Neurology: How epilepsy, vascular risk factors, and cognitive function relate

In large, population-based longitudinal studies, older adults with epilepsy declined cognitive abilities at an average faster
rate than expected by their age.
Longitudinal studies of aging that combine epilepsy determination with thorough risk factor characteristics and repeated cognitive measurements are well suited to elucidate modifiable factors
that accelerate cognitive decline in patients with epilepsy.
Identifying these factors can help guide the development of interventions to protect the cognitive health
of older adults with epilepsy.

Figure 1: Cover art of the paper

In the general aging literature, vascular risk factors (VRFs), such as high blood pressure, diabetes, and smoking, are associated
with the development of cognitive impairment and dementia.
About 35% of dementia is caused
by a combination of potentially modifiable risk factors.
However, in older adults with epilepsy, there is a clear lack of data
on the relationship between VRFs and cognitive processes.

Older adults with a combination of epilepsy and another risk factor may experience more cognitive decline than expected, not only more than those with epilepsy alone or another risk factor, but even more
than expected from the sum of the excessive declines associated with epilepsy alone and another risk factor.

This larger-than-expected decline in cognitive ability is called an "excessive decline due to the interaction" of epilepsy and other risk factors
.
In the Cardiovascular Health Study (CHS), as an example of this excessive decline due to the interaction of epilepsy and another factor, the average global cognitive decline in older adults with epidemic epilepsy and apolipoprotein 4 alleles has greatly exceeded expectations
.

The Vascular Health Study (CHS) is a population-based longitudinal cohort study of 5,888 U.

Figure 2: Graph of the paper results

From these models, they estimated excess average cognitive decline
due to epilepsy's interaction with each VRF.
The result
.
We observed an over-average decline in global cognitive ability (3MS) due to the interaction of epilepsy with hypertension (without the interaction, the 8-year average decline was 6.
6 points larger than expected; 95% CI: 1.
3, 12.
0) and abstinence from alcohol (5.
8 points larger than expected; 95% CI: 0.
3, 11.
3).

It was also observed that due to the interaction of epilepsy with previous strokes, the average decline in information processing speed (DSST) was too large (the average 9-year decline was 18.
1 points larger than expected; 95% CI: 7.
6, 28.
5), alcohol abstinence (6.
1 points larger than expected; 95% CI: 2.
5, 9.
8), and elevated triglyceride levels (2.
4 points per standard deviation than expected; 95% CI: 0.
4, 4.
3).