Social validation in aphasiology: Does judges' knowledge of aphasiology matter?

Abstract

Background: Social validity assessments can be used to examine clinical significance of changes due to treatment of aphasia. Behavioural researchers have noted the need to investigate various methodological issues in social validity research. For example, differences in rater characteristics have been noted to influence social validation ratings of treatment outcomes.Aims: This study examined the possibility of differences in social validity ratings across judges with varying degrees of knowledge of and experience with aphasia. The secondary purpose was to replicate results of previous research that showed the clinical significance of communication partner training. Research questions included: (1) Does the level of knowledge of aphasia and experience with persons with aphasia result in a difference in social validity ratings of pre- and post-training conversations between a student volunteer and an elder with aphasia? (2) Will the significant social validity findings previously obtained from members of the extended community be replicated (Hickey, 2000)?Methods & Procedures: Ten naïve individuals (no familiarity with aphasia), ten second-year graduate students majoring in speech-language pathology (some familiarity with aphasia), and ten Speech-Language Pathologists served as judges. After watching two pre- and two post-training videotaped conversations, the judges provided ratings for seven dimensions of conversations to examine clinical significance of changes in pre- and post-training conversations between a student volunteer and an elder with aphasia. A mixed design with between and within subjects effects, and interaction effects was used.Outcomes & Results: Repeated measures ANOVA revealed significant main effects for group on two items, significant main effects for training on all seven items, and significant interaction effects for five items. Pre-training ratings showed greater variability than post-training ratings. Naïve judges provided the lowest pre-training ratings, and generally, the most change in pre- and post-training ratings. Post-training ratings of the three groups became more similar.Conclusions: This study suggests that truly naïve judges who are representative of the general public may provide the most robust findings in social validation studies of aphasia treatment outcomes. However, further research is needed to determine the source of variability beyond level of knowledge of aphasia. This study also replicated the results of previous research by revealing the clinical significance of communication partner training for elders with aphasia.