Vocabulary acquisition in aphasia: Modality can matter

The present case study investigated modality-specific aspects of novel word acquisition in aphasia. It was prompted by recent aphasia case studies indicating great interindividual variability in the ability to learn and maintain novel words in aphasia. Moreover, two previous case studies revealed a striking effect of input modality by showing effective word learning and re-learning via visual input only (Kohen, Sola, Tuomiranta, Laine, & Martin, 2012; Tuomiranta et al., 2014). The present participant TS with chronic nonfluent aphasia and post-semantic anomia was administered novel word-referent learning tasks. In the first experiment, the learning phase included simultaneous phonological and orthographic input, while the follow-up was probed separately for spoken and written responses. In the second experiment, we studied the effect of four different input and output modality combinations on her ability to learn to name the novel items. In the first experiment, TS's spoken naming performance during the learning phase was just within the range of healthy controls. Maintenance declined and remained outside that range during the whole 6-month follow-up. However, TS maintained the learned words better in written than in spoken naming throughout the follow-up, and in written naming, her maintenance stayed within the control's range up to 8 weeks post-training. The second experiment indicated that the best learning outcome was achieved with orthographic input. Orthographic input combined with orthographic output resulted in fast and accurate learning of the novel words. Interestingly, TS's test profile was opposite to her learning profile, as she repeated better than she read aloud in the linguistic background assessment. The results from the present case highlight the importance of multiple learning channels for word acquisition in individuals with aphasia. Probing the functionality of different input and output channels for learning may also prove valuable in tailoring effective treatment for persons with aphasia.