Carolyn Falconer

Use of semantic feature analysis in group discourse treatment for aphasia: Extension and expansion

Background: Semantic feature analysis (SFA) is a treatment for lexical retrieval impairment in which participants are cued to provide semantic information about concepts they have difficulty naming, in an effort to facilitate accurate lexical retrieval (Boyle, 2004a). Previous work has provided preliminary evidence that persons with aphasia who participated in SFA-focused group aphasia treatment demonstrate improved lexical retrieval in discourse, with additional improvements observed in either general communication informativeness or efficiency (Antonucci, 2009). Furthermore, results suggested that individuals with differing mechanisms of anomia could derive benefits from participation in SFA-focused group treatment. Aims: The aim of the current study was to investigate further training of SFA in connected speech during group aphasia treatment. This study expanded and extended previous work (Antonucci, 2009), through the addition of participants with more varied aetiologies and severities of aphasia, and through the introduction of home practice. It was hypothesised that lexical retrieval during discourse would improve, as would overall communicative informativeness and/or efficiency. Methods & Procedures: Four individuals with aphasia participated in biweekly group treatment during which SFA was trained through connected speech tasks. Three participants presented with stroke aphasia, while one demonstrated aphasia consequent to traumatic brain injury. Discourse measures included those for overall communicative informativeness and efficiency (Nicholas & Brookshire, 1993) and for word-class-specific lexical retrieval (Mayer & Murray, 2003). Effect sizes were calculated for all discourse measures. Pre- and post-treatment performance on the spontaneous speech portion of the Western Aphasia Battery-Revised was also analysed relative to discourse measures, to corroborate findings from more frequently repeated probes. Outcomes & Results: All four participants demonstrated improvement to communicative informativeness and/or efficiency in connected speech tasks. Conclusions: Results provide additional support for the hypothesis that SFA administered during group aphasia treatment can be used successfully to facilitate improvement of communicative effectiveness. These results also support previous findings that individuals with differing aetiologies and natures of word retrieval impairment may benefit from participation in the same SFA-focused group aphasia treatment. Future work proceeding from this study may be directed towards differentiating which aspects of the treatment are most effective across participants with varied naming impairment, what is the optimal group composition and size, and towards discerning the most effective methods for facilitating and monitoring home practice.

Cascading activation from lexical processing to letter-level processing in written word production

Descriptions of language production have identified processes involved in producing language and the presence and type of interaction among those processes. In the case of spoken language production, consensus has emerged that there is interaction among lexical selection processes and phoneme-level processing. This issue has received less attention in written language production. In this paper, we present a novel analysis of the writing-to-dictation performance of an individual with acquired dysgraphia revealing cascading activation from lexical processing to letter-level processing. The individual produced frequent lexical–semantic errors (e.g., chipmunk → SQUIRREL) as well as letter errors (e.g., inhibit → INBHITI) and had a profile consistent with impairment affecting both lexical processing and letter-level processing. The presence of cascading activation is suggested by lower letter accuracy on words that are more weakly activated during lexical selection than on those that are more strongly activated. We operationalize weakly activated lexemes as those lexemes that are produced as lexical–semantic errors (e.g., lethal in deadly → LETAHL) compared to strongly activated lexemes where the intended target word (e.g., lethal) is the lexeme selected for production.

Do activated letters influence lexical selection in written word production

Background: Written communication has become increasingly important since the advent of digital media such as emailing and texting. Research into the nature of interaction between the cognitive processes underlying production have focused on spoken language. Less is known about the processes underlying written word production. Aims: We investigated the presence of feedback from letter activation to lexical selection in written word production. The presence of feedback would lead to greater-than-chance orthographic overlap between targets and semantically-related word errors in acquired dysgraphia, as the semantic neighbours of a target word sharing orthographic structure would receive extra support during lexical selection. Methods & Procedures: The orthographic overlap of written semantically-related word errors from an individual with acquired dysgraphia was compared to chance distributions of overlap generated using a word association database. We used a Monte Carlo procedure to select random “pseudo-errors” from the top semantic associates for each target word. 10,000 hypothetical datasets were generated for two distinct hypotheses regarding the likelihood of selecting particular semantically-related word errors. Outcomes & Results: The orthographic overlap between target words and semantically-related word errors for the individual with dysgraphia was greater than any of the hypothetical datasets, indicating that the target-error pairs shared more orthographic structure than expected by chance (p < .0001). Conclusions: We obtained evidence that feedback from letter activation influenced lexical selection in a case of impairment. The presence of feedback from letter activation to lexical selection may be useful in developing strategies leading to improved language production in individuals with dysgraphia and aphasia.

Robotic Arm Rehabilitation in Chronic Stroke Patients With Aphasia May Promote Speech and Language Recovery (but Effect Is Not Enhanced by Supplementary tDCS)

Objective: This study aimed to determine the extent to which robotic arm rehabilitation for chronic stroke may promote recovery of speech and language function in individuals with aphasia. Methods: We prospectively enrolled 17 individuals from a hemiparesis rehabilitation study pairing intensive robot assisted therapy with sham or active tDCS and evaluated their speech (N = 17) and language (N = 9) performance before and after a 12-week (36 session) treatment regimen. Performance changes were evaluated with paired t-tests comparing pre- and post-test measures. There was no speech therapy included in the treatment protocol. Results: Overall, the individuals significantly improved on measures of motor speech production from pre-test to post-test. Of the subset who performed language testing (N = 9), overall aphasia severity on a standardized aphasia battery improved from pre-test baseline to post-test. Active tDCS was not associated with greater gains than sham tDCS. Conclusions: This work indicates the importance of considering approaches to stroke rehabilitation across different domains of impairment, and warrants additional exploration of the possibility that robotic arm motor treatment may enhance rehabilitation for speech and language outcomes. Further investigation into the role of tDCS in the relationship of limb and speech/language rehabilitation is required, as active tDCS did not increase improvements over sham tDCS.