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Biomedical subjects

S Noachtar

Publications and source records attributed to S Noachtar.

63 records · Page 4Linked to original sources
PubMed1995

Amnesia of the epileptic aura.

In a prospective study lasting 6 months, we recorded on video 108 seizures with aura of 23 patients in an attempt to evaluate the mechanisms involved in the encoding of memories. In 88 of those seizures, we also recorded an EEG. The percentage of auras remembered decreased significantly with increasing severity of the seizures. The recollection of auras was also significantly dependent on the ictal EEG changes during the aura. Ninety-seven percent of the auras without EEG changes, 94% of the auras with unilateral EEG changes, and 73% of the auras with bilateral EEG changes during the aura were remembered. The spread of the ictal EEG pattern during the aura also showed a significant correlation with the severity of the ensuing seizure. Three patients with bitemporal epilepsy made up a considerable proportion of those who never remembered their aura before secondary generalized tonic-clonic seizures (2 of 3) and of those who had a transient postictal amnesia of their aura (2 of 3). The only patient who failed to remember a previously documented isolated aura also suffered from bitemporal epilepsy. During the second part of the study, we questioned whether information provided during the history could be helpful in defining the type of epilepsy syndrome or localizing the EEG seizure pattern of the 80 patients who had been admitted for presurgical epilepsy diagnosis. Localized (regional, unilateral, and independent left and right lateral) EEG seizure patterns occurred in 82% of the 51 patients with auras in their history as compared with 24% of the 17 patients who did not have auras in their history (p < 0.01).

Amnesia↗
PubMed1995

[Function-controlled neurosurgery. Neurophysiologic and neuropsychological monitoring during surgery of the nervous system].

Neuromonitoring of neural structures has become increasingly common during surgery near cortical areas representing sensorimotor and language function (epilepsia, tumors), in the brain stem and the spinal cord (tumors), near cranial nerves (cerebellopontine angle tumors, trigeminal neuralgia, hemifacial spasm), and in the cauda equina (tumors, tethered spinal cord). The technical spectrum to monitor these operations includes electrical cortical stimulation to evoke sensorimotor phenomena and language disturbances, electroneurography and -myography of the cauda equina, motor cranial nerves and nuclei, and somatosensory, motor and acoustic evoked potentials. The goals of intraoperative neuromonitoring are: (1) minimizing the risk of suffering neurological and neuropsychological injury as a result of surgery; (2) extending the surgical spectrum to lesions that have previously been considered inoperable or hazardous to operate upon; (3) intraoperative electrophysiological documentation that the goal of surgery has been achieved; (4) intraoperative basic research.

Brain↗
PubMed1995

[Focal epilepsy with seizures from the supplementary sensorimotor area. False interpretation as a spinal disease].

The symptomatology of focal epileptic seizures depends on the brain region involved in the epileptic discharge. We report a case in which ictal symptomatology was misinterpreted to be a spinal disease, leading to MRT, CT and X-ray of the lumbar region, which revealed normal results. The ictal symptomatology consisted of a tingling sensation in the lower back, followed by a feeling of tonic tension of the proximal left leg. Ictal EEG video recordings consistently revealed an EEG seizure pattern over the right parasagittal frontocentral region. We concluded that the patient is suffering from a focal epilepsy. The seizures most probably arise from the supplementary sensorimotor region. Carbamazepine treatment rendered the patient free of seizures.

Adult↗
PubMed1995

[Analysis of postoperative seizure recurrence after 65 temporal lobe partial resections].

Sixty-five patients (aged between 3 years 5 months and 60 years) suffering from medically resistant temporal lobe epilepsy (TLE) were operated on over a period of 33 months in Bethel Epilepsy Center. Thirty-three patients had mesial TLE and 32 patients had TLE of different etiology. The postoperative follow-up lasted 2 years in 30 patients and was on average 13.2 months or at least 8 months in the 35 patients who did not have their last examination 2 years after surgery. Many of the patients (70.9%) were seizure-free; 92.3% achieved a rewarding improvement in seizure frequency and quality of life. Reduction of medication was the cause for relapse in 10 patients, in 6 patients incomplete resection, and in 5 patients the prognosis was not good even before surgery. The cause remained unclear in 4 patients. Freedom from seizures was achieved again by renewed medication or by repeated operation in 10 of 25 patients.

Adolescent↗
PubMed1987

Response of polygraphic sleep to phenytoin treatment for epilepsy. A longitudinal study of immediate, short- and long-term effects.

Report on a prospective longitudinal study of alterations in polygraphic sleep by phenytoin monotherapy for epilepsy. A first dose of 100mg already caused abbreviation of sleep latency and an increase of slow-wave sleep in the first NREM-REM cycle. In the course of adjustments to steady state, an increase of Stage 3 + 4 sleep in the later REM cycles developed, such that the percentage of slow-wave sleep for the whole night was also augmented, whereas the percentage of light sleep decreased. Sleep structure was affected particularly in the third NREM-REM cycle. With continuing therapy, however, these effects were reversed. The only permanent effect was an abbreviated sleep latency. There were only minimal differences in the response of generalized and of localization-related epilepsies. Serum drug levels had only a very limited influence, seizure control and length of follow-up had no influence on the results. As a collateral finding, a delayed further decrease of epileptic discharges during sleep was observed under long-term conditions in patients who were seizure-free and had been so since adjustment to the steady state.

Adult↗
PubMedDate not supplied

Pattern visual evoked potentials recorded from human occipital cortex with chronic subdural electrodes.

Pattern evoked potentials to full- and partial-field stimulation were recorded simultaneously from scalp electrodes and from subdural electrodes located over the temporal and occipital cortex, including electrodes placed over or close to the lower lip of the calcarine fissure. High-amplitude pattern evoked potentials were recorded exclusively from electrodes localized in the vicinity of the calcarine fissure and showed a positive-negative deflection in phase with surface recordings, followed by a second negative peak phase reversed with respect to the major surface positive peak ("P100"). The findings suggest that the initial component is an expression of the afferent volley and that the second component (equivalent of the surface "P100") is most probably generated as a dipole strictly localized to the visual cortex in close proximity of the calcarine fissure (area 17 and/or area 18).

Adult↗