What is a Stroke? Understanding Strokes

A stroke is a medical emergency that occurs when the blood supply to any part of your brain is interrupted. This can lead to brain damage, disability, or even death. The good news is that if you know what to do in response to stroke symptoms and it's recognized quickly enough, then chances are better than ever for recovery!

What is a Stroke? The Definition

A stroke, also referred to as a cerebrovascular accident (CVA), is defined as a neurologic event caused by a change in blood flow to the brain. This has two primary causes of stroke: ischemic, when there is a decrease in blood flow to the brain; and hemorrhagic, when there is bleeding within the brain.

What is a Stroke? Understanding Symptoms

The most common symptoms of a stroke can include one or more of the following: numbness or weakness on one side of the body, confusion, dizziness, difficulty speaking or understanding speech, and vision problems. Even though many people associate a stroke with a headache, this is only common with a hemorrhagic stroke, which is significantly less prevalent (~10%) than an ischemic stroke. The symptoms  each person will experience can vary significantly.

Why the varied symptoms? Brain Anatomy

A quick dive into brain anatomy can help us understand why stroke symptoms can be so different for each individual. The brain is the center of our nervous system, and is made up of three major parts: the cerebrum (the largest part), the brain stem, and the cerebellum. Each has a unique role to play in everyday life such as thinking, breathing, and heart rate regulation. All of these areas are susceptible to damage from lack of blood supply after a stroke.

Here are some symptoms examples:

• Frontal Lobe Stroke (most common)- difficulty sequencing movement, paralysis, or confusion
• Parietal Lobe Stroke- difficulty with the perception of language, vision, or sensation
• Temporal Lobe Stroke- poor memory, depth perception, and speech; changes in behavior and emotions
• Occipital Lobe Stroke- facial drooping, slurred speech, arm weakness
• Brain Stem Stroke- changes in coordination, onset of dizziness or vertigo
• Other differentiating areas where a stroke can occur include the cortex, basal ganglia, cerebellum and more

How Blood Gets to the Brain

Blood is supplied to the brain via two pathways, the carotid arteries in the side of the neck and the vertebral arteries along the spine itself. From these larger arteries, they then branch into cerebral arteries that bring blood to different areas of the brain (anterior, middle, and posterior). Like anywhere else in the body, blood in the brain flows through a vast network of smaller and smaller arteries until it reaches the tiny capillaries that surround each brain cell.

Due to its close proximity to the larger carotid arteries and the vast blood supply it provides to the brain, the middle cerebral artery is the most common area for a stroke to occur.

Understanding Strokes

Strokes can be a frightening experience, but it's important to remember that they are treatable. Having a better understanding of what a stroke is and potential symptoms are your best line of defense. If you or someone you know experiences any of these, don't hesitate to seek medical help immediately!