A review of conduction aphasia.

In this paper, a historical overview of the interpretation of conduction aphasia is initially presented. It is emphasized that the name conduction aphasia was proposed by Wernicke and was interpreted as a disconnection between the temporal and frontal brain language areas; this interpretation was re-taken by Geschwind, attributing the arcuate fasciculus the main role in speech repetition disturbances and resulting in the so-called Wernicke-Geschwind model of language. With the introduction of contemporary neuroimaging techniques, this interpretation of conduction aphasia as a disconnection syndrome due to an impairment of the arcuate fasciculus has been challenged. It has been disclosed that the arcuate fasciculus does not really connect Wernicke's and Broca's areas, but Wernicke's and motor/premotor frontal areas. Furthermore, conduction aphasia can be found in cases of cortical damage without subcortical extension. It is concluded that conduction aphasia remains a controversial topic not only from the theoretic point of view, but also from the understanding of its neurologic foundations.