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Biomedical subjects

S Kochen

Publications and source records attributed to S Kochen.

10 recordsLinked to original sources
PubMed1999

Seizures of temporal lobe epilepsy: identification of subtypes by coherence analysis using stereo-electro-encephalography.

OBJECTIVES: Two subtypes of temporal lobe epilepsy (TLE) according to the structures initially involved during seizures are currently recognized: medial TLE (MTLE) and lateral (or neocortical) TLE (LTLE). A few reports have suggested that the classification of TLE subtypes might be larger according to variations in the interactions between medial structures and the neocortex. In this study, we analyzed these interactions using coherence analysis of stereo-encephalographic (SEEG) signals during spontaneous seizures. METHODS: Twenty-seven patients with drug-resistant TLE, diagnosed from ictal SEEG recordings obtained during pre-surgical evaluation, were studied. Orthogonally implanted depth electrodes with multiple leads according to Talairach's method were used to sample medial and neocortical structures. Coherence analysis of ictal discharges was performed between two SEEG bipolar signals from adjacent leads located either in medial structures (amygdala and hippocampus) or in neocortical regions of the temporal lobe. A new algorithm, which was designed to reduce the bias inherent in coherence estimation, was used to compute the coherence. RESULTS: We were able to classify TLE seizures (TLES) into 4 distinct categories: (1) 'medial' TLES, characterized by medial onset with later involvement of the neocortex in the form of a 'phasic' discharge. High ictal coherence values were observed between medial structures; (2) 'medial-lateral' TLES which started in medial structures with a fast low-voltage discharge (FLVD) which rapidly affects the neocortex (< or = 3 s). High coherence values were observed between medial and lateral structures; (3) 'lateral-medial' TLES, which are different from medial-lateral TLES in that the FLVD starts in the lateral neocortex and involves the amygdala and/or hippocampus almost immediately after; (4) 'lateral' TLES: characterized by a neocortical onset, a delayed involvement of medial structures (when present), and high coherence values between neocortical structures. CONCLUSIONS: These results demonstrate the existence of numerous interactions between medial limbic structures and the neocortex during TLE seizures. Such findings could have implications for surgical strategies and the prognosis of epilepsy surgery, particularly when limited resection is indicated.

Adolescent↗
PubMed1997

A double-blind controlled clinical trial of oxcarbazepine versus phenytoin in adults with previously untreated epilepsy.

In the last 5 years oxcarbazepine (OXC) has been registered in many countries for use as first-line and add-on treatment for partial seizures with or without secondarily generalized seizures (PS) and generalized tonic-clonic seizures without partial onset (GTCS). Its use as monotherapy in adults with newly diagnosed epilepsy was investigated in this double-blind, randomized, parallel-group comparison with phenytoin (PHT). A total of 287 adult patients, with either PS or GTCS, were randomized. After retrospective baseline assessment, patients were randomized to OXC or PHT in a 1:1 ratio. The double-blind treatment phase was divided into two periods: a flexible titration period of 8 weeks, followed by 48 weeks of maintenance treatment. In the efficacy analyses, no statistically significant differences were found between the treatment groups. Seventy patients (59.3%) in the OXC group and 69 (58.0%) in the PHT group were seizure-free during the maintenance period. A total of 56 of the patients in the OXC group discontinued treatment prematurely (five because of tolerability reasons) compared to 61 in the PHT group (16 for tolerability reasons). The number of premature discontinuations due to adverse experiences showed a statistically significant difference in favour of OXC. There was no statistically significant difference between the groups with respect to the total number of premature discontinuations. This trial provides further support for the efficacy and safety of OXC as first-line treatment in adults with PS and GTCS. In addition, the results show that OXC has significant advantages over PHT in terms of tolerability.

Adolescent↗
PubMed1991

[Status of cerebral cortical excitability in juvenile myoclonus epilepsy].

The myoclonic epilepsies constitute an heterogeneous group of entities characterized by primary generalized seizures, whose common critical manifestation is myoclonus. Within this group there is a subset of patients, identified by Janz in 1955 as "Impulsive petit mal" and later named "Janz juvenile myoclonic epilepsy" (JJME) by Delgado-Escueta. Its most important clinical features are myoclonus, expressed as mild to moderate jerks of neck, shoulders and arms. These jerks are more frequent when awakening; they can be caused by sleep deprivation and emotional stress, without consciousness impairment. Usually neurologic examinations and mental status are normal. Response to specific treatment is good, with disappearance of seizures in most patients. We attempted to assess the pathophysiologic mechanisms involved in this kind of epilepsy. The existence of differences or similarities with the findings described in the other forms of myoclonic epilepsy was specially considered. In 14 patients with JJME, we performed C reflex studies with negative results. The mean amplitude of somato sensitive evoked potential (SSEP) was around 5 microV (normal values: 2.5 microV) in its different components. Shibasaki et al. suggested that the amplitude increase could be related to a cortical excitability increase at the somatosensory and motor level, which is the probable site of the epileptogenic area. Within the patient group with myoclonic progressive epilepsy (EMP) and continuous partial epilepsy (CPE), SSPEs amplitude ranged from 8 microV to 40 microV. In our patient group, the increase in SSPEs amplitude was smaller than the one observed in the other two entities. However, it was significantly higher than the mean value for the normal population.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[The role of the temporal cortex in long-latency auditory evoked potentials].

There is no definite agreement on the localization of the PEAL generators. However, some authors have claimed that the temporal auditive cortex plays a role. Based on these assumptions we searched for the eventual changes developing in PEALs in patients who applied for temporal epilepsy, where the temporal cortex activity is somehow impaired. Altogether 19 patients were explored. The results were compared with 17 matched healthy controls and 4 patients with focal epilepsy who, at the time of the study, received the same treatment as the temporal epileptic subjects. In every case PEATs and PEALs were studied. One thousand Hz less than time monoaural stimulation, 50 db and 50 ms duration was employed for evoking PEALs. Recording was done with surface electrodes located at Cz, F3 and F4 coupled with an electrode placed at the contralateral mastoid; 500 ms sweep were averaged. Band-pass was set up between 1 and 125 Hz and latencies and amplitudes were studied for both types of evoked responses, PEATs and PEALs. No statistical difference was found between patients and both control groups when PEATs mean parameters were analyzed. For further PEALs results, patients were divided into 3 groups; a) Those with right temporal epilepsy (n = 6) (R); b) Those with left temporal epilepsy (n = 7) (L); c) Those in whom the affected side could not be determined (n = 7) (N). In R it was observed, when stimulating the left ear, a delay in the arrival of P1 (F4 mea 87 +/- 10.4 ms) and N1 (F4 mean 122.33 +/- 6.1 ms; Cz mean 170.75 +/- 18.8 ms) waves.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Self-help epilepsy groups: an evaluation of effect on depression and schizophrenia.

The general prevalence of depression and schizophrenia was determined in a random outpatient population (n = 67) of refractory epileptic patients by Minnesota Multiphasic Personality inventory (MMPI) and Beck Depression Inventory (BDI). Of those patients 25% showed scores of moderate or severe depression. Self-help group intervention modifies significantly (p < 0.001) general mean depression rates, especially dystimia. Male and female differences emerged in our study for previous prevalence and pattern of recovery.

Adult↗