Spoken language production as outcome measurement following constraint induced language therapy

Background: Spoken language production reflects a more natural communication aspect of language than most standardised aphasia tests. Several methods for text analysis have been developed; however, clinical application in speech-language therapy has so far been limited. Further exploration of the generalisation effect of specific impairment-based treatment forms to spontaneous speech and everyday communication is warranted. Aims: The present study explores the relevance of spoken language production for measurement of aphasia treatment outcome with constraint induced language therapy (CILT). The study investigates if improvement on standardised tests generalises to spoken language production with a focus on vocabulary and content. Methods & Procedures: Analyses are based on the pre- and post-intervention transcriptions of dialogical interviews with three speakers with aphasia participating in a clinical CILT treatment study in early aphasia rehabilitation. The analyses include quantitative measurements of the speech production (number of words, number of utterances, and mean length of utterance), of the lexical production of nouns and verbs (proportion, variation, frequency, and specificity), and of the content (proportion of informative utterances and meta-communicative utterances). In addition, the analyses include a qualitative evaluation of the content. Outcomes & Results: Results indicate an overall increase in noun production for all three cases post-CILT with individual differences in improvement of noun diversity and specificity. There is a slight decrease in the amount of verbs produced post-intervention, but more specific verbs are produced after the treatment. Content evaluation and the quantitative measures of content demonstrate increased informativeness on the individual level. Conclusions: The applied measures provide a helpful structure for interpreting outcome changes in the use of nouns and verbs. Analysis of spoken language production supports a generalisation effect of increased word production to a more demanding speech context (connected speech production).