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PubMed1993

A few thoughts on the history of epilepsy.

The history of epilepsy is a saga of the struggle by which scientific understanding of an unusual disease was gained by a long and circuitous route. In the beginning this affliction was attributed to demon possession and defied understanding for centuries when it was still regarded as a sacred disease and surrounded by superstition and mysticism; therapy of necessity had to follow similar lines of reasoning. The gradual realisation that cerebral dysfunction was the cause of this disease was highly significant although still followed by misunderstanding and misinterpretation--those two essential steps to progress. Clear, inspired reasoning and lucid clinical descriptions of epilepsy by John Hughlings Jackson and William Gowers set the scene for what was to follow. Experimental neurophysiology, cortical simulation, cortical localisation, new technologies of electro-encephalography, modes of visualisation of structures histologically and radiologically led to our present-day concepts of this complex disorder. We have been brought to new thresholds of understanding through the co-operative exertions of many workers from all parts of the world and this saga tells of some of the highest scientific accomplishments in medicine.

Epilepsy↗
PubMed1996

[Anatomo-functional localization in cerebral cortex. Application of imaging systems as a guide for resection of cortical lesions].

The stereo-encephalography of Talairach (SEG) makes it possible to obtain an individualized anatomofunctional map, based on the proportion of the telencephalum with an inter-commissurual line CA-CP. The aim of this paper was to design a method for the preparation of these maps, without need for the use of stereotactic equipment, and to apply this to the anatomofunctional localization of cortico-subcortical lesions. With the aid of a CAD programme (AUTOCAD v. 11), the images obtained using magnetic resonance (MR), with visualisation of the CA-AP line, skull X-ray (Rx) and cerebral angiograph (ADS) were superimposed. This was subsequently squared, as suggested by Talairach, permitting comparison between the maps (by standardization of the CA-CP line at 25 mm.) or with a stereotactic map. A total of 104 patients were studied, divided into three groups: A. Control 10 patients with slight HSA, with no ADS pathology. B. Resection of the lesion. 38 patients with vascular lesions (30) or benign tumours of less than 3mm (8). C. Epilepsy. 56 patients with drug-resistant epilepsy, with or without a visible lesion on RM (26 and 30 patients respectively). Outstanding amongst the results obtained were: confirmation of the close relationship of the telencephalum with the CA-AP line. Using our method there was great precision in superimposing anatomical structures. There was an error of less than 0.5cm in superimposing the corpus callosum and the pericallosum artery or Galen's vein. This made it possible for us (in group B) to localize subcortical lesions larger than 1cm without using a stereotaxic guide. In these cases we were guided by the cortical venous pattern which led to the lesion. In group C, use of these maps allowed us to obtain a functional surgical document exactly the same as the anatomofunctional maps of the SEG of Talairach.

Adult↗
PubMed1996

Epilepsy surgery.

Surgical therapy of epilepsy, although still underutilized, is presently well accepted and performed world-wide with increasing frequency. In the last decade the following changes have been noticed: non-invasive pre-surgical evaluation is increasingly carried out in close collaboration with referring centres so that often no (or only a very short) hospitalization is necessary in highly specialized epilepsy centres for this purpose. Stereoelectro-encephalography (SEEG) is used less often in invasive evaluation while the subdural strip and grid electrode-techniques are used more often. There is a general trend for a more flexible and collaborative multidisciplinary and multi-method approach utilizing the whole spectrum of modern diagnostic facilities in a more patient-oriented and therefore more cost-effective way. The main objective of the pre-surgical evaluation is to determine the onset area of the patient's spontaneous habitual seizures. The primary epileptogenic zone is not necessarily synonymous with the so-called lesional zone, although in the great majority of patients they are related. In a small percentage of candidates for epilepsy surgery additional special examinations are necessary to prevent and/or predict the degree of post-operative deficits. At present selective Amytal tests are often used but these invasive procedures might be replaced in the future by functional PET and functional MR studies. Surgery in patients with epilepsy can be categorized into: (i) lesion-oriented surgery (lesionectomy sensu stricto), (ii) epilepsy-oriented lesional surgery, (iii) surgery for epilepsy sensu stricto. Surgery is performed with a 'curative (= causal)' or a 'palliative' intention. Furthermore surgery can be categorized into standardized epilepsy surgery (such as anterior temporal lobe resection, selective amygdalohippeocampectomy, anterior callosotomy); and individually tailored surgical interventions. It is obvious that also so-called standardized operations are tailored to some degree, usually based on pre-operative findings as well as on intraoperative corticography and/or other intra-operative neurophysiological tests (functional mapping). Individually tailored operations comprise smaller topectomies and larger resections. Surgery for temporal lobe epilepsy still prevails. For mesial temporal lobe epilepsy more selective operations, such as the selective amygdalohippocampectomy, are increasingly performed. Today the majority of patients suffering from this syndrome can be evaluated non-invasively (or 'semi-invasively' with the foramen ovale electrode technique) in combination with MRI (including volumetry of the hippocampus) and PET or SPECT. In general one has the impression that extratemporal resections without a lesion are performed less often. But, if a morphological abnormality is present, pre-surgical evaluation (using grids), and surgery making use of 'functional mapping' are increasingly offered from more and more centres. Anterior callosal sections and functional hemispherectomies have also witnessed a renaissance. The most important standardized operations are reviewed.

Amygdala↗
PubMed1997

[Neurophysiological aspects of Proteus syndrome].

INTRODUCTION: The Proteus Syndrome was defined in 1983 by Wiedeman. However, the first case mentioned in the literature was that of Joseph Merrick, the Elephant Man, presented by Sir Frederick Treves in 1884. It is a rare pathological condition. Its multiple clinical features include; partial gigantism of hands and/or feet, pigmented nevi, hemihypertrophy of the body, tumors, skeletal anomalies, growth disorders and visceral anomalies. Hereditary transmission has not been clearly defined. Diagnosis and treatment require the participation of experts from several medical and surgical specialties. CLINICAL CASE: We present a case sent to our hospital for the surgical correction of cranio-facial malformations. Epileptic crises post-operatively indicated the need for neurological and neuro-physiological study. This was done by means of conventional electro-encephalography: brainstem, somato-sensorial and visual auditory evoked potentials, together with imaging techniques which showed the structural and functional asymmetry of the central nervous system at both cerebral and brainstem levels. CONCLUSIONS: Few neuro-physiological studies are included in the literature we reviewed for this paper. Therefore we do not know whether the functional anomalies of the central nervous system which we describe should be considered to be part of the syndrome.

Adult↗
PubMed1998

[Rasmussen syndrome].

INTRODUCTION: Rasmussen's encephalitis is a neurological disorder probably of immunological origin, characterized by intractable epilepsy, neurological deterioration and the presence of antibodies against R3 glutamate receptors. OBJECTIVE: To present the experience of an Argentinian Paediatric Neurology Service during the past 7 years. MATERIAL AND METHODS: We analyzed the clinical histories of 12 patients with RS as defined by the diagnostic criteria proposed by Hart et al. We evaluated the following parameters: neurological examination, neuropsychological assessment, types of crises, age of onset, frequency, distribution, electroencephalogram, video EEG, evoked potentials, neuro-radiological studies; CT and cerebral MR using gadolinium, SPECT, lumbar puncture and cerebral biopsy. RESULTS: The crises were of simple partial motor type in 12 cases, secondarily generalized partial crises in 7 cases, complex partial crises in 4 cases and partial and generalized motor states in 8 cases. RESULTS. The ictal EEGs during the continuous partial crises showed contralateral focal slow activity of the affected side of the body in 30% of cases. The neuro-radiological studies (CT and MR) showed signs of cerebral hemiatrophy in all 12 cases, hyper-intense images in the T2 sequences of the fronto-temporo-parietal regions in 5 cases, an asymmetric megacisterna magna in 1 case and hypoplasia of the cerebellar vermis in another case. CONCLUSIONS: The continuous partial crises showed little correlation with the electro-encephalography. Following administration of i.v. gammaglobulin there was a transient halt in progression of the neurological deterioration and control of the crises in 55% of the cases. Surgery continued to be the treatment recommended for control of the epileptic crises.

Adolescent↗
PubMed1976

A comparison of computer asisted tomography (EMI scanner) with conventional neuroradiologic methods in the investigation of patients clinically suspected of intracranial tumor.

Computerized tomography has been used as the initial radiologic investigation among 212 intracranial tumor suspects. Ninety-five of these patients were ultimately shown to have tumors as a result of all their investigations. Eighty tumors were clearly defined by EMI scanning, four further scans were suspicious but not unequivocally abnormal and six scans showed complications of the tumor rather than the lesion itself. Thus, only five scans were falsely negative in the presence of a tumor. The false positive and false negative rates for EMI scanning have been compared with conventional techniques and computerized tomography shown to compare favourably with angiography or encephalography.

Brain Neoplasms↗
PubMed1998

Functional magnetic resonance imaging: the basics of blood-oxygen-level dependent (BOLD) imaging.

There are 2 principal techniques of functional MRI (fMRI): the blood-oxygen-level dependent (BOLD) technique, which is the favoured method because no intravenous contrast medium is required, and the dynamic or exogenous technique. The BOLD technique takes advantage of the fact that the change from diamagnetic oxyhemoglobin to paramagnetic deoxyhemoglobin that takes place with brain activation results in decreased signal intensity on MRI. Commercially available scanners can be used to conduct single-slice BOLD fMRI experiments, but echo-planar hardware is needed for multislice wholebrain experiments. Sequence choices in BOLD fMRI include spin-echo and gradient-echo sequences, to which rapid acquisition with relaxation enhancement and echoplanar techniques may be applied. Optimal imaging parameters (echo time, slice thickness, field of view and flip angle) are important in maximizing signal-to-noise ratios. Various statistical techniques and software programs have been developed to interpret the large amounts of data gathered from BOLD fMRI experiments, which presents one of the biggest challenges in performing this technique with clinical MR units. Controversy exists regarding the effects of draining veins on cortical mapping, of inflow of blood into the imaging slice or volume, and of motion artifact. BOLD fMRI has demonstrated good correlation with positron emission tomography, magneto-encephalography and electrocorticographic recordings of motor responses. It has been used to study cortical activity of visual, motor, auditory and speech tasks as well as brain centres for smell, motor imagery, complex motion and memory. As such, it holds promise for the study of brain function, but must be subjected to larger studies comparing it with the gold standard of electrocorticographic mapping.

Arousal↗