Behavioral and neuronal changes during treatment of mixed transcortical aphasia: a case study

The development of language mechanisms outside the traditional language regions is evidenced by the case of K.S., a patient with chronic mixed transcortical aphasia, that is, good repetition performance compared to all other language abilities. The aphasia was caused by an infarction of the left a. carotis interna that completely destroyed the left perisylvian language region and adjacent structures. Five years post onset the patient underwent intensive aphasia therapy. In the treatment setting chosen, both speech production and comprehension abilities improved as demonstrated by adequacy and reaction time scores. It is argued that the behavioral changes observed are likely to be due to (a) newly acquired communicative strategies and (b) neuronal changes within K.S.'s brain. The behavioral changes are explained in terms of strengthening of synaptic connections and formation of Hebbian cell assemblies corresponding to words.