Self- and surrogate-reported communication functioning in aphasia.

Area of Science:

• Neuroscience
• Speech and Language Pathology
• Psychometrics

Background:

• Aphasia significantly impacts communicative functioning.
• Accurate measurement of communicative functioning is crucial for rehabilitation.
• The Aphasia Communication Outcome Measure (ACOM) assesses self- and surrogate-reported communication.

Purpose of the Study:

• To evaluate the dimensionality of the ACOM.
• To assess measurement invariance between self- and surrogate reports of aphasia communication.
• To determine if surrogate reports can reliably substitute for patient self-reports.

Main Methods:

• Confirmatory and exploratory factor analysis of ACOM item responses from 133 individuals with aphasia and their surrogates.
• Chi-square difference tests to evaluate patient-surrogate measurement invariance.
• Correlation and scatterplots to examine agreement between self- and surrogate reports.

Main Results:

• Three single-factor scales (Talking, Comprehension, Writing) demonstrated approximate measurement invariance.
• Patient-reported scores had higher variance than surrogate reports for Talking and Writing scales.
• Moderate-to-strong correlations were found between self- and surrogate reports, with significant individual disagreements.

Conclusions:

• Surrogate reports for aphasia communication functioning exhibit minimal bias and strong association but are not interchangeable with patient self-reports.
• Achieving measurement invariance may compromise scale reliability and content validity.
• Non-invariant self- and surrogate-report scales might be more suitable for certain applications in aphasia research.