Page 133 - The Memory Program How to Prevent Memory Loss and Enhance Memory Power

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Types of Small and Large Strokes

Thrombosis (clotting).
Embolism (blood clot from the heart is propelled into the brain).
Hemorrhage (bleeding, as from an aneurysm).

Embolism

I already described the mechanism behind clot or thrombus formation and the risk of hemorrhage
(bleeding) from an aneurysm. An embolus is a thrombus that initially forms in the heart, often
around a diseased heart valve. The thrombus is then mechanically dislodged and propelled by the
heart's pumping action into the big carotid arteries going in a straight line to the head. The embolus
flies through the wide carotids but then gets stuck in a slimmer branching artery inside the brain. The
result, like a thrombus, is a stroke called an infarction or infarct. The embolus just sits there,
blocking the blood vessel that used to supply the infarcting (dying) group of nerve cells in the brain.

Ministrokes

Ministrokes are usually caused by thrombosis, with clots forming in small sizes at different times
from months to years apart. The death of nerve cells caused by each little infarct leads to a small
degree of cognitive decline, including memory loss.

Typical Sequence of Symptoms

1. A sudden but small decline in mental faculties or slight weakness of an arm or leg.
2. Confusion and memory lapses that last a few days.
3. Gradual but incomplete recovery in mental faculties.

This sequence occurs because the brain reacts to the ministroke by pouring out edema fluid that
compresses the area surrounding the dying brain tissue. As the edema subsides, the nerve cells that
were compressed and paralyzed by the edema fluid regain their function, but those cells that already
died in the center of the ministroke (infarct) cannot recover. Hence, there is only partial clinical
recovery after each ministroke. If these little strokes occur repeatedly over several years, they can
lead to full-blown dementia with severe memory loss. The history of repeated, staggered decline with
incomplete