Language Decline Following White Matter Tract Damage During Anterior Temporal Lobe Resection in the Language Dominant Hemisphere
Abstract number :
787
Submission category :
9. Surgery / 9A. Adult
Year :
2020
Submission ID :
2423125
Source :
www.aesnet.org
Presentation date :
12/7/2020 9:07:12 AM
Published date :
Nov 21, 2020, 02:24 AM
Authors :
Lawrence Binding, University College London; Peter Taylor - University College London; Newcastle University; Pamela Thompson - University College London; National Hospital for Neurology and Neurosurgery, University College London Hospital; Sallie Baxendal
Rationale:
Anterior temporal lobe resection (ATLR) in the speech-dominant hemisphere can lead to language decline in 30-50% of patients, despite typically not resecting language-associated cortical areas. Deficits have been shown to arise when white matter (WM) is compromised (1). As that study only examined WM properties preoperatively, we here investigated if intra-operative dissection of language-related fiber bundles was associated with language decline.
Method:
Using 32 patients with left temporal lobe epilepsy, left-sided language dominance based on verbal fluency functional MRI (fMRI) who had undergone ATLR. Using diffusion MRI-based data we modified an automated tractography method (2) to reflect current literature and to reconstruct the arcuate (AF) and inferior fronto-occipital fasciculus (IFOF). Resection masks were manually drawn based on pre-/post-operative 3D-T1 scans. The percentage of tracts resected were weighted with language lateralization values from the pre-operative verbal fluency fMRI scan to emphasize heavily-ipsilateral language dependence. Language function was measured using a standardized graded naming test (GNT) and semantic fluency test before and 3 months post-surgery, with factors contributing to post-operative language decline assessed using stepwise linear regression.
Results:
Resection volume predicted GNT decline (F(1,31)=4.71, p=0.038, R2=.132) but not semantic fluency (F(1,31)=1.82, p=0.187, R2=0.055). Semantic fluency decline was best predicted by resection in two components of the AF terminating in the temporal lobe: pars triangularis and ventral precentral gyrus (F(2,27)=14.86, p< 0.001, adjusted R2=.489); with the best individual predictive component being connections from pars triangularis (F(1,28)=9.18, p=0.005, R2=.497). Here, 3 subjects yielded inadequate AF reconstruction. GNT decline was predicted by resection of IFOF connections from the superior frontal gyrus medial segment to the occipital/parietal lobe (F(1,23)=4.87, p=0.038, R2=.418); 8 subjects yielded inadequate tracts.
Surgery