Comparing the treatment effect of conversational and traditional aphasia treatments on linguistic complexity measures

Abstract

Linguistic complexity is frequently analyzed in studies of child language acquisition and impairment (Heilmann, Miller, & Nockerts, 2010; Price, Hendricks, & Cook, 2010) and the language of aging adults (Capilouto, Wright, & Wagovich, 2005; Kemper & Sumner, 2001; Kemper, Thompson, & Marquis, 2001; Kynette & Kemper, 1986; Shewan & Henderson, 1988) to document changes over time. There is little, if any, literature applying linguistic measures to analyze the language of individuals with aphasia as well as to analyze effects of different treatment measures. The current study analyzed semantic and syntactic components of linguistic complexity used by people with aphasia (PWA) during conversation probes to determine whether conversation therapy (Ctx) results in greater linguistic complexity than traditional stimulation therapy (Ttx). Two cases were taken from a prospective, single subject, A1B1A2B2A3 treatment study replicated across four individuals with aphasia (Savage et al., 2013). The language transcripts of two participants (P1 and P4), who received both Ctx and Ttx, were analyzed using Systematic Analysis of Language Transcripts (SALT; Miller & Iglesias, 2010) for six linguistic complexity measures: mean length of utterance (MLU), number of different words (NDW), type-token ratio (TTR), percent of utterances, percent of simple, and percent of complex utterances. These measures were compared between the treatments. Data analyses were conducted using effect size calculations and visual inspection. Results indicated that 4 of the 6 measures (MLU, TTR, % utterances, % complex utterances) showed greater gains in linguistic complexity following Ttx than Ctx. However, neither participant maintained gains once treatment was removed. This study provides preliminary evidence that linguistic complexity measures may provide useful treatment outcome measures for researchers and clinicians interested in treating PWA.