APHASIA is a very complex problem. It has been studied by neurologists, physiologists, psychologists, and speech clinicians. Because of the diverse approaches used by the investigators, aphasia has been a subject of great controversy. In recent years, however, it has become evident that, whichever approach interests the investigator, he must take account of the others.
A good definition of aphasia is given by Fulton1 in Howell's textbook on physiology, "The term aphasia means literally the loss of the power of speech, but the term is now used to include any marked interference with the ability either to use or to comprehend symbolic expression of ideas by spoken or written words or by gestures, or interferences with the use of language in thinking."
To be really exact, we should differentiate between speech and language. Language is a psychic process centered in the cortex and in its widest sense signifies the