Sometimes, strokes only affect one part of the body. Often, after people suffer strokes, they may find that they lose certain vital body functions that are controlled by the brain. This happens because the brain is divided into four main parts: right hemisphere, left hemisphere, cerebellum, and brain stem. Each part controls different areas of the body. Where a stroke occurs in the brain and the extent of the damage affects what body functions are disabled. In the severest of strokes, all body functions may be lost. It is possible, for less severe strokes, that the victim may not experience any loss of physical or mental function.
Right Hemisphere
This part of the brain control the left side of the body, short-term memory, and analytical and perceptual tasks such as judging distance, size, speed, and portion.
Light Hemisphere
The left hemisphere controls the right side of the body, speech and language, and long-term memory.
Cerebellum
The cerebellum controls balance and coordination.
Brain Stem
This important part of the brain controls eye movement, hearing, speech, swallowing, and life-supporting functions such as breathing, blood pressure, and heartbeat.
The process of a stroke, when affecting one area of the body, happens when the flow of blood to an area of the brain is blocked, which can cause the death of brain cells and brain tissue. Blood carries oxygen and other nutrients that the brain depends on, so when the blood flow stops, certain parts of the brain aren’t getting the nutrients and oxygen they need; thus, they die. As a result, certain functions of the body that are controlled by those particular nerve cells may lose their ability to perform.
There are two main types of stroke, ischemic and hemorrhagic. Each type has several subtypes of strokes that can occur. The different types of stroke are part of the reason why strokes affect just one or several parts of the body.
Hemorrhagic Stroke
The development of a hemorrhagic stroke shows one reason why strokes affect one or more than one part of the body. A hemorrhagic stroke is caused when blood vessels in the brain rupture and begin to bleed into the surrounding tissue. This bleeding compresses other blood vessels that are nearby and causes the surrounding tissue to not get oxygen. This type of stroke usually affects a big area of the brain and is much more severe than ischemic stroke. More body functions tend to be affected with this type of stroke because a larger area of the brain is affected.
There are different kinds of hemorrhagic strokes: intracranial hemorrhages, subarachnoid hemorrhage, epidural hematoma, subdural hematoma, and intracerebral hemorrhage. Because these different types of strokes affect different areas of the brain and spinal cord, different parts of the body may be affected.
Ischemic Stroke
The development of an ischemic stroke may not affect as many parts of the body as a hemorrhagic stroke. An ischemic stroke is caused when an artery supplying blood to the brain is blocked by a blood clot, which results in less blood flowing to the brain. An ischemic stroke differs from the hemorrhagic stroke because the blood clot remains in the same location and may only affect that one area of the brain, unlike when a blood vessel that bursts and impacts a large area of the brain. Thus, there may be a fewer parts of the body that are affected in an ischemic stroke. Ischemic strokes are much more common, as approximately 80 percent of all strokes are ischemic.
There are several different of types of ischemic strokes: embolic infarct, thrombotic infarct, and lacunar infarct. There are also types of ischemic stroke that happen due to undetermined causes. Each of these different types may differently affect the brain.