Aphasias

Aphasia is a neurological impairment of the human language system. Language includes several subsystems (speech sounds, grammatical structure, meaning) and is conveyed and understood through various input and output channels (spoken, written, gestured). In aphasia, each of these channels is affected to some degree, with difficulty ranging from minimal to severe. Minimal deficits include being slower to understand reading material, to get a joke in conversation, or to choose a precise word. Severe aphasia impairs even simple language tasks, such as matching a single printed word to the object it represents, or providing one's name and address.

Aphasia results from damage that is nearly always isolated to the left side of the brain. This damage interrupts the blood supply to the brain and starves the affected ...