Long-Term Epilepsy-Associated Tumors (LEATs): A Single-Center, Retrospective Series and Review of Literature on Factors Affecting the Seizure Outcome.

BACKGROUND: Tumors presenting with drug-resistant seizures are termed as long-term epilepsy-associated tumors (LEATs). LEATs are more common in the temporal lobe, occur predominantly in pediatric age, and focal neurological deficits are rare. In this article, we aim to highlight our surgical experience in terms of seizure outcome among LEATs and discuss the factors affecting outcome. METHODOLOGY: We have retrospectively analyzed all the operated cases of intra-axial brain tumors with seizures (2015-2019). The clinical and radiographic data were collected from the hospital record system. For comparison, 2 groups were made (group 1 with good seizure control, i.e., Engel 1; and group 2 poor seizure outcome, i.e., Engel 2 and 3). RESULTS: A total of 51 cases were included; the temporal lobe was the most common location (n = 27); 23 patients had seizure frequency of "more than 1 seizure per week." Focal unaware seizures/complex partial seizures were the most common type of seizures encountered (n = 28). At a mean follow-up of 39.60 months, 38 patients had Engel 1 (78.5%) outcome (35 cases [71.05%] had the seizure duration of ≤2 years). The median duration of symptoms (group 1, 25 months vs. group 2, 65 months) was significantly different (P = 0.002). On comparing patients with seizure duration, we found a statistically significant difference (P < 0.00001). CONCLUSION: A shorter duration of symptoms, younger age of the patient, partial/focal seizures, and gross total excision were predictors of a good seizure outcome. Histopathology of the tumor does not affect the outcome when one compares glioneuronal tumors with non-glioneuronal tumors.

Ictal Asystole Induced by Right Posterior Quadrant Epilepsy: Report of a Radically Treated Case.

BACKGROUND: Ictal asystole (IA) and ictal bradycardia (IB) are mainly seen with temporal or frontal lobe epilepsy. Many patients with these conditions undergo cardiac pacemaker therapy but not epilepsy surgery. CASE DESCRIPTION: We report the case of a 15-year-old boy with IA and IB secondary to right posterior quadrant epilepsy (PoQE) who underwent right posterior quadrant disconnection, but not cardiac pacemaker implantation. He has remained free from daily epileptic seizures, IA, and IB for more than 6 months postoperatively. This is the first report of a radically treated case with IA and IB caused by PoQE. CONCLUSIONS: Both temporofrontal lobe epilepsy and PoQE caused the IA and IB. Because a cardiac pacemaker only addresses arrhythmia, not epileptic seizures, radical treatment for both epilepsy and arrhythmia may be warranted for patients with medically intractable epilepsy.

Prolonged Blood-Brain Barrier Disruption Following Laser Interstitial Ablation in Epilepsy: A Case Series with a Case Report of Postablation Optic Neuritis.

OBJECTIVE: Laser interstitial thermal therapy has become increasingly popular for targeting epileptic foci in a minimally invasive fashion. Despite its use in >1000 patients, the long-term effects of photothermal injury on brain physiology remain poorly understood. METHODS: We prospectively followed clinical and radiographic courses of 13 patients undergoing laser ablation for focal epilepsy by the senior author (N.T.). Only patients with nonenhancing lesions and patients who had a delayed postoperative magnetic resonance imaging (MRI) scan with gadolinium administration approximately 6 months after ablation were considered. Volumetric estimates of the amount of enhancement immediately after ablation and on the delayed MRI scan were made. RESULTS: Median interval between surgery and delayed postoperative MRI scan was 6 months (range, 5-8 months). In 12 of 13 cases, persistent enhancement was seen, consistent with prolonged blood-brain barrier dysfunction. Enhancement, when present, was 9%-67% (mean 30%). There was no correlation between the time from surgery and the relative percentage of postoperative enhancement on MRI. The blood-brain barrier remained compromised to gadolinium contrast for up to 8 months after thermal therapy. There were no adverse events from surgical intervention; however, 1 patient developed delayed optic neuritis. CONCLUSIONS: Prolonged incompetence of the blood-brain barrier produced by thermal ablation may provide a path for delivery of macromolecules into perilesional tissue, which could be exploited for therapeutic benefit, but rarely it may result in autoimmune central nervous system inflammatory conditions.

Amygdalohippocampectomy for epilepsy in a patient with prior ipsilateral deep brain stimulator lead placement.

In light of failed medical therapy for movement disorders, the use of deep brain stimulation (DBS) has increased the last two decades. Many complications may transpire; however, to our knowledge, the literature does not mention the phenomena of brain shift from a second unrelated neurosurgical procedure and its theoretical effect on lead displacement and lead function. We present a patient with a left sided DBS for essential tremor and subsequent left amygdalohippocampectomy for temporal lobe epilepsy with minimal radiographic distortion of the DBS lead and without clinical or functional complications. A 47-year-old woman presented with bitemporal epilepsy secondary to a brain injury acquired in childhood in addition to a comorbid bilateral essential tremor, both refractory to medical intervention. A successful left-sided DBS placement was performed with satisfactory resolution of her essential tremor. The patient subsequently developed deterioration of seizure control, becoming refractory to anti-epileptic medications, requiring surgical intervention. A left-sided selective amygdalohippocampectomy and techniques to minimize brain shift were performed without complications. Postoperative imaging suggested minimal distortion of the DBS lead. This did not correspond with reemergence of her essential tremor, implying that the lead maintained functional utility. Brain shift secondary to a craniotomy may cause DBS lead displacement. This phenomenon should be considered when planning operative approaches and can be limited by selective resections. With the growing propensity for placement of DBS leads and the risk of lead displacement, it is important to consider operative approaches to minimize brain shift.

Jazz, guitar, and neurosurgery: the Pat Martino case report.

OBJECTIVE: We present the case of a professional jazz guitarist with temporal lobe epilepsy secondary to an arteriovenous cerebral malformation. CASE DESCRIPTION: The patient underwent a left temporal lobectomy in 1980. After surgery, he presented with severe retrograde amnesia and complete loss of musical interest and capabilities. The patient's musical abilities recovered over time, and he regained his previous virtuoso status. In 2007, his medical history, neuropsychologic functions, and structural magnetic resonance imaging study were examined and revealed a remarkable degree of recovery of memory and musical abilities in the context of extensive temporal lobe resection. The neuropsychologic findings and neuroanatomic features of the magnetic resonance imaging study were analyzed to try to understand the high degree of recovery of both long-term memory and musical processing abilities in this musician. CONCLUSIONS: This case reveals the possibility of an unusual degree of cerebral plasticity and reorganization. Additionally, it emphasizes the question of musical virtuosity. This report shows that the musical capabilities of professional musicians, in specific cases, can completely recover even when much of the left temporal lobe has been removed.

Auditory processing following consecutive right temporal lobe resections: a prospective case study.

BACKGROUND: The role of the right temporal lobe in processing speech is not well understood. Although the left temporal lobe has long been recognized as critical for speech perception, there is growing evidence for right hemisphere involvement. To investigate whether the right temporal lobe is critical for auditory speech processing, we studied prospectively a normal-hearing patient who underwent consecutive right temporal lobe resections for treatment of medically intractable seizures. PURPOSE: To test the hypothesis that the right temporal lobe is critical for auditory speech processing. RESEARCH DESIGN: We used a prospective, repeated-measure, single-case design. Auditory processing was evaluated using behavioral tests of speech recognition (words, sentences) under multiple listening conditions (e.g., quiet, background noise, etc.). Auditory processing of nonspeech sounds was measured by pitch pattern sequencing and environmental sound recognition tasks. DATA COLLECTION: Repeat behavioral testing was performed at four time points over a 2 yr period: before and after consecutive right temporal lobe resection surgeries. RESULTS: Before surgery, the patient demonstrated normal speech recognition in quiet and under real-world listening conditions (background noise, filtered speech). After the initial right anterior temporal resection, speech recognition scores declined under adverse listening conditions, especially for the left ear, but remained largely within normal limits. Following resection of the right superior temporal gyrus 1 yr later, speech recognition in quiet and nonspeech sound processing (pitch patterns, environmental sounds) remained intact. However, speech recognition under adverse listening conditions was severely impaired. CONCLUSIONS: The right superior temporal gyrus appears to be critical for auditory processing of speech under real-world listening conditions.

Transmantle sign in focal cortical dysplasia: a unique radiological entity with excellent prognosis for seizure control.

OBJECT: Focal cortical dysplasia (FCD) represents a spectrum of developmental cortical abnormalities and is one of the most common causes of intractable epilepsy in children and young adults. Outcomes after surgery for FCD are highly variable, and prognosticators of seizure freedom are unclear. In a subset of FCDs, a transmantle sign is observed on imaging that focally spans the entire cerebral mantle from the ventricle to the cortical surface. The aim of this study was to characterize seizure control outcomes and prognostic significance of the transmantle sign in FCD epilepsy. METHODS: Fourteen patients with the transmantle sign underwent epilepsy surgery for medically refractory epilepsy. Thirteen patients underwent resective surgery and 1 underwent multiple subpial transections with vagus nerve stimulator placement. Patient demographics, MRI, electroencephalography, intraoperative electrocorticography (ECoG), and pathology were reviewed. The results of this series were compared with those of 114 previously reported patients with FCD without the transmantle sign. RESULTS: All patients were found to have childhood seizure onset and concordant MRI and ECoG findings. The primary MRI findings associated with transmantle sign included gray-white junction blurring, appearance of cortical thickening, T2 or FLAIR abnormality, and bottom-of-the-sulcus dysplasia. The transmantle sign was usually a focal finding, typically confined to 1 or several gyri with well-circumscribed epileptic tissue. Correlation of the transmantle sign with FCD histopathological subtypes was highly variable. Patients who underwent complete resection of MRI and ECoG abnormalities (12 of 13 patients) became seizure free. When compared with 114 FCD patients without the transmantle sign, patients with the transmantle sign showed significantly improved seizure-free outcomes after complete resections (p = 0.04). CONCLUSIONS: The presence of the transmantle sign in patients with medically refractory partial epilepsy is associated with highly favorable seizure control outcomes after surgical treatment.

Successful treatment of mesial temporal lobe epilepsy with bilateral hippocampal atrophy and false temporal scalp ictal onset: a case report.

Patients with bilateral hippocampal atrophy (BHA) in a subgroup suffering from mesial temporal lobe epilepsy represent a therapeutic challenge. We achieved successful surgical treatment in a case with BHA and false lateralized ictal onset on video-scalp electroencephalogram (EEG). A 27-year-old male patient with seizures since the age of 15 years showed current seizures consisting of an epigastric aura, a feeling of difficulty in breathing and oroalimentary automatism, which were frequently followed by secondary generalization with right-arm tonic extension. MRI showed BHA with hyperintensity on FLAIR and a slightly smaller volume in the left hippocampus on volumetry. Ictal EEG started from the left anterior temporal and subtemporal regions, spreading to the right anterior to middle temporal region. Interictal EEG was not lateralized, and showed independent spikes in the bilateral anterior temporal and subtemporal regions. The patient underwent chronic intracranial EEG-monitoring, revealing that the seizure onset originated from the right hippocampus with a rapid spread to the hippocampus and lateral temporal cortex on the left side. We performed a right anterior temporal lobectomy with amygdalohippocampectomy. Histological diagnosis was classic hippocampal sclerosis. The patient has since been seizure-free for 4 years. In this case, false lateralization may have been caused by an atypical seizure-propagating route to the contralateral temporal region via the dorsal hippocampal commissure instead of the usual pathway to the ipsilateral temporal neocortex. The technique of bilateral intracranial EEG-monitoring is advantageous to lateralize the actual side, particularly in BHA patients even with clearly and falsely lateralized ictal onset on scalp-EEG.

Frederic Gibbs and his contributions to epilepsy surgery and electroencephalography.

Frederic Gibbs' (1903-1992) long research career was devoted to the understanding and treatment of epileptic phenomena and closely associated with the development of electroencephalography (EEG). After medical school, he joined the Harvard Neurological Unit at Boston City Hospital directed by Stanley Cobb. In the early 1930s, Gibbs developed a thermoelectric blood flow probe and, with William Lennox, proved in animals and humans that a seizure increases cerebral blood flow. By 1934, Gibbs became a pioneer in the field of EEG while working at Harvard with Hallowell Davis and Lennox, and was the first to convincingly record and report EEG findings in epilepsy and states of altered consciousness. Several years later, Gibbs and Lennox were the first to recommend cerebral excisions in several patients with uncontrolled epilepsy based on EEG. Moving to the University of Illinois at Chicago in 1944, Gibbs founded a consultation clinic for epilepsy, performed the first EEG depth recordings using pneumoencephalography-guided stereotaxy, and noted that sleep EEGs in patients with psychomotor seizures frequently disclosed temporal epileptic patterns. Gibbs convinced Percival Bailey to collaborate on patients with refractory temporal lobe psychomotor seizures without tumors. In 1947, the first nonlesional temporal lobe excisions based on EEG localization were performed in these patients, and, by 1948, anterior temporal lobectomy had become their procedure of choice. Gibbs and Lennox received the coveted Lasker Award among other honors as pioneers in establishing the modern era of epilepsy diagnosis and treatment.

Validation of connectivity-based thalamic segmentation with direct electrophysiologic recordings from human sensory thalamus.

Connectivity-based segmentation has been used to identify functional gray matter subregions that are not discernable on conventional magnetic resonance imaging. However, the accuracy and reliability of this technique has only been validated using indirect means. In order to provide direct electrophysiologic validation of connectivity-based thalamic segmentations within human subjects, we assess the correlation of atlas-based thalamic anatomy, connectivity-based thalamic maps, and somatosensory evoked thalamic potentials in two adults with medication-refractory epilepsy who were undergoing intracranial EEG monitoring with intrathalamic depth and subdural cortical strip electrodes. MRI with atlas-derived localization was used to delineate the anatomic boundaries of the ventral posterolateral (VPL) nucleus of the thalamus. Somatosensory evoked potentials with intrathalamic electrodes physiologically identified a discrete region of phase reversal in the ventrolateral thalamus. Finally, DTI was obtained so that probabilistic tractography and connectivity-based segmentation could be performed to correlate the region of thalamus linked to sensory areas of the cortex, namely the postcentral gyrus. We independently utilized these three different methods in a blinded fashion to localize the "sensory" thalamus, demonstrating a high-degree of reproducible correlation between electrophysiologic and connectivity-based maps of the thalamus. This study provides direct electrophysiologic validation of probabilistic tractography-based thalamic segmentation. Importantly, this study provides an electrophysiological basis for using connectivity-based segmentation to further study subcortical anatomy and physiology while also providing the clinical basis for targeting deep brain nuclei with therapeutic stimulation. Finally, these direct recordings from human thalamus confirm early inferences of a sensory thalamic component of the N18 waveform in somatosensory evoked potentials.

Utility of diffusion tensor imaging tractography in decision making for extratemporal resective epilepsy surgery.

PURPOSE: To assess the utility of diffusion tensor imaging tractography (DTIT) in decision making in patients considered for extratemporal resective epilepsy surgery. METHODS: We subjected 49 patients with drug-resistant focal seizures due to lesions located in frontal, parietal and occipital lobes to DTIT to map the white matter fiber anatomy in relation to the planned resection zone, in addition to routine presurgical evaluation. We stratified our patients preoperatively into different grades of risk for anticipated neurological deficits as judged by the distance of the white matter tracts from the resection zones and functional cortical areas. RESULTS: Thirty-seven patients underwent surgery; surgery was abandoned in 12 (24.5%) patients because of the high risk of postoperative neurological deficit. DTIT helped us to modify the surgical procedures in one-fourth of occipital, one-third of frontal, and two-thirds of parietal and multilobar resections. Overall, DTIT assisted us in surgical decision making in two-thirds of our patients. CONCLUSIONS: DTIT is a noninvasive imaging strategy that can be used effectively in planning resection of epileptogenic lesions at or close to eloquent cortical areas. DTIT helps in predicting postoperative neurological outcome and thereby assists in surgical decision making and in preoperative counseling of patients with extratemporal focal epilepsies.

Epilepsy surgery outcome in coexisting symptomatic refractory focal epilepsy and benign focal epilepsy of childhood.

Epilepsy surgery may successfully treat refractory symptomatic focal epilepsy in patients with coexisting benign focal epileptiform discharges. Reported here is the outcome after resective epilepsy surgery in three children with pharmacoresistant lesional focal epilepsy in whom seizures of benign focal epilepsy of childhood had been recorded. Two patients had left temporal epilepsy due to a malformation of cortical development; one of these had dual pathology, with additional ipsilateral hippocampal sclerosis. One child had catastrophic left hemispheric epilepsy due to left hemimegalencephaly. Frequent, habitual seizures of symptomatic epilepsy resolved after surgery (follow-up duration, 32-55 months); however, rare benign focal seizures of childhood have continued. These cases demonstrate that lesional pharmacoresistant focal epilepsy can be successfully treated with resective epilepsy surgery even when coexisting with benign focal epilepsy of childhood. During postoperative follow-up, careful documentation of breakthrough seizures due to benign focal epilepsy of childhood is important, so that these patients are not labeled as surgical failures.

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.

17-year-old girl with headache and complex partial seizure.

Supratentorial cortical ependymoma is a rare clinical entity where ependymoma occurring in the cortex without any connection to the ventricular system since ependymoma usually arises from the lining of the ventricular system or central canal of spinal cord. There have been 14 such cases reported in the literature.We report the first case of a supratentorial extraaxial cortical anaplastic ependymoma with minimal cortical attachment in a 17-years-old girl, presented with headache and complex partial seizure. Histological features of anaplasia including numerous mitoses, necrosis and high Ki-67 lead to postoperative adjuvant radiation therapy although gross total resection was achieved.

Epilepsy surgery for refractory epilepsy due to encephalocele: a case report and review of the literature.

The management of medically intractable epilepsy is frequently assisted by the identification of structural abnormalities made possible by modern imaging techniques. The association between meningoencephaloceles and epileptic seizures is well reported in the literature. We report a patient with refractory right frontal lobe epilepsy caused by a right nasal meningoencephalocele who was rendered seizure free by endoscopic nasal excision and skull base repair, obviating the need for resective epilepsy surgery. Epilepsy patterns associated with encephalocele and their management are reviewed.

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.