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ABSTRACT: Event-related potentials were recorded from 537 sites in the superior temporal plane and parietal lobe of 41 patients. Depth electrodes were implanted to localize seizure origin prior to surgical treatment. Subjects received an auditory discrimination task with target and non-target rare stimuli ("standard oddball paradigm"). In some cases, the target, distracting and frequent tones were completely balanced across blocks for pitch and volume. Variants included an analogous visual discrimination task, or auditory tasks where the rare target event was the omission of a tone, or the repetition of a tone within a series of alternating tones. In some subjects, the same auditory stimuli were delivered but the patient ignored them while reading. Three general response patterns could be distinguished on the basis of their wave forms, latencies and task correlates. First, potentials apparently related to rarity per se, as opposed to differences in sensory characteristics, or in habituation, were observed in the posterior superior temporal plane, beginning with a large positivity superimposed on early components. This positivity peaked at 150 msec after stimulus onset and inverted in sites superior to the Sylvian fissure. Subsequent components could be large, focal and/or inverting in polarity, and usually included a positivity at 230 msec and a negativity at 330 msec. All components in this area were specific to the auditory modality. Second, in the posterior cingulate and supramarginal gyri, a sharp triphasic negative-positive-negative wave form with peaks at about 210-300-400 msec was observed. This wave form was of relatively small amplitude and diffuse, and seldom inverted in polarity. It was multimodal but most prominent to auditory stimuli, appeared to remain when the stimuli were ignored, and was not apparent to repeated words and faces. Third, a broad, often monophasic, wave form peaking at about 380 msec was observed in the superior parietal lobe, similar to that which has been recorded in the hippocampus. This wave form could be of large amplitude, often highly focal, and could invert over short distances. It was equal to visual and auditory stimuli and was also evoked by repeating words and faces. The early endogenous activity in auditory cortex may embody activity that is antecedent to the other patterns in multimodal association cortex. The "triphasic" pattern may embody a diffuse non-specific orienting response that is also reflected in the scalp P3a. The later broad pattern may embody the cognitive closure that is also reflected in the scalp P3b or late positive component.
Electroencephalography and Clinical Neurophysiology 04/1995; 94(3):191-220.
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ABSTRACT: The goal of this study is to determine and localize the generators of different components of middle latency auditory evoked potentials (MLAEPs) through intracerebral recording in auditory cortex in man (Heschl's gyrus and planum temporale). The present results show that the generators of components at 30, 50, 60 and 75 msec latency are distributed medio-laterally along Heschl's gyrus. The 30 msec component is generated in the dorso-postero-medial part of Heschl's gyrus (primary area) and the 50 msec component is generated laterally in the primary area. The generators of the later components (60-75 msec) are localized in the lateral part of Heschl's gyrus that forms the secondary areas. The localization of N100 generators is discussed.
Electroencephalography and Clinical Neurophysiology 06/1994; 92(3):204-14.
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ABSTRACT: The diagnostic and therapeutic approach to intracranial lesions must be different considering the different possibilities offered by the various methods. The diagnostic reliability and safety of stereotactic biopsy are often indispensable in order to optimize the subsequent therapy. The results obtained in selected pathologies allow us to propose the stereotactic approach to treat: -various kind of cysts by aspiration and/or Beta endocavitary radiation therapy; -blood or abscessual collections that can be aspirated in a similar way; -arterio venous malformations or tumours by radiosurgery; -tumours by brachicurietherapy or by computer assisted stereotactic surgery. We present some cases treated at the C.H.S.A. of Paris and at the C.H.R.U. of Grenoble utilizing Talairach methodology.
The Italian Journal of Neurological Sciences 03/1992; 13(1):17-44.
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Advances in neurology 02/1992; 57:651-88.
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ABSTRACT: The localization of the primary auditory cortex in man was studied by direct recordings in 150 different sites in the superior transverse gyrus, especially in Heschl's gyrus and the planum temporale. The distribution of the primary evoked responses (N13/P17/N26) was studied in 15 epileptic patients who were candidates for surgical treatment. Precise topography of recording sites was determined stereotactically. Our results provide evidence for considering only a restricted portion of Heschl's gyrus (its posteromedial part) as the primary auditory area.
Brain 03/1991; 114 ( Pt 1A):139-51. · 9.46 Impact Factor
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ABSTRACT: Morphological brain asymmetries of the planum temporale, Sylvian fissure and insula were assessed by stereotactic-stereoscopic angiography in 70 epileptic patients without neuroradiological abnormalities, at angiography and CT in these regions. Fifty four patients were right-handers and 16 not right-handers. In 57 patients hemispheric speech dominance was evaluated by the Wada test and electroclinical correlations: in 8 patients, 4 men and 4 women, speech was located in right hemisphere or bilaterally. Lateral asymmetry was present in the regions examined. Correlations between the morphological measurements were not identical in the left and the right hemisphere. No significant relationship was found between anatomical asymmetries and handedness. In men, but not in women, significant differences were observed between the right-bilateral speech group (4 subjects) and the left speech group (31 subjects): right hemisphere regions, including the insula, were larger in the former than in the later whereas, left hemisphere regions were identical in both groups.
Revue Neurologique 02/1991; 147(1):35-45. · 0.49 Impact Factor
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ABSTRACT: In order to isolate the anatomical locus of neural activity primarily responsible for generating the scalp-recorded P3 (or P300), the topography of event-related potentials (ERPs) elicited during an auditory oddball task was compared between medial-to-lateral aspects of the frontal, parietal, and temporal lobes in 10 epileptic patients undergoing stereoelectroencephalography for seizure localization. Evidence of local ERP generation was obtained from each of these areas. Small amplitude P3-type potentials were sometimes observed to invert polarity across recording contacts in the frontal lobe. Large amplitude positive polarity P3-type components were observed in the lateral neocortex of the inferior parietal lobule (IPL), that rapidly attenuated in amplitude at more anterior, posterior, superior, inferior, and medial recording contacts. Large amplitude polarity inverting P3-type components were also observed to be highly localized to hippocampal contacts of temporal lobe electrodes. These data are discussed in the context of other recent studies of lesion effects, scalp topography, and intracranial recordings, and it is concluded that activity generated in the IPL is likely to make the major contribution to the scalp-recorded P3, with smaller contributions from these other sources. Finally, salient topographical differences between the intracranial distribution of the P3 and those of the N2 (or N200) and slow wave (SW) suggest that the generators of these components are not identical.
Electroencephalography and Clinical Neurophysiology 10/1990; 76(3):235-48.
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ABSTRACT: Stereotactic implantation of deep SEEG electrodes performed as a prelude to surgery in some patients with drug-resistant focal epilepsy requires previous "in vivo" identification and localization of the cortical and subcortical structures to be explored, visualized "semi-directly" "or directly" by neuroradiological imaging techniques. Stereoscopic stereotactic teleangiography is a safety factor in transcutaneous electrode implantation and biopsies, but it also localizes the cortical sulci in a "semi-direct" manner by identifying vascular segments deeply buried in this sulci, which constitute their lamina vascularis. Although RMI greatly contributes to the study of the pallium, visualizing fragments of sulci and gyri does not necessarily mean that these structures can be identified with certainty, notably on the convexity of the brain. To solve this problem, RMI sections are enlarged by a photographic process, then combined with the images obtained from neuroradiological stereotaxis by means of anatomical landmarks that are common to both types of documents, using the bicommissural reference systems, bicallosal l/nl or vascular segments. This enables the angiographic laminae vascularis, which define the sulci in a "semi-direct" manner, to be used a kind of "Ariadne's clew" to identify cortical structures on RMI sections. In percutaneous stereotactic electrode implantation, the choice of the trajectories results from a compromise between the need to reach the desired anatomical structures, identified and localized within the stereotactic space, and the necessity to avoid the blood vessels displayed by stereoangiography. In some cases, the accuracy of anatomical definition can be verified during the SEEG study and/or by the evoked potential technique. Once the electrodes have been removed, their traces can be identified in a control RMI examination which constitutes a further verification.
Journal of Neuroradiology 02/1990; 17(2):67-102. · 1.21 Impact Factor
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ABSTRACT: Between December 1979 and September 1986, 11 patients with colloid cysts of the third ventricle were operated on by a stereotactic procedure with Talairach's system. Stereoscopic angiography and ventriculographic study allowed for a percutaneous (twist-drill hole diameter: 2.5 mm) stereotactic aspiration of the cysts. The operations were successful, and there were no intraoperative or postoperative mortalities but just mild transient morbidity in three cases. Six cysts were evacuated completely, and five only partially. The mean residual volume was 19% of the initial one. Clinical and anatomical results are presented, and the advantages of this stereotactic procedure are discussed.
Surgical Neurology 11/1989; 32(4):294-9. · 1.67 Impact Factor
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ABSTRACT: Facilitation of the spinal monosynaptic reflex by auditory stimulation has been demonstrated previously in animals and man. Analysis of the time course of audiospinal facilitation (ASF) in normal subjects is reported. The role of the cerebral cortex in the control of audiospinal facilitation was investigated in 32 patients with anatomically well-circumscribed lesions, the precise topography of which was determined stereotaxically. Lesions of the caudal part (Heschl's gyrus and temporal plane) of the superior temporal gyrus selectively depressed ASF evoked by contralateral auditory stimulation. In contrast, lesions in temporal, parietal and occipital lobes had no effect. Results obtained with frontal lobe lesions were not homogeneous. The specific involvement of auditory cortex in the gating of behavioral audiomotor reactions is discussed.
Brain 05/1989; 112 ( Pt 2):375-91. · 9.46 Impact Factor
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ABSTRACT: Radiologists can now use Talairach's bicommissural reference system and simple T-weighted sagittal magnetic resonance imaging (MRI) sections to recognize the central sulcus of the brain with its spatial features. In this study of 50 MRI examinations performed on normal subjects with contiguous 9 mm thick sagittal sections related to a standard proportional model that takes into account variations in the size and shape of the brain, the central sulcus could be identified on each section, despite its complexity on lateral projections and its frequent changes of course. By comparisons with the co-planar stereotaxic atlas of Talairach and Tournoux, it will be possible to localize the classical functional areas of the telencephalon.
Journal of Neuroradiology 02/1989; 16(2):133-44. · 1.21 Impact Factor
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ABSTRACT: Two female patients presented a severe partial epilepsy of early onset and an extended right posterior hemispheric lesion of prenatal or perinatal origin. They were right-handed and all their first degree relatives were right-handed. Nevertheless, evidence of right hemispheric speech was documented in both patients, on the basis of a bilateral sodium amytal test in one case, and of a persistent aphasia after neurosurgical treatment in the other. The possible consequences of an early cerebral pathology on cerebral lateralization are discussed, including pathological right-handedness.
Revue Neurologique 02/1989; 145(1):31-6. · 0.49 Impact Factor
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ABSTRACT: The rational management of intracranial lesions should be based on the exact definition of the nature of the lesions and, when it is possible, on their spatial definition. Since External Radiotherapy (ERT) and cytostatic therapy are not free of undue effects, especially in children, such treatments should be used only when a "sure" diagnosis is obtained. The aim of this paper is to study the results allowed by the Talairach's stereotactic methodology in children. During the period January 1979-December 1986, 704 stereotactic procedures including serial biopsies, were performed at the S. Anne Hospital in Paris. One hundred forty-eight procedures (21%) concerned 134 children (78 M; 56 F) aged from 2 to 16 years. The interval between the occurrence of the first clinical symptoms and the stereotactic procedures varied between 1 and 180 months (m: 24 m). Fifty-two (40%) had previous therapeutic procedures without precise diagnosis. The lesions were hemispheric in 46 (34%) and deep seated in 88 (66%). The serial stereotactic biopsies proved the existence of a non-tumoural lesion in 20 children (14.9%): (cryptic vascular malformation: 5, cortical dysplasia: 3, haematoma: 3, ischaemia: 1, granuloma: 1, degenerative pathology: 2, cicatrix: 2, post-ERT alterations: 1, arachnoidal cyst: 2). Four were in the brain stem. In 3 patients (2%), a precise diagnosis was not obtained. The CT scan characteristics of the 20 non-tumoural lesions did not permit to establish a precise differential diagnosis. The therapeutic management was adapted to the diagnosis, avoiding potentially dangerous procedures in the 20 non-tumoural lesions.
Acta neurochirurgica. Supplement 02/1989; 46:75-8.
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ABSTRACT: The clinical and anatomical results of the treatment of 7 colloid cysts of third ventricle by stereotaxic aspiration are reported. A history of increased intracranial pressure was reported in all patients (4 females aged of 12, 16, 28, 38 years; 3 males aged of 36, 54, 59 years). A ventricular shunting device has been inserted in 4 patients. Pre-operative clinical findings were: signs of increased intracranial pressure (1 case), isolated memory disturbances (3 cases); motor weakness, memory disturbances and psychomotor slowness (2 cases); 1 of the 2 last cases had also thymic disturbances. Clinical examination was normal in 1 patient. CT-Scan revealed 5 hyperdense lesions, 3 with slight enhancement; 1 hypodensity encircled by an hyperdense ring without enhancement, 1 not enhancing isohypodensity. 6 colloid cysts were between the Foramens of Monro, 1 in the posterior third ventricle. Cyst volume ranged from 1.8 to 6.3 cc. (m: 3.4). Biventricular hydrocephalus was present in all but 1 patient. Stereotaxic aspiration of the cyst performed according to Talairach's system resulted in a release of C.S.F. circulation in all cases. 3 colloid cysts were aspirated completely, 4 were reduced to 3%, 11%, 12%, 33% of the initial volume. Post-operatively 2 patients presented with a transient meningeal reaction, 1 with a transient "myoclonic" syndrome. In 1 "completely aspirated" case a control CT-Scan showed, 5 years later, a small hyperdensity corresponding to 4% of the initial cyst volume. All patients lead a normal and useful life (Follow-up: 8-78 months, m: 45). Neurological examination is normal in 6 cases and shows a pre-existent facial asymmetry in 1. Ours results suggest that stereotaxic investigation should be the first safe procedure in order to achieve both diagnosis and treatment of colloid cysts of third ventricle.
Neurochirurgie 02/1988; 34(1):26-36. · 0.34 Impact Factor
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ABSTRACT: During the period January 1975-October 1987, we performed stereotactic ventriculocisternostomy (V.C.S.) on 23 patients (13 M., 10 F.; age: 11-73 years, m: 33). Sometimes used as an isolated therapeutic procedure, V.C.S. may also follow stereotactic biopsies using Talairach's methodology. Serial stereotactic biopsies were performed in 15 out of 23 patients showing 11 tumoral lesion, two arachnoïdal cysts and two cryptic vascular malformations. Eight patients presented with an isolated aqueductal stenosis. Among the 12 non tumoral patients, seven had very large triventricular hydrocephalus (6 with a retroclival dilatation of the third ventricle) and 5 showed significant dilatation. Of the 11 tumoral patients, 7 had significant ventricular dilatation (1 with a protrusion of the floor of the third ventricle) and 4 with modest dilation. V.C.S. is done by creating an opening (diameter: 5-6 mm) in the floor of third ventricle with a fine forceps introduced through a tubular guide (diameter: 2.45 mm). The percutaneous double oblique transfrontal trajectory (drill-hole: 2.5 mm of diameter) passing through the foramina of Monro, avoids superficial and deep vessels visualised on the previous Stereoscopic Tele-Angiographic and Ventriculographic study. A systematic verification of the V.C.S. patency is made intraoperatively by injection of iodine contrast medium into the third ventricle.
(non tumoral patients: 12) (m follow-up: 4 years): two patients needed a ventricular shunt after 3 and 1 months respectively, the first one because of an associated communicant hydrocephalus, the second because of a post-operative meningeal infection. Long-term clinical and CT-Scan follow-up showed that complete resolution (7 cases) or partial (2 cases) improvement of symptoms and signs was not accompanied by normalization of ventricular size, even though the dilatation was significantly reduced in 8 cases and to a lesser extent in 2.
(tumoral patients: 11) (m follow-up: 3 years). Hydrocephalus was reduced in 6 cases and remained unchanged in 5. Two patients needed a ventricular shunt 2 years after the V.C.S.: 1 patient, because of a tumoral recurrence involving the region of the fenestration, the second patient because of adhesive arachnoiditis following reoperation for suspicion of recurrence, though this was found to be granulomatous inflammation. Two patients died as a result of their tumors at 2 and 6 years.
Stereotactic V.C.S. is the treatment of choice for triventricular obstructive hydrocephalus even when there is no retroclival dilatation of the floor of the third ventricle.
Neurochirurgie 02/1988; 34(6):361-73. · 0.34 Impact Factor
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ABSTRACT: Stereotactic approach of anterior midline lesions which involve the septum-fornix-callosal region is a logical alternative to open surgery as a first choice. It contributes to know anatomical relations--particularly vascular and ventricular--of the lesion; it provides an accurate neuro-pathological diagnosis, with grading and spatial configuration of the lesion, and therapy in some cases. In other cases, it is a guide for appropriate therapeutic choice.
Neurochirurgie 02/1988; 34(5):315-22. · 0.34 Impact Factor
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ABSTRACT: The neuroradiological stereotactic examinations provide indispensable information to localize many intracranial lesions: the data obtained by the CT-Scan are complementary of the stereotactic ones. The transfer of the routine CT-Scan transverse axial slices into the Talairach stereotactic system needs a precise definition of the inclination of the plan of the slices and a correct evaluation of the mean magnification factor. The inclination of the slices is appreciated using the bony, vascular and ventricular landmarks clearly identified on the CT-Scan and stereoscopic stereotactic images. We compared the spatial "reconstructed" CT-Scan data with the histopathological findings obtained by serial stereotactic biopsies in 48 tumor patients. The error varied from 1.5 to 4.6% (m: 2.7 +/- 1.2) on the sagittal plane; from 1.3 to 10% (m: 5.8 +/- 3.4) on the transversal plane; from 2.5 to 4.3% (m: 3.5 +/- 0.7) on the axial plane. The mean global error was 3.7% +/- 2.3. The CT-Scan directly performed under stereotactic conditions (acrylic frame) seems to be the more useful procedure. Nevertheless considering the good precision obtained with our methodology applied to the Talairach's system, we consider it suitable when: a) the gantry of the CT-Scan apparatus is too narrow for the acrylic frame; b) the exploitation of previous CT-Scan examinations is necessary; c) patient refuses the discomfort of the acrylic frame.
Revue d& apos Electroencephalographie et de Neurophysiologie Clinique 04/1987; 17(1):11-24.
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ABSTRACT: This study concerns 180 patients (132 M; 48 F) (age: 2 to 69 years; m: 33 years) who underwent stereotactic procedures according to the methodology of Talairach and Szikla. Such procedures (stereotactic and stereoscopic angiography in all cases, and ventriculography in 81%) should permit a correct spatial definition of intracranial lesions. The informations provided by the angiography (normal in 7%) and by the ventriculography (normal in 11%) are complementary to those yielded by the TDM and permit an easier and safe stereotactic approach to the lesions. In 43% of patients the lesions were deep-seated (basal ganglia: 24; sellar region: 19; thalamo-peduncular: 13; brain stem: 6, etc.). The histological examination showed: low-grade gliomas in 43%; glioblastomas in 21%; non tumoral lesions in 17%. A precise diagnosis couldn't be obtained in 3.8%. The data provided by the stereo-EEG (in 11 patients suffering also of severe drug-resistant partial epilepsy) did not permit, alone, an histological diagnosis, excepted when electrodes explored a solid tumor. Two patients had a neurological impairment, and two died (one for extracerebral reasons). The authors consider that the TDM data and the informations given by the stereotactic procedures are complementary for obtaining valuable informations on the spatial organization of intracranial lesions and choosing the best treatment.
Revue d& apos Electroencephalographie et de Neurophysiologie Clinique 04/1987; 17(1):3-10.
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ABSTRACT: Histologic features of 100 supra-tentorial astrocytomas, oligodendrogliomas and oligo-astrocytomas obtained from serial stereotactic biopsies were compared with the corresponding CT scans. Topographic comparisons provided by visualization of the biopsy trajectories on post-biopsy CT scans were available in 24 cases. Areas of contrast enhancement and low attenuation were compared with the histologic grade of malignancy, tumor delimitation and structural type. The latter was determined as follows: Type I-solid tumor tissue without significant peripheral isolated tumor cells; Type II-solid tumor tissue associated with peripheral isolated tumor cells; Type III-isolated tumor cells only. There was a strong correlation between areas of contrast enhancement and tumor microvascularity. In addition, contrast enhancement occurred only in the solid tumor tissue component of the neoplasm. This correlation accounted for the relationship observed between CT images and the structural type of glioma. Contrast enhancement was constant in structural type I gliomas, inconstant in structural type II, and absent in structural type III. No correlation was found between malignancy and contrast enhancement. Contrast enhancement occurred in all grades of malignancy but was a constant feature of grade 4 gliomas. The volume of the tumors could not be reliably determined from CT images alone. Areas of low attenuation on contrast CT scans could correspond to either peritumoral edema or to edematous parenchyma infiltrated by isolated tumor cells. Serial stereotactic biopsies combined with calculations based on the CT scan provided a more precise definition of the tumor volume and identification of structural type. Such classification may prove useful in prospective analysis of various modes of therapy.
Journal of Neuro-Oncology 02/1987; 4(4):317-28. · 3.21 Impact Factor
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Applied neurophysiology 02/1987; 50(1-6):200-2.
