementia", to be published by Nova Science Publisher, Inc., New York. (Invited contribution, in press)
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Parra MA (2016). A commentary on Liang et al.'s paper with regard to emerging views of memory assessment in Alzheimer's disease. Cortex pii: S0010-9452(16)30159-9. doi: 10.1016/j.cortex.2016.06.006
Pietto M et al. (2016). Behavioral and electrophysiological correlates of memory binding deficits in patients at different risk levels for Alzheimer's disease. Journal of Alzheimer's disease (in press).
Rhodes S et al. (2016). Aging and feature binding in visual working memory: The role of presentation time. Quarterly Journal of Experimental Psychology Q J Exp Psychol (Hove).69(4):654-68.
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Koppara A et al. (2015) Feature binding deficits in subjective cognitive decline and in mild cognitive impairment. Journal of Alzheimer's Disease, Sep 24; 48 Suppl 1: S161-70.
Parra, MA et al. (2015). Gist-based illusions within and across memory domains in autism spectrum disorder. Memory DOI: 10.1080/09658211.2015.1004349.
Parra MA et al. (2015). Memory binding and white matter integrity in familial Alzheimer's disease. Brain 138, 1355-69.
Russ TC et al. (2015). Prediction of general hospital admission in people with dementia: cohort study. British Journal of Psychiatry, 206(2):153-9.
Geldorp B et al. (2014). Cognitive and neuropsychological underpinnings of relational and conjunctive working memory binding across age. Memory, 12:1-11.
MacPherson SE et al. (2015). Simultaneous performance of two memory tasks in preclinical Alzheimer's disease due to the E280A presenilin-1 mutation. Journal of Alzheimer's Disease, 44, 481-492.
Parra MA (2014). Overcoming barriers in cognitive assessment of Alzheimer's disease. Dementia & Neuropsychologia, Views & Reviews, 8, 95-98. http://www.demneuropsy.com.br/imageBank/PDF/en_v8n2a02.pdf
Ibañez A and Parra, MA (2014). Mapping memory binding onto the connectome's temporal dynamics: Towards a combined biomarker for Alzheimer's disease. Front. Hum. Neurosci. 8:237. doi: 10.3389/fnhum.2014.00237
Smith K et al. (2015). Comparison of Network Analysis Approaches on EEG Connectivity in Beta during Visual Short-Term Memory Binding Tasks. Conf Proc IEEE Eng Med Biol Soc.; 2015:2207-10. doi: 10.1109/EMBC.2015.7318829.
Smith K et al. (2015). Cluster-span threshold: An unbiased threshold for binarising weighted complete networks in functional connectivity analysis. Conf Proc IEEE Eng Med Biol Soc.; 2840-3. doi: 10.1109/EMBC.2015.7318983.
This work was presented 31 times at research conferences