1 June 2021
CANTAB used to assist with identifying patients with mild cognitive impairment and subjective cognitive impairment to develop and evaluate the feasibility of a Mediterranean diet and lifestyle education intervention
Dr. Andrea McGrattan, a Research Dietitian and Lecturer in Nutrition and Dietetics, spoke to us about her PhD research at Queen’s University Belfast, using CANTAB cognitive testing within a Mediterranean Diet feasibility study, “THINK-MED”, among people with cognitive impairment.
Can you tell us a little about yourself and your research group?
I am a Research Dietitian and I currently work as a Lecturer in Nutrition and Dietetics at Newcastle University, UK. My main research interests include risk reduction of cardiovascular and neurocognitive diseases. I am interested in the design, development and testing of diet and lifestyle interventions to promote behaviour change among at-risk populations. I am also interested in process evaluation methods understanding the impact and usefulness of complex interventions. It was my PhD studies at the Centre for Public Health, Queen’s University Belfast (QUB) with Professor Jayne Woodside and colleagues where my passion for diet and cognition research evolved. The Public Health Nutrition Group at QUB is focused on how diet and lifestyle factors affect chronic disease risk, including obesity, cardiometabolic disease and dementia with the ultimate aim of translating research findings into improvements in health care and public health policy.
What was the rationale behind your research?
Diet has been suggested to have a significant association with reducing cognitive decline and progression of dementia . A Mediterranean diet is characterised by a high intake of fruits, vegetables, wholegrain, nuts, legumes and olive oil, a moderate intake of fish, poultry and alcohol and a low intake of red meat .
Observational research evidence has shown how a greater adherence to a Mediterranean Diet is associated with reduced cognitive decline and dementia risk . This evidence is strengthened by analyses of the PREDIMED RCT , which demonstrated a significant effect of increased Mediterranean Diet adherence on clinical cognitive outcomes. Therefore, rationale exists for further intervention studies in non-Mediterranean countries and particularly among those at risk of cognitive decline to explore the diet and cognition link as well as identify the ability of individuals to incorporate this dietary pattern into their own lifestyles.
Which methods did you use?
We undertook a mixed methods pilot randomised controlled trial (RCT) to develop and evaluate the feasibility of a Mediterranean diet and lifestyle education intervention 'THINK-MED' among people with cognitive impairment. This study was funded by The Wellcome Trust – Seed Award in Science. We were interested in understanding the barriers and enablers to dietary change among people with cognitive impairment, to enable this information to be used to design and develop a Mediterranean diet and lifestyle intervention.
The RCT was conducted among a clinical cohort of patients who had Mild Cognitive Impairment (MCI) and a community-based sample of people with subjective cognitive impairment (SCI). The study included two phases; Phase I was a qualitative study to explore barriers and enablers to dietary change and Phase II was a pilot RCT to evaluate the feasibility of implementing this dietary intervention study. This research has provided useful learning to inform further follow-on trials.
How was cognition measured during the feasibility trial?
A comprehensive cognitive assessment was performed using a validated neuropsychological test battery provided by Cambridge Cognition Ltd. (CANTAB). This involved seven tests specific and sensitive to people with cognitive impairment, including: Motor Screening Task (MOT) Paired Associates Learning (PAL); Reaction Time (RTI); Rapid Visual Information Processing (RVP); Spatial Working Memory (SWM); Delayed Matching to Sample (DMS) and Pattern Recognition Memory (PRM). Cognition was measured at baseline (month 0) and end of study (either 6 or 12 months). As this was a feasibility study, we were interested in factors associated with implementation rather than cognitive changes.
Why did you choose CANTAB for your study?
The CANTAB cognitive test battery was useful for this research study as it incorporated tests that were specific and sensitive to people with cognitive impairment. In practice, the CANTAB software worked well, was user-friendly and was well-received by participants. Some, particularly those who were older, found certain tests challenging to follow at times. We were able to allow breaks in between tests, which appeared to help. The fact that the software can be accessed via iPad devices meant that it was easily transportable and useful for visiting participants out in the community.
What were your key findings and implications of your study?
Phase I highlighted that patients with MCI were interested in making changes to their diet and provided important information that helped to tailor the intervention study before pilot testing. In Phase II, we assessed the feasibility of recruitment into, and retention of, participants in the THINK-MED dietary intervention among a clinical sample of MCI patients and a community-based sample of participants with SCI.
There were challenges encountered during implementation of this pilot study in relation to recruitment of MCI patients, which affected the ability to meet the desired sample size and also the ability to retain participants for the full duration of the study, particularly those who were older and with MCI. Therefore, a tailored MD intervention among an MCI population may not be feasible and requires further pilot testing.
This research is important as it can inform future research and is relevant to researchers interested in enrolling participants at risk of cognitive decline into clinical trials.
1. Jennings, A.; Cunnane, S.C.; Minihane, A.M. Can nutrition support healthy cognitive ageing and reduce dementia risk? BMJ 2020, 369, m2269, doi:10.1136/bmj.m2269.
2. Bach-Faig, A.; Berry, E.M.; Lairon, D.; Reguant, J.; Trichopoulou, A.; Dernini, S.; Medina, F.X.; Battino, M.; Belahsen, R.; Miranda, G., et al. Mediterranean diet pyramid today. Science and cultural updates. Public Health Nutr 2011, 14, 2274-2284, doi:10.1017/s1368980011002515.
3. Lourida, I.; Soni, M.; Thompson-Coon, J.; Purandare, N.; Lang, I.A.; Ukoumunne, O.C.; Llewellyn, D.J. Mediterranean diet, cognitive function, and dementia: a systematic review. Epidemiology 2013, 24, 479-489, doi:10.1097/EDE.0b013e3182944410.
4. Martínez-González, M.A.; Salas-Salvadó, J.; Estruch, R.; Corella, D.; Fitó, M.; Ros, E. Benefits of the Mediterranean Diet: Insights From the PREDIMED Study. Prog Cardiovasc Dis 2015, 58, 50-60, doi:10.1016/j.pcad.2015.04.003.
Dr Andrea McGrattan - Research Dietitian and Lecturer in Nutrition and Dietetics at Newcastle University