Abstract
Methods
Responses to a large pool of items describing communication activities were collected from 133 community-dwelling persons
with aphasia of ≥ 1 month post-onset and their associated surrogate respondents. These responses were evaluated using confirmatory
and exploratory factor analysis. Chi-square difference tests of nested factor models were used to evaluate patient–surrogate
measurement invariance and the equality of factor score means and variances. Association and agreement between self- and surrogate
reports were examined using correlation and scatterplots of pairwise patient–surrogate differences.
with aphasia of ≥ 1 month post-onset and their associated surrogate respondents. These responses were evaluated using confirmatory
and exploratory factor analysis. Chi-square difference tests of nested factor models were used to evaluate patient–surrogate
measurement invariance and the equality of factor score means and variances. Association and agreement between self- and surrogate
reports were examined using correlation and scatterplots of pairwise patient–surrogate differences.
Results
Three single-factor scales (Talking, Comprehension, and Writing) approximating patient–surrogate measurement invariance were
identified. The variance of patient-reported scores on the Talking and Writing scales was higher than surrogate-reported variances
on these scales. Correlations between self- and surrogate reports were moderate-to-strong, but there were significant disagreements
in a substantial number of individual cases.
identified. The variance of patient-reported scores on the Talking and Writing scales was higher than surrogate-reported variances
on these scales. Correlations between self- and surrogate reports were moderate-to-strong, but there were significant disagreements
in a substantial number of individual cases.
Conclusions
Despite minimal bias and relatively strong association, surrogate reports of communicative functioning in aphasia are not
reliable substitutes for self-reports by persons with aphasia. Furthermore, although measurement invariance is necessary for
direct comparison of self- and surrogate reports, the costs of obtaining invariance in terms of scale reliability and content
validity may be substantial. Development of non-invariant self- and surrogate report scales may be preferable for some applications.
reliable substitutes for self-reports by persons with aphasia. Furthermore, although measurement invariance is necessary for
direct comparison of self- and surrogate reports, the costs of obtaining invariance in terms of scale reliability and content
validity may be substantial. Development of non-invariant self- and surrogate report scales may be preferable for some applications.
- Content Type Journal Article
- Pages 1-11
- DOI 10.1007/s11136-012-0224-5
- Authors
- Patrick J. Doyle, Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
- William D. Hula, Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
- Shannon N. Austermann Hula, Research Service, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
- Clement A. Stone, Department of Psychology in Education, University of Pittsburgh, Pittsburgh, PA, USA
- Julie L. Wambaugh, Research Service, VA Salt Lake City Healthcare System, Salt Lake City, UT, USA
- Katherine B. Ross, Audiology and Speech Pathology, Phoenix VA Healthcare System, Phoenix, AZ, USA
- James G. Schumacher, Audiology and Speech Pathology, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
- Journal Quality of Life Research
- Online ISSN 1573-2649
- Print ISSN 0962-9343