Functionally relevant items in the treatment of aphasia (part I): Challenges for current practice

Abstract

Background: Aphasiologists are motivated to select “functional”, “relevant” and “useful” items for use in therapy; yet the field lacks discussion on what is meant by these terms and how to identify such items.

Aims: The purpose of this article is to review the meaning of “functionally relevant” in the aphasia treatment literature and to specify challenges in identifying potentially relevant items for therapy.

Main Contribution: This article shows that aphasiologists lack clear definitions, strategies and concrete tools to assist with identification of functionally relevant items for language therapy. Two main categories of functional vocabulary are defined—personally chosen vocabulary and generally frequent vocabulary. The review of the existing aphasia literature demonstrates the strengths and weaknesses of these approaches. Two critical points are raised related to selection of therapy items using data from language corpora. Firstly, it is paradoxical that aphasiologists often try to target the most common vocabulary in therapy but that language corpora have not been used to determine the identity of the most frequent words. Secondly, the analyses of the language corpora show that the most frequent spoken words represent a wide variety of word classes, such as adjectives, adverbs and pronouns. Yet, only a few treatment studies have targeted words other than concrete nouns and verbs.

Conclusions: There is a need to use objective sources to identify and choose treatment targets. In addition, more therapy attempts should be directed to words other than the most concrete nouns and verbs. Use of frequency-based lists provides one way to identify and increase the number of items that are potentially relevant across people. Frequency-based vocabulary lists can also be used as a tool when asking people with aphasia or their significant others to identify items that they personally think should be targeted in therapy. Without creating and publishing common tools for this purpose, change in practice is difficult.

Keywords:

• Anomia
• Aphasia therapy
• Functional vocabulary
• Functionally relevant items
• Personally chosen items

Acknowledgments

Preparation of this manuscript was supported by two grants to the first author: NHMRC Centre for Clinical Research Excellence (CCRE) in Aphasia Rehabilitation (Australia) and the Foundations' Post Doc Pool (Finland). Lyndsey Nickels was supported by an ARC Future Fellowship.

Notes

¹ It may also be the case (as noted by a reviewer) that personally relevant items are more richly represented in the lexicon and this might make them more responsive to treatment.

² Imageability refers to ease of forming visual/mental representation of a word and concreteness refers to the degree to which a word's referents can be perceived through the senses. Both have ratings in the range 100–700 (imageability: min 129, max 669, mean 450; concreteness: min 158, max 670, mean 438) in the MRC Psycholinguistic Database (Coltheart, 1981). Imageability is closely related to concreteness and the ratings are highly correlated, but as Paivio, Yuille, and Madigan (1968) describe, there are exceptions; for example, emotion words, such as anger, are rated high for imageability but low for concreteness.

³ For the analyses, we selected 10 categories from amongst those used in the study of Van Overschelde, Rawson, and Dunlosky (2004). Although the participants of Van Overschelde et al. (2004) produced many more items in these 10 categories, we included only the most frequently produced items (n = 261) in our analyses. These items were those that 5% or more of the approximately 600 participants had generated when asked to produce names for the 10 categories.