Phonological output impairments in aphasia :different subgroups requiring different therapies?

Abstract

Background: One of the few studies to describe therapy for phonological assembly difficulties in aphasia is a single case by Franklin, Buerk and Howard (2002). Their client improved significantly in picture naming for treated and untreated words after therapy targeting auditory awareness and self-monitoring. Aims: This thesis comprises two studies. Study one aimed to determine whether the generalised improvements reported by Franklin et al (2002) are replicable with other people with impaired phonological assembly, and to explore any differences in outcome. Study two aimed to compare the effectiveness of Franklin et al’s therapy with a production-focussed approach. The overall aim of both studies was to discover whether different subgroups of people with phonological assembly difficulties may respond differently to therapy, and whether any differences in treatment outcome may provide insight into theoretical models of phonological output processing. Method: A case series of eight participants with aphasia with mixed impairments including phonological assembly difficulties is reported. In study one, four participants received a replication of the treatment described by Franklin et al. In study two, four further participants received a novel production therapy in addition to Franklin et al’s therapy. Outcomes: No participant responded in the same way as Franklin et al’s original client. All post-therapy naming improvements were item-specific, except for one participant, who also showed signs of spontaneous recovery. Two participants showed no significant naming improvements after either treatment. Conclusions: Whereas Franklin et al’s original client had a relatively pure post-lexical phonological assembly impairment, six of the eight participants in the current study had phonological assembly difficulties combined with either lexical retrieval or motor speech impairments. The item-specific naming gains were proposed to reflect improved mapping between semantics and lexical phonology, rather than improved phonological assembly. These results support a model of speech production containing both lexical and post-lexical levels of phonological processing.