Carotid Artery Blockage May Impair Memory, Cognitive Function

Patient Expert

Memory loss and difficulty thinking. We always jump to conclusions when we see these cognitive issues emerge that they're due to Alzheimer's disease. However, as I've mentioned before, that's not always the case. Instead, new research suggests that in some situations, cognitive impairment could be due to diminished blood flow to the brain.

Let me explain. Each person has two common carotid arteries on each side of the neck.   These arteries divide into internal and external carotid arteries. The external portion of these arteries are responsible for providing blood to the face, scalp and neck while the internal portion supplies blood to the front portion of the brain, which is responsible for thinking, speech, personality, sensory function and motor function.

However, as we age, we are at increased risk of having these arteries narrow, which is called carotid artery disease or stenosis. This narrowing is often caused by atherosclerosis, which happens when cholesterol, fat and other substances found in the blood stick to the artery walls and form plaque. This buildup causes narrowing or blockage.   And while you'd assume that this blockage would bring discomfort, in reality a person often does not know that there's a problem. For instance, my father ended up having 90 percent blockage in one carotid artery and had no idea that he was experiencing this health issue.

Now for the first time, researchers are studying the relationship between carotid artery disease and memory loss.   A new study out of Maryland involved 127 participants. Of those, 67 had carotid stenosis but didn't have any symptoms; the diameter of these participants' carotid arteries was 50 percent smaller than normal. The other participants did not have this type of stenosis, although they did have other cardiovascular risk factors such as diabetes, high blood pressure, high cholesterol and coronary artery disease.

The researchers screened all participants for cognitive function as well as specific areas of thinking, including memory, learning, decision-making, processing speed and language. Their analysis found that participants who had asymptomatic carotid stenosis performed significantly worse on tests for overall memory and thinking. These participants also performed worse on assessments of their motor speed, processing speed, learning and memory. However, language scores for these participants were comparable to the group that didn't have this type of stenosis.

While this is a small study, it does offer some important information for health care professionals. "To date, the focus of diagnosis and management of carotid artery blockages has been prevention of stroke since that was the only harm that these blockages were thought to cause to patients," said study author Dr. Brajesh K. Lal of the VA Maryland Health Care System's Baltimore VA Medical Center and the University of Maryland School of Medicine in Baltimore. "These results underscore the importance of assessing the status of memory and thinking in people with carotid artery narrowing."

I would also suggest that this study should send a signal to people who are worried about developing dementia to be proactive and vigilant in trying to eliminate risk factors of carotid artery stenosis. These risk factors include high levels of LDL (bad) cholesterol and triglycerides in the blood, smoking, high blood pressure, diabetes, obesity and a sedentary lifestyle.

You also should regularly see your doctor so if you are developing carotid artery disease, it can be diagnosed early. As part of a regular check-up, the doctor will listen to the carotid arteries with a stethoscope to see if there is an abnormal rushing sound.   Additional tests - such as a carotid angiography and a CT scan - may be requested.

If you do receive a diagnosis, treatment options will include medications, medical procedures as well as lifestyle changes. For instance, you'll be asked to focus your diet on foods that are low in saturated fat, cholesterol and sodium, and to exercise at least 30 minutes on most days. You also will be asked to limit the amount of alcohol you drink and to stop using any tobacco products.
Researchers have long believed a link existed between heart health and brain health. This latest study suggests that we should expand this linkage to include the health of blood vessels - and we need to do everything possible to keep them clear so that enough oxygen-rich blood can reach the brain.

Primary Sources for This Sharepost:

American Academy   of Neurology. (2014). Narrowing of neck artery without warning may signal memory and thinking decline.

Cleveland Clinic. (2014). Carotid artery disease.

National Heart, Lung and Blood Institute. (2010). What is carotid artery disease?