Functionally relevant items in the treatment of aphasia (part II): Further perspectives and specific tools

Background: This paper is the second in a two part series. In part I, we reviewed the concept of "functionally relevant" and the strategies underlying identification of such vocabulary items for aphasia treatment. Based on the review, we concluded that there is a lack of definitions, strategies and specific tools to assist with identification of functionally relevant items for aphasia therapy. We suggested that frequency-based vocabulary lists could and should be used to increase the number of potentially relevant items in aphasia therapy and that therapy should be directed to words other than the most concrete nouns and verbs. Aims: This article reviews the existing strategies and materials from adjacent fields relating to functionally relevant stimuli with the aim of establishing resources for identifying potentially relevant therapy items at the level of both vocabulary items and topics of conversation. Main contribution: By reviewing the core concepts and research from other fields, this article brings together knowledge and materials that can improve current practice regarding identification of functionally relevant items in aphasia therapy. The focus of the review is on studies that have been published in the field of augmentative and alternative communication (AAC) and research that has provided information on unimpaired and impaired adult speakers' everyday conversations. By reanalysing data sets from these studies and using a large psycholinguistic database, we present four resources. Two of the data sets provide evidence regarding the most frequent topics of conversation; one is based on unimpaired speakers conversations and the other extends this by including information from both unimpaired and aphasic speakers' topics of conversation. In addition, to provide evidence of the most frequent vocabulary in adult conversations, we present a list of words compiled from three separate data sets. Finally, a vocabulary list of the 1000 most frequent words retrieved from an objective frequency count (SUBTLEX-US) is presented. Together these resources provide a means for clinicians to select objectively frequent topics and vocabulary as stimuli for functionally relevant therapy. Conclusions: The agenda for future research is to identify specific vocabulary within the most common topics of conversation. The resources provided as part of this article serve as a first step towards the ultimate goal of enabling clinicians to select stimuli for therapy in a more systematic, transparent and objective way.