Efficacy and safety in frameless robot-assisted stereo-electroencephalography (SEEG) for drug-resistant epilepsy.

INTRODUCTION: Stereo-electroencephalography (SEEG) is an invasive procedure, used to identify the epileptogenic zone that can be surgically removed in order to treat drug-resistant epilepsy. Frameless robot-assisted positioning of depth electrodes permits a 3D approach with different obliquities and trajectories. The objective of the present study was to evaluate the morbidity and the accuracy related to this frameless procedure. PATIENTS AND METHODS: Sixty-six patients were managed wherein 901 electrodes were implanted during a 6-year-period. All patients had a postoperative CT-scan that was fused with preoperative MRI planning. In order to assess the accuracy of the procedure, the Euclidian distance was calculated between the coordinates of the planned trajectory and the actual position of the electrode at the entry point and at the target point for 857 electrodes. RESULTS: Among the 66 patients, one (1.5%) experienced a symptomatic brain haematoma and one (1.5%) a stroke-like migraine after radiation therapy (SMART) syndrome. There was no permanent morbidity or mortality. Compared to the classical SEEG approach, a higher rate of asymptomatic postoperative bleeding was found on the CT-scan in 8 patients (12.1%). Any infectious events were recorded. The median accuracy of frameless robotic SEEG procedure was equivalent to a 1.1mm error deviation (0.15-2.48) at the entry point and 2.09mm (1.06-3.72) at the target point respectively, with no differences for double obliquity trajectories. CONCLUSION: Frameless robot-assisted SEEG appears to be a safe procedure, providing sufficient accuracy in order to delineate the epileptogenic zone and represents a helpful tool in the pre-surgical management of refractory epilepsy.

Pure endoscopic management of epileptogenic hypothalamic hamartomas.

Hypothalamic hamartomas (HH) are rare congenital malformations located in the region of the tuber cinereum and third ventricle. Their usual clinical presentation is characterized by gelastic/dacrystic seizures which often become pharmaco-resistant and progress to secondary focal/generalized intractable epilepsy causing mostly in children cognitive and behavioral problems (particularly in cases of progressive epileptic encephalopathy) and precocious puberty. Whereas gelastic seizures can be surgically controlled either by resection of the lesion or disconnection (tissue-destructive) procedures, aimed at functionally prevent the spreading of the epileptic burst; generalized seizures tend to respond better to HH excision rather than isolated neocortical resections, which generally fail to control them. Prospective analysis of 14 consecutive patients harboring HH treated in an 8-year period; 12 patients had unilateral and two bilateral HH. All patients were managed by pure endoscopic excision of the HH. The mean operative time was 48 min and mean hospital stay was 2 days; perioperative blood loss was negligible in all cases. Two patients showed a transient diabetes insipidus (DI); no transient or permanent postoperative neurological deficit or memory impairment was recorded. Complete HH excision was achieved in 10/14 patients. At a mean follow-up of 48 months, no wound infection, meningitis, postoperative hydrocephalus, and/or mortality were recorded in this series of patients. Eight patients became seizure free (Engel class I), 2 other experienced worthwhile improvement of disabling seizures (Engel class II); 2 patients were cured from gelastic attacks while still experiencing focal dyscognitive seizures; and 2, having bilateral HH (both undergoing unilateral HH excision), did not experience significant improvement and required later on a temporal lobectomy coupled to amygdalohyppocampectomy. Overall, the followings resulted to be predictive factors for better outcomes in terms of seizure control: (1) cases of unilateral, Delalande class B, HH, (2) shorter history of epilepsy. Endoscopic resection of HH proved, in our series, to be effective in achieving complete control or in reducing the frequency of seizures. Furthermore, this approach has confirmed its minimally invasive nature with a very low morbidity rate: of note, it allowed to better preserve short-term memory and hypothalamic function.

Acute limbic encephalitis and glutamic acid decarboxylase antibodies: a reality?

Limbic encephalitis (LE) associated with glutamic acid decarboxylase antibodies (GAD-Ab) is rare. We describe a 30-year-old male with acute LE and GAD-Ab, with follow-up during 2 years of cognitive status including verbal episodic memory, number of seizures recorded by high-resolution video-EEG, brain MRI, 2-[18F]-fluoro-2-deoxyglucose PET and GAD-Ab titres. Treatment with corticosteroids, IV immunoglobulins, immunosuppressors and antiepileptic drugs resulted in improved memory status, disappearance of seizures and decreased GAD-Ab titres. Review of the other cases of literature and this case is in favour of the existence of autoimmune LE associated with GAD-Ab and supports the link between memory, temporal seizures and possibly GAD-Ab titres.

[Is there a bridge between migraine and familial mesial temporal lobe epilepsy?]. / Migraines et épilepsies temporales mésiales familiales : quel est le lien ?

Numerous reviews have emphasized the links between certain types of epilepsy and migraine. Historically, Gowers was one of the first, in 1907, to have drawn attention to a possible relationship between migraine headache and epilepsy in a period when no additional examination was available. In the last two decades, progress in molecular biology, electrophysiology, and neuro-imaging has enabled a better approach to the fundamental elements underlying the interrelationship between these two nosological domains. During this same time, a new term "channelopathy" has appeared in the literature. This term groups together affections involving a dysfunction of ion channels. In this article, the links between the different types of migraine and familial mesial temporal lobe epilepsy are illustrated by two case reports. This association does not appear to occur at random but would undoubtedly depend on a common genetic substratum, leading to a direct comorbidity. These occasional recurring symptoms would lie within the framework of a more general concept of "Primary Brain Channelopathies".

SPM analysis of ictal-interictal SPECT in mesial temporal lobe epilepsy: relationships between ictal semiology and perfusion changes.

A combination of temporo-limbic hyperperfusion and extratemporal hypoperfusion was observed during complex partial seizures (CPS) in temporal lobe epilepsy (TLE). To investigate the clinical correlate of perfusion changes in TLE, we analyzed focal seizures of increasing severity using voxel-based analysis of ictal SPECT. We selected 26 pre-operative pairs of ictal-interictal SPECTs from adult mesial TLE patients, seizure-free after surgery. Ictal SPECTs were classified in three groups: motionless seizures (group ML, n=8), seizures with motor automatisms (MA) without dystonic posturing (DP) (group MA, n=8), and seizures with DP with or without MA (DP, n=10). Patients of group ML had simple partial seizures (SPS), while others had CPS. Groups of ictal-interictal SPECT were compared to a control group using statistical parametric mapping (SPM). In ML group, SPM analysis failed to show significant changes. Hyperperfusion involved the anteromesial temporal region in MA group, and also the insula, posterior putamen and thalamus in DP group. Hypoperfusion was restricted to the posterior cingulate and prefrontal regions in MA group, and involved more widespread associative anterior and posterior regions in DP group. Temporal lobe seizures with DP show the most complex pattern of combined hyper-hypoperfusion, possibly related both to a larger spread and the recruitment of more powerful inhibitory processes.

Contribution of SISCOM imaging in the presurgical evaluation of temporal lobe epilepsy related to dysembryoplastic neuroepithelial tumors.

PURPOSE: Dysembryoplastic neuroepithelial tumors (DNTs) are a group of glioneuronal supratentorial and intracortical lesions often associated with the early onset of intractable and crippling partial seizures. They are characterized by their location, multinodular architecture, and heterogeneous cell composition, with a specific glioneuronal element in the specific form. Foci of cortical dysplasia may be associated with the tumoral lesion, and identifying the presence and the extent of cortical dysplasia is not always easy on magnetic resonance images (MRIs). The purpose of this article is to evaluate, retrospectively, the usefulness of ictal single-photon emission computed tomography (SPECT) imaging to assess the presence and the extent of cortical dysplasia associated with DNTs in nine patients with intractable temporal lobe epilepsy related to histopathologically confirmed DNTs. METHODS: The results of the subtraction of ictal and interictal SPECT coregistered to MRI (SISCOM) were compared with the results of the examinations of pathological material after surgery. RESULTS: SISCOM showed a strongly hyperperfused area corresponding anatomically to electroclinical abnormalities and to the location of DNTs on MRI. A circumscribed hyperperfusion was present in DNTs without cortical dysplasia, limited to the location of the tumor on MRI. In cases of associated cortical dysplasia, a widespread hyperperfusion including areas corresponding to normal perilesional regions on MRI was found. CONCLUSIONS: SISCOM, used among presurgical investigations, contributes to detecting cortical dysplasia associated with DNTs. Concordance between the symptomatogenic zone (defined from the medical history and electroclinical data), MRI scans, SISCOM pattern, and complete resection of the epileptic zone was predictive of a good postsurgical outcome.

Beneficial effect of fluoxetine in a case of sporadic hyperekplexia.

We studied a 67-year-old woman with a sporadic form of hyperekplexia, who experienced 8-10 excessive startle responses to unexpected stimuli per month. Therapy with fluoxetine had a definite beneficial effect. This finding supports the hypothesis that serotonergic mechanisms play a role in this disorder.

Reading epilepsy in a patient with previous idiopathic focal epilepsy with centrotemporal spikes.

RATIONALE: Reading epilepsy (RE) is a form of reflex epilepsy currently classified as an idiopathic localization-related epilepsy (ILAE, 1989). METHODS: We describe a 30 year-old right-handed male who suffered since the age of 8 from nocturnal partial motor seizures. Clinical features were typical of BECT. We reviewed the EEG recorded at that time which showed centrotemporal spike and waves. He was seizure-free from the age of 12 to the age of 17 when seizures evoked only by reading appeared. No other stimuli provoked seizures. Neurological and neuroradiological (CT and MR) investigations were normal. Baseline video-polygraphic EEG recordings were normal while reading aloud provoked myoclonic jerks in the facial muscles related to bilateral spike and wave discharges. Therapy with carbamazepine and valproic acid strongly reduced seizure frequency. CONCLUSION: Recent papers have debated the difficulties in classifying RE among the generalized or focal syndromes. Literature reports describe an association with RE and juvenile myoclonic epilepsy, supporting the hypothesis of an idiopathic generalized form. We report the first documented case with a clear-cut idiopathic localization-related epilepsy evolving to a primary reading epilepsy.