Aphasia occurs when a part of the brain is damaged, for example, in cases of stroke, head injury, infection or tumor. There are 2 areas of the brain that are mainly concerned with language – Wernike’s area and Broca’s area. They are located on the left side of the brain in most people. The Wernike’s area is located behind the Broca’s area. These are sensory and motor speech centers of the brain. These are connected with each other and other parts of the brain through a network of nerves. Damage to these or any connected areas or nerves could lead to aphasia. Aphasia can develop suddenly in cases of stroke, head injury and tumor or gradually in old age.

Aphasia is diagnosed through clinical examination aided with diagnostic studies such as CT scan, MRI, PET scan or using SPECT imaging. Some patients recover completely when the underlying cause is treated whereas some may worsen progressively. A number of patients benefit with speech therapy.