Behavioral Effects of Chronic Gray and White Matter Stroke Lesions in a Functionally Defined Connectome for Naming.
Shihui Xing, Ayan Mandal, Elizabeth H Lacey and 3 others
PMID 29890878WHAT IT FOUND
Naming ability after chronic left hemisphere stroke depends on the integrity of specific white matter tracts, not just the gray matter regions activated in healthy people.
Damage to these connections predicts poor word retrieval, while gray matter lesion volume alone does not.
Key findings
01Integrity of 14 white matter tracts in the left hemisphere correlated with naming performance, whereas damage to gray matter nodes did not after controlling for total lesion volume.
02Specific dorsal and ventral stream white matter tracts were uniquely associated with phonological and semantic processing measures, respectively.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
White matter tracts were reconstructed in healthy controls and applied to stroke survivors, which may not perfectly align with the actual damaged anatomy in patients. The study did not analyze naming errors (paraphasias) due to the limited number of test items. Right hemisphere white matter integrity did not correlate with naming outcomes in this left-hemisphere stroke cohort. The sample size (45 patients) may limit the sensitivity to detect smaller effects in specific gray matter regions.
Declared interests
The authors declared no potential conflicts of interest.
The easy way to misread this
Do not assume that damage to a specific gray matter region identified by fMRI in healthy people will cause a naming deficit. The study found that gray matter lesion load did not predict naming performance after controlling for total lesion volume, whereas white matter tract integrity did.