Abstract/Summary

Background and Rationale. Aphasia is a complex and heterogenous disorder. Important theoretical questions about language processing remain open, as do clinical questions about the most useful ways of categorising and describing language impairment. Aphasiology draws on multiple disciplines and methodologies in addressing these problems. One source of information is in the subjective experience of people with aphasia. For over 200 years people with aphasia have written about their experience of language impairment, and have shared these contributions with the community of researchers and clinicians working in aphasiology. At times these accounts have strongly informed the scientific literature. However, currently, despite the fact that modern autobiographical accounts of aphasia are increasing in quantity and diversity, there is little integration of these accounts with theoretical work. Metaphor structures our understanding of abstract topics in terms of familiar, concrete topics. Metaphor-led discourse analysis provides a rigorous methodology for the exploration of discourse data, has been widely used in healthcare, and has been applied in neurological and psychological conditions to describe diagnostically relevant symptoms. It has not previously been applied to the exploration of aphasia at the level of impairment. The research described here uses metaphor-led discourse analysis to explore subjective descriptions of language processing, in particular word finding and production difficulties, in order to demonstrate that insights from autobiographical accounts can contribute to open interdisciplinary questions in aphasiology. Aims. To explore the subjective experience of word finding and production impairment, as described in autobiographical accounts by people with aphasia, through metaphor-led discourse analysis. To interpret the findings of this analysis with reference to the theoretical literature on language processing. Method. First, a literature review was carried out to explore the number and range of autobiographical accounts of aphasia which are available. These were evaluated by era since the beginning of scientific aphasiology, with attention to the changing demographic and medical characteristics of the authors, exploration of representative content of accounts in each era, and evaluation of how they were received by the scientific community and integrated with the theoretical literature (or not). A convenience sample was selected of twelve autobiographical accounts which were produced in the last fifty years, and a dataset was created of all metaphorical expressions used to describe language processing in these accounts. Metaphorical expressions were then coded at two levels of abstraction according to the semantic domain of the metaphorical ‘vehicle terms’ (the words which carry the metaphorical meaning). Following this the metaphorical expressions were coded by topic (namely, language modality). A subset of the dataset was created to address word finding and production, a key symptom of all subtypes of aphasia. Chapter 4 describes the systematic metaphors which were used for word finding and production difficulties. Chapter 5 explores inner speech in four accounts in more detail, as this emerged as a salient symptom from the exploration of word finding and production difficulties. Finally, Chapter 6 describes the use of metaphor for metacognition in two accounts whose authors described metacognition as playing a role in their recovery of word finding ability. Results and Discussion. Chapter 2 describes the results of a literature review of autobiographical accounts of aphasia. The main findings are that the number and the diversity of such accounts has increased sharply over the last century and that this trend is likely to continue, and that these accounts contain insights which can make a valuable contribution to our theoretical understanding of language impairment, but that there is a lack of integration of modern autobiographical accounts with the scientific literature. Chapter 4 describes the findings of a metaphor-led discourse analysis of twelve autobiographical accounts of aphasia. The main metaphor used was the conventionally used one which represents words as objects and the mind as a container, but a wide range of other metaphors were also used. The metaphors used for word finding and production difficulties are consistent with fine-grained psycholinguistic theory. The subjective descriptions mapped onto modular levels of processing, with some authors describing multiple subjectively distinct impairments. Impaired self-monitoring was described primarily in terms also used for receptive language. Cognitive processes were also described as playing a role in language production. It was also found that the impairment of inner speech was a highly salient symptom for two of the authors. Chapter 5 describes the results of an in-depth analysis of descriptions of inner speech in four accounts which were selected because the authors reported inner speech impairment. This analysis found that two distinct concepts were described, using different metaphors, and as differentiated processes: phonological and dialogic inner speech. Impaired dialogic inner speech was described by two of the authors in terms of ‘voices’ and as a spiritual experience. Impaired phonological IS was described by two other authors primarily in terms of ‘objects’ and ‘containers’. A double dissociation of these different concepts of inner speech was seen across two accounts. These concepts are not consistently distinguished in the inner speech literature, this analysis shows the importance of this distinction for aphasia. Chapter 6 found that different approaches to the use of metaphor for metacognition were described as successfully contributing to recovery: reasoning with the use of one conventional metaphor and comparing multiple metaphors. This suggests that the process of engaging in metacognition using metaphor can be beneficial, regardless of the specific metaphors or the approach adopted. Conclusions and implications. The subjective experience of aphasia can be integrated with theories of language processing and contains information, not readily obtained by other methods, through the use of rigorous methods such as metaphor-led discourse analysis. The authors’ descriptions of their experiences were consistent with a modular account of word production that includes self-monitoring through receptive language and interacts with cognitive processes. Thus, the use of this method can guide model selection for clinical use; if a symptom is subjectively salient then important information may be missed if assessment and intervention is planned with reference to a model which does not capture this symptom. Additionally, the in-depth exploration of inner speech showed that this method can help to clarify theoretical concepts, through differences in the metaphors used and through description of dissociations across accounts. Finally, that metaphor is used spontaneously for metacognition by some people with aphasia suggests that metaphor may have application not only in assessment, but in supporting recovery and in intervention.