The effects of decreasing and increasing cue therapy on improving naming speed and accuracy for verbs and nouns in aphasia

Background: Verb impairments in aphasia have generated considerable theoretical interest in the literature (Druks, 2002; Druks Masterson, 2003; Marshall, 2003) but this is not reflected in the number of studies investigating therapies for verb impairments (Conroy, Sage, Lambon Ralph, 2006). Recent anomia therapy studies have compared errorless and errorful techniques (Abel, Schultz, Radermacher, Willmes, Huber, 2005; Fillingham, Hodgson, Sage, Lambon Ralph, 2003; Fillingham, Sage, Lambon Ralph, 2005a, 2005b, 2006). Decreasing cues have been proposed as the optimal interaction of low error and sustained effort in therapy in the amnesia literature (Komatsu, Mimura, Kato, Wakamatsu, Kashima, 2000). Following on from Conroy, Sage, and Lambon Ralph (2008), we predicted that decreasing cue therapy would result in greater effects in terms of both naming accuracy and speed relative to increasing cues. Aims: The present study aimed to answer the following questions: (1) Would naming therapy consisting of decreasing cues result in greater naming accuracy for verb and noun targets than therapy consisting of increasing cues? (2) Would decreasing cues result in speedier naming responses to verb and noun targets than increasing cues? Methods Procedures: A case-series study that utilised decreasing versus increasing cues as naming therapy for verbs and nouns was implemented with seven participants with aphasia of various sub-types and degrees of severity. A total of 120 target words were collated for each participant, divided into three sets, each consisting of 20 verbs and 20 nouns. Set A was used in decreasing cues therapy, set B in increasing cues therapy, and set C served as control items. Ten sessions of therapy were delivered to each therapy set concurrently. The speed of post-therapy naming responses as well as accuracy was recorded. Outcomes Results: All participants showed significant therapy gains after both decreasing and increasing cue therapies, with little or no change in naming of control sets. The two therapies were equivalent in the degree to which participants improved in naming accuracy and yielded almost identical overall speed of naming responses. Naming speeds for successfully named items, post-therapy, were faster for nouns than verbs (perhaps reflecting their shorter length), and faster at immediate than follow-up assessment. Conclusions: Decreasing cues are as effective in naming therapy as increasing cues, in terms of both accuracy and speed of naming for verbs and nouns.