Conduction aphasia

Overview
Conduction aphasia, also called associative aphasia, is a relatively rare form of aphasia, thought to be caused by a disruption in the fiber pathways connecting Wernicke's and Broca's areas. The arcuate fasciculus has previously been implicated as this fiber bundle, however more recent evidence suggests that the extreme capsule connects Wernicke's and Broca's areas.

Presentation
Patients with conduction aphasia show the following characteristics:


 * speech is fluent
 * comprehension remains good
 * oral reading is poor
 * Major Impairment in repetition
 * many phonemic paraphasias (phone substitution errors)
 * transpositions of sounds within a word ("television" &rarr; "velitision") are common.

To understand the symptoms, recall that Broca's area is associated roughly with expression, Wernicke's area with comprehension.

With both areas intact but the neural connections between them broken, there is the curious condition where the patient can understand what is being said but cannot repeat it (or repeats it incorrectly). This patient will also end up saying something inappropriate or wrong, realize his/her mistake, but continue making further mistakes while trying to correct it.