Mapping Common Aphasia Assessments to Underlying Cognitive Processes and Their Neural Substrates.
Elizabeth H Lacey, Laura M Skipper-Kallal, Shihui Xing and 2 others
PMID 28135902WHAT IT FOUND
Common aphasia tests often measure several language and cognitive processes at once.
In 38 people after left hemisphere stroke, naming tasks tracked word finding, but some WAB subtests relied on more than one process, so single scores need broader interpretation.
Key findings
01Four underlying language and cognitive processes accounted for 81% of the differences in test scores.
02Some common aphasia tests relied on more than one process, including letter fluency and the Boston Diagnostic Aphasia Examination embedded sentences task.
03Each process was linked to a separate left hemisphere lesion area, and the four lesion maps did not overlap.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
Only 38 participants were studied, all native English speakers with chronic left hemisphere stroke, so the results may not apply to acute stroke, right hemisphere stroke, other languages, or people with other neurological or psychiatric conditions. The study did not test a treatment or measure whether assessment based on these maps improves patient outcomes. The lesion-symptom maps show associations between damaged brain areas and scores; they do not prove that damage to a specific area caused a specific language process deficit. The authors state that multivariate lesion-symptom mapping must be interpreted with caution because the statistical weights do not necessarily correspond to the importance of each brain area. Several common tests scored on unexpected processes, but the paper does not provide diagnostic accuracy data for using those tests to make clinical decisions.
Declared interests
The authors declared no conflict of interest. The supplied text does not report a funding source.
The easy way to misread this
Do not read the brain-area associations as proof that a lesion caused a deficit or that changing aphasia tests will improve outcomes. The study was cross-sectional, included 38 people with chronic left hemisphere stroke, and did not test a treatment.