aphasia, language disturbance caused by a lesion of the brain, making an individual partially or totally impaired in his ability to speak, write, or comprehend the meaning of spoken or written words. It is distinguished from functional disorders such as stammering or stuttering, and from impaired speech due to physical defects in the organs used for speaking. Treatment consists of reeducation; the oral and lip-reading methods employed in the education of deaf and mute children have been found to be of assistance in therapy.

or dysphasia

Defect in the expression and comprehension of words, caused by damage to the frontal and temporal lobes of the brain. It can result from head trauma, tumour, stroke, or infection. Symptoms vary with the brain area involved, and the ability to put words in a meaningful order may be lost. Speech therapy may be useful. In some cases, improvement may be due to assumption of some language functions by other areas of the brain.

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