12th International Aphasia Rehabilitation Items



12th International Aphasia Rehabilitation Conference

Generalisation to untreated items in anomia therapy:

links to individuals’ language processing

Wendy Best1, Jennie Grassly2, Alison Greenwood2, Ruth Herbert3,

David Howard4 & Julie Hickin5,

1 University College London

2 Wycombe Primary Care Trust

3 University of Sheffield

4 University of Newcastle

5 City University

e-mail w.best@ucl.ac.uk

Phone 0207 679 4179

Background

The aim of therapy for word-retrieval problems with people with aphasia is for carry-over to everyday communication. This may be most likely if the therapy generalises to untreated words[1]. However, Howard (2000) claims there is little convincing evidence for generalisation. He suggests that both ‘semantic’ and ‘phonological’ therapies work by strengthening the links (‘mapping’) between semantic and phonological representations. This paper investigates generalisation to untreated items in anomia therapy by combining data over two recent studies and from the literature.

Method

Sixteen people with aphasia participated in two intervention studies for anomia (eight in each). The first, reported in Hickin et al. (2002), involved providing participants with a choice of phonological cues or a choice of orthographic cues to aid word finding. The length of the cues was increased until the word was successfully produced. Therapy took place once a week for eight weeks. The second study, carried out in a clinical setting, was similar except both phonological and orthographic information was provided for treated items. Both studies included experimental and personally chosen therapy items. In both studies one set of items was assessed twice prior to intervention, remained unseen throughout therapy and assessed again after therapy (n=100 study 1, n=50 study 2). Assessment was carried out which included language measures and participants’ views of the therapy.

Results

Fifteen of the sixteen participants showed improved naming following the cueing therapy. Importantly, four showed evidence of generalisation to untreated items. When participants were divided into those with more or less of a semantic deficit (using scores on word-to-picture matching and Pyramids and Palm Trees) and more or less of a phonological deficit (using proportion of phonological errors and the presence or absence of a length effect in picture naming) it is those who have both less semantic difficulties and more of a phonological deficit who showed the most change on untreated items[2].

Discussion

Clinicians aim to identify the level of deficit in order to help determine which therapy approach might be appropriate. In practice, however, one deficit rarely exists in isolation, people tend to present with mixed patterns spanning different levels. Our findings suggest that it is those who have less semantic difficulties and more phonological (i.e. post-lexical) production problems that are likely to improve in naming untreated items. Linking these findings with other cases from the literature, we suggest there generalisation from anomia therapy is likely when:

i) the main deficit is in post-lexical production, in the context of good semantic processing

ii) a new strategy develops e.g. from the combined use of orthography

and phonology (Best et al., 1997).

More broadly, we are suggesting that generalisation occurs when there is a change in processes or in strategy and not a change in representations or links between representations.

Finally, although generalisation is desirable, we would like to stress that item specific improvements can result in important changes in communication. This is particularly so when the items are functionally useful words chosen by the person with aphasia themselves.

References

Best, W., Howard, D., Bruce, C. & Gatehouse, C. (1997) Cueing the words: a single case study of treatments for anomia. Neuropsychological Rehabilitation, 7 (2), 105-14.

Hickin, J., Best, W., Herbert, R., Howard, D. and Osborne, F. (2002) Phonological therapy for word-finding difficulties: a re-evaluation. Aphasiology, 16, 981-1000.

Howard, D. (2000) Cognitive neuropsychology and aphasia therapy: the case of word retrieval. In: I Papathanasiou, ed. Acquired neurogenic communication disorders. London: Whurr.

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[1] It is in this sense that the term ‘generalisation’ is used here.

[2] There are, however, only two people who fall into this category. An additional participant has been recruited with phonological production problems and good semantic processing. His results will be incorporated before the conference.

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