Evaluating Change in the Communication Abilities of Aphasia Group Participants: An Investigation of Blind Versus Informed Res Introduction The Communicative Effectiveness Index (CETI; Lomas et al., 1989) is used extensively to measure changes in functional communication abilities of aphasic individuals (e.g., Sorin-Peters & Behrmann, 1995; Steele, Aftonomos, & Munk, 2003; Bakheit, Carrington, Griffiths, & Searle, 2005; Meinzer, Djundja, Barthel, Elbert, & Rockstroh, 2005; Saur et al., 2006). In our own clinic, it is administered annually to document functional communication changes in individuals who participate in our aphasia groups. The CETI comprises 16 communication situations for which a significant other is asked to rate the aphasic individual’s performance on a 10-centimeter visual analog scale. Examples of items include “Getting somebody’s attention” and “Having a one-to-one conversation with you.” The authors of the CETI recommend that, on repeat administrations, raters have their previous ratings available to them. Although we recognized the potential value of raters seeing previous responses in helping calibrate their current responses, we were concerned that the availability of the previous ratings may have a biasing effect. We were concerned, primarily, that significant others might automatically rate performance higher on repeat administrations, simply because they might postulate that because the aphasic individuals had been participating in therapeutic communication activities for a year, they must be getting better. We were also concerned that they might automatically rate performance higher to show us that they appreciated our efforts in the clinic, almost as a “good-faith gesture.” Such concerns are further substantiated by documented acquiescence responding bias in the elderly, that is, a tendency for older individuals to rate objects or attitudes favorably (e.g., Jayanti McManamon, & Whipple, 2004). Purpose The purpose of the current investigation is two-fold: (a) to document possible changes in functional communication for aphasic individuals participating weekly in group therapy, and (b) to determine if there are biasing effects of providing previous ratings (informed administration) versus not providing these ratings (blind administration) on the CETI. Method Data were collected during three CETI administration periods, each approximately one year apart. In the first administration period, raters were given an unmarked CETI form for responding. In the second administration period, about one year later, raters completed the CETI twice: first they completed an unmarked CETI form (blind administration) and then they completed their CETI form photocopied from the previous year, with their previous responses marked (informed administration). In the third administration period, approximately one year after the second, raters again completed the CETI twice: first on an unmarked form and then on a form with the previous year’s responses. The blind responses from the second administration period were used for informed responding in this third administration period regardless of whether raters had participated in the first administration period. This allowed more consistent administration across raters who participated in all three administration periods and those new in the second administration period. In all administration periods, CETI forms were provided to the rater to be taken home and completed at his or her convenience. Typically, forms were returned within one to two weeks. In the second and third administration periods, the second (marked) forms were provided when the first were returned. Again, the forms could be taken home and were typically returned within two weeks, although some were retained notably longer during the third administration period. When responding on a previously marked form, raters were asked to make their new responses in red ink to clearly differentiate their current responses from those of the previous year. Subjects Raters for 14 aphasia group participants completed all three CETI forms for the first and second administration periods (one blind form from the first and one blind and one informed from the second). Raters included 12 spouses or significant others and 2 parents of the aphasia group members. Raters for 17 aphasia group participants completed the corresponding three CETI forms for the second and third administration periods. Raters included 13 spouses or significant others, 3 parents, and 1 adult child of the aphasic individuals. Nine of these raters were also in the previous group of raters. Findings Analyses were designed to address the two questions of interest: (a) do CETI scores capture changes in functional communication for aphasia group participants? and (b) does informed responding positively bias results? Preliminary analyses revealed the following findings. To look at changes in functional communication over the period of one year, we looked first only at ratings from the blind conditions. Mean CETI scores from the blind condition in the first administration period were not significantly different from mean scores from the blind administration in the second administration period. Similarly, CETI mean scores from the blind condition in the second administration period were not significantly different from mean scores from the blind administration in the third administration period. To look at the possible bias of informed responding, we compared blind and informed responses from the same administration period. In the second administration period, mean CETI scores in the informed condition were higher than in the blind condition, but the difference was not statistically significant. Analysis of the blind and informed responses in the third administration period revealed the same profile: The mean CETI score in the informed condition was higher, but not significantly higher, than in the blind condition. Finally, we compared responses from the blind conditions in one year with responses from informed conditions one year later. This should incorporate changes in functional communication over the course of the year as well as any possible bias from informed responding. There was no significant difference in mean CETI scores between the blind condition in the first administration period and the informed condition in the second administration period. There was, however, a significant difference between the mean CETI scores for the blind condition in the second administration period and the informed condition in the third administration period: the mean score from the third administration period was significantly higher than that from the second administration period. Discussion The lack of significant changes in mean CETI scores in the blind conditions from year to year suggest that either there was truly little change in functional communication skills or that the CETI was not sensitive to the changes that did occur. With respect to the possible biasing effects of informed responding, the lack of significant differences between the blind and informed conditions in both the second and third administration periods suggests that our concerns regarding bias appear to be unfounded. However, the finding of a significant improvement in mean CETI scores from the blind condition in the second administration period to the informed condition in the third administration period, when no significant improvement was noted from the blind conditions over the same period, may support our initial concerns of a bias effect. Whether this effect should be viewed negatively or as an indication of greater test sensitivity will be discussed. Additional factors that may have contributed to the findings (e.g., aphasia severity, time post-onset), as well as some interesting individual results, will also be discussed. References Bakheit, A.M., Carrington, S., Griffiths, S., & Searle, K. (2005). High scores on the Western Aphasia Battery correlate with good functional communication skills (as measured with the Communicative Effectiveness Index) in aphasic stroke patients. Disability & Rehabilitation. 27(6), 287-91. Jayanti, R.K., McManamon, M.K., & Whipple, T.W. (2004). 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