MR tractography depicting damage to the arcuate fasciculus in a patient with conduction aphasia

Abstract

An 84-year-old right-handed man with a history of atrial fibrillation and a left parietal lobe infarct was admitted to the stroke unit due to a sudden decline in responsiveness. He was awake but silent, though his comprehension was intact. Slight weakness was noted in his right upper and lower extremities. On the third day, the patient regained his voice, but his speech was impaired with paraphasic errors and naming difficulties. Repetition was markedly impaired. The clinical findings suggested motor/conduction aphasia. An MR examination showed a left middle cerebral artery infarction involving the parietal lobe. Since both the Broca and Wernicke areas were not directly involved on the diffusionweighted imaging (DWI) study, we did MR tractography on the assumption that the left arcuate fasciculus may be damaged. These images revealed a brain infarct completely engulfing the left arcuate fasciculus, supporting the diagnosis of conduction aphasia 1 (figure; see also the video at www.neurology.org).

MR Tractography: A Review of Its Clinical Applications

“…More recent studies have shown that it may also be used to measure patient outcomes after stroke. [39][40][41] Attempts have also been made to assess the language circuits, [42][43][44] including the arcuate fasciculus, aˆber tract that connects the temporal lobe (primary auditory cortex), Wernicke's area, and Broca's area (frontal lobe). Thisˆber bundle is considered to be eloquent when the left hemisphere is considered, and vascular insult to this circuit can result in conduction aphasia.…”

“…Thisˆber bundle is considered to be eloquent when the left hemisphere is considered, and vascular insult to this circuit can result in conduction aphasia. 43 Studies have shown that the degree of damage to this circuit can predict the patient's language function in the chronic stage following the vascular event. 44 Tractography has also been used in theˆeld of pediatric ischemic brain insult.…”

A Review of Conduction Aphasia

“…According to Geschwind [18], disconnection syndromes were higher function deficits that resulted from white matter lesions or lesions of the association cortices; conduction aphasia was usually presented as the prototypal example of a disconnection syndrome. Since then, it has been generally assumed that, in conduction aphasia, the lesion affects the arcuate fasciculus [19,20] and sporadically an indirect pathway passing through the inferior parietal cortex [21••].…”

“…It is not easy to find cases of conduction aphasia with a lesion limited to the arcuate fasciculus. Although the arcuate fasciculus is often reported to be involved in conduction aphasia [19,20,28], cortical lesions alone without subcortical extension may also produce conduction aphasia [29,30]; furthermore, patients with lesions of the arcuate fasciculus may retain the language repetition ability [31,32], suggesting that the arcuate fasciculus is not crucial for language repetition.…”

Advances in Vascular Cognitive Impairment 2007

“…42 Cognitive studies as yet are limited but an elegant report by Yamada et al clearly shows quantifiable damage to the arcuate fasciculus in conduction aphasia. 43 A number of disconnection syndromes have also been studied in this way with correlation between the neuropsychological deficit and affected tracts. 41 Other data relating cognitive changes to tractography are so far few, but this technique promises expansion in hodology with the ultimate promise of standardized 3D hodological atlases.…”