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Biomedical subjects

E Wyllie

Publications and source records attributed to E Wyllie.

At least 19 recordsLinked to original sources
PubMed1992

Subdural electrodes in the presurgical evaluation for surgery of epilepsy.

This article gives first an overview of the advantages and disadvantages of electrodes of progressively greater invasiveness used in the evaluation of patients who are candidates for surgery of epilepsy. The following sections discuss the design of subdural electrodes, their clinical indications, and the relative advantages and disadvantages of subdural electrodes when compared with other invasive techniques.

Brain Mapping↗
PubMed1991

Basal temporal language area.

Language interference was elicited by electrical stimulation of the dominant basal temporal region in 8 out of 22 cases and in none of 7 cases with subdural electrodes implanted over the nondominant temporal lobe. Language interference was elicited by stimulation of electrodes placed over the fusiform gyrus 3-7 cm from the tip of the temporal lobe. Electrical stimulation of the basal temporal language area produced a global receptive and expressive aphasia with speech arrest at high stimulus intensities. Other higher cortical function, for example copying complex designs or memory of nonverbal information was intact, in spite of the total inability to process verbal information. At lower stimulus intensities partial aphasias with a predominant receptive component occurred. Surgical resection of the basal temporal language area produces no lasting language deficit.

Adolescent↗
PubMed1991

Outcome of psychogenic seizures in children and adolescents compared with adults.

We compared outcome of psychogenic seizures documented by video-EEG in 18 nonepileptic children and adolescents (ages 8 to 18; median, 14.5 years old) and 20 adults (ages 25 to 56; median, 34.0 years old). Outcome was significantly better for the younger patients at 1 year, 2 years, and 3 years after diagnosis. At these follow-up times, the percentages of children and adolescents free of psychogenic attacks were 73%, 75%, and 81%; at the same follow-up times, the percentages of adults free of psychogenic attacks were only 25%, 25%, and 40%. Factors leading to better outcome for younger patients may have been different psychological mechanisms at different ages of onset and greater effectiveness with earlier intervention.

Adolescent↗
PubMed1991

Routine laboratory monitoring for serious adverse effects of antiepileptic medications: the controversy.

Rare, serious adverse effects of antiepileptic drugs (AEDs) include hepatotoxicity and bone marrow suppression. Current management includes routine laboratory monitoring during therapy with AEDs, a practice, however, that is controversial, as some clinicians believe that such monitoring is ineffective and that clinical monitoring is sufficient. Unfortunately, routine laboratory monitoring cannot predict acute idiosyncratic drug reactions, which will remain unpreventable until specific markers are available to identify susceptible patients. Nevertheless, routine laboratory monitoring may be helpful for early detection of chronic adverse reactions such as subclinical hepatotoxicity, leukopenia, or thrombocytopenia, which are usually mild and clinically insignificant but are occasionally more severe. Routine liver function tests may be especially important during valproate therapy because pathologic data suggest that some cases of valproate (VPA)-induced hepatic failure are the result of chronic liver damage and cirrhosis. Although levels of hepatic enzymes may be elevated during an early reversible stage of VPA toxicity, by the time clinical symptoms develop, hepatic failure may be irreversible.

Anemia, Aplastic↗
PubMed1990

Intraoperative determination of the extent of corpus callosotomy for epilepsy: two simple techniques.

There is increasing interest in staged corpus callosotomy for intractable generalized epilepsy. At the first procedure, a portion (usually the anterior two-thirds) of the corpus callosum is sectioned. If seizures persist, completion of callosotomy or alternative treatment approaches can be considered. It is obviously important to ascertain that the desired extent of callosotomy was in fact accomplished at the time of initial operation. Our experience and the published literature indicate that the surgeon's impression at operation can be erroneous. We describe a technique of determining extent of corpus callosotomy during the procedure. The magnetic resonance imaging (MRI) scan in the midsagittal plane is used to select the desired extent of callosotomy. That point on the corpus callosum is characterized using simple planar geometry in relation to three anatomic landmarks in that same plane: the glabella, the inion, and the bregma (midline intersection of the coronal suture). The same point along the corpus callosum can then be located on a lateral skull x-ray using these same three anatomic landmarks. At surgery, an intraoperative lateral skull x-ray is obtained with a marking clip, thereby verifying the actual extent of callosotomy. We have verified the reliability of this scheme in 5 callosotomy procedures and have used this technique for intraoperative localization of midline and parasagittal targets in another 7 cases (3 tumors, 2 aneurysms, and 2 placements of interhemispheric subdural grids). In addition, we reviewed corpus callosum topography on 25 randomly selected MRI scans.(ABSTRACT TRUNCATED AT 250 WORDS)

Corpus Callosum↗
PubMed1990

Versive eye movements elicited by cortical stimulation of the human brain.

We studied the eye movements (EM) elicited by electrical stimulation of the frontal lobe in 19 awake patients evaluated with subdural electrodes for epilepsy surgery. All patients had only contralateral conjugated EM. They were saccadic in 16 patients (84%). Head version, always following the eye deviation, occurred in 11 patients (58%). We also determined the eye field somatotopic distribution analyzing the responses obtained from the electrodes adjacent to the eye fields. All patients had motor cortex contiguous to the eye fields. In 17 patients (90%) the eye fields were located in front or at the level of the motor representation. There was no silent cortex between the motor strip and the eye fields.

Adolescent↗
PubMed1990

Supplementary motor seizures mimicking pseudoseizures: some clinical differences.

Supplementary motor seizures (SMS) are among the group of frontal lobe seizures that may often be misdiagnosed as pseudoseizures (PS). We designed this study to determine the value of clinical phenomena in distinguishing between the two. In a series of patients with SMS, we identified those with symptoms mimicking PS and compared the clinical phenomena with those of clinically similar PS. We found that SMS are short in duration, stereotypic, tend to occur in sleep, and often present with a tonic contraction of the upper extremities in abduction. This sign was specific for SMS, particularly when occurring at the onset. Conversely, PS are long in duration, nonstereotypic, and occur in the awake state. We conclude that clinical phenomena may be useful in distinguishing PS from SMS, although the final diagnosis must be documented by neurophysiologic means.

Diagnosis, Differential↗
PubMed1990

Psychogenic seizures in children and adolescents: outcome after diagnosis by ictal video and electroencephalographic recording.

Psychogenic seizures in 21 nonepileptic children and adolescents, aged 8 to 18 (mean 14.5) years, were recorded by means of video recording and electroencephalography. The episodes included thrashing movements, limb jerking, or staring, with unresponsiveness. Ictal and interictal electroencephalograms showed no abnormalities after antiepileptic medication was discontinued. Fifteen patients had psychogenic seizures spontaneously during recording, and six had seizures in response to suggestion and intravenous saline injection. After the video-electroencephalographic evaluation, patients and families were told that the episodes were emotional in origin. All patients but 1 agreed to remain without antiepileptic medication, and 16 patients (76%) agreed to begin psychiatric treatment. At 6 to 66 (mean 30) months' follow-up, 14 of 18 (78%) were free of episodes. These data indicate that the majority of young patients with psychogenic seizures have a good outcome. A firm diagnosis is critical so that the episodes can be classified and emphasized as medically not worrisome, permitting a shift away from antiepileptic medication and toward psychiatric treatment.

Adolescent↗
PubMed1989

Speech manifestations in lateralization of temporal lobe seizures.

To evaluate the role of speech manifestations in lateralization of temporal lobe seizures, we reviewed videotapes of 100 complex partial seizures in 35 patients who underwent temporal lobectomy for intractable epilepsy. All patients had prolonged electroencephalographic video monitoring with scalp and subdural electrodes, and their speech dominance was determined with an intracarotid amobarbital test. Speech manifestations were observed in 79 seizures and were classified as vocalization, normal speech, or abnormal speech. Vocalization of sounds without speech quality occurred ictally in 48.5% of patients. Normal speech (identifiable speech) occurred ictally in 34.2% of patients. Abnormal speech (speech arrest, dysphasia, dysarthria, and nonidentifiable speech) occurred in 51.4% of patients, either ictally or postictally. Of all the above speech manifestations, only postictal dysphasia and ictal identifiable speech had significant lateralizing value: 92% of patients with postictal dysphasia had their seizures originating from the dominant temporal lobe (p less than 0.001), and 83% of those with ictal identifiable speech had their seizures from the nondominant side (p = 0.013). This study shows that speech manifestations are common in complex partial seizures of temporal lobe origin and can provide an excellent clinical tool for lateralization of seizure onset.

Adolescent↗
PubMed1989

Partial seizures in children: clinical features, medical treatment, and surgical considerations.

Partial seizures are not uncommon in children. They are classified into two types: simple partial, without impairment of consciousness, and complex partial, with impaired consciousness. For both types, the hallmark is onset of the seizure from a portion of one cerebral hemisphere, as indicated by focal spikes or sharp waves on EEG. The symptoms of simple partial seizures may include focal motor or somatosensory phenomena, special sensory phenomena, autonomic symptoms, or psychic symptoms, and these symptoms may occur alone or they may progress into a complex partial seizure with alteration of consciousness. The complex partial phase may include simply an arrest of ongoing activity with altered awareness and a blank empty stare, or there may also be automatisms, including movements which are gestural, alimentary, mimicking, verbal, or ambulatory. Automatisms are predominantly seen in complex partial seizures arising from temporal areas, but they also may be seen in seizures with extratemporal onset. If the epileptic discharge spreads throughout both cerebral hemispheres, the child will have a secondarily generalized tonic-clonic convulsion. EEG should be performed in any child who is suspected of having partial seizures. If there are focal spikes or sharp waves, then there is strong supportive evidence for a diagnosis of partial seizures in the proper clinical setting. It should be remembered, however, that a normal routine EEG cannot be used to "rule out" a diagnosis of epilepsy in patients who have episodes that sound like simple or complex partial seizures. An underlying etiology may be found in a significant percentage of children with partial seizures. Most of these etiologies are static, and the seizures are the result of a previous cerebral insult, but some patients may have slow-growing gliomas or other mass lesions. MRI or CT is indicated in essentially any child with partial seizures. Medical treatment is based on the idea of using single drugs to maximally tolerated doses, if needed, before beginning with two-drug regimens. If the child continues to have seizures despite aggressive trials of medication, then it is important to consider epilepsy surgery, either temporal lobectomy or other cortical resection. When children are identified as candidates for epilepsy surgery, they should be referred to specialized centers for further testing.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

Surgery of localization related epilepsies in children.

Surgery of epilepsy is as successful in children as in adults. With very few modifications, similar evaluation methods and surgical techniques can be used. However, in the selection of the surgical candidates special considerations are necessary in children to establish the stability of the epileptogenic focus (to exclude the possibility of a change with maturation) and to define the clinical syndrome which very frequently is still poorly defined in that age group. The expectation that surgery of epilepsy at an early age will facilitate rehabilitation efforts has still not been confirmed by systematic scientific studies. Surgery of epilepsy has not been attempted in a sufficient number of children under 5 yrs of age to establish its value in that age group.

Adolescent↗
PubMed1989

Dystonic posturing in complex partial seizures of temporal lobe onset: a new lateralizing sign.

We observed unilateral dystonic posturing of an arm or leg in 41 complex partial seizures (CPS) from 18 patients. In all cases this was contralateral to the ictal discharge. Unilateral automatisms occurred in 39 of 41 seizures on the side opposite the dystonic limb. Version occurred in 11 of the 41 CPS to the same side as the dystonic posturing and always followed the posturing. Subdural recordings of seven seizures showed ictal onset from the mesial basal temporal lobe. At the onset of dystonic posturing, maximum ictal activity was in the basal temporal lobe with minimal involvement of the cerebral convexity. Unilateral dystonic posturing occurs frequently in CPS of temporal lobe onset and is a lateralizing sign with a high degree of specificity. It probably reflects spread of the ictal discharge to basal ganglia structures.

Dystonia↗