A defect or loss of expression by speech, writing, signs, or of comprehending spoken or written language, as a result of injury or disease of the brain centers: Dr. Thompson, the new doctor at the speech clinic, specialized in working with clients who were suffering from aphasia.

Both survivors of the industrial explosion suffered aphasia and were unable to communicate to others or even to understand what was being communicated to them.

Impairment in the understanding of auditory language and communication, including the inability to write from dictation in the presence of normal hearing: Acoustic aphasia consists of sounds that are heard but which convey no meaning, however spontaneous speech, reading, and writing are supposedly not affected.

The inability to name objects or to recognize written or spoken names of objects: Because of his stroke, the patient suffered anomic aphasia and was unable to recognize the printed or spoken words for names of people, places, or things.

A type of partial or total loss of language skills as a result of brain damage: Patrick had ataxic aphasia and could not speak well enough to be understood and even his writing was so unrecognizable that no one could determine what he was trying to communicate.

Loss of the ability to name an object clearly seen until it has been perceived through some other sense; such as hearing, touching, smelling, or tasting.