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M Baulac

Publications and source records attributed to M Baulac.

At least 19 recordsLinked to original sources
PubMed1995

Is interictal temporal hypometabolism related to mesial temporal sclerosis? A positron emission tomography/magnetic resonance imaging confrontation.

The mechanism of interictal glucose hypometabolism remains unclear, but this abnormality occurs more frequently in temporal lobe epilepsy (TLE) than in other types of partial epilepsy. Therefore temporal hypometabolism has been suggested to reflect mesial temporal sclerosis (MTS). To investigate this, we selected 22 patients with refractory partial epilepsy of mesial temporal lobe origin (MTLE) who had hippocampal atrophy based on magnetic resonance imaging (MRI) volumetric analysis. We then analyzed the metabolic correlates of unilateral hippocampal atrophy. Thirteen temporal regions of interest (ROI) were defined on MRI scans for each individual and then applied to high-resolution FDG-positron emission tomography (PET) images obtained parallel to the long axis of the hippocampus. The most hypometabolic regions were the temporal pole and the hippocampal region. When we analyzed ensembles of temporal regions grouped into related networks, the temporolimbic network, which included the hippocampal region and the temporal pole, was abnormal in 95% of the patients at a 3-SD threshold. PET hypometabolism was highly correlated with the degree of hippocampal atrophy in this network, but not in other parts of the temporal lobe, which were less frequently hypometabolic. These data indicate that hypometabolism is a consequence of MTS in the temporolimbic region but not necessarily in the other parts of the temporal lobe. Our results also suggest that the combination of PET and MRI may facilitate the noninvasive diagnosis of MTLE.

Adult↗
PubMed1995

Memory disorders in probable Alzheimer's disease: the role of hippocampal atrophy as shown with MRI.

Magnetic resonance based volumetric measures of hippocampal formation, amygdala (A), caudate nucleus (CN), normalised for total intracranial volume (TIV), were analysed in relation to measures of cognitive deterioration and specific features of memory functions in 18 patients with probable Alzheimer's disease. Neuropsychological examination included the mini mental state examination (MMSE), the Mattis dementia rating scale (DRS), tests of executive functions, assessment of language abilities and praxis, the Wechsler memory scale (WMS), the California verbal learning test (CVLT) and the Grober and Buschke test. The volume of the hippocampal formation (HF/TIV) was correlated with specific memory variables: memory quotient and paired associates of the WMS; intrusions and discriminability at recognition for the Grober and Buschke test. By contrast, except for intrusions, no correlations were found between memory variables and the volume of amygdala (A/TIV). No correlations were found between the volume of caudate nuclei (CN/TIV) and any neuropsychological score. The volume of the hippocampal formation was therefore selectively related to quantitative and qualitative aspects of memory performance in patients with probable Alzheimer's disease.

Aged↗
PubMed1995

Developmental abnormalities of the medial temporal lobe in patients with temporal lobe epilepsy.

PURPOSE: To evaluate MR temporal lobe malformations and their frequency in patients with temporal lobe epilepsy. METHODS: Two hundred twenty-two consecutive adult patients with temporal lobe epilepsy of varying severity were investigated with 1.0-T or 1.5-T MR units using three-dimensional T1-weighted acquisition protocol. RESULTS: Sixteen patients (7.2%) presented with malformations of the temporal lobe. Four patterns of malformations were encountered: (a) heterotopia (n = 1), lining the temporal horn of the lateral ventricle; (b) focal neocortical dysgenesis (n = 6), which consisted of cortical thickening, poor gray/white matter demarcation, abnormal gyration (n = 5), or limited schizencephaly (n = 1); (c) hippocampal malformations (n = 5), which presented as abnormal hippocampal formation associated with a cyst (n = 2), isolated malformation of the subiculum (n = 1), or bilateral hippocampal malformation (n = 2) consisting of an abnormal shape and a misplaced fimbria; (d) complex malformations of the temporal lobe, combining categories a, b, and c (n = 4). The age at onset, severity of the disease, and occurrence of generalized tonicoclonic seizures were not significantly different between patients with malformations and the entire population of patients with temporal lobe epilepsy. CONCLUSION: MR analysis of temporal lobe malformations allowed a precise determination of the extent of the malformations and the presence or absence of associated hippocampal disease, all of which are of great help in the preoperative evaluation of patients with intractable epilepsy.

Adolescent↗
PubMed1994

Value of magnetic resonance imaging-based measurements of hippocampal formations in patients with partial epilepsy.

OBJECTIVE: To determine the occurrence of magnetic resonance imaging-detected hippocampal atrophy (HA) in patients with partial epilepsy (temporal and extratemporal, cryptogenic, or symptomatic). Magnetic resonance imaging-detected HA has been demonstrated to be both sensitive and specific for hippocampal sclerosis in cryptogenic temporal lobe epilepsy. DESIGN: Patients' hippocampal formations were measured on a computerized system using T1-weighted, 5-mm contiguous magnetic resonance coronal images made perpendicular to the hippocampus long axis. Hippocampal atrophy was defined on the basis of a normative asymmetry index and correlated with the epileptogenic focus defined by clinical, electroencephalographic, and magnetic resonance imaging (apart from HA) localizing data. PATIENTS AND CONTROL SUBJECTS: Seventy patients with intractable complex partial seizures of temporal, extratemporal, or undefined origin and 21 healthy control subjects. RESULTS: Hippocampal atrophy was present in 70% of patients with cryptogenic temporal lobe epilepsy (TLE) (n = 40), 44% of patients with symptomatic TLE (n = 9), 29% of patients with extratemporal epilepsy (n = 14), and 6% of unclassified patients (n = 16). In the cryptogenic TLE category, HA was marked and usually concordant (93%) with electroencephalographic lateralization. Hippocampal atrophy was often mild in the extratemporal epilepsy category. With the use of a wider confidence interval (+/- 3.1 SD instead of +/- 2.2 SD), HA specificity for TLE increased to 93%, HA specificity for lateralizing cryptogenic TLE reached 96%, and HA sensitivity for cryptogenic TLE stood almost unchanged (68%). We found a link between early convulsions and HA occurrence. CONCLUSIONS: Hippocampal atrophy is a marker for TLE. Dual pathologic findings are detected in 44% of symptomatic TLE cases. Mild HA is rarely associated with extratemporal epilepsy. Magnetic resonance imaging-based hippocampal volumetric analysis is a useful method to localize the origin of partial complex seizures.

Adult↗
PubMed1994

Hippocampal formations imaging with axial sections parallel to their longitudinal axis.

The complex shape of hippocampal formation (HF) and its obliquity make its morphological analysis difficult using brain imaging techniques. Adapted planes of section are required. The hippocampal axial plane (HAP) parallel to the hippocampus long axis is able to provide a complete and comprehensive view of the structure. HF has a rostrocaudal extent and is divided into three parts, head, body, and tail. Histological sections in the HAP display very well the pattern of the cell layers, with their transversal folding at the head and the tail. At more ventral levels, HF sections consist of parts of the CA1 field and the subicular complex. These are completely embedded in the temporal lobe and separated from its medial surface by the white matter and the cortical plate of the parahippocampal gyrus. More dorsal sections allow the study of the amygdala, uncus and fimbria. Functional images of HF can be accurately defined by combining magnetic resonance imaging (MRI), positron emission tomography (PET), or single photon emission computed tomography (SPECT) in this plane. According to the small dorsal-ventral dimension of the structures, a few slices can cover the whole HF and precise regions of interest may be outlined.

Brain↗
PubMed1994

[Topographic analysis of interictal spikes in the presurgical evaluation of severe partial epilepsy].

Fifteen patients have been examined: ten suffered from partial epilepsy of presumed mesiotemporal origin (group 1) and the other five presented partial epilepsy with non mesiotemporal or extra temporal epileptic focus (group 2). But in all cases, visual inspection of EEG traces demonstrated focally temporal interictal spikes. We have studied the spike voltage distributions and their corresponding scalp current density fields. Spike voltage topography revealed no significant difference between the two groups. Conversely SCD fields pointed out different specific characteristics according to the group. In the group 1, the gradient was always transversal, between the anterior temporal and the homolateral pre-frontal zones whereas in the group 2 it was antro-posterior in four patients. A more complete analysis of interictal spike by SCD representation should be useful in présurgical evaluation of patients with focal epilepsy.

Adult↗
PubMed1994

[Surgery for temporal lobe epilepsy].

Interest in surgery for intractable temporal lobe epilepsy has increased during the last ten years, mainly due to a better identification of the epileptogenic focus by modern imaging techniques (MRI) or functional tools (TEP and SPECT scanning). Depth electrodes recording is not mandatory and can be restricted to patients who do not meet congruent non invasive criteria. Simultaneously, modification of surgical techniques has been proposed: in addition to classical temporal lobectomy, other methods are used in order to minimize the resection of temporal lateral neocortex, and increase that of mesial temporal structures; the latter can be selectively performed through amygdalo-hippocampectomy. Outcome of surgery is generally excellent or good. More than three-fourths of patients are seizure free or show major reduction in seizure frequency. Outcome at the end of the second year is a good indication of long-term prognosis.

Cerebral Cortex↗
PubMed1994

Carbamazepine and its epoxide: an open study of efficacy and side effects after carbamazepine dose increment in refractory partial epilepsy.

We evaluated the efficacy, development of adverse effects, and possible correlation between the plasma concentration of carbamazepine (CBZ) and its major metabolite, carbamazepine-10,11-epoxide (CBZ-E), in a group of epileptic patients in whom selective increases in CBZ doses were made. Eighteen patients with refractory partial epilepsy participated in an open trial. Five were on monotherapy and 13 on polytherapy. All the patients were on CBZ before the trial and had plasma levels within the therapeutic range (17-42 mumol/L). After a baseline period, CBZ doses were progressively increased either to reach a 50% reduction in seizure frequency for 2 months or until side effects appeared. Thirty-nine percent of the patients had a 50% decline in seizure frequency, but only 17% improved for > 6 months. Mild or moderate side effects were observed in 78% of the patients. Side effects were correlated with CBZ plasma levels but not with CBZ-E plasma levels. Correlation between CBZ and CBZ-E plasma levels were found in the monotherapy group, but not in the polytherapy group. Our results confirm that higher doses of CBZ can successfully be used in some patients with refractory partial epilepsy. Furthermore, the plasma level of CBZ-E does not seem to be a useful indicator of toxicity in CBZ-treated ambulatory epileptic patients.

Adolescent↗
PubMed1994

Amygdalohippocampal MR volume measurements in the early stages of Alzheimer disease.

PURPOSE: To evaluate the accuracy of hippocampal and amygdala volume measurements in diagnosing patients in the early stages of Alzheimer disease. METHODS: Measurements of the hippocampal formation, amygdala, amygdalohippocampal complex (the two measurements summed), caudate nucleus, and ventricles, normalized for total intracranial volume, were obtained on coronal sections (1.5 T, 400/13 [repetition time/echo time], 5 mm) of 13 patients in the mild (minimental status > or = 21) and five patients in the moderate stages of Alzheimer disease (10 < minimental status < 21), and eight age-matched control subjects. RESULTS: For patients with a minimental status score of 21 or greater, atrophy was significant for the amygdala and hippocampal formation (-36% and -25% for amygdala/total intracranial volume and hippocampal formation/total intracranial volume, respectively), but not for the caudate nucleus. No significant ventricular enlargement was found. For patients with a minimental status score less than 21, atrophy was more severe in all structures studied (amygdala/total intracranial volume, -40%; hippocampal formation/total intracranial volume, -45%; caudate nucleus/total intracranial volume, -21%), and ventricles were enlarged (63%). No overlap was found between Alzheimer disease and control values for the amygdalohippocampal volume, even in the mild stages of the disease. In Alzheimer disease patients, hippocampal formation volumes correlated with the minimental status. CONCLUSION: Hippocampal and amygdala atrophy is marked and significant in the mild stages of Alzheimer disease. Volumetric measurements of the amygdala and the amygdalohippocampal complex appear more accurate than those of the hippocampal formation alone in distinguishing patients with Alzheimer disease.

Aged↗
PubMed1993

Impairment of consciousness induced by valproate treatment following neurosurgical operation.

Eight patients, who underwent neurosurgery for various supratentorial lesions presented unexplained impairment of consciousness during the first post-operative days. These states ranged from stupor to deep coma, and two patients had an emergency re-exploration. All these patients were receiving the usual dosage (1000 to 1500 mg per day) of Valproic acid (VPA). The treatment had been initiated either several weeks or months previously in 4 cases, and was thus well tolerated, or the day before surgery in the 4 other cases. EEG recordings displayed diffuse abnormalities, delta waves and/or high voltage triphasic complexes, that led to the diagnosis of VPA intolerance and drug withdrawal. Then full clinical recovery and EEG clearing occurred within 1 to 5 days. VPA intolerances are wellknown but remain exceptional, about 1 case per 100.000. In our neurosurgical population, however, the rate was higher, approximately 2%. Wide areas of blood brain barrier destruction may contribute to the higher frequency of this easily reversible cause of post-operative stupor or coma.

Adolescent↗
PubMed1992

[Research and surgical treatment of epilepsy].

The currently available surgical procedures for the treatment of epilepsy, from fundamental data to therapeutic results, including various means of investigation are reported. The work is based on a review of the literature and on the cases studied by the two teams from the Universities of Montreal and Bordeaux who share the same concept of epilepsy surgery. The patient groups of the two teams include 316 S.E.E.G., 214 cortectomies, 39 callosotomies and 2 multiple sub-pial transsections. In the first part, the authors attempt to demonstrate that the epileptic focus corresponds to the region where the seizures arise, that this focus is not directly comparable to the region where inter-ictal spikes are recorded and sometimes becomes autonomous from the causal lesion. The epileptic phenomenon has a definite harmful effect on cerebral functions and a probable self-aggravating potential. The second chapter summarizes the clinical data on which the indications and contraindications are based. These obviously depend on whether the intervention is intended to be curative or palliative. Various non-invasive and invasive investigations are then reviewed, according to their relative importance and the experience of each team. The main points developed are: the electroclinical correlations during seizures, the symptomatological data for differentiating between temporal and frontal lobe seizures, the contribution of M.R.I. in demonstrating the epileptogenic and epileptic lesions, the electrophysiological information suggesting that S.E.E.G. remains the most informative mean of investigation. The various methods of investigation of assessing electrical, functional (cerebral blood flow, metabolism) and morphological aspects of epilepsy, supply non-redondant findings about the localisation of the epileptic focus. The chapter on surgical techniques mainly discusses the various modes of implantation of subdural and intracerebral electrodes and reports the same rate of morbidity in both cases. Orthogonal teleradiography is still perfectly suited to the implantation of intracerebral electrodes. S.E.E.G. is still the most anatomically precise technique. However, in certain conditions, extraoperative E.Co.G. is more adequate. New surgical modalities have recently appeared such as the multiple subpial transsections which allow treatment of epileptic foci unapproachable by cortectomy and such as modified techniques of hemispherectomy, which by decreasing morbidity, renew interest in them. In the chapter on surgical results, the authors emphasize the methodological problems of evaluation that partly account for their wide variability. The results obtained with the various surgical modalities are reviewed. The outcome in cortectomies is discussed at length in terms of the data from the literature as well as the results reported by both teams.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1991

The commissuro-mamillary plane in MRI of the brain (preliminary communication).

MRI sections of the brain in the coronal plane through the line joining the anterior commissure and the mamillary bodies display the constituent parts of the basal forebrain. The visualisation of the septal nuclei and the anterior columns of the fornix show the importance of this plane in the study of behaviour disorders and amnesic syndromes.

Corpus Striatum↗
PubMed1990

[Alcohol and epilepsy].

Two kinds of epileptic events are frequently related to alcohol consumption: 1) seizures triggered by alcohol withdrawal. Often multiple, they occur within between 10 and 48 hours after discontinuing or reducing alcohol intakes and can be followed by a delirium tremens. 2) recurring unprovoked seizures. They are usually rare, 1 or 2 yearly. The risk is increased for heavy drinkers but returns to normal for ex-drinkers. Seizures related to alcoholism are usually generalized tonico clonic seizures with normal EEG and CT-scan. When partial seizures are identified they are attributed to preceding brain damage, head trauma or stroke.

Alcohol Drinking↗
PubMed1990

The commissuro-mamillary plane in MRI of the brain (preliminary communication)

MRI sections of the brain in the coronal plane through the line joining the anterior commissure and the mamillary bodies display the constituent parts of the basal forebrain. The visualisation of the septal nuclei and the anterior columns of the fornix show the importance of this plane in the study of behaviour disorders and amnesic syndromes.

Brain↗
PubMed1989

Radiological studies in trigeminal nerve pathology.

The authors have used CT scans and MRI to study pathology in anatomical and radiological correlations of brain slices. The CT scan was particularly useful for studying structures at the skull base, although at the level of the posterior fossa such scans could visualize only those tumors that were larger than 8 mm. even after injection. The CT scan was found to be the most useful examination before surgery for facial neuralgia. In contrast MRI gave a precise cisternal course of the trigeminal nerve and its relations with vascular structures.

Cranial Nerve Neoplasms↗
PubMed1989

Obsessive-compulsive and other behavioural changes with bilateral basal ganglia lesions. A neuropsychological, magnetic resonance imaging and positron tomography study.

Eight patients are reported who shared the combination of bilateral basal ganglia lesions and a frontal lobe-like syndrome. The main features were inertia and loss of drive, with preservation of intellectual function. Some patients showed stereotyped activities with compulsive and obsessive behaviour which were sometimes highly elaborate in pattern. Extrapyramidal clinical signs were absent or mild. Brain damage, related to anoxic or toxic encephalopathy, was demonstrated by CT scans and MRI. The lesions appeared to be confined to the lentiform nuclei, particularly affecting the pallidum, although there was generalized brain atrophy in 2 cases. Positron emission tomography (PET) in 7 patients revealed hypometabolism of the prefrontal cortex relative to other parts of the brain. The PET studies suggest dysfunction of the prefrontal cortex as a result of damage to the lentiform nuclei. These clinical, anatomical and functional observations emphasize the role of the circuits linking the prefrontal associative cortex and some specific areas of the neostriatum, including the pallidum. The existence of distinct nonoverlapping circuits in the motor field or in the associative field can explain the fact that basal ganglia lesions may give rise to a clinical picture that is either purely motor, purely behavioural (as in some of our patients), or both. Similarities existed between some symptoms found in our patients and certain features of major psychiatric illnesses such as severe depression, catatonic schizophrenia, and obsessive-compulsive disorder. This raises the hypothesis that some aspects of these psychiatric disorders could be related to structural and physiological disturbances in the systems linking the frontal associative cortex and the basal ganglia.

Adult↗
PubMed1989

[Cyclosporin and convulsions after cardiac transplantation].

6 p. 100 of a population of 129 heart transplant recipients presented isolated convulsions under cyclosporin (Ci) immunosuppressive treatment. These seizures were unexplained by acute causes, infectious or cerebro-vascular. Seizures started generally a few days after Ci therapy onset, and led often to severe convulsive states, with sometimes a status epilepticus. For most of them, Ci serum levels were within, or just above, the recommended therapeutic range. Ischemic brain damage that occurred prior to surgery and Ci therapy, could be a contributing factor to Ci-induced seizures in this population of heart transplant recipients.

Adolescent↗