Biomedical subjects

B Turak

Publications and source records attributed to B Turak.

At least 19 recordsLinked to original sources

PubMed2006

Effects of gap junction blockers on human neocortical synchronization.

Field potentials and intracellular recordings were obtained from human neocortical slices to study the role of gap junctions (GJ) in neuronal network synchronization. First, we examined the effects of GJ blockers (i.e., carbenoxolone, octanol, quinine, and quinidine) on the spontaneous synchronous events (duration = 0.2-1.1 s; intervals of occurrence = 3-27 s) generated by neocortical slices obtained from temporal lobe epileptic patients during application of 4-aminopyridine (4AP, 50 muM) and glutamatergic receptor antagonists. The synchronicity of these potentials (recorded at distances up to 5 mm) was decreased by GJ blockers within 20 min of application, while prolonged GJ blockers treatment at higher doses made them disappear with different time courses. Second, we found that slices from patients with focal cortical dysplasia (FCD) could generate in normal medium spontaneous synchronous discharges (duration = 0.4-8 s; intervals of occurrence = 0.5-90 s) that were (i) abolished by NMDA receptor antagonists and (ii) slowed down by carbenoxolone. Finally, octanol or carbenoxolone blocked 4AP-induced ictal-like discharges (duration = up to 35 s) in FCD slices. These data indicate that GJ play a role in synchronizing human neocortical networks and may implement epileptiform activity in FCD.

4-Aminopyridine↗

PubMed2005

Dystonic posturing in seizures of mesial temporal origin: electroclinical and metabolic patterns.

OBJECTIVE: To test the hypothesis that extratemporal neuronal networks are involved in dystonic posturing (DP) observed in mesial temporal epilepsy (MTLE). METHODS: The authors analyzed electroclinical findings in 36 patients with MTLE with or without DP. Three DP types were defined (types I, II, III) corresponding to a gradual increase in duration and complexity. Interictal [18F]fluorodeoxyglucose-PET in different groups and subgroups was compared with control subjects using statistical parametric mapping software (SPM99). RESULTS: DP was found in 20 patients (55%), contralateral to the epileptogenic focus in 95%. Patients with DP had longer seizure duration, higher frequency of head deviation, salivation, motor manifestations, secondary generalization, severe clouding of consciousness, and prolonged postictal confusion when compared with patients without DP. Ictal discharge patterns during DP consisted of fast rhythmic activity spreading to frontal or suprasylvian areas, whereas slow rhythmic activity restricted to the temporal areas occurred in the absence of DP. In patients with DP, widespread temporal and extratemporal hypometabolism including the putamen was found. Hypometabolism was restricted to the anteromesial part of the temporal lobe and anterior insula in patients without DP. Putaminal hypometabolism was found in all DP types, but different extratemporal cortical involvements were found in DP subgroups: insula and inferior frontal gyrus in type I, inferior and superior frontal gyri and anterior cingulate gyrus in type II, and parietal areas in type III. CONCLUSION: Dystonic posturing may result from involvement of both putaminal and extratemporal cortical areas. Moreover, different frontal or parietal networks may be involved according to the duration or complexity of dystonic posturing.

Adolescent↗

PubMed2005

[Massive haemorrhage after dorsal decompressive laminectomy].

We describe a case of a massive haemorrhage after dorsal decompressive laminectomy. The biological syndrome was at first a disseminated intravascular coagulation (DIC), rapidly complicated by a secondary fibrinolysis. The usual treatment of DIC with plasma and platelet transfusion failed to control bleeding and the patient underwent four repeat operations for relapsing rapidly evolving paraplegia. Aprotinine treatment stopped the haemorrhage. The vertebral metastasis causing spinal compression proved to be of prostatic origin.

Adenocarcinoma↗

PubMed2005

[Results of the Sainte-Anne - Lyons series of 318 oligodendroglioma in adults].

INTRODUCTION: Incidence of cerebral oligodendrogliomas is increasing because of better recognition made possible by improved classifications. We studied a homogeneous series using the Sainte-Anne grading scale in order to better understanding the history of these tumors with or without treatment and to assess prognosis and associated factors. PATIENTS AND METHODS: A retrospective series of 318 adult patients with oligodendroglioma (OLG) treated at Hôpital Sainte-Anne, Paris (SA) and Hôpital Neurologique, Lyons (L) between 1984 and 2003 was analyzed: 182 grade A OLG (SA + L), 136 grade B among which a homogenous series of 98 (SA) were included. For grade A: age at diagnosis ranged from 21 to 70 (mean: 41), sex ratio was 1.28. For grade B: age at diagnosis ranged from 12 to 75 (mean: 45.5), sex-ratio was 1.58. The main first symptoms were: epilepsy (A: 91.5%; B: 76%), intracranial hypertension (A: 7.9%; B: 14.6%), neurological deficit (A: 5.1%; B: 17.7%). The most frequent locations were: frontal, insular and central for both A and B. Mean size was 55 mm for grade A, 62 mm for B. Calcifications were found in 20% of A, 48.5% of B. No tumor was enhanced on imaging (CT/MRI) in grade A, all but 7 in grade B. All patients underwent surgery either for biopsy (A: 47.2%; B: 53%), or removal which was partial (A: 26.4% vs B: 19.4%) or extended (A: 36.3% vs B: 37.8%). Fifty-six patients underwent 2 procedures and 12 three procedures. Radiotherapy was performed in 76.9% of grade A, and 91% of B patients, in the immediate postoperative period for 71% A and 82.7% B. Chemotherapy was delivered for 36% of grade A (in the event of transformation to grade B or failure of radiotherapy) and 67.5% of B patients. Among grade A tumors, 38% transformed into grade B within a mean delay of 51 months with a mean follow-up of 78 months. RESULTS: Median survival was 136 months for grade A and 52 for grade B. Survival at 5, 10 and 15 was 75.5%, 51% and 22.4% for grade A vs 45.2%, 31.3% and 0% for grade B respectively. In univariate and multivariate analysis, grade A survival was associated with age at diagnosis, tumor size, large removal and response to radiotherapy. Grade B survival was associated with age at diagnosis, wide removal and sharply defined limits of the tumor on imaging. CONCLUSIONS: Analysis of both published data and this series underlines many prognostic parameters. It shows that OLG are heterogeneous tumors even in each grade (A and B). Treatment should consequently progress towards more targeted procedures for patients mainly with postoperative radiotherapy and chemotherapy.

Adolescent↗

PubMed2005

[Adult supratentorial oligodendrogliomas. Surgical treatment: indications and techniques].

Surgical resection is the first step in the treatment of adult supratentorial oligodendrogliomas (OLG). However, the role of resection on prognosis, the most appropriate time for surgery along the natural history of those tumors, and the best operative strategy remain debated. Survival curves after resection vary greatly among reported series, in particular as a result of a persisting confusion in identification and classification of cerebral OLG. Surgical or stereotactic biopsy is the first surgical procedure which enables confirmation of the diagnosis suggested on imaging, assessment of extension of tumor cell infiltration beyond abnormalities limit described an imaging, and currently available molecular biology studies. Biopsies may be the only surgical procedure in patients having a deep-seated tumor with minimal mass effect, or prior to a surgical resection or a "wait and watch" strategy. Surgical resection is indicated for the other patients. However, it has not been demonstrated that time for resection has an influence on survival, excepted in patients with rapidly growing tumors, with mass effect causing increased intracranial pressure. A wait and watch strategy is therefore warranted in patients with a tumor aspect suggestive of a grade A OLG; surgical resection may be indicated later. There is a current trend for maximal safe resection, preserving functional cerebral areas, since truly complete resection of the tumor including infiltration is exceptional. However, from the contradictory results reported to date, one cannot ascertain whether large or complete resection based on imaging is associated with significantly longer survival. Neuronavigation guidance, intraoperative imaging, and cortical stimulation techniques are helpful neurosurgical techniques enabling maximal safe resection with preservation of functional areas.

Adult↗

PubMed2004

GABAA receptor-dependent synchronization leads to ictogenesis in the human dysplastic cortex.

Patients with Taylor's type focal cortical dysplasia (FCD) present with seizures that are often medically intractable. Here, we attempted to identify the cellular and pharmacological mechanisms responsible for this epileptogenic state by using field potential and K+-selective recordings in neocortical slices obtained from epileptic patients with FCD and, for purposes of comparison, with mesial temporal lobe epilepsy (MTLE), an epileptic disorder that, at least in the neocortex, is not characterized by any obvious structural aberration of neuronal networks. Spontaneous epileptiform activity was induced in vitro by applying 4-aminopyridine (4AP)-containing medium. Under these conditions, we could identify in FCD slices a close temporal relationship between ictal activity onset and the occurrence of slow interictal-like events that were mainly contributed by GABAA receptor activation. We also found that in FCD slices, pharmacological procedures capable of decreasing or increasing GABAA receptor function abolished or potentiated ictal discharges, respectively. In addition, the initiation of ictal events in FCD tissue coincided with the occurrence of GABAA receptor-dependent interictal events leading to [K+]o elevations that were larger than those seen during the interictal period. Finally, by testing the effects induced by baclofen on epileptiform events generated by FCD and MTLE slices, we discovered that the function of GABAB receptors (presumably located at presynaptic inhibitory terminals) was markedly decreased in FCD tissue. Thus, epileptiform synchronization leading to in vitro ictal activity in the human FCD tissue is initiated by a synchronizing mechanism that paradoxically relies on GABAA receptor activation causing sizeable increases in [K+]o. This mechanism may be facilitated by the decreased ability of GABAB receptors to control GABA release from interneuron terminals.

4-Aminopyridine↗

PubMed2001

GABA-mediated synchronization in the human neocortex: elevations in extracellular potassium and presynaptic mechanisms.

Field potential and extracellular [K(+)] ([K(+)](o)) recordings were made in the human neocortex in an in vitro slice preparation to study the synchronous activity that occurs in the presence of 4-aminopyridine (50 microM) and ionotropic excitatory amino acid receptor antagonists. Under these experimental conditions, negative or negative-positive field potentials accompanied by rises in [K(+)](o) (up to 4.1 mM from a baseline of 3.25 mM) occurred spontaneously at intervals of 3-27 s. Both field potentials and [K(+)](o) elevations were largest at approximately 1000 microm from the pia. Similar events were induced by neocortical electrical stimuli. Application of medium containing low [Ca(2+)]/high [Mg(2+)] (n=3 slices), antagonism of the GABA(A) receptor (n=7) or mu-opioid receptor activation (n=4) abolished these events. Hence, they represented network, GABA-mediated potentials mainly reflecting the activation of type A receptors following GABA release from interneurons. The GABA(B) receptor agonist baclofen (10-100 microM, n=11) reduced and abolished the GABA-mediated potentials (ID(50)=18 microM). Baclofen effects were antagonized by the GABA(B) receptor antagonist CGP 35348 (0.1-1 mM, n=6; ID(50)=0.19 mM). CGP 38345 application to control medium increased the amplitude of the GABA-mediated potentials and the concomitant [K(+)](o) rises without modifying their rate of occurrence. The GABA-mediated potentials were not influenced by the broad-spectrum metabotropic glutamate agonist (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (100 microM, n=10), but decreased in rate with the group I receptor agonist (S)-3,5-dihydroxyphenylglycine (10-100 microM, n=9). Our data indicate that human neocortical networks challenged with 4-aminopyridine generate glutamatergic-independent, GABA-mediated potentials that are modulated by mu-opioid and GABA(B) receptors presumably located on interneuron terminals. These events are associated with [K(+)](o) elevations that may contribute to interneuron synchronization in the absence of ionotropic excitatory synaptic transmission.

4-Aminopyridine↗

PubMed2001

[Functional neurosurgery for epilepsy].

Introduced at the end of the last century, epilepsy surgery is indicated in patients with intractable partial seizures and based on the resection of the epileptogenic cerebral tissue from which ictal discharges originate. Palliative procedures include seizure spread pathways interruption (callosotomy, multiple subpial transections) and chronic stimulation of the vagus nerve. Complete preoperative investigations including seizure observation, clinical tests, video-EEG, MRI and functional MRI, and PET-scan are performed in order to identify the epileptogenic zone. In difficult cases, invasive seizure monitoring through depth electrode implantation (SEEG) is performed. Resections for temporal lobe seizures are associated with favorable outcome: 60 to 90% of patients will be seizure-free after surgery. A less favorable outcome is observed after extra-temporal resections: 40 to 60% seizure-free patients. A better outcome is observed after surgery for epilepsy associated with an image-defined lesion, most often a tumor, rather than for cryptogenic epilepsy. Tumors associated with chronic partial epilepsy are indolent, most of them are dysembryoplastic neuroepithelial tumors (DNET). Outcome after palliative procedures are more variable, depending on the etiology of epilepsy.

Epilepsy↗

PubMed2001

Parieto-temporal rhythms in the 6-9 Hz band recorded in epileptic patients with depth electrodes in a self-paced movement protocol.

OBJECTIVES: Description of 6-9 Hz rhythmic electrical activity observed on recordings from electrodes implanted in the cortex of epileptic patients undergoing presurgical evaluation. METHODS: Recordings were obtained from 74 patients with multilead electrodes in the frontal, parietal and temporal cortex. The motor task consisted of a self-paced fist clenching movement at approximately 10 s intervals. Events within a window extending from 4 s before to 1 s after movement EMG onset were analyzed. RESULTS: (i) Spindle-like rhythmic activity at 6-9 Hz was observed in 29 patients. (ii) This activity was located in the inferior parietal and superior temporal areas. (iii) Enhancement of rhythmic activity occurred when patients were asked to perform the motor task. (iv) A striking tendency to phase-locking of rhythmic oscillations on consecutive trials was noted during the 3-2 s epoch before movement EMG onset. CONCLUSION: Whether this intracerebrally recorded 6-9 Hz rhythmic activity belongs to the mu-alpha class or is a special type of theta, and if it is related to the epileptic process or to drug treatment remain open to discussion. Motor-task related enhancement and phase-locking suggest that this activity may be one more indicator of movement preparation.

Electrodes, Implanted↗

PubMed2001

[Characteristics of epileptic seizures associated with cerebral arteriovenous malformations].

PURPOSES: The purpose of this study is to analyze the characteristics of epileptic seizures associated with cerebral arteriovenous malformations treated by radiosurgery. PATIENTS AND METHODS: Seven hundred and two patients are studied (406 men, 296 women) with a mean age of 33 when radiosurgery was performed. 210 patients had epileptic seizures; those seizures either uniquely revealed the arteriovenous malformation or were associated with other clinical signs. Seizures occurring after an hemorrhage were excluded from the study. We studied the age category upon seizures occurrence, the malformation localization, type of seizure (partial, generalized, or partial secondary generalized), the history related to the epileptic seizures, the clinical topographical correlation, the number of seizures, their duration prior to the radiosurgery, antiepileptic treatment provided, electroence-phalographic characteristics, angiographic characteristics, prior endovascular or surgical treatment, and factors associated with severe seizure. RESULTS: Epileptic seizures revealed the arteriovenous malformations in 30% of the cases; they predominated between 10 and 40 years (80.5%) with a peak between 20 and 30 years. The malformation localization most frequently associated with seizures were temporal and rolandic for partial seizures, whereas frontal or sylvian localization were predominantly associated with generalized seizures. The type of seizure was, in all cases, related to the malformation localization because of the initial signs seizure. 47.6% of the patients showed a limited number of seizures (between 2 and 20), 27.6% showed only a single seizure, and 24.7% suffered from severe epilepsy. Generalized seizures are unique in the majority of cases (61.8%) whereas partial seizures were severe in 47.6% of the cases. The majority of patients are under a single-drug therapy (79%). The EEG patterns showed a small increase of slow and sharp localized waves in patients presenting seizures compared with the global population (27% and 15% respectively). Severe seizures predominated between 10 and 19 years of age; seizures were exclusively partial in 59.6% of the cases and secondary generalized in 40.4%, their frequencies were between 1 to 4 per month in the majority of cases (59.1%), the delay was often more than 10 years (57.7%), status epilepticus was rare (5.8%), temporal and rolandic localization were predominant, social and professional insertion of the patient was preserved in 87.5% of the cases, and seizures did not provoke any death. The angiographic characteristics associated with seizures were: superficial localization, volume, superficial venous drainage, recruitment and venous divergence. CONCLUSION: Anatomic and topographic characteristics of cerebral arterio-venous malformations may provide information on the features of seizures associated with them.

Adolescent↗

PubMed2001

[Characteristics of headache associated with cerebral arteriovenous malformations].

BACKGROUND: and purposes. The purpose of this study was to identify the specific characteristics of headaches associated with cerebral arteriovenous malformations in order to differentiate them from other known entities of headaches such as migraine, cluster headache, and trigeminal neuralgia. This differentiation allows an early diagnosis of cAVM and a treatment to be administrated before any cerebral hemorrhage. PATIENTS AND METHODS: The study included 700 patients with cAVM and treated by radiosurgery. Out of this series, only 109 (48 males, 61 females, mean age of 33) presented with headaches. Headaches were studied as a possible revelation mode of a cAVM, either as an isolated sign, preceding an epileptic seizure, a cerebral hemorrhage, or associated with a neurological deficit. Analysis concerned 13 clinical parameters and 30 anatomic parameters based on angiography. RESULTS: Headaches were found in 15.6%; they were isolated in 6%. They preceded a cerebral hemorrhage in 12.6%, constituting an early alarm signal when increasing in intensity, frequency and duration. They were associated with seizures or a neurological deficit in 9.6%. We found a predominant female sex-ratio (0.78) and occurrence at a young age (72.3% between 10 and 40 years). Headaches were non-pulsating in 95.3%; nausea, vomiting, light or sound phobia were only found in 4.7%. Headaches were unilateral and homolateral to the malformation in 80%, corresponding to the malformation topography in 97.4% in posterior location and 80% in anterior location. Associated neurological symptoms existed in 20.2%; related to the malformation and lasting 5 to 30 minutes. Duration of pain episodes was less than 3 hours in 77% with a frequency of 1 to 2 per month in 82.5%. Pain was mild and responded to simple analgesics. A family migraine was found in only 3 patients. The angiographic characteristics of the malformations were meningeal afferences, superficial venous drainage and posterior location. CONCLUSIONS: Headaches associated with cerebral arterio-venous malformations form a distinct category that can be determined from specific characteristics; this should help an early diagnosis of cerebral arterio-venous malformations in order to start a treatment before the occurrence of cerebral hemorrhage.

Adolescent↗

PubMed2001

[Radiosurgery of cerebral arteriovenous malformations: target definition strategy].

BACKGROUND AND PURPOSE: Description and critical review of our procedure of definition of the target of irradiation of a cerebral arteriovenous malformations. PATIENTS: and method. Fixation of the stereotactic frame, performing of stereotactic angiography and CT scanner were described, and the target including nidus and venous collectors of the a cerebral arteriovenous malformations defined. CONCLUSION: The use of several three-dimensional imaging techniques can improve and simplify the method of delineating target with a reduction of radio-induced complications.

Cerebral Angiography↗

PubMed2001

[Prospects and future: evolution of stereotactic methodology for planning].

We have been using the stereotactic methodology of Talairach for Linac radiosurgery of cerebral arteriovenous malformations since 1984, and updated it with addition of CT and MR images into the stereotactic space. The target remains defined, as in most other centers, by stereotactic angiography. However, tridimensional configuration of cerebral arteriovenous malformations is better defined using MR or CT-angiography. Therefore, pre-radiosurgical imaging tends to combine multimodal images oriented into the stereotactic space. Frame-based radiosurgery, with invasive frame placement, will be replaced in the future by frameless irradiation with real-time tracking of the patients head, as performed by the recently described Cyber-knife. Intraoperative X-ray will be no longer long-distance fixed equipments but mobile, short-distance fluoroscopic systems integrated in the surgical workstation environment. Finally, biplane conventional angiography performed for cerebral arteriovenous malformations identification will be replaced by CT and MR-angiography, except in some cases who could still require DSA for accurate target identification.

Algorithms↗

PubMed2001

[Cerebral arteriovenous malformations treated by radiosurgery: a series of 705 cases].

BACKGROUND AND PURPOSE: After a review of the main radiosurgical published series, to evaluate our own series of 705 patients with cerebral arteriovenous malformations treated by radiosurgery alone or in combination with embolization or surgery. PATIENTS: and method. From January 1984 to December 1998, 705 patients were treated by a multidisciplinary team including neurosurgeons, neuroradiologists, radiophysicians and radiotherapists. Age of revelation of the cerebral arteriovenous malformations ranged between birth to 73 years (mean 27, median 25). Age at time of radiosurgery ranged between 7 and 75 years (mean 33, median 31). There were 410 males for 295 females (sex- ratio 1.4). Symptoms of revelation were hemorrhage for 59%, seizures for 23%, headaches for 14% and progressive deficits for 4%. Discovery of cerebral arteriovenous malformation was fortuitous in 4% of cases. Repartition following Spetzler's grading was 12% in grade I, 36% in grade II, 40% in grade III, 12% in grade IV and 0% in grade V. Maximal size ranged between 4 and 60 mm (mean 23, median 20). Volume ranged between 0.2 and 24.3 cc (mean 3.8, median 2.8). Majority of cerebral arteriovenous malformations were large size (42% with size higher than 25 mm) and large volume (54% higher than 10 cc. 54% of patients had treatment prior radiosurgery: 38% had embolization, 10% were operated, 4% were treated by radiosurgery (reirradiation) and 3% were operated and embolized. RESULTS: Overall complete obliteration rate was 55%. The obliteration rate was correlated with size (77% for cAVMs lower than 15 mm, 62% for cerebral arteriovenous malformations between 15 and 25 mm, and 44% for cerebral arteriovenous malformations higher than 25 mm), with volume (94% for cerebral arteriovenous malformations lower than 1 cc, 64% between 1 and 4 cc, 48% between 4 and 10 cc, and 62% for cerebral arteriovenous malformations higher than 10 cc), dose at reference isodose, minimal dose, morphological parameters (presence of dural components, arteriolovenous fistula, plexiform angioarchitecture, arterial steal, arterial recruitment, deep exclusive drainage, venous plicature, venous confluence, venous ectasia, venous reflux), sectional topography and good recovery of the target. Embolization was a confusion factor not associated with obliteration rate. After multivariate analysis, only Dmin and complete coverage of the cerebral arteriovenous malformations were correlated with obliteration rate. Delay of obliteration was significantly correlated after multivariate analysis with Dmin, complete coverage, arteriolovenulary angioarchitecture (positive correlation) and venous ectasia (negative correlation). CONCLUSION: Overall complete obliteration rate is unreliable data to assess efficacy of radiosurgical method in the tretment of cerebral arteriovenous malformations. The obliteration rate must be interpretated after stratification on several morphological and dosimetric parameters.

Adolescent↗

PubMed2001

[Surgical removal of radio-induced lesions after radiosurgery of cerebral arteriovenous malformations].

Radioinduced lesions after radiosurgery of cerebral arteriovenous malformations may be associated with an increased signal on T2-weighted and gadolinium enhancement on T1-weighted MR images. They do not have necessarily a poor prognosis. These lesions are mostly asymptomatic. But in a few cases they can be associated with severe clinical symptoms which can become corticodependant or corticoresistant. We present the 5 cases of such cerebral arteriovenous malformations treated by radiosurgery, out of our series of 705 patients. The removal was easier than that of untreated cerebral arteriovenous malformations, and led to a complete recovery of symptoms and progressive decrease of imaging abnormalities. Such surgery should be proposed in case of symptomatic radioinduced lesions which fail to respond to steroids.

Adult↗

PubMed2001

[Evolution of epileptic seizures associated with cerebral arteriovenous malformations after radiosurgery].

The goal of this study is to evaluate the response of epileptic seizures associated with cerebral arteriovenous malformations following radiosurgery and determine the factors associated with a positive outcome. The series included 210 patients (123 men, 87 women) with a mean age of 33. One hundred seventy three patients out of 210 were controlled after radiosurgery. Seizures completely disappeared in 58% of cases and decreased in 18%. Anti-epileptic treatment was stopped in 44%. Sex and age upon seizure appearance were not found as determining factors in patients whose seizures disappeared after radiosurgery. Generalized seizures disappeared following radiosurgery in 90.7%, partial secondary generalized seizures in 53.5%, and partial seizures in only 39.6%. Frontal or temporal malformations are associated with a better response after radiosurgery than sylvian or rolandic location. Seizure disappearance was maximal in case of isolated seizure prior to the radiosurgery (84.4%), was reduced to 61.2% when seizures were limited to 2 to 20, and disappeared in 21.4% in severe seizures. Epilepsy present less than 3 years prior to radiosurgery disappeared in 71.9%; was reduced to 45% when the delay was over 3 years. Seizures disappeared in 64.4% when the malformation was obliterated, they were reduced to 46.9% when malformations persisted. The persistence of severe seizures following radiosurgery was linked to persistence of the malformation. On the other hand early seizures occurred in 3.3% during the first 48 hours following radiosurgery; they disappeared in 72.2% after that period. De novo seizures also occurred in 1.7% and disappeared in all these cases. In conclusion, seizures associated with cerebral arteriovenous malformations respond well to radiosurgery; the malformation obliteration evokes its association with the seizure; the seizure disappearance in spite of persistence of the malformation evokes the positive effect of radiotherapy on epileptic seizures.

Adolescent↗

PubMed2001

[Course of headaches associated with cAVMs after radiosurgery].

The purpose of this study is to evaluate the response of headaches associated with cerebral arteriovenous malformations following radiosurgery and determine the factors that are associated with a positive outcome. From our series of 700 patients whose cAVM was treated by radiosurgery, this study includes 109 patients (48 males, 61 females) with a mean age of 32 when radiosurgery was performed. Headaches resolved in 37 patients (53.7%), decreased in 14 patients (20.3%), persisted in 16 patients (23.2%), and even increased in frequency in 2 (2.9%). Headaches disappeared 2 years following radiosurgery in the majority of patients (31 out of 37: 83.3%). The disappearance rate of headaches was better when it was the only sign of the malformation (64%) or preceded an epileptic seizure (60%) with respect to the case when it preceded cerebral hemorrhage (34.8%). Headaches having the best response were those with 1 to 2 episodes per month (64.9%) and whose episode duration was less than 3 hours (67.6%). Unilateral headaches accounted for 86.5% of resolved headaches whereas bilateral headaches were only 8.1% and even less were the diffuse ones (5.4%). The best evolution was obtained for those associated with a parietal location of the cerebral arteriovenous malformation, followed by rolandic (respectively 55.5% and 50%). Occipital malformation was associated with headache disappearance in 38.1% and temporal with 34.3%, whereas frontal location was associated with headache disappearance in only 25% of the cases. Headache disappearance was often correlated with cerebral arteriovenous malformation outcome after radiosurgery (64.9% of disappearance in case of complete obliteration). However, in 24.8%, headaches disappeared prior to the malformation obliteration and were associated with a decrease of the flow, of the nidus volume or with the nidus disappearance with the persistence of a precocious venous drainage. Headaches disappeared in spite of the malformation persistence in 5.4% of the cases. We found de novo headaches in one patient one year following RS. Another patient presented an episode of headache 12 hours following RS. The course of headaches associated with cerebral arteriovenous malformations after radiosurgery is positive in the majority of cases and correlated to the malformation outcome. This correlation suggests a link between cerebral arteriovenous malformations and headaches and the equal benefit of radiosurgery on both of them.

Adolescent↗

PubMed2000

Stereoelectroencephalography in focal cortical dysplasia: a 3D approach to delineating the dysplastic cortex.

Focal cortical dysplasia (FCD) is an increasingly recognized cause of intractable epilepsy. Surgical data suggest that the dysplastic cortex should be removed to obtain freedom from seizures, but the prognosis remains poor as FCD is difficult to delineate by imaging. We retrospectively analysed a series of 28 patients (aged 5-41 years, median 16.5 years) with FCD who had been investigated by stereoelectroencephalography (SEEG) between 1964 and 1995. Neurophysiological data were correlated with histological findings and surgical outcome. MRI was available for only seven patients. Severe partial epilepsy of early onset, pre-existing neurological deficit (68%) and cognitive impairment were the main clinical features. FCD was distributed equally between all lobes except for the temporal lobe, and was found predominantly on the mesial aspect of the cerebral hemispheres. SEEG findings provided evidence of dysplastic tissue epileptogenicity, as demonstrated by intralesional rhythmic spike discharges, the onset of ictal discharges and a low epileptogenic threshold. The epileptogenic zone corresponded to histologically defined FCD in 82% of the cases. Despite the lack of adequate neuroimaging in most cases, 64% of the patients became seizure-free after surgery. The main predictors of a favourable outcome were complete removal of the epileptogenic zone (P< 0.01) and complete removal of the dysplastic cortex (P< 0.01). These results emphasize the usefulness of neurophysiological data in accurately assessing the extent of the FCD.

Adolescent↗