Hemiplegia refers to paralysis or abnormal movements on one side of a person, either the right or left. The affected side, or hemisphere, can be completely paralyzed or weakened, or it may move in rigid, stiff movements. Hemiplegia may be characterized by many other problems. For example, the use of one hand may be limited, there may be a problem with balance, speech may be affected or visual field problems may exist.

Hemiplegia can be a disorder present at or around birth, or it may be acquired after birth. The underlying cause of hemiplegia is damage to the brain as a result of disrupted blood flow. This disruption can be caused by several factors.

There are many different types of hemiplegia. Facial hemiplegia is characterized by paralysis of one particular side of the face. Cerebral hemiplegia occurs when a brain lesion disrupts the flow of blood to the brain. Spastic hemiplegia is characterized by paralysis along with spastic movements of the affected side. Spinal hemiplegia is caused by lesions that have formed on the spine.

The most common cause of hemiplegia is stroke. A stroke occurs either when a blood clot forms and obstructs normal blood flow or when a blood vessel breaks, cutting off or disrupting blood flow. Stroke is the main cause of cerebral palsy, which is another major cause of hemiplegia. Perinatal strokes, which occur in infants within three days of their birth, can cause cerebral palsy in children. Cerebral palsy limits function not specifically by total paralysis, but rather by uncontrollable spasms.

Another cause of hemiplegia can be the resulting disruption of blood flow to the brain due to an injury to the brain’s motor centers. The excessive bleeding that accompanies some head injuries either deprives the brain of blood or affects the blood vessels through swelling. If a person suffers an injury to the right side of the brain, the left side of the body experiences the paralysis or weakness. If the left side is affected, then the right side of the body will experience hemiplegia.

Hemiplegia is similar to another condition called hemiparesis, but it is far more serious. Hemiparesis is usually characterized by one side of the body that is affected not by paralysis, but by a less severe state of weakness.

It is difficult to prevent stroke and cerebral palsy in infants, so good prenatal care is essential in preventing this condition. Diabetics and those with high blood pressure and/or cholesterol are at high risk for having a stroke, as are those who are obese, smoke, don’t exercise and drink alcohol excessively.