A stroke occurs when there is a disturbance of the blood supply to the brain. When the blood supply is cut off to an area of the brain this leads to the death of that part of the brain. Whatever part of the body that part of the brain controlled, it can no longer do so.
Aphasia is mostly caused by a cerebral vascular accident (CVA), so called stroke. This can be as a result of an embolus, thrombosis or haemorrhage. The latter is a burst artery with blood pouring into the brain. While an embolus is a blood clot that has formed on the inside of the heart or the inside of an artery, braking loose and travelling in the blood until it ‘jams’ in a small artery. The narrowing of an artery by deposits of fat is a thrombosis.
Aphasia can also develop after a person sustains a brain injury from head trauma such as traffic or sports accident, or in street violence, or brain tumor, or an infection, such as herpes encephalitis, or disease.