The relationship between novel word learning and anomia treatment success in adults with chronic aphasia

Learning capacity may influence an individual's response to aphasia rehabilitation. However, investigations into the relationship between novel word learning ability and response to anomia therapy are lacking. The aim of the present study was to evaluate the novel word learning ability in post-stroke aphasia and to establish the relationship between learning ability and anomia treatment outcomes. We also explored the influence of locus of language breakdown on novel word learning ability and anomia treatment response.

30 adults (6F; 24M) with chronic, post-stroke aphasia were recruited to the study. Prior to treatment, participants underwent an assessment of language, which included the Comprehensive Aphasia Test and three baseline confrontation naming probes in order to develop sets of treated and untreated items. We also administered the novel word learning paradigm, in which participants learnt novel names associated with unfamiliar objects and were immediately tested on recall (expressive) and recognition (receptive) tasks. Participants completed 48 h of Aphasia Language Impairment and Functioning Therapy (Aphasia LIFT) over a 3 week (intensive) or 8 week (distributed) schedule. Therapy primarily targeted the remediation of word retrieval deficits, so naming of treated and untreated items immediately post-therapy and at 1 month follow-up was used to determine therapeutic response.

Performance on recall and recognition tasks demonstrated that participants were able to learn novel words; however, performance was variable and was influenced by participants' aphasia severity, lexical-semantic processing and locus of language breakdown. Novel word learning performance was significantly correlated with participants' response to therapy for treated items at post-therapy. In contrast, participants' novel word learning performance was not correlated with therapy gains for treated items at 1 month follow-up or for untreated items at either time point. Therapy intensity did not influence treatment outcomes.

This is the first group study to directly examine the relationship between novel word learning and therapy outcomes for anomia rehabilitation in adults with aphasia. Importantly, we found that novel word learning performance was correlated with therapy outcomes. We propose that novel word learning ability may contribute to the initial acquisition of treatment gains in anomia rehabilitation.