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Summary Objective We aimed to predict language deficits after epilepsy surgery. In addition to evaluating surgical factors examined previously, we determined the impact of the extent of functional magnetic resonance imaging (fMRI) activation that was resected on naming ability. Method Thirty‐five adults (mean age 37.5 ± 10.9 years, 13 male) with temporal lobe epilepsy completed a preoperative fMRI auditory description decision task, which reliably activates frontal and temporal language networks. Patients underwent temporal lobe resections (20 left resection). The Boston Naming Test (BNT) was used to determine language functioning before and after surgery. Language dominance was determined for Broca and Wernicke area (WA) by calculating a laterality index following statistical parametric mapping processing. We used an innovative method to generate anatomic resection masks automatically from pre‐ and postoperative MRI tissue map comparison. This mask provided the following: (a) resection volume; (b) overlap between resection and preoperative activation; and (c) overlap between resection and WA. We examined postoperative language change predictors using stepwise linear regression. Predictors included parameters described above as well as age at seizure onset (ASO), preoperative BNT score, and resection side and its relationship to language dominance. Results Seven of 35 adults had significant naming decline (6 dominant‐side resections). The final regression model predicted 38% of the naming score change variance (adjusted r2 = 0.28, P = 0.012). The percentage of top 10% fMRI activation resected (P = 0.017) was the most significant contributor. Other factors in the model included WA LI, ASO, volume of WA resected, and WA LI absolute value (extent of laterality). Significance Resection of fMRI activation during a word‐definition decision task is an important factor for postoperative change in naming ability, along with other previously reported predictors. Currently, many centers establish language dominance using fMRI. Our results suggest that the amount of the top 10% of language fMRI activation in the intended resection area provides additional predictive power and should be considered when planning surgical resection.

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Background and Objectives:Task-fMRI is a clinical tool for language lateralization, but has limitations, and cannot provide information about network-level plasticity. Additional methods are needed to improve the precision of presurgical language mapping. We investigate language resting-state functional connectivity(RS fMRI;FC) in typically developing children and children with epilepsy. Our objectives were to: 1)Understand how FC components differ between typically developing (TD) children and those with epilepsy. 2)Elucidate how the location of disease (frontal/temporal epilepsy foci) effects FC. 3)Investigate the relationship between age and FC.Methods:Sample includes 55 TD children (mean age 12 years, range 7-18, and 31 patients with focal epilepsy (mean age 13) with same range. All subjects underwent RS fMRI. Using a bilateral canonical language map as target, vertex wise intra-hemispheric FC map and inter-hemispheric FC map for each subject were computed and thresholded at top 10% to compute an FC laterality index (FCLI;((L-R)/(L+R)) of the frontal and temporal regions for both integration (intra-hemispheric FC; FCLIi) and segregation (Inter-hemispheric FC; FCLIs) maps.Results:We found FC differences in the developing language network based on disease, seizure foci location, and age. Frontal and Temporal FCLIi was different between groups (t(84)=2.82, p<.01; t(84)=4.68, p<.01, respectively). Frontal epilepsy foci had the largest differences from TD (Cohen’s D Frontal FCLIi=0.84, FCLIs=0.51; Temporal FCLIi=1.29). Development and disease have opposing influences on the laterality of FC based on groups. In the frontal foci group, FCLIi decreased with age (r=-0.42), whereas in the temporal foci group FCLIi increased with age (r=0.40). Within the epilepsy group, increases in right frontal integration FCLI relates to increased right frontal task activation in our mostly left language dominant group (r=.52, p<.01). Language network connectivity is associated with higher verbal intelligence in children with epilepsy (r=.45, p<.05).Discussion:These findings lend preliminary evidence that FC reflects network plasticity in the form of adaptation and compensation, or the ability to recruit support and reallocate resources within and outside of the traditional network to compensate for disease. FC expands on task-based fMRI and provides complementary and potentially useful information about the language network that is not captured using task-based fMRI alone.