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Biomedical subjects

L Carmant

Publications and source records attributed to L Carmant.

34 records · Page 2Linked to original sources
PubMed1996

Pharyngeal dysesthesia as an aura in temporal lobe epilepsy.

PURPOSE: Because oral, buccal, and sometimes oral-pharyngeal manifestations in epilepsy are linked to the central-temporal region, we studied 3 patients with childhood-onset partial seizures that consistently began with pharyngeal dysesthesias, described as either throat tingling or burning, to localize seizure onset. METHODS: Because of an intractable clinical course, each patient underwent invasive video-EEG monitoring, which localized the epileptogenic zone to the mesial temporal lobe. The 3 patients underwent temporal lobe resections. RESULTS: All 3 patients achieved remission of the pharyngeal auras and a 90-100% reduction in the frequency of their seizures. CONCLUSIONS: Pharyngeal dysesthesias can be the initial manifestation of complex partial seizures (CPS) of temporal lobe origin.

Adolescent↗
PubMed1996

Ictal and interictal technetium-99m-bicisate brain SPECT in children with refractory epilepsy.

UNLABELLED: Identification of epileptogenic foci in patients with refractory epilepsy remains a significant diagnostic challenge. Magnetic resonance imaging studies frequently fail to reveal an anatomic origin for the seizures, and scalp electroencephalography is often limited to identification of the involved hemisphere. Functional imaging modalities such as PET and SPECT are more promising tools for this application because they reflect the functional pathology associated with the seizure. These changes are more pronounced ictally, but until recently, no radiopharmaceutical was available that could be used routinely for ictal SPECT. The present study was therefore undertaken to determine whether 99mTc-bicisate could be used in ictal SPECT in pediatric patients with refractory epilepsy, to compare the patterns of ictal and interictal blood flow in these patients and to compare the localization information provided by ictal SPECT with that available from other techniques. METHODS: Technetium-99m-bicisate/SPECT was compared prospectively with scalp EEG for its ability to identify a possible seizure focus in pediatric patients with refractory epilepsy. Ictal and interictal SPECT studies were performed in 10 patients (3-19 yr old, mean age 10.9 +/- 4.3 yr; 7 female, 3 male) in whom MRI scans revealed no lesions that might be responsible for the seizures. RESULTS: Ictal SPECT was performed in all patients, and all ictal studies revealed focal perfusion abnormalities. By comparison, four of the interictal SPECT studies showed regional hypoperfusion that corresponded to the regions of hyperperfusion in the ictal studies, and three showed regional hyperperfusion corresponding to the hyperperfused regions in the ictal studies. Three interictal studies revealed no abnormal perfusion. Scalp EEG provided localization information in five patients. CONCLUSION: These initial results suggest that ictal SPECT with 99mTc-bicisate is a more promising tool for the identification of epileptogenic foci than interictal SPECT or scalp EEG in patients without focal abnormalities on MRI.

Brain↗
PubMed1995

Effect of kainic acid-induced status epilepticus on inositol-trisphosphate and seizure-induced brain damage in mature and immature animals.

We investigated the role of excitatory amino acids in the activation of the phosphoinositide pathway during kainic acid-induced seizures in mature and immature animals. Kainic acid caused more severe seizures in the immature animals, but no hippocampal damage or induction of phosphoinositide hydrolysis. In mature animals, seizures were mild but severe hippocampal damage was seen and was associated with a marked and sustained release of inositol-trisphosphate, suggesting a role of this pathway and intracellular calcium stores in seizure-induced brain damage.

Aging↗
PubMed1995

Anterior neck recording of intraoperative somatosensory-evoked potentials in children.

STUDY DESIGN: The authors have developed technique of using anterior neck derivations to record posterior tibial nerve N28 during operative somatosensory-evoked potential monitoring. OBJECTIVE: This prospective study of 10 patients compared the ease of application of electrodes and stability of waveforms with "traditional" posterior neck recordings. SUMMARY OF BACKGROUND DATA: Somatosensory-evoked potential monitoring has been used in children since the 1980s. A number of important factors, patient related and technical, are unique to this age group, which can cause difficulty with execution and interpretation. A major patient-related problem is unreliability of the cortical response in somatosensory-evoked potential monitoring because of the effect of inhalation anesthesia. This has been described as occurring more often in the pediatric group, perhaps because of the continuing maturation of the complex somatosensory system. Thus, the authors have relied heavily on the cervical potential to monitor spinal cord integrity. Recording the cervical response using the traditional "posterior" montage may be technically impossible if the electrodes lie within the operative field. METHODS: Posterior tibial somatosensory-evoked potentials were performed according to the guidelines of the American Electroencephalographic Society. Additional recordings were obtained from two anterior neck sites. Multiple reference electrodes were used to evaluate which montage rendered the most reliable waveform. RESULTS: Optimal montage for recording an anterior neck potential was cricoid cartilage-Cz'. There were no significant differences in the onset latency or peak amplitudes between the anterior and posterior cervical recordings. CONCLUSIONS: The anterior neck derivation was found to be an acceptable adjunct to posterior montages, being stable, of comparable latency, and of stable amplitude. Electrodes are easier to apply, less invasive than nasopharyngeal or esophageal electrodes. This technique allows one to examine patients who previously could not be monitored.

Adolescent↗
PubMed1995

EEG prior to hemispherectomy: correlation with outcome and pathology.

Hemispherectomy, for the treatment of seizures, is highly successful but has a significant morbidity rate. The procedure is usually restricted to patients with an intractable seizure disorder and hemiparesis. Because of the inherent risk of surgery, patient selection is a critical issue. This report describes the evaluation of background activity and ictal patterns on surface and invasive EEG in 12 children who underwent both anatomical (7) and functional (5) hemispherectomy in order to determine the role of electroencephalography in the selection of patients for hemispherectomy, and to correlate EEG findings with underlying pathology and outcome. A favorable outcome was predicted by an interictal EEG with two or more of the following: suppression over the abnormal hemisphere, absence of contralateral slowing, absence of generalized discharges and absence of bilateral independent spiking; or by unilateral onset of ictal discharges on invasive intracerebral EEG recording. Outcome did not correlate with the underlying pathology. Hemispherectomy can be successful in patients with a variety of predominantly unilateral pathologic entities.

Brain↗
PubMed1995

Psychogenic seizures: video telemetry observations in 27 patients.

Psychogenic seizures are unusual during the first decade of life. To compare the clinical features of psychogenic seizures in young children with those of teenagers, the long-term electroencephalographic and video monitoring studies of all patients younger than 18 years of age with recorded episodes diagnosed as psychogenic seizures were reviewed from a single hospital during the past 7 years. The 27 patients were divided into 2 age groups: group A, 6-9 years (n = 5), and group B, 10-17 years (n = 22). All patients had habitual episodes recorded during monitoring. Although the adolescents displayed clinical patterns similar to adult patients with psychogenic seizures, the children demonstrated a clinical pattern characterized mainly by prolonged staring and unresponsiveness. The most common behaviors in the adolescent group were tremor (45%), intermittent stiffening (41%), and out-of-phase movements of the extremities (36%). Fifteen percent of the patients had a history of seizures. This study suggests that young children with psychogenic seizures have clinical profiles different from that of teenagers.

Adolescent↗
PubMed1995

Pseudoseizure manifestations in two preschool age children.

We report two patients with epilepsy with pseudoseizures at age 6 years. Both presented with intractable staring spells. Pseudoseizures were provoked and aborted by suggestion, leading to the diagnosis. In both patients, evidence of a neuropsychological disturbance was later found and psychotherapy started. Monitoring of intractable staring episodes is recommended prior to escalating antiepileptic drug levels or resorting to polytherapy. In addition, differentiation from other non-epileptic phenomena is necessary to initiate proper therapy.

Anticonvulsants↗
PubMed1995

Corpus callosotomy in children.

All of the reports of corpus callosotomy have been limited by their necessarily retrospective nature, lack of control groups, and failure to quantify seizure frequency and duration before and after the surgery. In addition, interpretation of results has been confusing by inconsistent selection criteria of patients, varying surgical procedures employed, and short duration of follow-up. Nevertheless, this procedure remains a last hope for many children with severe intractable epilepsy and unquestionably assists in the management of many such children. There is a need to evaluate this surgical procedure fully to optimize its utilization further.

Adolescent↗
PubMed1994

Activity of S-adenosylmethionine decarboxylase, a key regulatory enzyme in polyamine biosynthesis, is increased in epileptogenic human cortex.

OBJECTIVE: We measured the activity of S-adenosylmethionine decarboxylase, a key regulatory enzyme of polyamine biosynthesis, in the temporal cortex of patients with epilepsy. DESIGN: Cortical surgical specimens were obtained following anterior temporal lobe resection for intractable epilepsy. Enzyme activity was compared in nonepileptogenic (n = 16) and epileptogenic (spontaneously discharging; n = 19) regions. RESULTS: Mean enzyme activity was increased by 44% in samples from epileptogenic cortex compared with samples from nonepileptic regions. The S-adenosylmethionine decarboxylase activity in regions of focal epileptogenic discharges was also increased in five patients compared with paired samples from the nonepileptogenic portion of the same gyrus (+55%). CONCLUSIONS: Elevated activity of S-adenosylmethionine decarboxylase in regions of active epileptogenic cortical discharges suggests that a disturbance of the polyamine system may be involved in the maintenance of hypersynchronous discharges, perhaps through a modulatory action at the excitatory N-methyl-D-aspartate-preferring glutamate receptor.

Adenosylmethionine Decarboxylase↗
PubMed1994

Technetium-99m HmPAO brain SPECT and outcome of hemispherectomy for intractable seizures.

With recent descriptions of the modified hemispherectomies and hemicorticectomy, there has been renewed interest in hemispherectomy for treatment of intractable seizures with hemiparesis. Because long-term outcome remains uncertain, patient selection remains difficult. 99mTc-HmPAO brain SPECT has been a helpful adjunct in the evaluation of epilepsy surgery candidates. We report SPECT scan findings in 7 patients who underwent hemispherectomy and compare these results with scalp EEG findings. Six patients had unilateral SPECT findings and all had a favorable outcome, regardless of surface EEG findings.

Adolescent↗
PubMed1994

Efficacy of felbamate in therapy for partial epilepsy in children.

Thirty children (2 to 17 years of age) with refractory partial seizures received open-label felbamate as an add-on medication to their background antiepileptic drugs. The dose was increased up to a maximum of 45 mg/kg. Compared with baseline seizure activity, there was a 53% decrease in seizure frequency during felbamate therapy; 50% of the patients had more than a 50% decrease in seizure frequency. Patients older than 10 years of age were more likely to have a favorable response. Age correlated positively with felbamate concentrations and negatively with apparent felbamate clearance. Transient weight loss occurred in 57% of the patients; the weight loss was maximal after 12 weeks of initiation of felbamate, and subsided after the twentieth week of treatment. Anorexia and insomnia were reported in 20% and 16% of the patients, respectively. Adverse effects were generally tolerable; felbamate therapy was discontinued because of side effects in only one patient, because of a rash. We conclude that felbamate can be a useful and well-tolerated medication in the treatment of refractory partial epilepsy in children. However, increased apparent clearance of this drug in younger children should be considered in treatment of this age group.

Adolescent↗
PubMed1994

Commissurotomies in children.

Although corpus callosotomy has been used since 1940 to treat severe, medically intractable seizure disorders, controversy remains as to when, or even if, the surgery should be performed. Unlike other types of surgical therapy of epilepsy where the epileptic focus is identified and removed, corpus callosotomy is used to interrupt the propagation of epileptic discharges. The procedure is primarily used in patients with secondarily generalized seizures in whom focal resections are not possible. Long-term follow-up studies of post-callosotomy patients are few and flawed by lack of accurate seizure counts and quality-of-life measures. Although it remains difficult to predict those patients who will benefit from the surgery, it appears that patients with "drop" attacks benefit the most from the procedure.

Animals↗
PubMed1993

Anterior interosseous neuropathy in the postpartum period.

The anterior interosseous neuropathy is a rare focal neuropathy with typical clinical and electromyographic features. Most commonly reported etiologies include lesion of the median nerve following fracture of the radius and ulna, acute or repeated trauma or prolonged pressure on the forearm. In some cases, no predisposing factors can be elicited. Over a one-year period, two young women in their late twenties were evaluated for weakness of the flexor pollicis longus, flexor digitorum profundus of the 2nd and 3rd fingers, and pronator quadratus muscles that occurred within a month following parturition. Nerve conduction studies and concentric needle electrode examination of the upper extremities performed respectively 3 and 10 months after the onset of symptoms confirmed a severe anterior interosseous neuropathy and excluded more common conditions such as carpal tunnel syndrome, cervical radiculopathy or brachial plexopathy. The prognosis was unfavorable in both cases.

Adult↗
PubMed1991

Clinical correlates and electroencephalographic characteristics of two additional patterns related to 14 and 6 per second positive spikes.

Two additional patterns, minuscule 28 per second positive spikes and huge N-shape potentials, have been identified exclusively in the EEGs of patients with 14 and 6 per second positive spikes. They occur predominantly during drowsiness and light sleep, usually in children, seldom in young adults. Their presence adds little to the clinical relevance of positive spikes. Familiarization with the N-shape potentials--the commoner of the two patterns--is important, lest they are mistaken for interictal abnormalities of significance such as atypical spike-wave complexes.

Adult↗
PubMedDate not supplied

Developmental bilateral perisylvian dysplasia.

Acquired bilateral anterior opercular lesions result in the characteristic Foix-Chavany-Marie syndrome that features expressive dysphasia and pseudobulbar palsy. A developmental congenital variant that represents a restricted disorder of neuronal migration was recently reported. We report a newborn with autopsy-confirmed developmental bilateral perisylvian dysplasia. Polymicrogyria was found on detailed histologic study confirming the only prior pathologic study of this syndrome. The clinical heterogeneity of this disorder with neonatal and childhood modes of presentation is reviewed. Speculation regarding pathogenesis focuses on either a genetically determined selective aberration of neuronal migration or an in utero postmigration vascular accident.

Abnormalities, Multiple↗