The president’s cognitive health: winning with the MoCA

To the Editor,

While some individuals diagnozed with mild cognitive impairment (MCI) are able to maintain normal function, greater than 50% go on to develop dementia in later life1. It is for this reason that a tool sensitive for detecting MCI, such as the Montreal Cognitive Assessment (MoCA), has become increasingly useful for practitioners and scientists alike. The author of the present article rightly acknowledges that the MoCA is a more appropriate tool in detecting MCI than the traditional mini-mental state examination2. However, consideration should be given to Dr Ronny Jackson's somewhat parochial description of the nature of this test. He states that this test takes "significantly longer to complete" than a variety of other tests. We would be interested to know the cognitive assessments that Dr Jackson considered given that there are a number of validated cognitive tools available that are considerably longer in duration than the expected 10 minutes it takes to administer the MoCA3.

It is also pertinent to raise awareness to the limitations of the MoCA, notwithstanding the complexity of the clinical challenge underlying diagnosis. While in this instance it is of no concern to Donald Trump, there are issues surrounding the specificity of this assessment in that definitive cut-off points for cognitive impairment and dementia have not yet been widely agreed upon4. Therefore, it is possible that MCI or even dementia could be misdiagnozed (or indeed missed) by a consulting physician. In addition to this, it is worth remembering that some individuals may have neuropathological characteristics of dementia and remain asymptomatic5. In these cases, neuropsychological assessments are unable to detect asymptomatic dementia.

While Donald Trump does not apparently suffer from any cognitive deficits, he should be made aware of the susceptibility of the brain to neurodegeneration and a decrease in cognitive function with age. However, there is good news for Trump; regular physical activity can decrease the risk of cognitive impairment and dementia in the elderly 6. The underlying mechanisms are not entirely clear, though regular aerobic exercise has the capacity to increase grey and white matter within various regions of the cerebral cortex7, many of which are involved in the cognitive processes assessed in the MoCA. Furthermore, regular aerobic exercise has been associated with increases in potent growth factors, notably brain-derived neurotrophic factor that likely contributes to hippocampal hypertrophy and improved memory in older adults8.

We also need to highlight the importance of cerebral blood flow (CBF), since good perfusion makes for good (brain) performance and politics! This has become increasingly significant in light of recent evidence suggesting that the inexorable decline in CBF with advancing age likely contributes to the pathophysiology of cognitive decline and dementia. However, exercise across the adult lifespan can improve both perfusion and vasoreactivity helping turn back the brain's "hands of time", buying the older adult a brain that functions as if it were at least a decade younger; in essence, disassociating chronological from biological ageing9. While these findings are relevant for those that have been exercising throughout their lives, it is not too late for inactive individuals to make the transition and start building a better brain (i.e. there's still a window of opportunity for Trump). In support, 12 weeks of aerobic exercise activity has been shown to improve perfusion and vasoreactivity irrespective of (chronological) age10.

With the above information in (the active) mind, we would recommend that Donald Trump chooses to walk rather than use the buggy next time he is on the golf course! To what extent improved perfusion makes for improved politics remains to be established, no doubt an avenue ripe for future research!

References
1. Gauthier S, Reisberg B, Zaudig M, et al. Mild cognitive impairment. The Lancet 2006;367(9518):1262-70.
2. Chinthapalli K. The president's cognitive health: winning with the MoCA. BMJ 2018;360:k424.
3. Woodford H, George J. Cognitive assessment in the elderly: a review of clinical methods. QJM: An International Journal of Medicine 2007;100(8):469-84.
4. Lees R, Selvarajah J, Fenton C, et al. Test accuracy of cognitive screening tests for diagnosis of dementia and multidomain cognitive impairment in stroke. Stroke 2014;45(10):3008-18. doi: 10.1161/STROKEAHA.114.005842
5. Driscoll I, Troncoso J. Asymptomatic Alzheimer's disease: a prodrome or a state of resilience? Current Alzheimer Research 2011;8(4):330-35.
6. Laurin D, Verreault R, Lindsay J, et al. Physical activity and risk of cognitive impairment and dementia in elderly persons. Archives of neurology 2001;58(3):498-504.
7. Colcombe SJ, Erickson KI, Scalf PE, et al. Aerobic exercise training increases brain volume in aging humans. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 2006;61(11):1166-70.
8. Erickson KI, Voss MW, Prakash RS, et al. Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences 2011;108(7):3017-22.
9. Bailey DM, Marley CJ, Brugniaux JV, et al. Elevated aerobic fitness sustained throughout the adult lifespan is associated with improved cerebral hemodynamics. Stroke 2013;44(11):3235-8. doi: 10.1161/STROKEAHA.113.002589
STROKEAHA.113.002589 [pii] [published Online First: 2013/08/22]
10. Murrell CJ, Cotter JD, Thomas KN, et al. Cerebral blood flow and cerebrovascular reactivity at rest and during sub-maximal exercise: effect of age and 12-week exercise training. Age 2013;35(3):905-20.