This information aims to provide an overview of hemiplegia, the impacts it may have on a child and the support available. Although this information only covers childhood, hemiplegia is a lifelong condition and so it also affects adults. It is our goal to develop services and information for adults with hemiplegia in the future, but in the meantime we hope this will give you general idea of hemiplegia and the effects of the condition.
Hemiplegia (sometimes called hemiparesis) is a condition that affects one side of the body (Greek ‘hemi’ = half). We talk about a right or left hemiplegia, depending on the side affected. It is caused by injury to parts of the brain that control movements of the limbs, trunk, face, etc. This may happen before, during or soon after birth (up to two years of age approximately), when it is known as congenital hemiplegia (or unilateral cerebral palsy), or later in life as a result of injury or illness, in which case it is called acquired hemiplegia. Generally, injury to the left side of the brain will cause a right hemiplegia and injury to the right side a left hemiplegia.
One child in 1,000 is born with hemiplegia, making it a relatively common condition. About 80% of cases are congenital, and 20% acquired.
You may also be told that hemiplegia is a form of cerebral palsy, a descriptive name for a wider group of conditions in which movement and posture are affected owing to injury to the brain. These conditions are lifelong and non-progressive i.e. they do not get worse, but they may look different over time, partly because the child is growing and developing.