Biomedical subjects

K Ostrowsky

Publications and source records attributed to K Ostrowsky.

7 recordsLinked to original sources

PubMed2006

Hemispheric lateralization of cognitive functions in children with centrotemporal spikes.

We assessed the impact of unilateral epileptic foci in benign idiopathic partial epilepsy of childhood with rolandic discharges (BECT) on performance and hemispheric specialization in lateralized cognitive functions. Six children with BECT with a left-sided focus (BECT-L), 6 children with BECT with a right-sided focus (BECT-R), and 12 control children were tested in verbal, visual-spatial, and visual-attention tasks, with visual hemifield presentation. Children with BECT-R were impaired in the visual-spatial task relative to those with BECT-L, and the typical left-hemisphere (LH) advantage was not reported in the verbal task in children with BECT-L. Additionally, the classic global superiority effect was lacking in children with BECT-R, which may be due to impaired performance of the right hemisphere specialized in global (vs local)-level processing. These data argue for the deleterious effect of epileptic discharges per se on cognitive functions in the developing brain, and the decisive role of epileptic focus lateralization in specific cognitive impairments and hemispheric specialization.

Child↗

PubMed2002

Temporopolar changes in temporal lobe epilepsy: a quantitative MRI-based study.

OBJECTIVES: To quantify the morphologic changes of temporopolar structures to better understand the pathophysiology of anterior temporal white matter increased T2 signal observed in temporal lobe epilepsy (TLE). METHODS: MRI was performed in 30 patients with TLE and in 30 normal control subjects and independently assessed by visual analysis and quantitative measurements. Specifically, the temporal pole (TP) volume, as well as its gray and white matter components, was measured using three-dimensional T1 MR images and a semiautomatic protocol. The authors tested whether the presence of an increased T2-weighted signal in the anterior temporal white matter was associated with significant TP atrophy. The associations between the TP volume and MRI signs of hippocampal sclerosis, age at onset, seizure frequency, duration of illness, and a history of febrile convulsions were also studied. RESULTS: Both right and left TLE populations demonstrated a reduction of the temporopolar white and gray matter volumes ipsilateral to seizure onset (p < 0.02 in right TLE; p < 0.0001 in left TLE). Twenty-two patients (72%) exhibited significantly abnormal TP volume measurements, which correctly lateralized the epileptogenic zone in all cases. The presence of an increased T2-weighted signal in the anterior temporal white matter (ISWM), but not that of hippocampal sclerosis, was associated with a greater TP volume asymmetry index (p < 0.05). CONCLUSIONS: The temporal pole is frequently atrophic ipsilateral to seizure onset in refractory TLE. The association between TP atrophy and ISWM suggests that both abnormalities might derive from a common pathologic process.

Adolescent↗

PubMed2001

Neurophysiological monitoring for epilepsy surgery: the Talairach SEEG method. StereoElectroEncephaloGraphy. Indications, results, complications and therapeutic applications in a series of 100 consecutive cases.

OBJECT OF THE STUDY: In some candidates for epilepsy surgery in whom the decision to operate is difficult to make, invasive presurgical investigations, namely depth electrode recordings, may be needed. The SEEG (StereoElectroEncephaloGraphy) method consists of stereotactic orthogonal implantation of depth electrodes (5 to 15, 11 on average). The object of this study is to clarify the indications for SEEG, to expose its complications, and to display its usefulness in terms of surgical strategy and results. PATIENTS AND METHODS: 100 patients, suffering from drug-resistant epilepsy and selected as candidates for surgical resection, underwent SEEG between 1996 and 2000. A total of 1,118 electrodes were implanted. For each single case, the sites of implantation of the electrodes were chosen in order to determine either the side of the onset of seizures, or the uni- or multilobar feature of them, or a possible operculo-insular propagation from a temporal onset, and also, using direct electrode stimulation, the proximity of speech or motor area. RESULTS: Complications occurred in 5 patients (2 superficial infections, 2 breakages of electrodes, and 1 intracerebral hematoma responsible for death). SEEG was helpful in most (84%) of the 100 patients to confirm or annul surgical indication, and to adjust the extent of the resection. In some cases (14%), SEEG allowed to propose a resection that might have been disputable based solely on noninvasive investigation data. For frontal epilepsy, SEEG was crucial in all cases to delineate the extent of resection. CONCLUSION: SEEG proved to be a relatively safe and a very useful method in 'difficult' candidates for epilepsy surgery. In addition, in some cases the implanted electrodes can be used to perform therapeutic RF thermocoagulation of epileptic foci or networks.

Adult↗

PubMed2000

The first case of new variant Creutzfeldt-Jakob disease in France: clinical data and neuropathological findings.

Clinical data and autopsy findings in a case of new variant Creutzfeldt-Jakob disease (vCJD) are reported. This case, the first histologically confirmed case described outside the United Kingdom, very much resembles the cases described by Will et al. [(1996) Lancet 347:921-925] and Zeidler et al. [(1997) Lancet 350:903-908, 908-910]. Neuropathological studies failed to reveal any conspicuous clues that could be relevant for understanding the pathophysiology of the disease. For epidemiological surveillance, neuropathologists should scrutinize suspected cases keeping in mind the possibility of vCJD.

Adult↗

PubMed2000

Functional mapping of the insular cortex: clinical implication in temporal lobe epilepsy.

PURPOSE: We report the results of 75 intracortical electrical stimulations of the insular cortex performed in 14 patients during stereo-electroencephalography (SEEG) investigation of drug-resistant partial epilepsy. The insular cortex was investigated on electroclinical arguments suggesting the possibility of a perisylvian spread or a rapid multilobar diffusion of the discharges during video EEG. METHODS: In these 14 patients, 27 stereotactically implanted transopercular electrodes reached the insular cortex (11 the right insula, 16 the left insula). Square pulses of current were applied between the two deepest adjacent contacts of each transopercular electrode using low (1 Hz) or high-frequency (50 Hz) stimulation. Only symptoms evoked in the absence of afterdischarges were analyzed. RESULTS: Clinical responses were evoked in 10 of the 14 patients (in 20 of the 27 insular sites) and showed a clear topographic specificity inside the insular cortex. Viscerosensitive and visceromotor responses, similar to those evoked by temporomesial stimulation, were evoked by anterior insular stimulation and somesthetic sensation, similar to those evoked by opercular cortex stimulation, by posterior insular stimulation. CONCLUSIONS: The topographic organization of the induced responses within the insular cortex suggest that two different cortical networks, a visceral network extending to the temporomesial structures and a somesthetic network reaching the opercular cortex, are disturbed with stimulation of the anterior or the posterior insula, respectively. Thus ictal symptoms associated with the spread of the epileptic discharges to the insular cortex might be difficult to distinguish from those usually reported during temporomesial or opercular discharges.

Adult↗

PubMed2000

The role of the insular cortex in temporal lobe epilepsy.

The role of the insular cortex in the genesis of temporal lobe epileptic (TLE) seizures has been investigated in 21 patients with drug-refractory TLE using chronic depth stereotactic recordings of the insular cortex activity and video recordings of ictal symptoms during 81 spontaneous electroclinical seizures. All of the recorded seizures were found to invade the insula, most often after a relay in the ipsilateral hippocampus (19/21 patients). However, 2 patients had seizures that originated in the insular cortex itself. Ictal symptoms associated with the insular discharges were similar to those usually attributed to mesial temporal lobe seizures, so that scalp video-electroencephalographic monitoring does not permit making any difference between ictal symptoms of temporo-mesial and insular discharges. A favorable outcome was obtained after a temporal cortectomy sparing the insular cortex in 15 of 17 operated patients. Seizures propagating to the insular cortex were found to be fully controlled by surgery, whereas those originating in the insular cortex persisted after temporal cortectomy. The fact that seizures originating in the insular cortex are not influenced by temporal lobectomy is likely to explain some of the failures of this surgical procedure in TLE.

Adolescent↗

PubMed1997

Severe pathological crying after left anterior choroidal artery infarct. Reversibility with paroxetine treatment.

BACKGROUND: There is increasing evidence that serotonergic neurotransmission may be damaged in poststroke pathological crying. A correlation between the clinical severity of pathological crying and the size of stroke-induced serotonergic pathway lesions is commonly accepted. We present a case of severe pathological crying after a limited left anterior choroidal artery territory infarction. CASE DESCRIPTION: A right-handed 55-year-old man who was a heavy smoker was admitted to the hospital after a right hemiplegia of sudden onset. Clinical examination revealed a right global hemiplegia including the face and a right hemihypoesthesia. Cerebral CT scan and MRI showed an infarct in the retrolenticular part of the posterior limb of the left internal capsule extending upward into the posterior paraventricular corona radiata region. Transesophageal echocardiography revealed an atrial septal aneurysm of 15-mm excursion without associated patent foramen ovale. From the first day of admission, the patient exhibited very frequent and intense fits of pathological crying. Their persistence led to initiation of treatment with the selective serotonin reuptake inhibitor paroxetine on day 30. Complete and immediate resolution of pathological crying occurred 24 hours after onset of therapy. Follow-up examination at day 90 confirmed the absence of relapse of pathological crying. CONCLUSIONS: We conclude that poststroke pathological crying in our patient may have been due to unilateral disruption of the capsular ascending projections of the serotonergic brain stem raphe nuclei. A small left-sided capsular lesion may have led to severe pathological crying. This disabling condition may be reversible with selective serotonin reuptake inhibitor therapy.

Cerebral Arteries↗