One other, much less common, type of aphasia has been associated with damage to the arcuate fasciculus and is called conduction aphasia. Individuals suffering from this disorder sometimes mispronounce words, but typically do not have articulation problems. They are fluent, but may have disrupted rhythm because of pauses and hesitations. Comprehension of spoken words is normally good. However, the task of repeating a word or phrase (spoken by someone else) creates major difficulty, with forms such as vaysse and fosh being reported as attempted repetitions of the words “base” and “wash.” What the speaker hears and understands can’t be transferred very successfully to the speech production area.

It should be emphasized that many of these symptoms (e.g. word-finding difficulty) can occur in all types of aphasia. They can also occur in more general disorders resulting from brain disease, as in dementia and Alzheimer’s disease. Difficulties in speaking can also be accompanied by difficulties in writing. Impairment of auditory comprehension tends to be accompanied by reading difficulties. Language disorders of the type we have described are almost always the result of injury to the left hemisphere. This left hemisphere dominance for language has Language and the brain 163 also been demonstrated by another approach to the investigation of language and the brain.