Intrahemispheric reorganization of language in children with medically intractable epilepsy of the left hemisphere.

We investigated language representation in nine children (six male, three female; 5.6-17.7 years of age) who underwent surgical treatment of medically intractable epilepsy of the left hemisphere. Although interhemispheric reorganization has been previously documented in similar groups, this is the first study to systematically evaluate possible intrahemispheric effects of early insult. All cases had left hemisphere seizure foci and underwent extraoperative stimulation mapping (ESM) for language localization prior to receiving cortical resections. To compare ESM findings across subjects and to assess intrahemispheric reorganization, we developed a novel coregistration technique whereby independent raters plotted two-dimensional (2D) ESM findings in 3D standard space. Expressive language sites identified with ESM were compared with a structural probability map of pars opercularis, or Broca's area. The average difference between independent raters' estimates of 28 language sites was 3.9 mm (SD = 2.0), indicating excellent agreement; the coregistration procedure permitted assessment of 2D ESM findings in 3D standard space. We observed language sites in regions substantially anterior and superior to canonical Broca's area, possibly reflecting intrahemispheric reorganization. Findings suggest that left hemisphere insult in young children may result in anterior displacement of language within the frontal cortex.     

Spatiotemporal dynamics of auditory and picture naming-related high-gamma modulations: A study of Japanese-speaking patients

ObjectiveTo characterize the spatiotemporal dynamics of auditory and picture naming-related cortical activation in Japanese-speaking patients.MethodsTen patients were assigned auditory naming and picture naming tasks during extraoperative intracranial EEG recording in a tertiary epilepsy center. Time-frequency analysis determined at what electrode sites and at what time windows during each task the amplitude of high-gamma activity (65–95 Hz) was modulated.ResultsThe superior-temporal gyrus on each hemisphere showed high-gamma augmentation during sentence listening, whereas the left middle-temporal and inferior-frontal gyri showed high-gamma augmentation peaking around stimulus offset. Auditory naming-specific high-gamma augmentation was noted in the bilateral superior-temporal gyri as well as left frontal-parietal-temporal perisylvian network regions, whereas picture naming-specific augmentation was noted in the occipital-fusiform regions, bilaterally. The inferior pre- and postcentral gyri on each hemisphere showed modality-common high-gamma augmentation time-locked to overt responses.ConclusionsThe spatiotemporal dynamics of auditory and picture naming-related high-gamma augmentation in Japanese-speaking patients were qualitatively similar to those previously reported in studies of English-speaking patients.SignificanceThe cortical dynamics for auditory sentence recognition are at least partly shared by cohorts speaking two distinct languages. Multicenter studies regarding the clinical utility of high-gamma language mapping across Eastern and Western hemispheres may be feasible.     

Language dominance determined by whole brain functional MRI in patients with brain lesions

BACKGROUND: Functional MRI (fMRI) is of potential value in determining hemisphere dominance for language in epileptic patients. OBJECTIVE: To develop and validate an fMRI-based method of determining language dominance for patients with a wide range of potentially operable brain lesions in addition to epilepsy. METHODS: Initially, a within-subjects design was used with 19 healthy volunteers (11 strongly right-handed, 8 left-handed) to determine the relative lateralizing usefulness of three different language tasks in fMRI. An automated, hemispheric analysis of laterality was used to analyze whole brain fMRI data sets. To evaluate the clinical usefulness of this method, we compared fMRI-determined laterality with laterality determined by Wada testing or electrocortical stimulation mapping, or both, in 23 consecutive patients undergoing presurgical evaluation of language dominance. RESULTS: Only the verb generation task was reliably lateralizing. fMRI, using the verb generation task and an automated hemispheric analysis method, was concordant with invasive measures in 22 of 23 patients (12 Wada, 11 cortical stimulation). For the single patient who was discordant, in whom a tumor involved one-third of the left hemisphere, fMRI became concordant when the tumor and its reflection in the right hemisphere were excluded from laterality analysis. No significant negative correlation was obtained between lesion size and strength of laterality for the patients with lesions involving the dominant hemisphere. CONCLUSION: This fMRI method shows potential for evaluating language dominance in patients with a variety of brain lesions.     

Clinical functional MRI of the language domain in children with epilepsy

Functional MRI (fMRI) for the assessment of language functions is increasingly used in the diagnostic workup of patients with epilepsy. Termed "clinical fMRI," such an approach is also feasible in children who may display specific patterns of language reorganization. This study was aimed at assessing language reorganization in pediatric epilepsy patients, using fMRI. We studied 26 pediatric epilepsy patients (median age, 13.05 years; range, 5.6-18.7 years) and 23 healthy control children (median age, 9.37 years; range, 6.2-15.4 years), using two child-friendly fMRI tasks and adapted data-processing streams. Overall, 81 functional series could be analyzed. Reorganization seemed to occur primarily in homotopic regions in the contralateral hemisphere, but lateralization in the frontal as well as in the temporal lobes was significantly different between patients and controls. The likelihood to find atypical language organization was significantly higher in patients. Additionally, we found significantly stronger activation in the healthy controls in a primarily passive task, suggesting a systematic confounding influence of antiepileptic medication. The presence of a focal cortical dysplasia was significantly associated with atypical language lateralization. We conclude that important confounds need to be considered and that the pattern of language reorganization may be distinct from the patterns seen in later-onset epilepsy.     

Task-dependent changes in brain activation following therapy for nonfluent aphasia: discussion of two individual cases.

The complex process of cortical reorganization of language-related brain regions during recovery from aphasia and the effects of therapeutic interventions on brain systems are poorly understood. We studied two patients with chronic aphasia and compared their functional neuroanatomical responses to a younger control group on two tasks, an oral-reading task involving overt speech and a "passive" audiovisual story-comprehension task. Following identical therapy, we re-examined behavioral (language) and functional neuroanatomical changes using the same functional magnetic resonance imaging (fMRI) tasks. We hypothesized that better recovery would be associated with brain activation patterns more closely resembling healthy controls, whereas positive responses to language treatment would be associated with increased activity in undamaged left perisylvian areas and/or right-hemisphere areas homologous to the damaged regions. For the participant with a frontal lesion who was most responsive to therapy, brain activation increased in the right hemisphere during oral-reading, but decreased bilaterally in most regions on story-comprehension. The other participant with a temporal-parietal lesion showed decreased activation, particularly in the right hemisphere, during oral-reading but increased activation bilaterally on story-comprehension. Results highlight individual variability following language therapy, with brain activation changes depending on lesion site and size, language skill, type of intervention, and the nature of the fMRI task.     

Noninvasive brain stimulation in the treatment of aphasia: exploring interhemispheric relationships and their implications for neurorehabilitation

Aphasia is a common consequence of unilateral stroke, typically involving perisylvian regions of the left hemisphere. The course of recovery from aphasia after stroke is variable, and relies on the emergence of neuroplastic changes in language networks. Recent evidence suggests that rehabilitation interventions may facilitate these changes. Functional reorganization of language networks following left-hemisphere stroke and aphasia has been proposed to involve multiple mechanisms, including intrahemispheric recruitment of perilesional left-hemisphere regions and transcallosal interhemispheric interactions between lesioned left-hemisphere language areas and homologous regions in the right hemisphere. Moreover, it is debated whether interhemispheric interactions are beneficial or deleterious to recovering language networks. Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are two safe and noninvasive procedures that can be applied clinically to modulate cortical excitability during poststroke language recovery. Intervention with these noninvasive brain stimulation techniques also allows for inferences to be made regarding mechanisms of recovery, including the role of intrahemispheric and interhemispheric interactions. Here we review recent evidence that suggests that TMS and tDCS are promising tools for facilitating language recovery in aphasic patients, and examine evidence that indicates that both right and left hemisphere mechanisms of plasticity are instrumental in aphasia recovery.     

Recovery from wernicke's aphasia: A positron emission tomographic study

Changes in the organization of the brain after recovery from aphasia were investigated by measuring increases in regional cerebral blood flow (rCBF) during repetition of pseudowords and during verb generation. Six right-handed patients who had recovered from Wernicke's aphasia caused by an infarction destroying the left posterior perisylvian language zone were compared with 6 healthy, right-handed volunteers. In the control subjects, strong rCBF increases were found in the left hemisphere in the posterior part of the superior and middle temporal gyrus (Wernicke's area), and during the generation task in lateral prefrontal cortex (LPFC) and in inferior frontal gyrus (Broca's area). There were some weak right hemisphere increases in superior temporal gyrus and inferior premotor cortex. In the patients, rCBF increases were preserved in the frontal areas. There was clear right hemisphere activation in superior temporal gyrus and inferior premotor and lateral prefrontal cortices, homotopic to the left hemisphere language zones. Increased left frontal and right perisylvian activity in patients with persisting destruction of Wernicke's area emphasizes redistribution of activity within the framework of a preexisting, parallel processing and bilateral network as the central mechanism in functional reorganization of the language system after stroke.     

FMRI activation in language areas correlates with verb generation performance in children

Functional MRI mapping of language areas in children frequently employs a covert verb generation task. Because responses are not monitored, the relationship between fMRI activation and task performance is unknown. We compared fMRI activation during covert and overt verb generation to performance during the overt task. 15 children, ages 11-13 years, listened to concrete nouns and responded with related verbs covertly and overtly. A clustered fMRI acquisition allowed for recording of overt responses without motion artifacts. Region of interest analysis was also performed in areas that exhibited correlation between activation and performance during overt verb generation in left inferior frontal and left superior temporal gyri (along with their right hemisphere homologues). Regression analysis determined that during both covert and overt generation, left hemisphere regions showed positive correlations with average counts of verbs generated during the overt task. These results suggest that increased verb generation performance leads to increased activation. In addition, overt performance may be used as an estimator of covert performance.     

Anatomical and functional distribution of functional MRI language mapping

ObjectiveThe aim of the present study was to compare localization of the language cortex using electrical cortical stimulation (ECS) and functional magnetic resonance imaging (fMRI) to establish the relevance of fMRI language mapping.MethodsLanguage mapping with fMRI and functional ECS mapping were retrospectively compared in ten patients with refractory epilepsy who underwent fMRI language mapping and functional ECS mapping between June 2012 and April 2019. A shiritori task, a popular Japanese word chain game, was used for fMRI language mapping.ResultsBOLD signal activation was observed in the left inferior frontal gyrus (including the pars opecularis and the pars triangularis), and superior temporal gyrus, which is a language-related area, as well as in the left superior and middle frontal gyri, the intraparietal sulcus, and fusiform gyrus. These results were compared with ECS to elucidate the functional role of the activated areas during fMRI language tasks. These activated areas included language areas, negative motor areas, supplementary motor areas (SMAs), and non-functional areas.ConclusionThe activated areas of fMRI language mapping include language-related areas, the negative motor area, and SMAs. These findings suggest the involvement of language and higher order motor networks in verbal expression.     

Motor cortex localization using functional MRI and transcranial magnetic stimulation.

OBJECTIVE: Congenital brain lesions producing focal seizures may be accompanied by reorganization of the areas responsible for motor and sensory functions within the brain due to a phenomenon that has been termed "neuronal plasticity." This can be studied using functional MRI (fMRI) and transcranial magnetic stimulation (TMS). Using either method, the motor cortex can be localized noninvasively, but to date there have been few studies correlating the level of agreement between the two techniques. METHODS: We used fMRI and TMS to localize the motor cortex in a young woman with intractable focal seizures, congenital left arm weakness, and a dysplastic right hemisphere on MRI. RESULTS: There was excellent agreement in the localization of motor representation for each hand. Both were predominantly located in the left hemisphere. fMRI also showed an area of posterior activation in the right hemisphere, but there was no evidence of descending corticospinal projections from this site using TMS, direct cortical stimulation, and Wada testing. CONCLUSIONS: Functional MRI (fMRI) and transcranial magnetic stimulation (TMS) were successfully used to localize cortical motor function before epilepsy surgery. Each technique demonstrated migration of motor function for the left hand to the left motor cortex. After resection of the dysplastic right precentral gyrus there was no permanent increase in weakness or disability. The two techniques are complementary; fMRI indicates all cortical areas activated by the motor task, whereas TMS identifies only those areas giving rise to corticospinal projections.     

Intracarotid amobarbital (Wada) test for language dominance: correlation with results of cortical stimulation

Eighty-eight patients had bilateral intracarotid amobarbital (Wada) testing to determine hemispheric dominance for language in preparation for epilepsy surgery, as well as unilateral extraoperative cortical electrical stimulation using subdural electrode arrays. In none of the patients with left dominance by Wada testing were language areas found with right-sided stimulation, but two patients with right dominance by Wada testing had language areas mapped on the left side. These findings suggest that left dominance by Wada testing is strong evidence for exclusive lateralization of language function in the left hemisphere, but there is concern about the ability of the Wada test to exclude the possibility of some left-sided language function despite apparent right-sided dominance. Patients with left dominance on Wada testing do not need cortical stimulation before extensive right temporal lobectomy, but we believe that patients with right or bilateral dominance on Wada testing should have cortical stimulation for localization of language areas if extensive left or right temporal or frontal resection is planned.     

Cortical stimulation mapping and Wada results demonstrate a normal variant of right hemisphere language organization

Purpose: Exclusive right hemisphere language lateralization is rarely observed in the Wada angiography results of epilepsy surgery patients. Cortical stimulation mapping (CSM) is infrequently performed in such patients, as most undergo nondominant left hemisphere resections, which are presumed not to pose any risk to language. Early language reorganization is typically assumed in such individuals, taking left hemisphere epileptiform activity as confirmation of change resulting from a pathologic process. We present data from CSM and Wada studies demonstrating that right hemisphere language occurs in the absence of left hemisphere pathology, suggesting it can exist as a normal, but rare variant, in some individuals. Furthermore, these data confirm the Wada test findings of atypical dominance. Methods: Cortical stimulation mapping data were examined for all right hemisphere surgical patients with right hemisphere speech at our center between 1974 and 2006. Of 1,209 interpretable Wada procedures, 89 patients (7.4%) had exclusive right hemisphere speech, and 21 (1.7%) of these patients underwent surgery involving the right hemisphere. Language site location was determined by examining intraoperative photographs, and site distribution was statistically compared to published findings from left hemisphere language dominant patients. Key Findings: Language cortex was identified in the right hemisphere during CSM for all patients with available data. All sites could be classified in superior or middle temporal gyri, inferior parietal lobe, or inferior frontal gyrus, all of which were common zones where language was identified in the left hemisphere dominant comparison sample. Significance: Results suggest that the Wada procedure is a valid measure for identifying right hemisphere language processing without any false lateralization found in the patients mapped with CSM (i.e., a positive Wada is 100% sensitive for finding right hemisphere language sites), and that the distribution of language sites is consistent across right hemisphere and left hemisphere language dominant patients, supporting the theory that right hemisphere language can occur as a normal variant of language lateralization.     

Functional mapping of the insular cortex: clinical implication in temporal lobe epilepsy

PURPOSE: We report the results of 75 intracortical electrical stimulations of the insular cortex performed in 14 patients during stereo-electroencephalography (SEEG) investigation of drug-resistant partial epilepsy. The insular cortex was investigated on electroclinical arguments suggesting the possibility of a perisylvian spread or a rapid multilobar diffusion of the discharges during video EEG. METHODS: In these 14 patients, 27 stereotactically implanted transopercular electrodes reached the insular cortex (11 the right insula, 16 the left insula). Square pulses of current were applied between the two deepest adjacent contacts of each transopercular electrode using low (1 Hz) or high-frequency (50 Hz) stimulation. Only symptoms evoked in the absence of afterdischarges were analyzed. RESULTS: Clinical responses were evoked in 10 of the 14 patients (in 20 of the 27 insular sites) and showed a clear topographic specificity inside the insular cortex. Viscerosensitive and visceromotor responses, similar to those evoked by temporomesial stimulation, were evoked by anterior insular stimulation and somesthetic sensation, similar to those evoked by opercular cortex stimulation, by posterior insular stimulation. CONCLUSIONS: The topographic organization of the induced responses within the insular cortex suggest that two different cortical networks, a visceral network extending to the temporomesial structures and a somesthetic network reaching the opercular cortex, are disturbed with stimulation of the anterior or the posterior insula, respectively. Thus ictal symptoms associated with the spread of the epileptic discharges to the insular cortex might be difficult to distinguish from those usually reported during temporomesial or opercular discharges.     

Spracherhaltende Resektion einer fokalen kortikalen Dys­plasie neben dem Broca‑Areal

We report the case of a 14-year-old male with a history of focal seizures since the age of six due to a focal cortical dysplasia located within the left frontal lobe. The patient’s seizures proved to be refractory to treatments with Oxcarbazepine, Lamotrigine, Valproate, and Clobazame. Because fMRI for language mapping suggested a close spatial relationship of the lesion and Broca’s area, invasive language mapping was performed using a subdural grid for direct cortical stimulation. This suggested a clear topographic distinction between the lesion and Broca’s area, finally enabling language retaining lesionectomy. This case illustrates some pitfalls of fMRI language mapping in preoperative workup for epilepsy surgery.     

Lessons for neuropsychology from functional MRI in patients with epilepsy

This contribution aims to review the major findings of pre- and postsurgical functional magnetic resonance imaging (fMRI) in patients with refractory epilepsy from a neuropsychological perspective. We compared the contribution of fMRI with the intracarotid amytal procedure (IAP) with respect to functional mapping of language and memory in patients with therapy-resistant epilepsy. We conclude that using comprehensive language paradigms, fMRI has been able (1) to provide estimates of the degree of language lateralization including the degree of involvement of the nondominant hemisphere, (2) to provide information on the location of its activated network during expressive and receptive language, and (3) to help delineate eloquent language regions in the vicinity of the surgical target, thus preventing postoperative complications. The contribution of the frequently observed nondominant hemisphere activation to language should be explored and its clinical relevance determined. Evidence from fMRI studies is accumulating that reorganization of cognitive and motor function favors the activation of contralateral homotopic areas, although this process is far from understood. The exact functional contribution of atypical areas of activation should be investigated critically. In the presurgical evaluation process, detailed and reliable localization of language and memory functions of the individual patient is mandatory and should be the ultimate goal in the development of comprehensive clinical fMRI protocols.     

FMRI lateralization of expressive language in children with cerebral lesions

PURPOSE: Lateralization of language function is crucial to the planning of surgery in children with frontal or temporal lobe lesions. We examined the utility of functional magnetic resonance imaging (fMRI) as a determinant of lateralization of expressive language in children with cerebral lesions. METHODS: fMRI language lateralization was attempted in 35 children (29 with epilepsy) aged 8-18 years with frontal or temporal lobe lesions (28 left hemisphere, five right hemisphere, two bilateral). Axial and coronal fMRI scans through the frontal and temporal lobes were acquired at 1.5 Tesla by using a block-design, covert word-generation paradigm. Activation maps were lateralized by blinded visual inspection and quantitative asymmetry indices (hemispheric and inferior frontal regions of interest, at p<0.001 uncorrected and p<0.05 Bonferroni corrected). RESULTS: Thirty children showed significant activation in the inferior frontal gyrus. Lateralization by visual inspection was left in 21, right in six, and bilateral in three, and concordant with hemispheric and inferior frontal quantitative lateralization in 93% of cases. Developmental tumors and dysplasias involving the inferior left frontal lobe had activation overlying or abutting the lesion in five of six cases. fMRI language lateralization was corroborated in six children by frontal cortex stimulation or intracarotid amytal testing and indirectly supported by aphasiology in a further six cases. In two children, fMRI language lateralization was bilateral, and corroborative methods of language lateralization were left. Neither lesion lateralization, patient handedness, nor developmental versus acquired nature of the lesion was associated with language lateralization. Involvement of the left inferior or middle frontal gyri increased the likelihood of atypical language lateralization. CONCLUSIONS: fMRI lateralizes language in children with cerebral lesions, although caution is needed in interpretation of individual results.     

Development of a functional magnetic resonance imaging protocol for intraoperative localization of critical temporoparietal language areas

The aim of this study was to evaluate the use of functional magnetic resonance imaging as an alternative to intraoperative electrocortical stimulation mapping for the localization of critical language areas in the temporoparietal region. We investigated several requirements that functional magnetic resonance imaging must fulfill for clinical implementation: high predictive power for the presence as well as the absence of critical language function in regions of the brain, user-independent statistical methodology, and high spatial accuracy. Thirteen patients with temporal lobe epilepsy performed four different functional magnetic resonance imaging language tasks (ie, verb generation, picture naming, verbal fluency, and sentence comprehension) before epilepsy surgery that included intraoperative electrocortical stimulation mapping. To assess the optimal statistical threshold for functional magnetic resonance imaging, images were analyzed with three different statistical thresholds. Functional magnetic resonance imaging information was read into a surgical guidance system for identification of cortical areas of interest. Intraoperative electrocortical stimulation mapping was recorded by video camera, and stimulation sites were digitized. Next, a computer algorithm indicated whether significant functional magnetic resonance imaging activation was present or absent within the immediate vicinity (<6.4mm) of intraoperative electrocortical stimulation mapping sites. In 2 patients, intraoperative electrocortical stimulation mapping failed during surgery. Intraoperative electrocortical stimulation mapping detected critical language areas in 8 of the remaining 11 patients. Correspondence between functional magnetic resonance imaging and intraoperative electrocortical stimulation mapping depended heavily on statistical threshold and varied between patients and tasks. In 7 of 8 patients, sensitivity of functional magnetic resonance imaging was 100% with a combination of 3 functional magnetic resonance imaging tasks (ie, functional magnetic resonance imaging correctly detected all critical language areas with high spatial accuracy). In 1 patient, sensitivity was 38%; in this patient, functional magnetic resonance imaging was included in a larger area found with intraoperative electrocortical stimulation mapping. Overall, specificity was 61%. Functional magnetic resonance imaging reliably predicted the absence of critical language areas within the region exposed during surgery, indicating that such areas can be safely resected without the need for intraoperative electrocortical stimulation mapping. The presence of functional magnetic resonance imaging activity at noncritical language sites limited the predictive value of functional magnetic resonance imaging for the presence of critical language areas to 51%. Although this precludes current replacement of intraoperative electrocortical stimulation mapping, functional magnetic resonance imaging can at present be used to speed up intraoperative electrocortical stimulation mapping procedures and to guide the extent of the craniotomy.     

Functional MRI in a 6-year-old boy with unilateral cortical malformation: concordant representation of both hands in the unaffected hemisphere

Functional magnetic resonance imaging (fMRI) was performed in a 6-year-old boy with a complex malformation of the right hemisphere who suffered from pharmaco-refractory epilepsy. Clinical examination revealed left-sided hemiparesis and marked mirror movements of the opposite hand both during paretic and non-paretic hand movements. Functional MRI of repetitive unimanual grasping demonstrated that the two hands share a common cortical representation located in the central motor region of the unaffected left hemisphere. The affected right hemisphere did not show any activation during either task. This case study demonstrates the feasibility and usefulness of motor fMRI in young children before they undergo epilepsy surgery.     

Lessons learned from a comparison of language localisation using fMRI and electrocortical mapping: case studies of neocortical epilepsy patients

Electrocortical mapping (ECM) is recognised as an established method for localisation of eloquent cortex in patients undergoing resective surgery for epilepsy management. Functional MRI (fMRI) has been utilised for language and other cortical function localisation. We describe language localisation in two patients using both ECM and fMRI. Co-registration of fMRI and ECM revealed that although two fMRI tasks localised multiple language areas, the verb generation task had an advantage over the semantic decision/tone decision task in that there was a clear overlap between the language areas identified by the verb generation task and ECM. In addition to the language areas detected by ECM, fMRI showed other language-related areas that may be important for post-operative language outcome. Therefore, fMRI may provide additional and complementary information to ECM in presurgical evaluation of patients with epilepsy. The correlation between fMRI and ECM may depend on the language testing methods utilised during the procedures.     

Imaging language networks before and after anterior temporal lobe resection: results of a longitudinal fMRI study

Purpose: Anterior temporal lobe resection (ATLR) controls seizures in up to 70% of patients with intractable temporal lobe epilepsy (TLE) but, in the language dominant hemisphere, may impair language function, particularly naming. Functional reorganization can occur within the ipsilateral and contralateral hemispheres. We investigated reorganization of language in left‐hemisphere–dominant patients before and after ATLR; whether preoperative functional magnetic resonance imaging (fMRI) predicts postoperative naming decline; and efficiency of postoperative language networks. Methods: We studied 44 patients with TLE due to unilateral hippocampal sclerosis (24 left) on a 3T GE‐MRI scanner. All subjects performed language fMRI and neuropsychological testing preoperatively and again 4 months after left or right ATLR. Key Findings: Postoperatively, individuals with left TLE had greater bilateral middle/inferior frontal fMRI activation and stronger functional connectivity from the left inferior/middle frontal gyri to the contralateral frontal lobe than preoperatively, and this was not observed in individuals with right TLE. Preoperatively, in left and right TLE, better naming correlated with greater preoperative left hippocampal and left frontal activation for verbal fluency (VF). In left TLE, stronger preoperative left middle frontal activation for VF was predictive of greater decline in naming after ATLR. Postoperatively, in left TLE with clinically significant naming decline, greater right middle frontal VF activation correlated with better postoperative naming. In patients without postoperative naming decline, better naming correlated with greater activation in the remaining left posterior hippocampus. In right TLE, naming ability correlated with left hippocampal and left and right frontal VF activation postoperatively. Significance: In left TLE, early postoperative reorganization to the contralateral frontal lobe suggests multiple systems support language function. Postoperatively, ipsilateral recruitment involving the posterior hippocampal remnant is important for maintaining language, and reorganization to the contralateral hemisphere is less effective. Preoperative left middle frontal activation for VF was predictive of naming decline in left TLE after ATLR.