Clinical outcomes of pediatric hemispherectomy following unsuccessful subhemispheric resection for refractory epilepsy: a case review study.

OBJECTIVE: Epilepsy surgery remains one of the most underutilized procedures in epilepsy despite its proven superiority to other available therapies. This underutilization is greater in patients in whom initial surgery fails. This case series examined the clinical characteristics, reasons for initial surgery failure, and outcomes in a cohort of patients who underwent hemispherectomy following unsuccessful smaller resections for intractable epilepsy (subhemispheric group [SHG]) and compared them to those of a cohort of patients who underwent hemispherectomy as the first surgery (hemispheric group [HG]). The objective of this paper was to determine the clinical characteristics of patients in whom a small, subhemispheric resection failed, who went on to become seizure free after undergoing a hemispherectomy. METHODS: Patients who underwent hemispherectomy at Seattle Children's Hospital between 1996 and 2020 were identified. Inclusion criteria for SHG were as follows: 1) patients ≤ 18 years of age at the time of hemispheric surgery; 2) initial subhemispheric epilepsy surgery that did not produce seizure freedom; 3) hemispherectomy or hemispherotomy after the subhemispheric surgery; and 4) follow-up for at least 12 months after hemispheric surgery. Data collected included the following: patient demographics; seizure etiology; comorbidities; prior neurosurgeries; neurophysiological studies; imaging studies; and surgical details-plus surgical, seizure, and functional outcomes. Seizure etiology was classified as follows: 1) developmental, 2) acquired, or 3) progressive. The authors compared SHG to HG in terms of demographics, seizure etiology, and seizure and neuropsychological outcomes. RESULTS: There were 14 patients in the SHG and 51 patients in the HG. All patients in the SHG had Engel class IV scores after their initial resective surgery. Overall, 86% (n = 12) of the patients in the SHG had good posthemispherectomy seizure outcomes (Engel class I or II). All patients in the SHG who had progressive etiology (n = 3) had favorable seizure outcomes, with eventual hemispherectomy (1 each with Engel classes I, II, and III). Engel classifications posthemispherectomy between the groups were similar. There were no statistical differences in postsurgical Vineland Adaptive Behavior Scales Adaptive Behavior Composite scores or postsurgical full-scale IQ scores between groups when accounting for presurgical scores. CONCLUSIONS: Hemispherectomy as a repeat surgery after unsuccessful subhemispheric epilepsy surgery has a favorable seizure outcome, with stable or improved intelligence and adaptive functioning. Findings in these patients are similar to those in patients who had hemispherectomy as their first surgery. This can be explained by the relatively small number of patients in the SHG and the higher likelihood of hemispheric surgeries to resect or disconnect the entire epileptogenic lesion compared to smaller resections.

Prognostic Value of Preoperative and Postoperative Electroencephalography Findings in Pediatric Patients Undergoing Hemispheric Epilepsy Surgery.

OBJECTIVE: The seizure outcomes after hemispheric epilepsy surgery have been excellent, with 54%-90% of patients achieving long-term freedom from seizures. Similarly, the neuropsychological outcomes have been favorable. The prognostic value of pre- and postoperative electroencephalography (EEG) has not been well-studied. In the present study, we characterized the value of the pre- and postoperative EEG findings for predicting the seizure and neuropsychological outcomes for pediatric patients undergoing hemispherectomy. METHODS: A total of 22 children who had undergone functional hemispherectomy at our institution from 2010 to 2020 were included. The ictal and interictal findings were categorized as ipsilateral to the operated hemisphere, independently arising from the contralateral hemisphere, and/or generalized. The seizure outcomes were classified using the Engel scale. All neuropsychological evaluations were performed in accordance with our institution's protocol. The relationship between the EEG findings and outcomes was analyzed. RESULTS: Of the 22 patients, 19 (86%) were seizure free (Engel class IA) at the latest follow-up (mean, 4.2 years). On the preoperative EEGs, 9 had had seizures, all had had ipsilateral interictal discharges, and 9 had had contralateral interictal discharges. On the postoperative EEGs, obtained a median of 1 year after surgery, 3 had had seizures, 16 had had ipsilateral interictal discharges, and 5 had had contralateral interictal discharges. Of the 3 patients with seizures found on the postoperative EEG, all were clinically free of seizures. The patients who had not achieved Engel class IA were not significantly more likely to have abnormalities found on the EEG. The neuropsychological scores were stable from before to after surgery, with no evidence of EEG abnormalities having predictive value. CONCLUSIONS: The seizure and neuropsychology outcomes after hemispherectomy were excellent in our study, with 86% of our cohort achieving freedom from seizures. The presence, lateralization, and evolution of pre- and postoperative EEG abnormalities were not predictive of the outcomes.

Precision medicine in pediatric temporal epilepsy surgery: optimization of outcomes through functional MRI memory tasks and tailored surgeries.

OBJECTIVE: The goal of epilepsy surgery is both seizure cessation and maximal preservation of function. In temporal lobe (TL) cases, the lack of functional MRI (fMRI) tasks that effectively activate mesial temporal structures hampers preoperative memory risk assessment, especially in children. This study evaluated pediatric TL surgery outcome optimization associated with tailored resection informed by an fMRI memory task. METHODS: The authors identified focal onset TL epilepsy patients with 1) TL resections; 2) viable fMRI memory scans; and 3) pre- and postoperative neuropsychological (NP) evaluations. They retrospectively evaluated preoperative fMRI memory scans, available Wada tests, pre- and postoperative NP scores, postoperative MRI scans, and postoperative Engel class outcomes. To assess fMRI memory task outcome prediction, the authors 1) overlaid preoperative fMRI activation onto postoperative structural images; 2) classified patients as having "overlap" or "no overlap" of activation and resection cavities; and 3) compared these findings with memory improvement, stability, or decline, based on Reliable Change Index calculations. RESULTS: Twenty patients met the inclusion criteria. At a median of 2.1 postoperative years, 16 patients had Engel class IA outcomes and 1 each had Engel class IB, ID, IIA, and IID outcomes. Functional MRI activation was linked to NP memory outcome in 19 of 20 cases (95%). Otherwise, heterogeneity characterized the cohort. CONCLUSIONS: Functional MRI memory task activation effectively predicted individual NP outcomes in the context of tailored TL resections. Patients had excellent seizure and overall good NP outcomes. This small study adds to extant literature indicating that pediatric TL epilepsy does not represent a single clinical syndrome. Findings support individualized surgical intervention using fMRI memory activation to help guide this precision medicine approach.

Concordance of functional MRI memory task and resting-state functional MRI connectivity used in surgical planning for pediatric temporal lobe epilepsy.

OBJECTIVE: Assessing memory is often critical in surgical evaluation, although difficult to assess in young children and in patients with variable task abilities. While obtaining interpretable data from task-based functional MRI (fMRI) measures is common in compliant and awake patients, it is not known whether functional connectivity MRI (fcMRI) data show equivalent results. If this were the case, it would have substantial clinical and research generalizability. To evaluate this possibility, the authors evaluated the concordance between fMRI and fcMRI data collected in a presurgical epilepsy cohort. METHODS: Task-based fMRI data for autobiographical memory tasks and resting-state fcMRI data were collected in patients with epilepsy evaluated at Seattle Children's Hospital between 2010 and 2017. To assess memory-related activation and laterality, signal change in task-based measures was computed as a percentage of the average blood oxygen level-dependent signal over the defined regions of interest. An fcMRI data analysis was performed using 1000 Functional Connectomes Project scripts based on Analysis of Functional NeuroImages and FSL (Functional Magnetic Resonance Imaging of the Brain Software Library) software packages. Lateralization indices (LIs) were estimated for activation and connectivity measures. The concordance between these two measures was evaluated using correlation and regression analysis. RESULTS: In this epilepsy cohort studied, the authors observed concordance between fMRI activation and fcMRI connectivity, with an LI regression coefficient of 0.470 (R2 = 0.221, p = 0.00076). CONCLUSIONS: Previously published studies have demonstrated fMRI and fcMRI overlap between measures of vision, attention, and language. In the authors' clinical sample, task-based measures of memory and analogous resting-state mapping were similarly linked in pattern and strength. These results support the use of fcMRI methods as a proxy for task-based memory performance in presurgical patients, perhaps including those who are more limited in their behavioral compliance. Future investigations to extend these results will be helpful to explore how the magnitudes of effect are associated with neuropsychological performance and postsurgical behavioral changes.

A clinically applicable functional MRI memory paradigm for use with pediatric patients.

OBJECTIVE: Clinically employable functional MRI (fMRI) memory paradigms are not yet established for pediatric patient epilepsy surgery workups. Seeking to establish such a paradigm, we evaluated the effectiveness of memory fMRI tasks we developed by quantifying individual activation in a clinical pediatric setting, analyzing patterns of activation relative to the side of temporal lobe (TL) pathology, and comparing fMRI and Wada test results. METHODS: We retrospectively identified 72 patients aged 6.7-20.9 years with pathology (seizure focus and/or tumor) limited to the TL who had attempted memory and language fMRI tasks over a 9-year period as part of presurgical workups. Memory fMRI tasks required visualization of autobiographical memories in a block design alternating with covert counting. Language fMRI protocols involved verb and sentence generation. Scans were both qualitatively interpreted and quantitatively assessed for blood oxygenation level dependent (BOLD) signal change using region of interest (ROI) masks. We calculated the percentage of successfully scanned individual cases, compared 2 memory task activation masks in cases with left versus right TL pathology, and compared fMRI with Wada tests when available. Patients who had viable fMRI and Wada tests had generally concordant results. RESULTS: Of the 72 cases, 60 (83%), aged 7.6-20.9 years, successfully performed the memory fMRI tasks and 12 (17%) failed. Eleven of 12 unsuccessful scans were due to motion and/or inability to perform the tasks, and the success of a twelfth was indeterminate due to orthodontic metal artifact. Seven of the successful 60 cases had distorted anatomy that precluded employing predetermined masks for quantitative analysis. Successful fMRI memory studies showed bilateral mesial temporal activation and quantitatively demonstrated: (1) left activation (L-ACT) less than right activation (R-ACT) in cases with left temporal lobe (L-TL) pathology, (2) nonsignificant R-ACT less than L-ACT in cases with right temporal lobe (R-TL) pathology, and (3) lower L-ACT plus R-ACT activation for cases with L-TL versus R-TL pathology. Patients who had viable fMRI and Wada tests had generally concordant results. SIGNIFICANCE: This study demonstrates evidence of an fMRI memory task paradigm that elicits reliable activation at the individual level and can generally be accomplished in clinically involved pediatric patients. This autobiographical memory paradigm showed activation in mesial TL structures, and cases with left compared to right TL pathology showed differences in activation consistent with extant literature in TL epilepsy. Further studies will be required to assess outcome prediction.

Pediatric hemispherectomy outcome: Adaptive functioning, intelligence, and memory.

OBJECTIVE: Our purpose was to characterize neuropsychological evaluation (NP) outcome following functional hemispherectomy in a large, representative cohort of pediatric patients. METHODS: We evaluated seizure and NP outcomes and medical variables for all post-hemispherectomy patients from Seattle Children's Hospital epilepsy surgery program between 1996 and 2020. Neuropsychological evaluation outcome tests used were not available on all patients due to the diversity of patient ages and competency that is typical of a representative pediatric cohort; all patients had at least an adaptive functioning or intelligence measure, and a subgroup had memory testing. RESULTS: A total of 71 hemispherectomy patients (37 right; 34 females) yielded 66 with both preoperative (PREOP) plus postoperative (POSTOP) NPs and 5 with POSTOP only. Median surgery age was 5.7 (IQR 2-9.9) years. Engel classification indicated excellent seizure outcomes: 59 (84%) Class I, 6 (8%) Class II, 5 (7%) Class III, and 1 (1%) Class IV. Medical variables - including seizure etiology, surgery age, side, presurgical seizure duration, unilateral or bilateral structural abnormalities, secondarily generalized motor seizures - were not associated with either Engel class or POSTOP NP scores, though considerable heterogeneity was evident. Median PREOP and POSTOP adaptive functioning (PREOP n = 45, POSTOP n = 48) and intelligence (PREOP n = 29, POSTOP n = 36) summary scores were exceptionally low and did not reveal group decline from PREOP to POSTOP. Fifty-five of 66 (85%) cases showed stability or improvement. Specifically, 5 (8%) improved; 50 (76%) showed stability; and 11 (16%) declined. Improve and decline groups showed clinically interesting, but not statistical, differences in seizure control and age. Median memory summary scores were low and also showed considerable heterogeneity. Overall median PREOP to POSTOP memory scores (PREOP n = 16, POSTOP n = 24) did not reveal declines, and verbal memory scores improved. Twenty six percent of intelligence and 33% of memory tests had verbal versus visual-spatial discrepancies; all but one favored verbal, regardless of hemispherectomy side. SIGNIFICANCE: This large, single institution study revealed excellent seizure outcome in 91% of all 71 patients plus stability and/or improvement of intelligence and adaptive functioning in 85% of 66 patients who had PREOP plus POSTOP NPs. Memory was similarly stable overall, and verbal memory improved. Medical variables did not predict group NP outcomes though heterogeneity argues for further research. This study is unique for cohort size, intelligence plus memory testing, and evidence of primacy of verbal over visual-spatial development, despite hemispherectomy side. This study reinforces the role of hemispherectomy in achieving good seizure outcome while preserving functioning.

Awake Mapping of the Auditory Cortex during Tumor Resection in an Aspiring Musical Performer: A Case Report.

INTRODUCTION: Preoperative functional MRI (fMRI) and intraoperative awake cortical mapping are established strategies to identify and preserve critical language structures during neurosurgery. There is growing appreciation for the need to similarly identify and preserve eloquent tissue critical for music production. CASE REPORT: A 19-year-old female musician, with a 3- to 4-year history of events concerning for musicogenic seizures, was found to have a right posterior temporal tumor, concerning for a low-grade glial neoplasm. Preoperative fMRI assessing passive and active musical tasks localized areas of activation directly adjacent to the tumor margin. Cortical stimulation during various musical tasks did not identify eloquent tissue near the surgical site. A gross total tumor resection was achieved without disruption of singing ability. At 9-month follow-up, the patient continued to have preserved musical ability with full resolution of seizures and without evidence of residual lesion or recurrence. CONCLUSION: A novel strategy for performing an awake craniotomy, incorporating preoperative fMRI data for music processing with intraoperative cortical stimulation, interpreted with the assistance of a musician expert and facilitated gross total resection of the patient's tumor without comprising her musical abilities.

Cognitive characteristics of mitochondrial diseases in children.

INTRODUCTION: This retrospective descriptive study was undertaken to further define the intelligence profiles of children with mitochondrial disorders, in the context of seizures and age of symptom onset. METHODS: We retrospectively identified forty-nine pediatric patients with definitive mitochondrial disease diagnoses and complete intelligence or adaptive functioning testing data. Patients were 0-216 months at onset of symptoms and 61-250 months of age at testing. Twenty-four of 49 patients had seizures. Twenty-one of the 24 patients with seizures had medically intractable seizures. All patients had Wechsler Intellectual Quotient (IQ) testing, except nine patients with seizures who were unable to engage in IQ testing and were assessed with a structured parent interview measure, the Vineland Adaptive Behavior Scales. We used descriptive and exploratory data analysis methods to characterize test results. RESULTS: Distribution of ages for patients with the Vineland assessment was younger than those given the Wechsler. The median overall score (combining Wechsler and Vineland summary scores) for all patients was 85 (interquartile range [IQR]: 50, 102), with the group without seizures obtaining a higher median Full Scale IQ (FSIQ) of 100 (IQR: 86, 109), compared to the group with seizures with a median FSIQ of 67 (IQR: 49.5, 89), a difference that is both statistically and clinically different (Δ = 33; 95% CI: 9, 52). The adaptive function measure was composed of patients only with intractable epilepsy and yielded the lowest overall median summary score of 43 (IQR: 37, 50). This general trend in differences between the FSIQ scores of the groups with and without seizures was also seen across all subscale measures analyzed-IQ index scores and two subtest scores, Digit Span and Coding-though differences were not always statistically different. Vargha-Delaney's A effect sizes ranged between 0.68 and 0.90, trends that mirrored those of distributional and median differences. Groups without versus with seizures differed most distinctly in Performance IQ (PIQ), with the group without seizures' median PIQ being 100 (IQR 94, 112) versus the group with seizures' median PIQ being 63 (IQR 54, 84), a difference of 37 points (95% CI). DISCUSSION: Results suggest that patients with mitochondrial diseases with seizures and early onset disease represent a worse cognitive phenotype, as compared with those with no seizures, who can have average intelligence. Results are discussed in the context of current literature.

Changes in resting-state connectivity in pediatric temporal lobe epilepsy.

OBJECTIVE Functional connectivity magnetic resonance imaging (fcMRI) is a form of fMRI that allows for analysis of blood oxygen level-dependent signal changes within a task-free, resting paradigm. This technique has been shown to have efficacy in evaluating network connectivity changes with epilepsy. Presurgical data from patients with unilateral temporal lobe epilepsy were evaluated using the fcMRI technique to define connectivity changes within and between the diseased and healthy temporal lobes using a within-subjects design. METHODS Using presurgical fcMRI data from pediatric patients with unilateral temporal lobe epilepsy, the authors performed seed-based analyses within the diseased and healthy temporal lobes. Connectivity within and between temporal lobe seeds was measured and compared. RESULTS In the cohort studied, local ipsilateral temporal lobe connectivity was significantly increased on the diseased side compared to the healthy temporal lobe. Connectivity of the diseased side to the healthy side, on the other hand, was significantly reduced when compared to connectivity of the healthy side to the diseased temporal lobe. A statistically significant regression was observed when comparing the changes in local ipsilateral temporal lobe connectivity to the changes in inter-temporal lobe connectivity. A statistically significant difference was also noted in ipsilateral connectivity changes between patients with and those without mesial temporal sclerosis. CONCLUSIONS Using fcMRI, significant changes in ipsilateral temporal lobe and inter-temporal lobe connectivity can be appreciated in unilateral temporal lobe epilepsy. Furthermore, fcMRI may have a role in the presurgical evaluation of patients with intractable temporal lobe epilepsy.

Corticospinal tract atrophy and motor fMRI predict motor preservation after functional cerebral hemispherectomy.

OBJECTIVE The potential loss of motor function after cerebral hemispherectomy is a common cause of anguish for patients, their families, and their physicians. The deficits these patients face are individually unique, but as a whole they provide a framework to understand the mechanisms underlying cortical reorganization of motor function. This study investigated whether preoperative functional MRI (fMRI) and diffusion tensor imaging (DTI) could predict the postoperative preservation of hand motor function. METHODS Thirteen independent reviewers analyzed sensorimotor fMRI and colored fractional anisotropy (CoFA)-DTI maps in 25 patients undergoing functional hemispherectomy for treatment of intractable seizures. Pre- and postoperative gross hand motor function were categorized and correlated with fMRI and DTI findings, specifically, abnormally located motor activation on fMRI and corticospinal tract atrophy on DTI. RESULTS Normal sensorimotor cortical activation on preoperative fMRI was significantly associated with severe decline in postoperative motor function, demonstrating 92.9% sensitivity (95% CI 0.661-0.998) and 100% specificity (95% CI 0.715-1.00). Bilaterally robust, symmetric corticospinal tracts on CoFA-DTI maps were significantly associated with severe postoperative motor decline, demonstrating 85.7% sensitivity (95% CI 0.572-0.982) and 100% specificity (95% CI 0.715-1.00). Interpreting the fMR images, the reviewers achieved a Fleiss' kappa coefficient (κ) for interrater agreement of κ = 0.69, indicating good agreement (p < 0.01). When interpreting the CoFA-DTI maps, the reviewers achieved κ = 0.64, again indicating good agreement (p < 0.01). CONCLUSIONS Functional hemispherectomy offers a high potential for seizure freedom without debilitating functional deficits in certain instances. Patients likely to retain preoperative motor function can be identified prior to hemispherectomy, where fMRI or DTI suggests that cortical reorganization of motor function has occurred prior to the operation.

Impact of epilepsy surgery on development of preschool children: identification of a cohort likely to benefit from early intervention.

OBJECT: Outcomes of focal resection in young children with early-onset epilepsy are varied in the literature due to study differences. In this paper, the authors sought to define the effect of focal resection in a small homogeneous sample of children who were otherwise cognitively intact, but who required early surgical treatment. Preservation of and age-appropriate development of intelligence following focal resection was hypothesized. METHODS: Cognitive outcome after focal resection was retrospectively reviewed for 15 cognitively intact children who were operated on at the ages of 2-6 years for lesion-related, early-onset epilepsy. Intelligence was tested prior to and after surgery. Effect sizes and confidence intervals for means and standard deviations were used to infer changes and differences in intelligence between 1) groups (pre vs post), 2) left versus right hemisphere resections, and 3) short versus long duration of seizures prior to resection. RESULTS: No group changes from baseline occurred in Full Scale, verbal, or nonverbal IQ. No change from baseline intelligence occurred in children who underwent left or right hemisphere surgery, including no group effect on verbal scores following surgery in the dominant hemisphere. Patients with seizure durations of less than 6 months prior to resection showed improvement from their presurgical baseline in contrast to those with seizure duration of greater than 6 months prior to surgery, particularly in Wechsler Full Scale IQ and nonverbal intelligence. CONCLUSIONS: This study suggests that surgical treatment of focal seizures in cognitively intact preschool children is likely to result in seizure remediation, antiepileptic drug discontinuation, and no significant decrement in intelligence. The latter finding is particularly significant in light of the longstanding concern associated with performing resections in the language-dominant hemisphere. Importantly, shorter seizure duration prior to resection can result in improved cognitive outcome, suggesting that surgery for this population should occur sooner to help improve intelligence outcomes.

High-fat diets and seizure control in myoclonic-astatic epilepsy: a single center's experience.

PURPOSE: To determine the efficacy of the Modified Atkins Diet (MAD) and Ketogenic Diet (KD) in seizure control within a population of myoclonic-astatic epilepsy (MAE) patients. METHODS: This was a retrospective, single center study evaluating the seizure control by high fat diets. Seizure diaries kept by the parents performed seizure counts. All patients met the clinical criteria for MAE. RESULTS: Nine patients met the clinical criteria. We found that both the MAD and KD were efficacious in complete seizure control and allowed other medications to be stopped in seven patients. Two patients had greater than 90% seizure control without medications, one on the KD and the other on the MAD. Seizure freedom has ranged from 13 to 36 months, and during this time four patients have been fully weaned off of diet management. One patient was found to have a mutation in SLC2A1. CONCLUSION: Our results suggest that strictly defined MAE patients respond to the MAD with prolonged seizure control. Some patients may require the KD for seizure freedom, suggesting a common pathway of increased requirement for fats. Once controlled, those fully responsive to the Diet(s) could be weaned off traditional seizure medications and in many, subsequently off the MAD or KD.

Mitochondrial electron transport chain deficiency, cardiomyopathy, and long-term cardiac transplant outcome.

Organ transplantation in multisystemic mitochondrial cytopathies is usually not performed because of perceived untoward complications. We report three patients with demonstrated oxidative phosphorylation defects and dilated cardiomyopathy who underwent cardiac transplant. All three patients tolerated immunosuppression medications and have had an excellent long-term outcome. Our results suggest that with proper patient selection in this population, cardiac transplantation is feasible and can have good outcomes.

Functional magnetic resonance imaging for presurgical evaluation of very young pediatric patients with epilepsy.

OBJECT: The authors describe their experience with functional MR (fMR) imaging in children as young as 5 years of age, or even younger in developmental age equivalent. Functional MR imaging can be useful for identifying eloquent cortex prior to surgical intervention. Most fMR imaging clinical work has been done in adults, and although children as young as 8 years of age have been included in larger clinical series, cases in younger children are rarely reported. METHODS: The authors reviewed presurgical fMR images in eight patients who were 8 years of age or younger, six of whom were 5 or 6 years of age. Each patient had undergone neuropsychological testing. Three patients functioned at a below-average level, with adaptive functioning age scores of 3 to 4 years. Self-paced finger tapping (with passive movement in one patient) and silent language tasks were used as activation tasks. The language task was modified for younger children, for whom the same (not novel) stimuli were used for extensive practice ahead of time and in the MR imaging unit. Patient preparation involved techniques such as having experienced staff present to work with patients and providing external management during imaging. Six of eight patients had extensive training and practice prior to the procedure. In the two youngest patients, this training included use of a mock MR unit. RESULTS: All cases yielded successful imaging. Finger tapping in all seven of the patients who could perform it demonstrated focal motor activation in the frontal-parietal region, with expected activation elsewhere, including in the cerebellum. Three of four patients had the expected verb generation task activations, with left-hemisphere dominance, including a 6-year-old child who functioned at the 3-year, 9-month level. The only child (an 8-year-old) who was not prepared prior to the imaging session for the verb generation task failed this task due to movement artifact. CONCLUSIONS: Despite the challenges of successfully using fMR imaging in very young and clinically involved patients, these studies can be performed successfully in children with a chronological age of 5 or 6 years and a developmental age as young as 3 or 4 years.

Use of dexmedetomidine in awake craniotomy in adolescents: report of two cases.

Awake craniotomy is a key tool in resection of lesions near critical functional regions, particularly the speech area. Craniotomy with an awake portion for mapping may be performed in carefully selected adolescents and preteenaged children. A number of different regimens may be used for sedation and anesthesia in these cases. We describe two adolescent patients in whom awake craniotomy was performed using an intravenous anesthesia technique with dexmedetomidine and without need for airway instrumentation.