Two Cases of Hemodialysis-associated Chronic Portal-systemic Shunt Encephalopathy (CPSE) with Opposite Changes in the Blood Ammonia Concentrations during Hemodialysis: A Case Report and Literature Review.

The onset of hyperammonemia due to the flow of ammonia-rich portal vein blood through a portal-systemic shunt causes a type of encephalopathy known as chronic portal-systemic shunt encephalopathy (CPSE). We herein report two cases of CPSE that presented with opposite changes in the blood ammonia concentrations during hemodialysis. It is curious that the encephalopathy was ameliorated by hemodialysis in case 1, but not case 2. Therefore, it is necessary to recognize CPSE and assess the blood ammonia concentrations in dialysis patients who develop a disturbance of consciousness, even if the serum transaminase level is normal.

Translational realistic expectations of chronic cerebral hypoxemia in rat model after bilateral commom carotid artery ligation. Neurocognitive aspects.

PURPOSE: To evaluate the effects of chronic cerebral hypoxia on memory of rats submitted to bilateral common carotid artery ligation (BCCL). METHODS: Every each week, for 16 weeks, 31 rats were tested for memory using a water and land mazes and compared with 30 normal rats (control group A). The variables were expressed by their mean and standard error of the mean (SEM). p<0.05 was used for rejecting the null hypothesis. The study was approved by the Ethics Committee for animal investigation. RESULTS: There was a significant increase in the latency time, in the survival water and land mazes, after four weeks (study group B) follow-up. However, without any medication or therapeutically induced measures, after 16 weeks (study group C) follow-up the latency mean times tend to be similar to control group (A) in the neurocognitive tests. CONCLUSIONS: Neurocognitive deficits after 16 weeks post-operative follow-up of rats that underwent bilateral common carotid artery ligation is a natural adaptive phenomenon. Thus, is not realistic to allow translational information from this animal model for therapeutically approaches aiming at to prevent, or to improve brain damage in human beings suffering from chronic deprivation of adequate blood supply.

Serious adverse effects of gamma knife radiosurgery for mesial temporal lobe epilepsy.

Gamma knife radiosurgery (GKRS) for mesial temporal lobe epilepsy (MTLE) has been proposed as an alternative to surgical resection. We report serious adverse effects of the treatment after follow-up periods over 9 years in 11 patients treated with GKRS between 1997 and 2000. The target volume of the entorhinoamygdalohippocampectomy area was 4.8-17.1 ml. Marginal dose of 20-25 Gy to the 50% isodose was delivered. One patient was drowned after suffering seizure 7 months after GKRS. Two patients did not show any reduction in seizure frequency over 9 and 18 months. Both patients requested open surgery and became seizure-free postoperatively. Four of the other eight patients were classified as Engel's class I within 4 years after GKRS. One of the four patients experienced symptomatic radiation-induced cerebral edema transiently, one developed radiation necrosis and required surgery 5 years after GKRS, and one developed cognitive impairment with hemiparesis 10 years after GKRS. Magnetic resonance (MR) imaging showed a large cyst in the irradiated temporal lobe. This patient recovered fully after the cyst excision. Only one patient became seizure-free and antiepileptic drug-free without symptomatic radiation-induced complications. However, MR imaging revealed abnormal enhancement, cyst formation, and diffuse white matter change in the irradiated temporal lobe 9 years after GKRS. GKRS for MTLE causes adverse effects of delayed seizure remission and symptomatic radiation-induced complications. Therefore, GKRS cannot be considered as an ideal alternative to surgery for MTLE. Long-term follow-up studies including MR imaging with contrast medium are required for the patients even after successful control of seizures.

Efficacy of temporal lobe surgery for epilepsy in patients with negative MRI for mesial temporal lobe sclerosis.

Epilepsy surgery is a successful treatment for refractory temporal lobe epilepsy (TLE). Reports suggest fewer seizure-free outcomes for patients with TLE and who have a negative brain MRI (nMRI) for mesial temporal sclerosis. Data were collected prospectively from patients with nMRI who underwent temporal lobe surgery for TLE characterized by unilateral ictal temporal lobe seizure onset based on a scalp video electroencephalogram or invasive subdural electrode recordings. A total of 86 patients were followed for at least 24 months after surgery. Outcome was evaluated using the Engel classification. Seizure control was obtained by 55% (47/86) of patients (Class [CL]-I), 27% (23/86) showed significant improvement (CL-II) and 19% (16/86) were deemed surgical failures. Shorter duration of epilepsy, later onset of seizures, and ictal theta rhythm (5-7 Hz) were the most significant predictors of postoperative seizure control. Although hypometabolism on positron emission tomography scan and significant memory disparity (>2.5/8) were not significant prognosticators independently, cumulatively they were predictors for favorable outcome.

Braun's flexor tendons transfer in disabled hands by central nervous system lesions.

INTRODUCTION: Since Braun's article, the nonfunctional hand of brain-injured patients has not been the subject of many publications. The objective of surgical treatment is to open the hand for hygiene and cosmetic reasons. The technique consists in lengthening the extrinsic flexor tendons group. HYPOTHESIS: The purpose of this work is to assess eventual functional benefits from superficialis-to-profundus tendon transfer according to Braun. MATERIAL AND METHODS: Our series comprised 15 patients aged a mean 55 years, operated using the Braun procedure for a nonfunctional hand (19 hands). Additional procedures were performed as required by the local condition (neurotomy of the deep branch of the ulnar nerve, wrist fusion, tenotomy of the flexors of the wrist and flexor pollicis longus, tenodesis of the extensors of the wrist). The results were assessed by the analysis of finger opening ability and by a specific scoring system (Mini Hand Score; MHS) rated from 6 (no discomfort) at 20 (major discomfort). RESULTS: The mean follow-up was 6 months. We observed imperfect results: thumb opening incapacity, spasticity of the intrinsic flexors, and hyperextension of the wrist. The preoperative MHS was a mean 13.87 out of 20 and the postoperative MHS was 9.67 out of 20, with a very substantial difference. DISCUSSION: Our easy-to-use system for evaluating the nonfunctional hand (MHS) was shown to be very effective in demonstrating the improvement of the postoperative result. The originality of our series was to show that Braun's original operation goals were only exceptionally and remotely achieved and that an additional technical procedure must be nearly systematically considered. All the patients in our series were followed up in multidisciplinary team visits where the patient's family and caretakers were encouraged to give their point of view. Level of evidence Level IV. Retrospective study.

Contralateral MRI abnormalities in candidates for hemispherectomy for refractory epilepsy.

PURPOSE: To assess the impact of contralateral magnetic resonance imaging (MRI) findings on seizure outcome after hemispherectomy for refractory epilepsy. METHODS: We retrospectively reviewed 110 children, 0.4-18 (median 5.9) years of age, who underwent hemispherectomy for severe refractory epilepsy at Cleveland Clinic Children's Hospital. In children with contralateral (as well as ipsilateral) MRI findings appreciated preoperatively, the decision to proceed to surgery was based on other features concordant with the side with the most severe MRI abnormality, including ipsilateral epileptiform discharges, lateralizing seizure semiology, and side of hemiparesis. RESULTS: We retrospectively observed contralateral MRI abnormalities (predominantly small hemisphere, white matter loss or abnormal signal, or sulcation abnormalities) in 81 patients (74%), including 31 of 43 (72%) with malformations of cortical development (MCD), 31 of 42 (73%) with perinatal injury from infarction or hypoxia, and 15 of 25 (60%) with Rasmussen's encephalitis, Sturge-Weber syndrome, or posttraumatic encephalomalacia. Among 84 children (76%) with lesions that were congenital or acquired pre- or perinatally, 67 (83%) had contralateral MRI abnormalities (p = 0.02). Contralateral findings were subjectively judged to be mild or moderate in 70 (86%). At follow-up 12-84 (median 24) months after surgery, 79% of patients with contralateral MRI abnormalities were seizure-free compared to 83% of patients without contralateral MRI findings, with no differences based on etiology group or type or severity of contralateral MRI abnormality. DISCUSSION: MRI abnormalities, usually mild to moderate in severity, were seen in the contralateral hemisphere in the majority of children who underwent hemispherectomy for refractory epilepsy due to various etiologies, especially those that were congenital or early acquired. The contralateral MRI findings, always much less prominent than those in the ipsilateral hemisphere, did not correlate with seizure outcome and may not contraindicate hemispherectomy in otherwise favorable candidates.

Early acute hemispheric stroke after carotid endarterectomy. Pathogenesis and management.

PURPOSE: A major stroke after carotid endareterectomy (CEA) is an event that should be managed according to a planned strategy. Literature data on this issue are not definitive. We reviewed our series in the attempt to define an algorithm of treatment if this complication occurs. METHODS: A consecutive series of 413 CEAs in 390 patients was considered. All operations were performed under general anaesthesia and EEG monitoring. An indwelling shunt was inserted only according to EEG changes. Direct closure of the arteriotomy was performed in all cases. Intraoperative ultrasound was not routinely employed before 2004. Patients who suffered from the new onset of an ischaemic hemispheric deficit or the worsening of a pre-existing deficit within 72 h after surgery were included in the present study. RESULTS: Sixteen patients (3.9%) suffered from perioperative stroke. Seven patients presented neurological deficits that rapidly and spontaneously resolved. In nine cases (2.2%) a major stroke occurred. Acute occlusion of the internal carotid artery (ICA), with or without embolic blocking of the omolateral M1 segment, occurred in eight cases; in one case a patent ICA was associated with the occlusion of two frontal branches of the omolateral middle cerebral artery. Seven cases were reoperated on. The ICA was reopened in all these cases except one. Among these seven cases, three (42%) had a good outcome. CONCLUSIONS: A major stroke after CEA is caused, in most of cases, by the acute ICA occlusion with or without intracerebral embolic occlusion. Reopening of the occluded ICA gives good results when intracerebral vessels are patent and when the occluded ICA is satisfactorily reopened. An algorithm of planned reactions in case of perioperative stroke is finally proposed.

Bilateral submandibulectomy for the treatment of drooling in children with neurological disability.

AIM OF THE STUDY: Drooling is common in children with neurological disabilities (ND), and constitutes an additional burden with many medical complications in an already socially disadvantaged patient. This study aims to evaluate the effectiveness of bilateral submandibulectomy (BS) to treat drooling with regard to the parental satisfaction grade, complications and recurrence of drooling in children with ND. PATIENTS/MATERIAL AND METHODS: A retrospective study was performed of all children with ND and drooling who underwent BS in our Department between January 1996 and November 2008. Data were taken from surgical records and patient files. Parental satisfaction was graded into four classes: A: 75-100% satisfaction (infrequent drooling, small amounts; absence of drooling); B: 50-75% satisfaction (occasional drooling, on and off all day; infrequent drooling, small amounts); C: 25-50% satisfaction (frequent drooling, but not profusely; occasional drooling, on and off all day); D: 0-25% satisfaction (constant drooling, always wet; frequent drooling, but not profusely). RESULTS: BS was performed in 85 patients (38% male; 62% female; median age, 9 years). 35 patients had to be excluded from our study because their medical records were unavailable. Only 3 out of the remaining 50 patients had recurrence. Parental satisfaction grade (PSG) was A in 26 cases (55.3%); B in 15 (31.9%); C in 3 (6.4%) and D in 3 (6.4%). The first follow-up was usually 1 week after surgery (median, 2 weeks). The incidence of post-surgery complications was 4% and all complications were minor. DISCUSSION/CONCLUSIONS: Assessment of the results achieved was subjective as it was not possible to quantify the amount of drooling precisely before/after surgery. Nevertheless, BS was found to be an easy and safe procedure as the low rate of complications demonstrates. It was also found to be an effective procedure; there were only 3 recurrences, and PSG in 87.2% of cases was either A or B, indicating a minimum improvement in drooling of 50%.

Denuded human amniotic membrane seeding bone marrow stromal cells as an effective composite matrix stimulates axonal outgrowth of rat neural cortical cells in vitro.

BACKGROUND: Previous studies have shown that axonal outgrowth in the damaged central nervous system is closely related to the local microenvironment. Transplantation of bone marrow stromal cells (BMSC) or BMSC with some biomaterials has been used to treat various central nervous system diseases with some success. In the current study, we investigated if BMSC on denuded human amniotic membrane (DhAM) as a composite matrix could stimulate axonal outgrowth or not. METHOD: After completely removing the cells on the amniotic membrane with a tryptic and mechanical approach, we seeded BMSC on it. The MTS was applied to test the cytotoxicity of DhAM compared with PLGA and PLL. The morphology of the BMSC was observed by light, electronic and laser confocal microscopy. We also used four kinds of substance (PLL, DhAM, BMSC + PLL, BMSC + DhAM) to coculturing with the cortical neurons. Finally, the lengths of axons in each group were studied using the positive axon-specific marker NF-H. FINDINGS: The DhAM was devoid of cellular components and only its intact basement membrane was left. BMSC grew on the substrate and proliferated with a flat to fusiform morphology. In the MTS test, the results indicated that BMSC cultured in DhAM extract had a high survival rate (> 80%). Moreover, the cortical neural axons in the experimental group (BMSC + DhAM) were longer (287.37 +/- 12.72 microm) than in the other groups (P < 0.01). CONCLUSIONS: This study demonstrates that the DhAM was a good carrier to support growth of BMSC and BMSC on DhAM was an effective composite matrix to support the outgrowth of the axons of rat cortical neurons in vitro. Future studies of the use of the composite matrix in disorders are planned.

Brain repair how stem cells are changing neurology.

The concept that everything can die, but nothing can regenerate in the brain has been replaced with new hope that stem cells will provide avenues to repair the damaged central nervous system (CNS). The treatment of brain damage has been demonstrated preclinically using a variety of stem cell sources. The prototypical cell that gives rise to the CNS is the neural stem cell (NSC). NSCs differentiate into site-appropriate phenotypes when transplanted into the damage brain and can recover lost functions. In some cases, cells can be pre-differentiated into a particular neuronal phenotype, such as dopaminergic cells, that can then be transplanted ectopically to promote behavioural improvements in conditions like Parkinson's disease. Early clinical studies in PD have demonstrated the proof of principle that this approach can improve neurodegenerative disease. The current review will discuss the different sources of stem cells in their preclinical and clinical application, as well as providing an overview as to the issues that need to be addressed to ensure a successful translation from bench to bedside.

The effect of haematoma, brain injury, and secondary insult on brain swelling in traumatic acute subdural haemorrhage.

OBJECTIVE: The high mortality of acute subdural haematoma (ASDH) is largely explained by its frequent association with primary brain damage consisting of contusion and brain swelling. However, the nature and causes of brain swelling after traumatic brain injury are multifactorial and poorly understood. The purpose of this study was to investigate the pathophysiology of brain swelling associated with ASDH in traumatic brain injury. METHODS: We examined whether the thickness of the haematoma, parenchymal injury, or presence of a secondary insult had an effect on traumatic brain swelling. The variables that might affect the pathophysiology of ASDH were examined, including: (1) age and mechanism of injury, (2) neurological findings, (3) secondary insult and extracranial injuries, (4) pre-operative computed tomography (CT) scan results, and (5) outcome. RESULTS: A total of 212 patients were included in this study. On CT scan, 159 patients (75.0%) did not have brain swelling, 29 (13.7%) had hemispheric brain swelling, and 24 (11.3%) had diffuse brain swelling. Brain swelling associated with ASDH is caused by secondary insult in addition to parenchymal injury. In the present study, the outcome of ASDH associated with brain swelling was poor, even when treated with early surgical evacuation; the mortality rate of such patients was over 75%. CONCLUSIONS: Given our findings, it is possible that the poor outcome of ASDH patients depends not only on the characteristics of the haematoma itself, but also on the presence of additional cerebral parenchymal injury and secondary insult.

Diffusion tensor imaging and white matter tractography in patients with brainstem lesions.

BACKGROUND: Diffusion tensor imaging (DTI) and white matter tractography (WMT) are promising techniques for estimating the course, extent, and connectivity patterns of the white matter (WM) structures in the human brain. In this study, we investigated the ability of DTI and WMT to visualize white matter tract involvement for the preoperative surgical planning and postoperative assessment of brainstem lesions. METHODS: Preoperative and postoperative DTI data (echo-planar, 1.5T) were retrospectively analyzed in 10 patients with brainstem lesions (3 diffuse, 7 focal). WMT applying a tensor deflection algorithm was used to reconstruct WM tracts adjacent to the lesions. Reconstructed tracts included corticospinal tracts and medial lemnisci. The clinical and imaging follow-up data were also compared and analyzed. FINDINGS: WMT revealed a series of tract alteration patterns including deviation, deformation, infiltration, and apparent tract interruption. WMT reconstructions showed that the major WM tracts were preserved during surgery and improved in position and appearance postoperatively. These findings correlated with the improvement or preservation of neurological function as determined by clinical assessment. CONCLUSIONS: Compared with the information provided by conventional MR imaging, DTI and WMT provided superior quantification and visualization of lesion involvement in eloquent fibre tracts of the brainstem. Moreover, DTI and WMT were found to be beneficial for white matter recognition in the neurosurgical planning and postoperative assessment of brainstem lesions.

Amniotic fluid derived stem cells ameliorate focal cerebral ischaemia-reperfusion injury induced behavioural deficits in mice.

The present study has been designed to investigate the effect of amniotic fluid derived stem cells on focal cerebral ischaemia-reperfusion injury induced behavioural deficits in mice. Middle cerebral artery occlusion of 60 min followed by reperfusion for 7 days was employed in present study to produce ischaemia and reperfusion induced cerebral injury in mice. Assessment of cognitive behaviour was done using elevated plus maze. Assessment of neurological severity score was employed to assess motor, sensory, reflex, and balance tests in a composite manner. Adhesive-removal somatosensory test was employed to evaluate somatosensory deficit. Partial occlusion of middle cerebral artery markedly impaired memory, motor coordination, sensorimotor ability and somatosensory functions as inferred from the results of elevated plus-maze test, adhesive-removal test and neurological severity score test. Intracerebroventricular administration of amniotic fluid derived stem cells/embryonic neuronal stem cells significantly reversed the focal cerebral ischaemia-reperfusion induced behavioural deficit measured in terms of loss of short-term memory, motor coordination, sensorimotor ability and somatosensory functions. Therefore, it may be concluded that stem cells derived from amniotic fluid exert beneficial effect on the ischaemic brain to an extent comparable to the neuroprotective effect of embryonic neuronal stem cells.

Developmental plasticity after right hemispherectomy in an epileptic adolescent with early brain injury.

OBJECTIVES: The authors present the case of an adolescent affected with refractory epilepsy due to a neonatal ischemic infarction of the right medial cerebral artery. Hemiplegic since the first months of life, she began presenting motor partial seizures associated with drop attacks at 4.5 years; these were initially well controlled by antiepileptic drugs, but at 10 years seizures appeared again and became refractory. Thus, at 14 years and 10 months, she was submitted to a right hemispherectomy that made her rapidly seizure free. In the post-surgical follow-up lasting 5 years, neuropsychological serial assessments showed an impressive progressive improvement of cognitive skills, namely, visuospatial abilities. This case seems to challenge the widely spread feeling that functional catch-up in brain-injured children could only occur early in life. In effect, the astonishing recovery especially of visuospatial skills in our case occurred in adolescence after a late surgical intervention of right hemispherectomy. METHODS: Different neuropsychological aspects are discussed. The reorganisation process recovered the spatial and linguistic abilities as well as the verbal and visuospatial memory; however, there was a persistent impairment of complex spatial and perceptual skills as well as recall abilities. Despite the deficit of complex visual stimuli processing, the patient showed a good performance in the recognition of unknown faces. CONCLUSIONS: Probably, the absence of seizures in the first 4 years of life could have allowed a generally adequate compensatory reorganisation, successively masked by the persistent and diffuse epileptic disorder. The seizure control produced by surgery eventually made evident the effectiveness of the brain reorganisation.

Hypothalamic hamartoma and epilepsy in children: illustrative cases of possible evolutions.

The progresses of neuroimaging have allowed an earlier detection of hypothalamic hamartoma in children presenting with gelastic or dacrystic seizures. Associated symptoms can include other types of seizures, precocious puberty, and behavioral or cognitive deterioration. Combination of all these features is not constant and, when present, their evolution may be variable. When epilepsy proves intractable, surgery may be a solution but is not without risks. Therefore, it can only be justified on the basis of a considerable degree of certainty on the progressive character of the disorder, both in terms of epilepsy and global development. Even though epilepsy is a major and usually the most important problem, it is not always possible to predict its course and to be able to evaluate its potential effects on development. Available data suggests that deterioration is partly related to the epileptogenic activity. We reviewed data from 16 personal cases and discussed the possible evolutions of the epilepsy syndrome on the basis of 6 illustrative cases and a review of the literature. We point out that seizures may start early in life and evolve either towards a catastrophic encephalopathy or may be transiently severe and will progressively settle down. Intermediate situations also exist as well as cases presenting with a mild epilepsy. In almost all cases cognitive difficulties are present and may be associated with behavioral disturbances. They are of variable severity, usually in relation to the severity of the epilepsy and the evolution of the EEG abnormalities. Some of our cases also illustrate that, in young children whose seizures are limited to "a sensation of a pleasant feeling", "a pressure to laugh" or "smiling", early detection of the hamartoma may still be difficult and the epilepsy pattern may be misdiagnosed as an epilepsy temporal or frontal origin. Detailed analysis of the electro-clinical evolution of representative cases highlights the variable expression of the epilepsy syndrome and renders difficult any dogmatic position on early surgery. However, recent data suggests that a surgical solution must be sought early. Prospective studies are needed to evaluate, not only outcome in terms of control the seizures without unacceptable side effects but also on the evolution of the cognitive and behavioral profile of children with HH and epilepsy are needed.

Intra-operative monitoring of brain tissue O2 (PtiO2) during aneurysm surgery.

BACKGROUND: Regional cerebral blood flow may be compromised during aneurysm surgery. This may occur during vessel occlusion by temporary cliping or result from the malposition of an aneurysm clip. In this report we monitored intra-operatively the brain tissue oxygen concentration (PtiO2) to visualize regional ischaemic events. METHOD: During surgery of 10 intracranial aneurysms, monitoring of PtiO2 was performed using a polarographic microcatheter (Licox, GMS-Kiel-Germany), which was placed in the vascular territory of the artery harboring the aneurysm. FINDINGS: No complications were observed after implantation of Licox electrodes. In 6 patients PtiO2 decreased during transient clipping. In two patients PtiO2 decreased below 2 mmHg without morphological or clinical signs cerebral ischemia. In four patients, without incidence during surgery, only minor oscillations were observed. CONCLUSION: Intra-operative monitoring of PtiO2 is a complimentary procedure to monitor cerebral perfusion and detect episodes of ischaemia. Given the rapid detection of these events, therapeutic intervention may be initiated before irreversible neuronal damage occurs.

[Craniocerebral trauma--new pathophysiological and therapeutic viewpoints]. / Das Schädel-Hirn-Trauma--neue pathophysiologische und therapeutische Gesichtspunkte. Teil 2: Die Behandlung in der Subakut- bis Spätphase.

AIM: The prognosis has markedly improved during the last years after mild and moderate head injuries. After severe head trauma, this evolution could not be observed so far. This requires a better understanding of pathophysiological interaction, especially in the subacute and late phase of trauma. METHODS: Review article. DISCUSSION: Causes for the development of secondary brain damage are the intracranial space demand after traumatic injury and edema formation which max result in ischemia, as well as inflammatory processes. Both isolated severe head trauma and polytrauma with or without brain damage may result in a systemic inflammatory response syndrome due to the synthesis of cytokines and other inflammatory mediators which may cause a single or multiple organ failure. The hypermetabolism after severe head trauma is often regarded as an interaction between the central nervous system and the whole organism by the activation of the neuroendocrine axis. Moreover, coagulation, metabolism and fracture healing are influenced by the onset of SIRS as well. CONCLUSION: Our knowledge about the bidirectional inflammatory interaction between brain and whole organism is still limited. It is generally accepted that extracranial complications are highly influential in determining the outcome from severe head injury.

Operative results without invasive monitoring in patients with frontal lobe epileptogenic lesions.

PURPOSE: To further explore the still controversial issues regarding whether all or most candidates for epilepsy surgery should be investigated preoperatively with invasive long-term video-EEG monitoring techniques (ILTVE). METHODS: We studied five patients with intractable seizures since early childhood using the same protocol: clinical evaluation, magnetic resonance imaging (MRI) with fluid-attenuated inversion recovery (FLAIR) sequences, long-term video-EEG (LTVE) monitoring with scalp electroencephalogram (EEG), interictal single photon emission computed tomography (SPECT), positron emission tomography (PET), and neuropsychological testing. The patients' seizures had clinical features suggesting a frontal lobe (FL) origin. MRI scans revealed focal cortical dysplasia (CD) in four patients and a probable gliotic lesion in the fifth. The findings in both PET and SPECT images were congruent with those of the MRI. Scalp LTVE failed to localize the ictal onset, although the data exhibited features suggestive of both CDs and FL seizures. On the basis of these results, surgery was performed with intraoperative corticography, and the cortical area exhibiting the greatest degree of spiking was ablated. RESULTS: Histopathologic study of four of the resected specimens confirmed the presence of CD, whereas in the fifth, there were features consistent with a remote encephaloclastic lesion. There were no postoperative deficits. Seizures in three of the patients were completely controlled at 2-3.5 years of follow-up; a fourth patient is still having a few seizures, which have required reinstitution of pharmacotherapy, and the fifth has obtained > or =70% control. All patients have had significant improvement in psychosocial measures. For comparison, five patients with generally similar clinical and neuroradiologic features to the previous group underwent preoperative ILTVE monitoring. The surgical outcomes between the two groups have not differed significantly. CONCLUSIONS: We conclude that patients with FL epilepsies may be able to undergo successful surgery without preoperative ILTVE monitoring, provided there is high concordance between neuroimaging tests (MRI, SPECT, PET) and the seizure phenotypes, even when routine EEGs and scalp LVTE fail to localize ictal onset unambiguously. The surgical outcomes of these patients generally paralleled those of the other subjects who also had FL epilepsy but who were operated on only after standard ILTVE monitoring.

Extraoperative cortical stimulation of motor function in children.

The purpose of the study was to investigate factors altering the amperage threshold needed to provoke functional responses in children with epilepsy. Twenty patients (4-18 years of age) who underwent epilepsy surgery at our institution from 1996-2000 after insertion of subdural grid electrodes were reviewed retrospectively. Extraoperative electrical cortical stimulation was performed with 50-Hz biphasic pulses of 0.2 ms in duration using a "distance reference" technique. Amperage thresholds of primary motor responses and afterdischarges were evaluated. The patients were grouped according to underlying pathology: eight with neuronal migration disorders (group A) and 12 with other disorders (group B). The motor cortex was defined successfully in all children because the afterdischarges threshold was higher than the motor cortical threshold. Amperage thresholds ranged from 2-20 mA (mean = 7.7) for primary motor function. An inverse relationship was found between amperage threshold and age: the younger the patient, the higher the threshold (P = 0.0005). Patients in group A required a higher amperage (2-20 mA, mean = 8.6) for motor cortical mapping than those in group B (2-14 mA, mean = 6.4). Younger children with neuronal migration disorders require a higher amperage threshold to achieve adequate motor functional mapping with careful observation of afterdischarges.