Aphasia is a combination of a speech and language disorder caused by damage to the brain that affects about one million individuals within the US. Most often caused by a cerebral vascular accident, which is also known as a stroke, aphasia can cause impairments in speech and language modalities. To be diagnosed with aphasia, a person's speech or language must be significantly impaired in one (or several) of the four communication modalities following acquired brain injury or have significant decline over a short time period (progressive aphasia). The four communication modalities are auditory comprehension, verbal expression, reading and writing, and functional communication.