Neurobehavioral response to increased treatment dosage in chronic, mild aphasia

Abstract

Intensive aphasia treatment has been employed with equivocal results likely due to variability in the severity of participants as well as in the parameters that comprise intensity (e.g., session duration). Constraint Induced Language Therapy (CILT; Pulvermüller et al., 2001) is an intensive aphasia therapy that has been replicated successfully and also tends to use similar dosage parameters across replication studies (e.g., Barthel, et al, 2008; Maher, 2006). Meinzer and colleagues (2008; 2007) found that it was their most severely affected participants who tended to benefit most from treatment of CILT, positing that those who had withdrawn from verbal communication the most were those most likely to benefit from the forced use inherent to CILT. It is also possible that since CILT and associated treatment materials was designed for more impaired participants; those more mildly affected may have been insufficiently challenged during the treatment period. If so, it follows that that neural change would be less likely. The present study employed a multiple probe technique (McReynolds & Kearns, 1983) in which CILT was delivered at a dosage of three hours per day for twenty days. A hierarchy of complex stimuli was created to pose adequate challenge for two individuals with mild aphasia. Discourse analysis and naming response time were used to quantify changes in language efficiency. In addition, fMRI scanning was performed at four time points throughout the treatment process in order to compare potential language changes to changes in neural activation patterns. These results are expected to add to the limited fMRI data currently available for intensive aphasia treatment