As most of you may already know, a stroke is somewhat of a "brain attack", or what happens when blood flow to a part of the brain stops. There are two main types of ischemic stroke: one in which a clot may form in an artery that is already very narrow creating a thrombotic stroke. In addition, a cerebral embolism, or an embolic stroke can occur in which a clot breaks off from some part of the body, or from a place in the blood vessels of the brain and travels up to the brain. Plaque built up on an artery wall or blood vessel from cholesterol, fat, and other substances can lead to a blood clot, which may block blood from reaching the brain and cause an ischemic stroke. On the other hand, a hemorrhagic stroke (less common) occurs when a blood vessel in part of the brain becomes weak enough to burst open, causing blood to leak into the brain.
The symptoms of stroke depend on what part of the brain is affected and usually develop suddenly and without warning. Symptoms of stroke are usually most severe at onset and may possibly slowly get worse, or they may occur on and off for the first day or two. The brain is an incredibly complex organ, with each area having a responsibility for a particular function or ability. The brain is divided into four primary parts: the right hemisphere, the left hemisphere, the cerebellum and the brain stem. The right hemisphere of the brain controls the movement of the left side of the body as well as analytical and perceptual tasks, such as judging distance, size, speed, or position and seeing how parts are connected to wholes. A stroke in the right hemisphere usually causes paralysis in the left side of the body known as left hemiplegia. Patients of right-hemisphere strokes may also have problems with their spatial and perceptual abilities in addition to changed behavior, judgment abilities, and short term memory difficulty. Similarly, survivors of left-hemisphere stroke may also develop memory problems, which can include shortened retention spans, difficulty learning new information and problems in generalizing and conceptualizing. The left hemisphere of the brain controls the movement of the right side of the body as well as speech and language abilities. A left-hemisphere stroke often causes paralysis of the right side of the body, known as right hemiplegia.
A stroke in the cerebellum can cause coordination and balance problems, dizziness, nausea, vomiting, and abnormal reflexes of the head and torso. The brain stem, however, is the area of the brain that controls all of our involuntary, "life-support" functions, such as heartbeat, blood pressure, and breathing rate. It also controls eye movements, hearing, speech and swallowing abilities. Survivors of a brain stem stroke may also develop paralysis in one or both sides of the body because of the impulses generated in the brain's hemispheres that must travel through the brain stem on their way to the appendiges.
Jill Bolte Taylor, a brain research scientist, experienced and studied her very own stroke in the left hemisphere, but after spending eight years recovering, she feels more enlightened and stronger than before. She gives a very emotional, captivating and detailed description of her experience during and after her stroke on T.E.D talks, for which I have provided the link below!
http://www.ted.com/talks/jill_bolte_taylor_s_powerful_stroke_of_insight.html
References:
http://www.stroke.org/site/PageServer?pagename=EFFECT
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001740/
I think Jill Taylor's talk was very interesting and informative. There's really no better way of learning about such an event (other than first hand experience) than hearing it from a "survivor." And by survivor I specifically someone who has recovered so well. I especially liked her connection between the 2 hemispheres and computer processors. Interestingly, it really helps to visualize the brain and the whole nervous system as a complex circuit, in terms of electrical engineering.
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