Regional Brain Dysfunction Associated with Semantic Errors in Comprehension.
Hinna Shahid, Rajani Sebastian, Donna C Tippett and 8 others
PMID 29359307WHAT IT FOUND
In acute left hemisphere stroke, damage or poor blood flow in left posterior superior temporal gyrus and retrolenticular white matter was linked to more semantic errors on spoken word-picture verification.
Larger lesion volume tracked more errors. No site was linked to more phonological errors.
Key findings
01Greater extent of tissue dysfunction in left posterior superior temporal gyrus and retrolenticular white matter was significantly associated with higher rate of semantic errors after controlling for lesion volume.
02Regardless of lesion site, volume of dysfunctional tissue was significantly correlated with rate of semantic, phonological, and target errors.
03Lesion site was an independent predictor of error rate only for semantic errors.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
Only five patients made exclusively semantic errors, so the semantic-error group was small. Many participants made combinations of error types, which makes it hard to separate one error pattern from another. The study did not test nonverbal or amodal semantics, so it cannot separate a problem with the concept itself from a problem linking the spoken word to the concept. Power may have been inadequate to find brain sites for phonological errors after controlling for lesion volume. The suggested treatment approach was not tested for efficacy in this paper.
Declared interests
The authors declare no competing financial interests. The article is listed as receiving NIH extramural research support.
The easy way to misread this
Do not conclude that damage to the left posterior superior temporal gyrus or retrolenticular white matter is the only cause of semantic comprehension errors, or that teaching semantic distinctions is proven effective. The paper reports associations in acute stroke and says further studies are needed to evaluate treatment efficacy across individuals.