New word learning in people with aphasia

Abstract

Background: The theory of speech and language therapy intervention for people with aphasia is still under-articulated, and some people with aphasia respond better to therapy than others. The reasons for individual variation in response to therapy have not yet been fully established but may partially reflect a person with aphasia's ability to utilise a range of cerebral mechanisms, such as re-accessing damaged neural pathways and establishing new ones. Most current therapies aim to help the person with aphasia access their previously available language abilities. New learning may offer an alternative therapy approach. However, there is little evidence to date on the effect of aphasia on a person's capability to learn new linguistic information. Aim: To explore the new vocabulary learning potential of people with aphasia. Methods & Procedures: Twelve participants, under the age of 65 years and with a range of aphasia severity and personal backgrounds, were taught 20 novel words over four consecutive days. Their learning of this new vocabulary was measured via a range of single-word processing tasks based on the cognitive neuropsychological model. Ten participants repeated the tasks a few days later to establish whether the new vocabulary had been retained in long-term memory. Outcomes & Results: All of the participants demonstrated some ability to learn the new vocabulary (both novel word forms and novel word meanings), with scores ranging from 15% to 99% on the various assessments. At the follow-up session, the ten participants retained between 49% and 83% of their previous scores. Conclusions: This study has important implications for aphasia rehabilitation as it has shown that people with aphasia have the potential to learn new linguistic material, even in the presence of severe language impairments. This capacity could be exploited in therapy. Previously known words could be taught as new. Pre-therapy assessment of the person with aphasia's learning capacity and style would promote individually-tailored learning experiences and so, potentially, more effective therapy and better clinical outcomes.