Frontal Lobectomy Research Articles

Frontal lobe disconnection: How I do it.

The objective of frontal lobe disconnection (FD) is to isolate the frontal lobe without removing brain parenchyma, to achieve epilepsy outcomes comparable to those for frontal lobectomy but with fewer complications, since a large post-operative cavity is not created. Main surgical steps include "Identification of the central sulcus" to ensure the preservation of motor function, and "Frontal lobe disconnection" comprising: 1) fronto-parietal disconnection; 2) fronto-basal disconnection; 3) anterior corpus callosotomy; and 4) insula and basal ganglia disconnection. In performing FD, consideration of the disconnection boundary based on an anatomical understanding of white matter tracts is essential.

Functional frontal lobectomy in the surgical treatment of pharmacoresistant frontal lobe epilepsy: how I do it

BackgroundFrontal lobe epilepsy is pharmacoresistant in 30% of cases, constituting 10–20% of epilepsy surgeries. For cases of no lesional epilepsy (negative MRI), frontal lobectomy is a crucial treatment, historically involving Frontal Anatomical Lobectomy (AFL) with a 33.3% complication risk and 55.7% seizure control.MethodsWe describe Frontal Functional Lobectomy (FFL), in which the boundaries are defined on the patient's functional cortico-subcortical areas, recognized with advanced intraoperative technologies such as tractography and navigated transcranial magnetic stimulation (nTMS).ConclusionsThe FFL allows for a broader resection with a lower rate of postoperative complications than the AFL.

Minimally invasive keyhole approach for supramaximal frontal glioma resections: technical note.

The authors aimed to review the frontal lobe's surgical anatomy, describe their keyhole frontal lobectomy technique, and analyze the surgical results. Patients with newly diagnosed frontal gliomas treated using a keyhole approach with supramaximal resection (SMR) from 2016 to 2022 were retrospectively reviewed. Surgeries were performed on patients asleep and awake. A human donor head was dissected to demonstrate the surgical anatomy. Kaplan-Meier curves were used for survival analysis. Of the 790 craniotomies performed during the study period, those in 47 patients met our inclusion criteria. The minimally invasive approach involved four steps: 1) debulking the frontal pole; 2) subpial dissection identifying the sphenoid ridge, olfactory nerve, and optic nerve; 3) medial dissection to expose the falx cerebri and interhemispheric structures; and 4) posterior dissection guided by motor mapping, avoiding crossing the inferior plane defined by the corpus callosum. A fifth step could be added for nondominant lesions by resecting the inferior frontal gyrus. Perioperative complications were recorded in 5 cases (10.6%). The average hospital length of stay was 3.3 days. High-grade gliomas had a median progression-free survival of 14.8 months and overall survival of 23.9 months. Keyhole approaches enabled successful SMR of frontal gliomas without added risks. Robust anatomical knowledge and meticulous surgical technique are paramount for obtaining successful resections.

Neuropathologic findings in a patient with Parry-Romberg syndrome: active cerebral vasculitis and brain injury

PurposeParry-Romberg syndrome (PRS) is a rare disorder characterized by slowly progressive hemifacial atrophy. Although the underlying etiology is unknown, proposed disease mechanisms which include autoimmune, infection, trauma, and other causes have been proposed as underlying disease mechanisms. Approximately, 10–20% of PRS patients have neurologic manifestations such as epilepsy, headaches, or associated vascular malformations. There are reports of PRS responsive to immunosuppressive medications, supporting the autoimmune hypothesis. Currently, the neuropathologic findings in patients with PRS are not well documented.MethodsHerein, we present a case of a 19-year-old female with PRS, who underwent partial frontal lobectomy for intractable epilepsy.ResultsThe resection specimen showed multifocal active lymphocytic (T-cell mediated) arteritis in midsized cortical arterioles, with the adjacent meninges showing fibrosis involving both the meningeal tissue and its vascular network. In addition, neuronal loss and gliosis were evident in the cortex, likely due to the associated vascular injury.ConclusionsThis report is the first to demonstrate active cerebral vasculitis in a patient with PRS, supporting the previous suspicion of inflammatory etiology in this disease. In addition, the widespread vascular fibrosis in the meningeal vessels and an area of cortical ischemia support the presence of previous inflammatory vascular processes in the area.

Bilateral and asymmetrical localization of language function identified by the superselective infusion of propofol in an epilepsy patient with a mild malformation of cortical development: illustrative case.

Atypical localization of language function can result in unexpected postsurgical deficits after cortical resection, but it is difficult to predict the risk in the presurgical evaluation. The authors experienced a rare case of the bilateral and independent existence of different components of language function identified by segmented evaluation of anatomical anterior and posterior language areas using the superselective infusion of propofol. A 32-year-old right-handed female presented with drug-resistant epilepsy. Comprehensive epilepsy evaluation suggested that the epileptic foci involved the whole left frontal lobe but provided less evidence of structural abnormality. To estimate the extent of functional deterioration likely to be caused by an extended left frontal lobectomy, the authors evaluated segmented cortical function in the ipsi- and contralateral hemispheres by the superselective infusion of propofol into the branches of the intracranial artery. The results revealed bilateral and asymmetrical localization of language function because the patient presented with different components of aphasia in each hemisphere. Based on the authors' assessment of her functional tolerance, an extended left frontal lobectomy was performed and resulted in neurological deficits within the anticipated range. An accurate understanding of the correlations between vascular and functional anatomy and the highly specific evaluation of language function provides more advanced presurgical assessment, allowing more tailored planning of cortical resection.

38 Language and memory outcome after frontal or temporal resection for epilepsy

Objective:The purpose of this investigation was to examine neuropsychological functioning after frontal (FL) or temporal lobectomy (ATL) in patients with localization related epilepsy. Few studies have compared cognitive changes following FL and ATL. Past research found improvement on measures of verbal and visual memory along with confrontation naming after FL (Busch et al., 2017). In contrast, a number of studies have reported verbal memory and naming decline in those undergoing left ATL. The current study examined post-operative cognitive changes in epilepsy patients who underwent either a left or right FL or ATL.Participants and Methods:Subjects include 430 patients (204 men, 225 women, 1 gender not specified), who underwent surgical resection; Right FL = 25, Left FL = 26, Right ATL = 211, Left ATL = 168. Patients had a mean FSIQ = 90, ages ranging from 18 to 71 (mean age = 37 years), right (n=359), left (n=50), or mixed (n=18) handedness, and education ranging from 3 to 22 years (mean = 12.9 years of education). Change from pre- to post FL and ATL was examined in the following domains: learning and memory [Long Term Storage for Selective Reminding Tests (SRT), Wechsler’s Memory Scale (WMS): Logical Memory Delayed Recall (LM) and Visual Reproduction Delayed Recall (VR)], and language [Boston Naming Test (BNT)].Results:A one-way ANOVA was used to examine changes in language and memory. Our findings revealed statistically significant differences between resection groups for LM, SRT, and BNT. There were significant declines (p<.001) for left ATL when compared to right ATL for LM, SRT, and BNT. There were significant declines for left ATL, when compared to the gains in both left (p<.001; p=.002) and right (p=.018; p=.008) FL for LM and BNT. Left ATL also had significant declines when compared to gains in SRT (p<.001) for right FL. There were significant declines for left FL when compared to right ATL for SRT (p=.007). Lastly, there were significant gains for right FL when compared to left FL for SRT (p=.020).Conclusions:The pre- to post-surgical neuropsychological change in learning, memory, and language is understudied in frontal lobe epilepsy (FLE); although several investigators reported some learning and memory impairments in FLE at either pre- or post-surgical time points (Johnson-Markve et al., 2011; Incisa Della Rocchetta et al., 1993). The current study suggests that resections of the frontal lobes are associated with better outcomes for naming and verbal memory (LM) when compared to left ATLs. Interestingly, verbal list learning declined more in left than right FL and right ATL patients suggesting a possible language based executive functioning component to this memory measure. As expected, our study further supports that left ATLs are associated with material specific memory declines. This pattern was not seen for those undergoing a right ATL (i.e., nonverbal memory did not decline in patients with right ATL).

P.096 Effectiveness of palliative focal resective surgery in intracranial EEG confirmed multifocal intractable epilepsy in adult patients

Background: Effectiveness of “palliative resections” of a dominant epileptogenic focus in adults with multifocal intractable epilepsy confirmed on intracranial EEG has rarely been reported. Methods: We retrospectively reviewed our database to identify patients who underwent focal resection after confirmation of multiple seizure foci on intracranial EEG. Results of presurgical investigations, intracranial EEG, procedures, complications and outcome were collected. Results: A total of 17 patients underwent palliative resection (8 left, 9 right). Preoperative MRI revealed malformations of cortical development in 6 patients, and MTS in 6 patients. Intracranial stereo EEG revealed 8 bilateral and 9 unilateral multifocal epileptogenic foci. Surgical procedures included anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy in 4 patients, ATL plus additional cortical resection in 7 patients, and extratemporal resection in 6 patients. One patient had dysphasia post ATL and a second patient had worsened cognitive dysfunction post extended frontal lobectomy. Favorable seizure outcome (Engel class I and II) was achieved in 10 patients (58.8%). Pathology revealed focal cortical dysplasia in 6 patients and hippocampal sclerosis in 5 patients. Conclusions: Palliative resection of a dominant epileptogenic focus confirmed by intracranial EEG is effective in carefully selected adult cases of intractable epilepsy, particularly in patients with lesional epilepsy.

Frontal lobe epilepsy and mild malformation with oligodendroglial hyperplasia: Further observations on electroclinical and imaging phenotypes, and surgical perspectives.

Mild malformation with oligodendroglial hyperplasia (MOGHE) is a recently described clinicopathologic entity, associated with drug-resistant epilepsy and extensive epileptogenic networks. Knowledge is accumulating about particular electroclinical phenotypes, correlations with imaging, and potential prognostic significance for surgical outcomes. The study adds relevant information by documenting the presence of a hyperkinetic frontal lobe seizure phenotype in adolescents and an epileptic encephalopathy phenotype in young children. Five cases were subjected to a structured presurgical evaluation protocol, including EEG-FMRI, chronic and acute invasive EEG, subjected to frontal lobe surgery with postoperative follow-up between 15 months and 7 years. In the two adult cases, surface EEG demonstrated lateralized widespread frontal lobe epileptogenicity and hyperkinetic semiological features. MRI demonstrated cortical white matter blurring and deeper white matter abnormalities. EEG-FMRI suggested concordant frontal lobe involvement. iEEG demonstrated a widespread frontal lobe epilepsy network. The three young children demonstrated a diffuse epileptic encephalopathy phenotype, with nonlocalizing, nonlateralizing surface EEG, and "spasms" as the main seizure type. MRI demonstrated extensive frontal lobe subcortical gray and white matter abnormalities, consistent with MOGHE literature for this age, while EEG-FMRI, in 2/3, demonstrated concordant frontal lobe involvement. They did not undergo chronic iEEG, and the resection was assisted by acute intraoperative ECoG. All cases were subjected to extensive frontal lobectomies with Engel class IA (2/5), IB (1/5), and IIB (2/5) outcomes. The study confirms the presence of frontal lobe epilepsy and epileptic encephalopathy phenotypes, in accordance with epilepsy phenotypes already described in MOGHE literature. Presurgical evaluation studies, including EEG-FMRI, can provide strong lateralizing and localizing evidence of the epileptogenic networks involved. All responded favorably to extensive frontal lobe resections, despite widespread epileptic activity recorded by surface and intracranial EEG pre- and postoperatively; an epileptic encephalopathy phenotype, in the first years of life, should not discourage such a resection.

Minimally invasive keyhole frontal lobectomy approach for supramaximal glioma resection: A technical note and complications report

Minimally invasive keyhole frontal lobectomy approach for supramaximal glioma resection: A technical note and complications report

Brenda Milner: Pioneer of the Study of the Human Frontal Lobes

Although the behavioral effects of damage to the frontal lobes date back to at least the late 19th century even midway through the 20th century very little was known about human frontal lobe function and there was a general consensus that the frontal lobe did not play a key role in cognition. This all changed when Brenda Milner published a chapter in a 1964 volume entitled: The Frontal Granular Cortex and Behavior. Milner’s chapter, “Some effects of frontal lobectomy in man,” was the first systematic study of the effect of frontal lobe excisions on cognition in human patients. Milner had access to a unique population of frontal excision patients at the Montreal Neurological Institute that were being treated by Wilder Penfield and his associates for a wide range of neurological disorders, including intractable epilepsy. Milner and her colleagues engaged in a more than 50-year study that has had a formidable impact on our understanding of frontal lobe function. Paralleling studies of frontal lobe function in non-humans they influence on understanding the evolution and function of the prefrontal cortex of mammals. Thus, although Brenda Milner is best known for her studies of human memory, she has had an equally important contribution to our understanding of the frontal lobes.

Neuropsychological outcomes after frontal lobectomy to treat intractable epilepsy

ObjectiveFrontal lobectomy is often used as a surgical treatment for frontal lobe epilepsy, especially when a large epileptogenic zone in the frontal lobe is inferred from preoperative evaluation. The frontal lobe is important for cognitive functions such as executive functions and verbal fluency, but the neuropsychological outcome after a frontal or prefrontal lobectomy that includes both the dorsolateral prefrontal cortex and ventral prefrontal cortex has not been studied thoroughly. In the present study, we evaluated neuropsychological outcomes after patients with frontal lobe epilepsy received a frontal or prefrontal lobectomy. MethodsWe retrospectively reviewed the data of patients with frontal lobe epilepsy who underwent a frontal or prefrontal lobectomy that includes both the dorsolateral prefrontal cortex and ventral prefrontal cortex at 16 years or older from October 2004 to December 2014, with a minimum postoperative follow-up of 24 months. We analyzed and compared neuropsychological outcomes, including executive functions, verbal fluency, intelligence, and memory, before and after the operation. ResultsEighteen patients were 16 years or older and underwent pre- and postoperative (2 years after the operation) neuropsychological evaluations. Patients showed significant deterioration only on the Benton Visual Retention Test. Performance on tests of frontal lobe functions, such as executive function and verbal fluency, showed no significant deterioration. ConclusionsOverall cognitive performance, including functions widely thought to depend on the frontal lobe, is stable after a frontal or prefrontal lobectomy to treat frontal lobe epilepsy.

A Concept of "Boundary Determination" by the Combination of a Local Flap and Free Tissue Transfer Useful for the Prevention of Postoperative Complications After Complex and Widespread Skull Base Reconstruction.

The transplanted tissue is sutured to the stumps of the bones in skull base reconstruction. Concerning reconstruction by free tissue transfer, it is difficult that the tissue is accurately sutured/fixed to a complex three-dimensional structure. The authors devised a technique in which free tissue transfer is combined with a local flap. A pericranial flap is sutured/fixed onto the irregular border between the cranial and nasal cavities. A free tissue graft is transplanted cranial or caudal to the determined border. Clinical presentation 1 is a patient with carcinoma of the frontal sinus (T4bN0M0). Resection of the frontal bone/nasal bone/medial and superior walls of the orbit, frontal lobectomy was performed. Clinical presentation 2 is a patient with carcinoma of the maxillary sinus (T4aN0M0). Extended total maxillectomy, simultaneous resection of the facial skin/temporal muscle were performed. There were no serious postoperative complications related to compression or occlusion of the cerebral parenchyma or paranasal sinus.

Automated analysis of cortical volume loss predicts seizure outcomes after frontal lobectomy.

Patients undergoing frontal lobectomy demonstrate lower seizure-freedom rates than patients undergoing temporal lobectomy and several other resective interventions. We attempted to utilize automated preoperative quantitative analysis of focal and global cortical volume loss to develop predictive volumetric indicators of seizure outcome after frontal lobectomy. Ninety patients who underwent frontal lobectomy were stratified based on seizure freedom at a mean follow-up time of 3.5 (standard deviation [SD] 2.5) years. Automated quantitative analysis of cortical volume loss organized by distinct brain region and laterality was performed on preoperative T1-weighted magnetic resonance imaging (MRI) studies. Univariate statistical analysis was used to select potential predictors of seizure freedom. Backward variable selection and multivariate logistical regression were used to develop models to predict seizure freedom. Forty-eight of 90 (53.3%) patients were seizure-free at the last follow-up. Several frontal and extrafrontal brain regions demonstrated statistically significant differences in both volumetric cortical volume loss and volumetric asymmetry between the left and right sides in the seizure-free and non-seizure-free cohorts. A final multivariate logistic model utilizing only preoperative quantitative MRI data to predict seizure outcome was developed with a c-statistic of 0.846. Using both preoperative quantitative MRI data and previously validated clinical predictors of seizure outcomes, we developed a model with a c-statistic of 0.897. This study demonstrates that preoperative cortical volume loss in both frontal and extrafrontal regions can be predictive of seizure outcome after frontal lobectomy, and models can be developed with excellent predictive capabilities using preoperative MRI data. Automated quantitative MRI analysis can be quickly and reliably performed in patients with frontal lobe epilepsy, and further studies may be developed for integration into preoperative risk stratification.

Verruconus gallopava CNS Infection in a Heart-Kidney Transplant Recipient

Introduction Dematiaceous fungal infections are uncommon and have diverse clinical manifestations. CNS involvement is among the rarest manifestations and typically presents as a brain abscess. Verruconus gallopava has been isolated in cases and appears to be associated with immunocompromised hosts, particularly the post-transplant population. There is no standardized treatment regimen for dematiaceous fungal CNS infections. Recommendations are largely based on in-vitro data and studies derived from case reports. Anti-fungal agents and complete excision of brain abscesses portends the best survival, although prognosis remains poor, with overall mortality >70%. Case Report Ms. H was a 50 yo F with a PMH of NICM c/b cardiorenal syndrome s/p combined heart-kidney transplant (on mycophenolate, tacrolimus and prednisone) who was brought to the ED 4 months post-transplant with altered mental status (AMS). 1 week prior to presentation, Ms. H developed intermittent headaches and progressive AMS. Vital signs WNL. Physical exam significant only for confusion and lethargy. Labs unremarkable. MRI brain revealed a L frontal lobe abscess w/ surrounding vasogenic edema and L-to-R midline shift. Ms. H underwent emergent L frontal craniectomy for abscess D&C. Empiric antibiotics were started and mycophenolate held. She worsened clinically and radiographically, compelling a L frontal lobectomy. Initial cultures grew mold, so liposomal amphotericin B (L-AmB) was added and antibiotics eventually discontinued. CT chest revealed a fungal abscess in the RLL, which was determined to be the primary source of infection. Cultures eventually speciated Verruconus gallopava, and voriconazole was added. Susceptibilities showed MICs of 2mcg/ml for AmB and 0.50 mcg/ml for voriconazole. However, she continued to decline, and voriconazole was switched to posaconazole (MIC of 0.25mcg/ml). Ms. H gradually improved and, after an 8-month hospital course, was discharged in stable condition on lifelong posaconazole monotherapy. At 1-year post-transplant f/u, L/RHC/biopsy showed hemodynamics WNL, CAV0, and no evidence of acute cellular rejection. Summary High clinical suspicion for dematiaceous fungi in brain abscesses is needed as these are rarely seen in practice. For Ms. H, a combination of posaconazole, L-AmB, and surgical intervention treated her life-threatening V. gallopava CNS infection.

Seizure and Elinical Outcomes After Frontal Lobectomy Stratified by Anatomic Resection

Seizure and Elinical Outcomes After Frontal Lobectomy Stratified by Anatomic Resection

1216 Markedly decreased ictal discharges with positive airway pressure (PAP) treatment in a patient with refractory epilepsy and severe obstructive sleep apnea

Abstract Introduction Individuals with epilepsy are at increased risk for obstructive sleep apnea (OSA). Treatment of OSA with positive airway pressure (PAP) can result in decreased seizure frequency in patients with epilepsy, possibly due to decreased sleep disruption and normalization of oxygenation saturation levels when using PAP. The following case report demonstrates an example in which treatment of OSA with PAP resulted in a dramatic improvement of electroencephalographic seizures. Report of Case A 32 year-old man with refractory epilepsy presented to our office complaining of loud snoring, witnessed apneas, and excessive daytime sleepiness. Despite prior left frontal and left anterior temporal lobectomy, vagus nerve stimulator treatment, and excellent treatment adherence to four different antiepileptic medications, the patient continued to have 1-3 clinical seizures per day. Physical examination was notable for obesity (BMI=39.4 kg/m2), high arched palate and Mallampati class 4 airway. Long-term eletroencephalogram (EEG) monitoring was significant for frequent interictal discharges during wakefulness and sleep, as well as frequent subclinical seizures during sleep characterized by C3/P3 polyspike bursts followed by brief rhythmic fast activity. A diagnostic polysomnogram revealed severe OSA (AHI=69/hour). The patient subsequently underwent a PAP titration study with extended EEG montage, which was notable for a marked decrease in polyspike discharges on effective PAP pressures, from an average of 24 polyspike discharges per hour on PAP pressures < 15 cm of water to an average of 3 polyspike discharges per hour on PAP pressures ≥ 15 cm of water. PAP treatment was initiated following the titration study. Conclusion This case demonstrates that effective treatment of OSA can lead to a reduction of abnormal EEG discharges in a patient with intractable epilepsy. Additional clinical follow up is needed to assess whether PAP treatment also resulted in decreased frequency of clinical seizures.

Examining the Utility of Resective Epilepsy Surgery in Children With Electrical Status Epilepticus in Sleep: Long Term Clinical and Electrophysiological Outcomes.

Background: Electrical Status Epilepticus in Sleep (ESES) is an epileptic encephalopathy syndrome characterized by infrequent clinical seizures and prominent interictal burden during slow wave sleep associated with cognitive deficits and behavioral dysfunction. Medical treatment with anti-epileptic drugs is often unsuccessful. Resective surgery may be a valuable option in carefully selected patients. This case series aims to describe the indications, long term results and utility of resective surgery for ESES.Methods: Information on 14 patients who underwent surgery for epilepsy and ESES at the Children's Hospital of Wisconsin between 2007 and 2017 is included. Clinical, electrographic and neuropsychological features and outcomes are described in detail.Results: The most common pathology was encephalomalacia due to perinatal middle cerebral artery stoke (5/14). Twelve patients had imaging findings of perinatal pathologies; however, two patients had normal magnetic resonance imaging. Surgery was performed to control refractory epilepsy in eight patients. Six patients had no clinical seizures for 1–6 years prior to surgery, one of which had no known clinical seizures at all. All showed cognitive declines (6/14) or impairment (8/14) on neuropsychological assessments, and surgery was suggested to minimize further cognitive declines. The most common surgical procedure was hemispherotomy (10/14). Temporo-parieto-occipital disconnection, frontal lobectomy, parieto-occipital resection, and limited corticectomy were also used, with good outcomes for the first three procedures. Clinical follow up mean was 4.4 years and 12 patients had excellent seizure outcome. Electroencephalography (EEG) follow up mean was 3 years and ESES resolved in 12/14 patients. All patients completed post-surgical neuropsychological evaluation with mean follow-up of 17.46 months.Conclusions: Resective surgery is an effective treatment for selected cases of ESES, producing long term seizure freedom, resolution of ESES and stabilization of cognitive and behavioral functioning in most patients. Our case series is the largest single center cohort description addressing resective surgery for ESES. Outcomes in this sample suggest that good long-term seizure, EEG and cognitive/behavioral outcomes can be achieved in patients with normal brain imaging and in limited lobar or multi-lobar resections. Moreover, patients with ESES and very infrequent clinical seizures can benefit from surgery with stabilization of cognitive and behavioral functioning.

Surgical Technique and Outcome of Extensive Frontal Lobectomy for Treatment of Intracable Non-lesional Frontal Lobe Epilepsy.

Although extensive frontal lobectomy (eFL) is a common surgical procedure for intractable frontal lobe epilepsy (FLE), there have been very few reports regarding surgical techniques for eFL. This article provides step-by-step descriptions of our surgical technique for non-lesional FLE. Sixteen patients undergoing eFL were included in this study. The goals were to maximize gray matter removal, including the orbital gyrus and subcallosal area, and to spare the primary motor and premotor cortexes and anterior perforated substance. The eFL consists of three steps: (1) positioning, craniotomy, and exposure; (2) lateral frontal lobe resection; and (3), resection of the rectus gyrus and orbital gyrus. Resection ahead of bregma allows preservation of motor and premotor area function. To remove the orbital gyrus preserving anterior perforated substance, it is essential to visualize the olfactory trigone beneath the pia. It is important to observe the surface of the contralateral medial frontal lobe for complete removal of the subcallosal area of the frontal lobe. Thirteen patients (81.25%) became seizure-free and three patients (18.75%) continued to have seizures. None of the patients showed any complications. The eFL is a good surgical technique for the treatment of intractable non-lesional FLE. For treatment of epilepsy by eFL, it is important to resect the non-eloquent area of the frontal lobe as much as possible with preservation of the eloquent cortex.

A-41 Verbal Fluency and Switching Accuracy Differences in Pediatric Epilepsy Pre- and Post- Surgery

Abstract Objective In patients with epilepsy, research is variable with regard to language difficulties. Previous research generally focuses on phonemic and semantic verbal fluency in pediatric populations post-surgery; however, few studies examine category switching accuracy. This study compared phonemic fluency, categorical fluency, switching accuracy, and the number of switches among pre-surgical and post-surgical groups. Methods Participants included 31 epilepsy patients (age 5-20 years old; M = 12.23 years pre-surgery; M = 14.72 years post-surgery; 20 males, 11 females) who underwent neuropsychological evaluations prior to and following open brain resection surgery (i.e., temporal lobectomy, temporal resection, frontal lobectomy). Verbal Fluency was assessed by the Delis-Kaplan Executive Functioning System (D-KEFS), measuring phonemic fluency, categorical fluency, switching accuracy, and the number of switches. Results Statistically significant differences were found between groups on the D-KEFS Verbal Fluency subtest using a one-way ANOVA. Specifically, switching accuracy decreased following surgery, F(1,25) = 6.470, p = 0.02 (M = 104.44 pre-surgery, M = 89.44 post-surgery). Further, a downward trend was noted regarding the number of switches between the two groups, F (1, 26) = 3.172, p = 0.09; however, no differences were found in phonemic, F(1,34) = 0.854, p = 0.63, and categorical, F(1,35) = 0.828, p = 0.37, fluency tasks. Conclusions Results from this study revealed a decrease in the participants ability to accurately switch between verbal categories following brain resection surgery. Similarly, a downward trend was noted for number of switches completed pre- and post- surgery. Consistent with previous research, phonemic and semantic verbal fluency tasks remain unchanged post-surgery. Implications of this study highlight the need to assess executive functioning after surgery as it has an impact on treatment outcome and school planning.

A-38 Examining Cognitive Differences of Pre- and Post- Surgery in Pediatric Epilepsy

Abstract Objective Intractable epilepsy is often associated with cognitive difficulties in the language domain. Few studies examining verbal domains of cognitive functioning indicate a small increase of verbal skills post-surgery. The current study compared Verbal IQ and Performance IQ domains in pediatric populations before and after open resection surgery. Method Participants included 31 epilepsy patients (age 5-20 years old; M = 12.23 years pre-surgery; M = 14.72 years post-surgery; 20 males, 11 females) who underwent neuropsychological evaluations prior to and following an open brain resection surgery (i.e., temporal lobectomy, temporal resection, frontal lobectomy). Cognitive ability was assessed by Weschler Abbreviated Scale of Intelligence (WASI) in order to analyze differences between pre-surgical and post-surgical cognitive function, specifically verbal comprehension and perceptual reasoning ability. Results No statistically significant differences were found, using a One-way ANOVA, between the two groups; however, a downward trend was noted for the Verbal IQ (VIQ) domain, F(1, 25) = 2.624, p = 0.118, including the verbal subtests vocabulary, F(1, 23) = 2.203, p = 0.151, and similarities, F(1, 24) = 1.678, p = 0.207. No differences or trends were noted within the Performance IQ (PIQ) domain, block design, or matrix reasoning. Conclusions Findings indicated that participants verbal ability decreased after epilepsy surgery when compared to prior evaluations. This is not consistent with previous research, which stated an increase in verbal abilities following surgical resection. Variable time between surgery and re-evaluation might account for discrepancies. Further, no differences in nonverbal reasoning abilities were noted. Results indicated a need for further research in open brain resection surgeries and the outcome of verbal processing.