Article

Performance variability in individuals with aphasia is typically
regarded as a nuisance factor complicating assessment and treatment. OBJECTIVE:
We present the alternative hypothesis that intraindividual variability represents
a fundamental characteristic of an individual's functioning and an important
biomarker for therapeutic selection and prognosis. METHODS: A total of 19
individuals with chronic aphasia participated in a 6-week trial of
imitation-based speech therapy. We assessed improvement both on overall language
functioning and repetition ability. Furthermore, we determined which pretreatment
variables best predicted improvement on the repetition test. RESULTS: Significant
gains were made on the Western Aphasia Battery-Revised (WAB) Aphasia Quotient,
Cortical Quotient, and 2 subtests as well as on a separate repetition test. Using
stepwise regression, we found that pretreatment intraindividual variability was
the only predictor of improvement in performance on the repetition test, with
greater pretreatment variability predicting greater improvement. Furthermore, the
degree of reduction in this variability over the course of treatment was
positively correlated with the degree of improvement. CONCLUSIONS:
Intraindividual variability may be indicative of potential for improvement on a
given task, with more uniform performance suggesting functioning at or near peak
potential.
CI - (c) The Author(s) 2016.

Langue : ANGLAIS