Inevitably, the brain is the organ that captures neuropsychologists’ attention. At the same time, it is obvious that the brain is not an independent or isolated entity but part of a complex system such as the human body, whose health depends on a delicate balance between all its systems. Neuropsychologists sometimes do forget this part by getting swept up in brain-centric views. However, inertia and going with the flow is not the answer;neuropsychologists, as connoisseurs of attentional control processes, have been able to redirect the focus of attention and broadentheir concept of brain health.
For some time now, neuropsychologists have been searching for the connection between body, brain and cognition, discovering that treatments like chemotherapy, risk factors for cardiovascular disease, and conditions such as cancer, kidney disease, or in this particular case, heart disease, have systemic effects and can also affect the brain health and its functioning, as any otherpart of the system.
Association between heart disease and cognitive impairment
There are not many published studies on neuropsychology in the context of cardiovascular disease, and I am talking about cardiovascular disease in general because itcovers a wide array of disorders that cannot be addressed independently in this post (1). The abovementioned studies are stubbornly consistent in confirming the relationship between heart disease and cognitive impairment (2).
However, it should also be noted that the descriptions of the neuropsychological profile that have been published are, in general, extremely vague with very little precision. This may be due to the fact thatmany of these studies only use cognitive screening tests as neuropsychological performance measures.
Screening measures usually result in a number, a total score that is used as the cut-off point between cognitive normality and cognitive impairment.It is clear that this form of cognitive assessment is extremely poor, since the opportunity to reflect the true cognitive state of the patients is missed, as it does not allow for an interpretation of the neuropsychological assessment from the perspective of the studyof cognitive processes (MILBER 3), a much more interesting and detailedanalysis than the global scores of screening tests.
Not to mention the additional limitations of this type of tests when assessing clinical populations with suspected subtle cognitive impairment (e.g., patients with cardiovascular diseases). In any case, the conclusions regarding cognitive impairment in this population are quite similar and describe a neuropsychological profile characterized by deficits in attention, memory, executive functions,and information processing speed(4).
These conclusions also tend to point to mood disorders such as anxiety and depression, which are fairly commonin people suffering from cardiovascular disease. However, if we delve deeper into the analysisof the neuropsychological profile of these patients, the rate of declineincertain executive processes stands out, along with a striking decline in processing speed.
Based on the above, and if we transfer to this population Salthouse’s theory(5) regarding the effects of information processing speedon cognition, and add the role of executive deficits in the encoding and retrieval of information stored inmemory, we can begin to construct a more concrete hypothesis concerning cognitiveimpairment observed in people with cardiovascular disease.
Structural and functional brain integrity
However, brain health is not only limited to proper cognitive function, but also to structural and functional brain integrity. On this subject, there is published data pointing to a number of brain regions that may be more vulnerable to the physiological changes that occur in patients with cardiac conditions. These regions include the hippocampal formation, anterior cingulate cortex, prefrontal cortex, temporoparietalregions, and white matter. In addition, although scarcer, there is also some data on functional brain connectivity, which have shown connectivity alterations in middle orbitofrontal regions, typically associated with executive functions(7).
Once the association between heart disease and cognitive impairment has been established, we must go one step further. Neuropsychology as a science cannot be limited to the mere description of a phenomenon, it must also explain it and predict it. It is here where much of the interest from studies with cardiac patients resides, since another conclusiondrawn from several studies on this issue is that there is a highinterindividual variability regarding neuropsychological deficits among this population. That is, some patients present withdeficitswhile others do not.
We must therefore ask ourselves: what factors are involved in this variability? The main hypotheses considered in an attempt to explain the association between heart disease and cognitive impairment revolve arounda number of factors such as:
- Decrease in cerebral oxygen saturation
- Cerebral hypoperfusion (brain ischemia)
- Functional state of the myocardium
- Antithrombotic treatment
- Risk factors for cardiovascular disease (smoking, high blood pressure, diabetes mellitus, obesity and sedentary lifestyle)
While there is no conclusive data yet, variables associated with the functional state of the myocardium seem to be relevant, such as, for example, the left ventricular ejection fraction, which refers to the capacity of the myocardium to pump out blood with each contraction and supply the rest of the body. Simply put, if the machine that supplies the body with blood, nutrients and oxygen is damaged, we may suspect that the brain, a very sensitive organ, suffers and is damaged by a drop in blood perfusion and oxygen levels below a critical threshold.
Activities of daily living
Finally, the icing on the cake, the issue that closes the circle when it comes to caring for neuropsychological patients. The literature firmly indicates that the detection of cognitive impairment is key due to its significant impact on the correct performance of activities of daily living. This consideration is also applicable to patients with cardiovascular diseases, since suspected cognitive impairment could interfere with their ability to carry out self-careactivities, take medication, carry out health programs, monitor cardiac rehabilitation programs, return to work, leisure and social relations. In short, cognitive impairment may interfere with the well-being, independence, and quality of life of these patients (8).
By: Ángel Luis Martínez Nogueras. Neuropsychologist at Neurobase.
If you liked this blog post about the association of cardiovascular disease and cognitive impairment, you might like the following as well:
- Chiari Malformation Type I. A Clinical Case
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- Applications of neuromodulation in neurorehabilitation
- Página web de la fundación del corazón: https://fundaciondelcorazon.com/informacion-para-pacientes/enfermedades-cardiovasculares.html
- Eggermont LH, De Boer K, Muller M, Jaschke AC, Kamp O, et al. (2012) Cardiac disease and cognitive impairment: a systematic review. Heart 98:1334-30.
- Kaplan, E. (1988). The process approach to neuropsychological assessment. Aphasiology, 2(3-4), 309-311.
- Dardiotis, E., Giamouzis, G., Mastrogiannis, D., Vogiatzi, C., Skoularigis, J., Triposkiadis, F., &Hadjigeorgiou, G. M. (2012). Cognitive impairment in heartfailure. Cardiology Research and Practice, 1. https://doi.org/10.1155/2012/595821.
- Salthouse, T. A. (1996). Theprocessing-speed theory of adult age differences in cognition. Psychologicalreview, 103(3), 403.
- Almeida OP, Garrido GJ, Beer C, Lautenschlager NT, et al. (2012). Cognitive and brain changes associated with ischaemic heart disease and heart failure. Europeanheartjournal 2012; 34: 1769-1776. 7.
- Bernard C, Catheline G, Dilharreguy B, Couffinhal T, et al. Cerebral changes and cognitive impairment after an ischemic heart disease: a multimodal MRI study. Brainimaging and behavior 2015
- Zuccala, G., Onder, G., Pedone, C., Cocchi, A., Carosella, L., Cattel, C., … &Bernabei, R. (2001). Cognitivedysfunction as a major determinant of disability in patients with heart failure: resultsfrom a multicentresurvey. Journal of Neurology, Neurosurgery & Psychiatry, 70(1), 109-112.