Subdural motor cortex stimulation: feasibility, efficacy and security on a series of 18 consecutive cases with a follow-up of at least 3 years.

BACKGROUND: Motor cortex stimulation (MCS) is considered to be an effective treatment in some types of chronic refractory neuropathic pain. The aim of this study is to evaluate and confirm the feasibility, efficacy and security of our surgical technique for subdural motor cortex stimulation (SD MCS) on 18 consecutive cases with follow-up of at least 3 years. METHODS: Our population consists of 18 consecutive patients (12 male) between 2000 and 2010, with a mean age of 63 years (11-91). The mean follow-up was 86 months (20-140 months). We identified the central sulcus by using classical anatomic landmarks and neuronavigation (BrainLab system; BrainLAB, Inc., Redwood City, CA). An elongated craniotomy (3 cm in length, 1 cm in width) was performed followed by linear opening of the dura mater. An eight-polar plate electrode (Specify Lead, 3998; Medtronic, Minneapolis, MN) was then slipped smoothly through this linear opening. In patients with interhemispheric electrodes (patients 2 and 17), we performed a parasagittal craniotomy of 4 cm length and 2 cm width. RESULTS: At last follow-up assessment, 14 patients had a favourable outcome (77.7 %): 10 patients with excellent relief of pain (>80 %), 1 with good relief of pain (60-80 %) and 3 with satisfactory relief of pain (50-60 %). Four patients showed bad results (<50 %). We did not observe any late complications specific to SD MCS. CONCLUSION: We report an efficacy at least as good as ED MCS, with no complications specific to SD MCS, even with prolonged follow-up. The data are insufficient to actually prove a lower energy use in SD MCS.

Anti-N-methyl-D-aspartate receptor encephalitis with favorable outcome despite prolonged status epilepticus.

BACKGROUND: To describe a case of auto-immune encephalitis in an adolescent with favorable outcome despite prolonged status epilepticus. METHODS: A 17 year old Asian man without previous medical history developed alteration of consciousness and partial seizures. The diagnosis of anti-N-methyl-D-aspartate receptor encephalitis was confirmed by the detection of specific antibodies in both cerebrospinal fluid and serum. RESULTS: The clinical course was complicated by prolonged status epilepticus which was refractory to a large number of antiepileptic drugs, including barbiturate coma. Immunomodulatory therapy included steroids, plasma exchanges, and intravenous immunoglobulins. After 86 days of intensive therapy, the patient regained consciousness progressively. Brain magnetic resonance imaging never demonstrated any lesion. Extensive search for a tumor was negative. At 12 month follow-up, the patient had made an excellent recovery. CONCLUSION: Auto-immune encephalitis is likely underdiagnosed in adolescents. In their most severe presentation, seizures may be resistant to a large number of anti-epileptic drugs, and the clinical improvement seems to be mainly because of the immunomodulatory therapy. Relapse is possible, as well as the delayed development of a teratoma or other tumor.

Automated electrical source imaging with scalp EEG to define the insular irritative zone: Comparison with simultaneous intracranial EEG.

OBJECTIVE: To evaluate the accuracy of automatedinterictallow-density electrical source imaging (LD-ESI) to define the insular irritative zone (IZ) by comparing the simultaneous interictal ESI localization with the SEEG interictal activity. METHODS: Long-term simultaneous scalp electroencephalography (EEG) and stereo-EEG (SEEG) with at least one depth electrode exploring the operculo-insular region(s) were analyzed. Automated interictal ESI was performed on the scalp EEG using standardized low-resolution brain electromagnetic tomography (sLORETA) and individual head models. A two-step analysis was performed: i) sublobar concordance betweencluster-based ESI localization and SEEG-based IZ; ii) time-locked ESI-/SEEG analysis. Diagnostic accuracy values were calculated using SEEG as reference standard. Subgroup analysis wascarried out, based onthe involvement of insular contacts in the seizure onset and patterns of insular interictal activity. RESULTS: Thirty patients were included in the study. ESI showed an overall accuracy of 53% (C.I. 29-76%). Sensitivity and specificity were calculated as 53% (C.I. 29-76%), 55% (C.I. 23-83%) respectively. Higher accuracy was found in patients with frequent and dominant interictal insular spikes. CONCLUSIONS: LD-ESI defines with good accuracy the insular implication in the IZ, which is not possible with classical interictalscalpEEG interpretation. SIGNIFICANCE: Automated LD-ESI may be a valuable additional tool to characterize the epileptogenic zone in epilepsies with suspected insular involvement.

Ictal EEG source imaging and connectivity to localize the seizure onset zone in extratemporal lobe epilepsy.

PURPOSE: To evaluate the yield of Functional Connectivity (FC) in addition to low-density ictal Electrical Source Imaging (ESI) in extratemporal lobe epilepsy (ETLE), using an automated algorithm for analysis. METHOD: Long-term EEG monitoring of consecutive ETLE patients who underwent surgery was reviewed by epileptologists, and seizure onsets characterized by rhythmical activity were identified. A spectrogram-based algorithm was developed to select objectively the parameters of ESI analysis. Two methods for SOZ localization were compared: i) ESI power, based on LORETA exclusively; ii) ESI + FC, including a Granger causality-based connectivity analysis. Results were determined at a sublobar level. The resection zone, in relation to 1-year follow-up surgical outcome, was considered as reference standard for diagnostic accuracy analyses. RESULTS: Ninety-four seizures from 24 patients were analyzed. At seizure-level, ESI power showed 36 % sensitivity and 72 % specificity (accuracy: 45 %). ESI + FC significantly improved the accuracy, with 52 % sensitivity and 84 % specificity (accuracy: 61 %, p = 0.04). Results of ESI + FC were equally valuable in patients with lateralized or bilateral/generalized visual interpretation of ictal EEG. In a patient level sub-analysis, upon blinded clinical interpretation, ESI + FC showed a correct localization in 67 % of patients and substantial inter-rater agreement (kappa = 0.64), against 27 % achieved by ESI power, with fair inter-rater agreement (kappa = 0.37). CONCLUSION: FC significantly improves SOZ localization compared to ESI solely in ETLE. Ictal ESI + FC could represent a novel option in the armamentarium of presurgical evaluation, aiding also in patients with visually non-localizable scalp ictal EEG. Prospective studies evaluating the clinical added value of automated low-density ictal ESI may be justified.

Additional clinical value of voxel-based morphometric MRI post-processing for MRI-negative epilepsies: a prospective study.

Magnetic resonance imaging is of paramount importance in the presurgical evaluation of drug resistant epilepsy. Detection of a potentially epileptogenic lesion significantly improves seizure outcome after surgery. To optimize the detection of subtle lesions, MRI post-processing techniques may be of essential help. In this study, we aimed to evaluate the detection rate of the voxel-based morphometric analysis program (MAP) in a prospective trial. We aimed to study the MAP+ findings in terms of their clinical value in the decision-making process of the presurgical evaluation. We included, prospectively, 21 patients who had negative MRI by visual analysis. In a first step, results of the conventional non-invasive presurgical evaluation were discussed, blinded to the MAP results, in multidisciplinary patient management conferences to determine the possible seizure onset zone and to set surgical or invasive evaluation plans. Thereafter, MAP results were presented, and the change of initial clinical plan was recorded. All MAP detections were reaffirmed by a neuroradiologist with epilepsy expertise. For the 21 patients included, mean age at the time of patient management conference was 26 years (SD 15 +/- years, range: 5-54 years). In total, 4/21 had temporal lobe epilepsy and 17/21 had extra-temporal lobe epilepsy. MAP was positive in 10/21 (47%) patients and in 6/10 (60%) a diagnosis of focal cortical dysplasia was confirmed after neuroradiologist review, corresponding to a 28% detection rate. MAP+ findings had a clear impact on the initial management in 7/10 patients (7/21, 33% of all patients), which included an adaptation of the intracranial EEG plan (6/7 patients), or the decision to proceed directly to surgery (1/7 patients). MRI post-processing using the MAP method yielded an increased detection rate of 28% for subtle dysplastic lesions in a prospective cohort of MRI-negative patients, indicating its potential value in epilepsy presurgical evaluation.

Prolonged unconsciousness in a patient on automated peritoneal dialysis.

A 79-year-old man with end-stage renal disease treated by automated peritoneal dialysis was referred to the emergency department for altered consciousness. The first investigations, including toxicology screening, failed to reveal the precise etiology. The patient was treated for a possible seizure. After the progression of central nervous system depression with bradypnea, the patient was intubated and mechanically ventilated. It appeared later on that he had ingested by mistake one of his wife's medications, baclofen. Baclofen was detected in the blood sampled on admission at a level above the therapeutic range. Baclofen is mainly excreted by the kidney. A short-term administration of low-dose of baclofen is not effectively removed by peritoneal dialysis and may result in prolonged but reversible coma.

Post-resection electrocorticography has no added value in epilepsy surgery.

Intra-operative electrocorticography (ECoG) has been traditionally used in the surgical management of medically refractory partial epilepsies to identify the limits of the epileptogenic zone. This retrospective study had as goal to evaluate whether tailored surgery based on the presurgical evaluation completed by intra-operative post-resection ECoG improves outcome. We reviewed 94 cases of epilepsy surgery with intra-operative ECoG and determined how many had an ECoG-guided surgical procedure in addition to the initial planned surgery. We also reviewed the presence of specific recurrent ECoG patterns of interictal epileptiform discharges (IED) in the exposed cortical surface, such as: electrographic seizures, bursts, intermittent spike waves, polyspikes or fast rhythms and continuous or quasi-continuous spiking. When performing a post-resection ECoG-tailored surgery, outcome did not improve in lesional or non-lesional epilepsy. Postoperative residual IED did not correlate with a poorer outcome. In our study, the persistence of post-resection IED on ECoG is not correlated with outcome in patients with lesional or non-lesional epilepsy.

Early experiences with tachycardia-triggered vagus nerve stimulation using the AspireSR stimulator.

Many epilepsy patients treated with vagus nerve stimulation additionally use an "on-demand" function, triggering an extra stimulation to terminate a seizure or diminish its severity. Nevertheless, a substantial number of patients are not able to actively trigger stimulations by use of a magnet, due to the absence of an aura or inability for voluntary actions in the early phase of a seizure. To address this need, a novel implantable pulse generator, the AspireSR VNS system, was developed to provide automated ictal stimulation triggered by a seizure-detecting algorithm. We report our experience with three patients in assessing the functionality of ictal stimulation, illustrating the detection system in practice. Detection of ictal tachycardia and variable additional detections of physiological tachycardia depended on the individual seizure-detecting algorithm settings.

Recurrent seizure and sustained encephalopathy associated with dimethylsulfoxide-preserved stem cell infusion.

We report the case of a patient who received two infusions of dimethylsulfoxide (DMSO) cryopreserved autologous peripheral blood progenitor cells (PBPCs) after myeloablative chemotherapy for a relapsing lymphoma. A 49-year-old man presented an episode of tonic-clonic seizure over a few minutes after the start of each infusion and developed a profound and sustained but reversible encephalopathy with coma after the second infusion. The patient's neurological condition correlated well with the electrophysiological findings (electroencephalogram and multimodality evoked potentials) and, to a lesser extent, with the radiological abnormalities (magnetic resonance imaging). Severe but reversible neurological complications may occur with the infusion of PBPCs cryopreserved with DMSO.

Impact of early hemispherotomy in a case of Ohtahara syndrome with left parieto-occipital megalencephaly.

This report illustrates the usefulness and safety of very early hemispherotomy in an infant with Ohtahara syndrome (OS) secondary to left parieto-occipital megalencephaly. It provides evidence that surgical intervention might provide promising results in selected cases, and that young age is not a contraindication for this type of surgery.

Deep EEG recordings of the mammillary body in epilepsy patients.

PURPOSE: To our knowledge, the epileptic and nonepileptic electroencephalographic (EEG) discharges recorded within the human mammillary body (MB) and mammillothalamic tract (MTT) areas have never been published. Herein, we present the EEG recordings from these structures in patients with refractory epilepsy (RE). METHODS: Three men (ages 41-43 years) were enrolled in a clinical trial for deep brain stimulation (DBS) of MB-MTT in RE. Previous evaluations had demonstrated a low likelihood of successful response to medication or resective surgery. DBS macroelectrodes were bilaterally implanted within the MB-MTT under general anesthesia and their location checked by magnetic resonance imaging (MRI). We obtained a surface-depth EEG for a 2- to 4-day period, including monitoring of the cardiorespiratory and mnemonic functions. RESULTS: The background pattern of EEG recorded from MB-MTT was low-amplitude (usually <25 microv for MB and <20 microv for MTT) waves with a variable combination of theta-beta rhythms. In two patients, pseudoperiodic slow spikes were unilaterally recorded with or without clinical signs. For one patient, several focal ictal discharges were recorded in the right MB without scalp EEG changes. CONCLUSIONS: The analysis of our depth EEG revealed that the theta-beta pattern represents the predominant physiologic profile of MB. Paroxysmal epileptiform discharges can be observed in human MB. These data supplement those available from animal observations.

Epileptic discharges in a mammillary body of a patient with refractory epilepsy.

Objectives. To document epileptiform discharges recorded within a mammillary body (MB) of a patient with chronic refractory epilepsy (CRE). Materials and Methods. A 37-year-old man, whose epilepsy was not controlled by medication or vagus nerve stimulation, was enrolled in a study of the effects of deep brain stimulation of the MB and mammillothalamic tract (MTT) in CRE. Surface and deep EEG recordings were obtained for 3 days before implantation of the macroelectrodes and for 4 days after implantation of the macroelectrodes but before implantation of the stimulator battery. Results. Paroxysmal epileptiform discharges were recorded in the right MB while other surface and deep recordings, in particular from the right MTT, were silent. When these discharges were longer than 100 sec, they spread to the right MTT area and then to the left MB and MTT area. Simultaneously, the patient became agitated and confused. Conclusions. This original observation indicates that subcortical neuronal structures, such as the MB, may sustain epileptiform discharges in humans.

Predicting spinal cord ischemia before endovascular thoracoabdominal aneurysm repair: monitoring somatosensory evoked potentials.

PURPOSE: To present a method of predicting spinal cord ischemia before deployment of an endograft in the thoracoabdominal aorta. CASE REPORT: A 76-year-old high-risk patient presented with an aneurysm of the distal thoracic and proximal abdominal aorta. An endovascular treatment was scheduled, but before deployment of the endograft, occlusion of the aneurysmal segment was monitored for 15 minutes using multilevel somatosensory evoked potentials (SEP). An external axillofemoral bypass was necessary during the test period to prevent distal ischemia; transesophageal echocardiography verified the absence of flow inside the aneurysm during occlusion. Because no SEP changes occurred during the 15-minute test, a 20-cm-long endograft was deployed. No postoperative neurological event was encountered, and the aneurysm has remained successfully excluded with shrinkage of the sac diameter by 1 cm at 6 months. CONCLUSIONS: An occlusion test to detect spinal cord ischemia before deployment of an endograft could be useful in lowering the risk of paraplegia associated with endovascular treatment of thoracoabdominal aneurysm.