Lesions, lemmas and lehapu : anomia in two Sesotho-English bilingual speakers.

Abstract

Rationale: Aphasia and anomia affect the communication abilities of thousands of South African stroke survivors. Therapy provision in South Africa is a challenging endeavour. Clinicians must provide therapy to clients who speak languages which have rarely, if ever, been the focus of clinical study. Models developed for use with clients who speak English or related languages may not be suitable for speakers of other, parametricallydiverse languages. Bilingualism is widespread in South Africa, yet therapeutic insights on how best to treat bilingual speakers are only beginning to inform clinical research and practice. Time and financial support are also lacking in many clinical settings. Aim: This study represents an attempt to establish which of four treatment conditions (initial phoneme cueing, codeswitch1 cueing, true phonemic cueing and prosodic cueing) is most effective at facilitating improved naming performance in two Sesotho-English bilingual speakers with post-stroke anomia. Methodology: Commercially-available tests of naming ability were found to be statistically invalid since they seemed to assess familiarity with Western culture and artifacts rather than naming ability. Working in conjunction with ten neurologically unimpaired Sesotho speakers living in the Northern Free State, community-referenced words lists were developed for use in this study. Two bilingual Sesotho-English speakers with post-stroke anomia participated in this study. T. was assessed and found to present with classical anomia, while S. presented with output anomia. T.’s word finding difficulties are characterized by pauses, use of vocalizers and part-whole productions, while S. tends to produce semantic paraphasias during anomic moments. 1 In keeping with trends present in research literature (e.g. Auer, 1999), codeswitching will be designated by a single, unhyphenated word. xi Each treatment condition (initial phoneme cueing, codeswitch cueing, true phonemic cueing and prosodic cueing) were allocated a word list. Pre-- and post-intervention scores of naming ability on these treatment lists and four lists of semantically related words were compared. The treatment conditions were evaluated in terms of three constructs commonly employed in anomia literature: potency (the degree to which a technique helps a speaker relearn words directly targeted in therapy), semantic generalizability (the degree to which a technique helps a speaker relearn words semantically related to those directly targeted in therapy) and persistence (the degree to which therapy effects are longlived.). The sign-test was used to determine statistical significance or otherwise. Results and discussion: Neither initial phoneme cueing nor codeswitch cueing were associated with statistically significant potency in either participant. Both true phonemic cueing and prosodic cueing were associated with statistically significant levels of potency in both participants. None of the treatment conditions were associated with statistically significant semantic generalizability in either participant. In the case of S., codeswitch cues appeared lead to an increase in the number and complexity of semantic paraphasias. No significant decrease in any of the gains made during the intervention portion of the study were noted one month after the conclusion of the study. Explanations for these results, informed by cognitive neuropsychology, are provided. Possible refinements to models of lexical retrieval in monolingual and bilingual speakers are postulated. Conclusion: The results of this study suggest that speech-language pathologists in South Africa should not rely solely on therapy approaches developed for use with Englishspeakers. Instead, a parametrically informed approach, which draws heavily on cognitive neuropsychological understandings of bilingual functioning, may be helpful in furnishing speech-language pathologists in South Africa with the tools they need to provide services. The local community needs to play a role in developing materials for use in therapy and assessment in challenging environments. New therapy techniques should be weighed against commonly used measures of therapy efficacy to determine the best course of treatment.