Executive Dysfunction Predicts Stroke Risk

There is a large body of evidence to link cognitive decline in aging with corresponding decline in blood vessel integrity. A variety of processes in aging contribute to failing elasticity and structural remodeling of blood vessel walls, which in turn cause deterioration in the whole cardiovascular system as it tries to adapt to changing characteristics of blood flow. It is probably the case that a fair degree of cognitive deterioration in every individual is caused by physical damage to the brain resulting from issues in the vascular system: many ongoing instances of tiny blood vessels failing, causing blockages or bleeds that harm small areas of brain tissue.

Individually these events are unnoticeable, but over time they add up, and the worse the state of your cardiovascular system the worse the impact on your brain. Thus we should expect to see strong correlations between decline in cognitive function and risk of catastrophic structural failure in the cardiovascular system. The interesting part of this ugly process is that because of the way the brain works, this distribution of physical damage results in very different levels of harm to various different aspects of cognition:

Although stroke is known to result in executive dysfunction, little is known about executive dysfunction as a risk factor for stroke. Canadian Study of Health and Aging (CSHA), a longitudinal population based study of elderly Canadians, was conducted in three waves in 1990-1991 (CSHA-1), 1995-1996 (CSHA-2), and 2001-2002 (CSHA-3). In a cross-sectional analysis on CSHA-1 subjects, any association between stroke history and cognitive function was studied. In a prospective analysis, CSHA-1 stroke-free subjects were followed to CSHA-2 to see if there was any difference in stroke incidence among subjects with different baseline cognitive status. And, in a validation study CSHA-2 stroke-free subjects were followed to CSHA-3 to see if the prospective analyses findings could be replicated.

In the cross-sectional analysis, subjects who had stroke in their history had significantly lower executive function, not memory function, scores than subjects without any stroke in their history. In the prospective and validation studies, stroke incidence was affected by neither executive nor memory scores. When the analysis was restricted to normal cognition subjects, lower executive function, not memory function, scores predicted stroke incidence, and remained significant after controlling for stroke risk factors. We found executive dysfunction to be a powerful stroke risk factor among cognitively normal subjects. Testing for executive dysfunction may help identify individuals at risk for stroke in time to prevent them.

Link: http://dx.doi.org/10.1016/j.jns.2015.01.010

Comments

"We found executive dysfunction to be a powerful stroke risk factor among cognitively normal subjects. Testing for executive dysfunction may help identify individuals at risk for stroke in time to prevent them."

This shows the problem with the concept of treating some defined pathologies as "disease" and assuming that if you don't have these conditions, you're healthy.

The research makes it clear that if you have executive dysfunction, you've already had miniature strokes, lots of them, slowly and surely killing your brain. How can they even say "executive dysfunction" and "cognitively normal" in the same sentence? If you let high cholesterol invade your brain, you're already screwed up for life (or until the right bioengineering lab can get you these chunks of your brain back).

Posted by: Slicer at January 29th, 2015 12:01 PM

@Slicer: Scary, isn't it? All these little problems building up that we don't make screens for because nobody wants to spend the money or cause too big a stir.

Posted by: Seth at January 29th, 2015 12:25 PM

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