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Biomedical subjects

L J Willmore

Publications and source records attributed to L J Willmore.

At least 37 records · Page 2Linked to original sources
PubMed1999

A comparison of magnetoencephalography, MRI, and V-EEG in patients evaluated for epilepsy surgery.

PURPOSE: To determine the efficacy and relative contribution of several diagnostic methods [ictal and interictal scalp and intracranial EEG, magnetic resonance imaging (MRI), and magnetoencephalography (MEG)] in identifying the epileptogenic zone for resection. METHODS: This was a prospective study using a masked comparison-to-criterion standard. Fifty-eight consecutive patients with refractory partial epilepsy from two university comprehensive epilepsy programs were studied. Patients who were evaluated for and underwent epilepsy surgery were recruited. The main outcome measure was the efficacy of each diagnostic method to identify the resected epileptogenic zone, when referenced to surgical outcome. RESULTS: MEG (52%) was second only to ictal intracranial V-EEG in predicting the epileptogenic zone for the entire group of patients who had an excellent surgical outcome (seizure free or rare seizure). In a subanalysis, for patients who had temporal lobe surgery, this same relation was seen (MEG, 57%, ictal intracranial V-EEG, 62%). With extratemporal resection, ictal (81%) and interictal (75%) intracranial EEG were superior to MEG (44%) in predicting the surgery site in those patients with an excellent outcome. Finally, for all patients who had a good surgical outcome, MEG (52%) was better than ictal (33%) or interictal (45%) scalp VEEG in predicting the site of surgery. CONCLUSIONS: These results indicate that MEG is a very promising diagnostic method and raise the possibility that it may obviate the need for invasive EEG in some cases or reduce the length of scalp EEG evaluation in others.

Adolescent↗
PubMed1999

Safety and tolerability of gabapentin as adjunctive therapy in a large, multicenter study.

PURPOSE: To evaluate the tolerability and safety of gabapentin (GBP) as add-on therapy for seizure control. METHODS: Conducted in an outpatient setting and reflecting usual practice, this study compared tolerability of GBP dosages < or = 1,800 versus >1,800 mg/day, when these doses were required to achieve the most effective seizure control. Two analyses of adverse events are presented: tolerability and safety. In the tolerability analysis, each patient served as his or her own control to compare the occurrence of adverse events at GBP < or =1,800 versus >1,800 mg/day. The safety analysis required patients to receive at least one dose of GBP and have a follow-up contact. RESULTS: A total of 2,216 patients enrolled in this open-label, 16-week study and were evaluable for safety. Of these, 74.0% completed the 16-week study, and 281 met the tolerability criteria. Within these 281 patients, two mutually exclusive groups were compared (a) those reporting adverse events at only < or =1,800 mg/day (low dose); and (b) those reporting adverse events at only >1,800 mg/day (high dose). Three adverse events (asthenia, headache, and dizziness) were observed in a statistically significantly larger number of patients at only the low dose than in the group reporting these same adverse events at only the high dose, suggesting that patients who tolerated GBP at < or = 1,800 mg/day did not experience a significant increase in adverse events with dosages >1,800 mg/day. Overall, 10.6% of the 2,216 patients in the safety population prematurely withdrew because of adverse events, and 3.5% discontinued because of lack of efficacy. Safety and tolerability of GBP was rated as excellent or good for 78.5% of all patients. CONCLUSIONS: Gabapentin doses >1,800 mg/day were as well tolerated as doses < or =1,800 mg/day and were not associated with more adverse events.

Acetates↗
PubMed1999

Magnetoencephalographic mapping of the language-specific cortex.

OBJECT: In this paper the authors introduce a novel use of magnetoencephalography (MEG) for noninvasive mapping of language-specific cortex in individual patients and in healthy volunteers. METHODS: The authors describe a series of six experiments in which normative MEG data were collected and the reliability, validity, and topographical accuracy of the data were assessed in patients who had also undergone the Wada procedure or language mapping through intraoperative cortical stimulation. CONCLUSIONS: Findings include: 1) receptive language-specific areas can be reliably activated by simple language tasks and this activation can be readily recorded in short MEG sessions; 2) MEG-derived maps of each individual are reliable because they remain stable over time and are independent of whether auditory or visual stimuli are used to activate the brain; and 3) these maps are also valid because they concur with results of the Wada procedure in assessing hemispheric dominance for language and with the results of cortical stimulation in identifying the precise topography of receptive language regions within the dominant hemisphere. Although the MEG mapping technique should be further refined, it has been shown to be efficacious by correctly identifying the language-dominant hemisphere and specific language-related regions within this hemisphere. Further development of the technique may render it a valuable adjunct for routine presurgical planning in many patients who harbor tumors or have epilepsy.

Acoustic Stimulation↗
PubMed1998

Quality of life perception in patients with intractable epilepsy or pseudoseizures.

OBJECTIVES: To contrast and compare self-reported quality of life in patients with intractable epilepsy and pseudoseizures and to examine the relationship between self-reports and objective measures of cognitive functioning in both of these groups. DESIGN: Case series using profile analysis and analysis of covariance. SETTING: University epilepsy surgery program. PARTICIPANTS: Forty-three patients with intractable complex partial seizures of unilateral temporal lobe origin and 25 patients with pseudoseizures. MEASURES: Quality of Life in Epilepsy Inventory-89; neuropsychological tests assessing verbal memory, nonverbal memory, naming, and attention; and the Depression Scale (2) of the MMPI-2 (Minnesota Multiphasic Personality Inventory). RESULTS: Patients with pseudoseizures described themselves as more limited in the physical health domain than patients with complex partial seizures. Self-perceptions of cognitive functioning were similar between groups, despite the superior performance of patients with pseudoseizures on objective measures. Self-perception of cognitive dysfunction was related to mood disorder in the pseudoseizure group only, and there were no relationships between subjective and objective measurements of cognitive status within this group independent of mood disorder. For the complex partial seizures group, relationships between subjective and objective measures of cognitive function were dependent on the side of seizure onset. CONCLUSIONS: Results are consistent with hypotheses that suggest that patients with pseudoseizures focus on physical rather than psychological explanations for stress, and that this focus is related, at least in a subgroup of patients, to mood disorder. Results also provide support for the validity of the Quality of Life in Epilepsy Inventory-89 in populations with intractable seizure disorder, although there is evidence for a possible floor effect on some of the subscales.

Adolescent↗
PubMed1998

Amygdalar injection of FeCl3 causes spontaneous recurrent seizures.

Rats were microinjected with a 100 mM aqueous solution of ferric chloride into the left amygdaloid body. Behavior was observed and depth electroencephalograms were recorded over the 30 days following injection. All of the FeCl3-injected rats developed isolated epileptiform discharges from the ipsilateral amygdala soon after injection. Within 5 days epileptiform discharges were arising as well from the contralateral amygdala and behavioral seizures were observed. These spontaneous seizures occurred in a pattern associated with stage 4 kindling, with rearing and bilateral forelimb clonus. Seizures persisted during the 30 days of the experiment. Recording from chronically implanted depth electrodes showed development of spike discharges, with recurrent seizures arising from amygdalar regions with propagation into both hippocampi. Aqueous iron is known to initiate lipid peroxidation by free radical mechanisms. Our observations suggest that epileptogenesis followed by chronic, spontaneous seizures could be initiated by deposition of iron-containing compounds into limbic structures of the rat.

Amygdala↗
PubMed1998

Antiepileptic drug therapy in the elderly.

Populations are aging, and the incidence of epilepsy is increased in the elderly population. These demographic facts emphasize the importance of understanding the use of antiepileptic drugs in older patients. Healthy elderly have expected alterations in renal blood flow, hepatic volume and function, and alterations in fat-to-lean ratio of body composition. All of these changes make elderly patients vulnerable to dose-related adverse effects of the standard antiepileptic drugs. Newly developed compounds without enzyme induction effects and renal routes of excretion may be more favorable for use in elderly patients.

Aged↗
PubMed1998

Epilepsy emergencies: the first seizure and status epilepticus.

Patients experiencing a first seizure need a careful history and examination to confirm that the presenting seizure is truly the initial event and to identify other possible risk factors for recurrence. The decision of whether to start therapy should be made by the clinician and a fully informed patient. Status epilepticus presents in several forms, with generalized convulsive status epilepticus (GCSE) being the most dramatic. Management of GCSE requires life support and monitoring measures as well as timely administration of antiepileptic drugs (AEDs) to terminate the seizure and reduce the risks for morbidity and mortality. Benzodiazepines, phenytoin, and phenobarbital can all be used to treat GCSE. Clinicians need to be familiar with the dosage and administration, adverse events, time to onset, and duration of action of these drugs. Should seizures continue or recur despite AED administration, induction of coma with pentobarbital may be considered. This must be done with continuous EEG and other physiologic monitoring in an intensive care unit. Additional assessment of the patient who has experienced GCSE focuses on identification of the underlying cause.

Anticonvulsants↗
PubMed1997

A case-control evaluation of treatment efficacy: the example of magnesium sulfate prophylaxis against eclampsia in patients with preeclampsia.

Randomized trials are the optimal approach for evaluations of treatment efficacy but may not always be feasible. We study the adequacy of the case-control design in evaluating efficacy in a situation where the investigated therapy, namely the administration of magnesium sulfate for the prevention of eclampsia in patients with preeclampsia, has a suspected strong protective effect. A total of 66 cases of eclampsia were ascertained from among deliveries occurring between 1977 and 1992 at two hospitals in Houston, Texas. Randomly selected preeclamptic controls were matched to cases based on hospital and month of delivery. Magnesium sulfate administration prior to seizure occurrence had a strong protective effect against eclampsia in patients with preeclampsia (OR, 0.02; 95% CI, 0.01-0.05). This protective effect remained when controls were stratified by the degree of severity of preeclampsia (mild-to-moderate OR, 0.03, 95% CI, 0.01-0.09 and severe OR, 0.005; 95% CI, 0.0005-0.04) and when cases were stratified by the timing of the first seizure (antepartum and intrapartum seizures OR, 0.01; 95% CI, 0.003-0.05 and postpartum seizures OR, 0.03; 95% CI, 0.005-0.15). The effect also remained after adjustment for other important predictors in a multivariate logistic regression model (OR, 0.11; 95% CI, 0.03-0.38). The results of this study are in support of a recent randomized trial on the efficacy of magnesium sulfate as a prophylactic agent against eclampsia. Although there are serious potential sources of bias in this study, the magnitude of the protective effect of magnesium sulfate minimizes the likelihood that this effect can be explained by bias. Observational studies could be appropriate complements or alternatives to randomized trials in situations where a strong treatment effect is expected.

Adult↗
PubMed1997

Identification of side of seizure onset in temporal lobe epilepsy using memory tests in the context of reading deficits.

Sixty patients with temporal lobe epilepsy were classified into reading deficient (RD; n = 21) and non-reading deficient (non-RD; n = 39) groups. Selective deficits in verbal or nonverbal memory, consistent with side of seizure onset, were evident in the non-RD patients. Both verbal and nonverbal memory performance were reduced equivalently in individuals with RD, regardless of side of seizure onset. As a result, memory tests that were accurate in identifying side of seizure onset in the non-RD group were not as accurate in the RD group. When individual cases were classified using a clinically applicable decision rule, significantly more RD patients were either unclassifiable or incorrectly classified than were non-RD patients. Findings suggest that preoperative memory data obtained from individuals with epilepsy and evidence of RD may not be as valid an indicator of side of seizure onset as are those obtained from patients without RD.

Achievement↗
PubMed1997

Asymmetries in the effect of side of seizure onset on recognition memory following intracarotid amobarbital injection.

PURPOSE: To assess interhemispheric differences in recognition memory for objects during the intracarotid amobarbital sodium procedure (IAP). METHODS: The recognition memory for real objects of patients with either right (RTLE; n = 28) or left (LTLE; n = 22) temporal lobe epilepsy was assessed at baseline, and after left and right intracarotid amobarbital sodium injection. RESULTS: There were no differences between groups on baseline performance. Performance following injection ipsilateral to the side of seizure focus was relatively lower for the LTLE as compared with the RTLE group, but this difference did not reach statistical significance. However, performance following injection contralateral to the side of seizure focus was significantly lower for the RTLE as compared with the LTLE group. Within-group differences in performance after ipsilateral as compared with contralateral injection were significant for the RTLE but not the LTLE group. The difference in interhemispheric asymmetry in IAP memory performance between RTLE and LTLE groups was reflected in decreased ability to classify LTLE patients as compared with RTLE patients about side of seizure onset, using a clinically applicable decision rule. CONCLUSIONS: Recognition memory during the IAP for real objects, simultaneously named and presented visually during encoding, is mediated effectively by both the left and right hemisphere when there is no seizure focus present. However, memory appears to be more vulnerable to the presence of a seizure focus in the right as compared with the left hemisphere.

Adolescent↗
PubMed1997

Corpus callosotomy for medically intractable seizures.

To identify factors influencing outcome and morbidity in patients selected for corpus callosotomy, we retrospectively reviewed 23 patients with intractable generalized seizures who underwent corpus callosotomy between 1991 and 1994. Three patients had a complete corpus callosotomy, while 20 had an anterior callosotomy. Three of those patients subsequently had completion of the anterior callosotomy. Overall, 41% of patients were nearly or completely free of the seizure types targeted for surgical treatment, while another 45% had seizures less than half as frequently. Four patients developed simple partial motor seizures after callosotomy. A transient disconnection syndrome was observed in 57% of patients. The best predictor of good outcome was a normal preoperative MRI. Mentally retarded patients had poorer outcomes. Outcome was not predicted by extent of callosal section or lateralization on neurological examination, EEG, MRI, and SPECT. Completion of anterior callosotomy resulted in significant reductions in seizure frequency. Though most patients do not become seizure-free after corpus callosotomy, worthwhile palliation of an otherwise intractable illness can be achieved. An analysis of prognostic factors should lead to better selection of patients for surgery.

Adolescent↗
PubMed1997

Adult experience with lamotrigine.

Lamotrigine is a phenyltriazine derivative with anticonvulsant properties that initially was tested in adults with partial seizures. Pharmacokinetics in adults includes a volume of distribution of 1.0 to 1.3 L/kg. Plasma protein binding is 55% and none of the metabolites are active as anticonvulsants. The placebo-controlled studies evaluated the responder rate as the percent of patients with 50% or greater seizure reduction when compared to baseline assessment. The responder rate for 300 mg per day was 20% and 36% for 500 mg per day dosages. Adverse events were infrequent but the occurrence of rash appeared to correlate with rapid ascension dosing and comedication with valproic acid. Slow titration is required when initiating treatment with lamotrigine. Accumulating experience in adults suggests that lamotrigine has a broad spectrum of effect; data from further controlled trials should suggest other clinically important forms of epilepsy that respond to lamotrigine.

Adult↗
PubMed1997

Effects of duration of epilepsy on the uncoupling of metabolism and blood flow in complex partial seizures.

We derived interhemispheric asymmetry indices (AIs) in interictal glucose uptake and blood flow in the temporal lobes of patients with intractable complex partial seizures from 18F and 15O positron emission tomograms. All patients subsequently underwent either left (n = 16) and right (n = 18) temporal lobectomy. We determined the effects on AIs of clinical seizure variables, including duration of seizure disorder, age at seizure onset, frequency of complex partial seizures, history of secondary generalization, history of febrile seizures, and magnetic resonance imaging evidence for mesial temporal sclerosis. Duration of seizure disorder produced the only significant effects. Degree of interhemispheric asymmetry in both glucose uptake and blood flow increased with duration of seizure disorder. However, the rate of increase in asymmetry was significantly greater for glucose uptake than for blood flow. These results indicate that uncoupling of metabolism and blood flow is a progressive process that results from the differential response of glucose metabolism and blood flow to chronic seizure activity. The results also suggest that duration of seizure disorder may be an important variable to consider in the interpretation of PET studies for evaluation of seizure surgery candidates.

Adult↗
PubMed1996

Effect of TJ-960 (a Japanese herbal medicine) on free radical changes within an iron-induced focal epileptogenic region in rat brain measured by in vivo L-band electron spin resonance.

In vivo L-band electron spin resonance (ESR) system was used to measure the decay of nitroxide radicals in the living rat cerebrum containing a cortical area with an iron-induced epileptogenic region. Carbamoyl-PROXYL (3-carbamoyl-2,2,5,5-tetramethyl-1-pyrrolinyloxy) was injected intraperitoneally. The decay of nitroxide radicals in the iron-injected regions at the subacute stage of epileptogenesis was prolonged. The Japanese herbal medicine, sho-saiko-to-go-keishi-ka- shakuyakuto (TJ-960), a compound known to have free radical scavenging activity, inhibited the delay of nitroxide radical decay in the rat cerebrum with an iron-induced epileptic focus following injection of carbamoyl-PROXYL. TJ-960 did not affect the decay of nitroxide radicals in the control rats' brain. These data show that TJ-960 has the scavenging activity for free radicals generated within an iron-induced epileptogenic regions of rat brain.

Animals↗
PubMed1996

Lateralization of memory for music: evidence from the intracarotid sodium amobarbital procedure.

The present study was conducted to determine whether material-specific memory for unfamiliar tonal patterns could be demonstrated for the right temporal lobe during the intracarotid sodium amytal procedure (IAP). Thirty-one patients with intractable complex partial seizures associated with either left temporal lobe epilepsy (LTLE) or right temporal lobe epilepsy (RTLE) underwent assessment of memory for tonal patterns during a baseline phase and right and left cerebral hemisphere anaesthesia during the IAP. Patients were presented unfamiliar tonal patterns which were later selected from a set of distracter patterns. Findings indicated that there was no difference between the LTLE and RTLE patients during injection of the right cerebral hemisphere suggesting no specific involvement of left mesial temporal structures. However, a significant effect was noted during left injection with the LTLE group performing significantly better than the RTLE group. This latter finding supports a specific role of right mesial temporal lobe structures in mediating memory for music.

Adult↗
PubMed1996

Reduction in nitric oxide synthase activity with development of an epileptogenic focus induced by ferric chloride in the rat brain.

Intracortical injection of iron ion has been shown to induce recurrent seizures and epileptic discharges in electrocorticograms. The importance of the effects of NO on seizure control systems and their regulation is suggested. In this paper, we examined the changes in nitric oxide synthase (NOS) activity in the epileptogenic focus induced by intracortical injection of iron ion at 5 min, 10 min, 1 h, 3 h and 3 days. Iron ion significantly decreased NOS activity in the cortex at the injection site 5 min, 3 h and 3 days after injection. These results suggest that the formation of an epileptic focus induced by iron ion is accompanied by decreased NOS activity.

Animals↗
PubMed1996

Effects of temporal lobe epilepsy on spatial and figural aspects of memory for a complex geometric figure.

The preoperative delayed memory performance on the Rey-Osterrieth Complex Figure (Lezak, 1983) of 54 patients with complex partial seizures of temporal lobe origin was analyzed using 3 different indices. One index (composite) was derived using a common scoring method that included both spatial and figural aspects of memory in its score. The other two indices were derived emphasizing either spatial or figural aspects of memory for the elements of the figure separately. All 3 indices distinguished between individuals with right-sided (RTLE) and left-sided (LTLE) seizure onset. However, spatial memory was significantly lower than figural memory in individuals with RTLE as compared to those with LTLE. Both the spatial and figural memory indices were significantly lower in the presence of magnetic resonance imaging (MRI) evidence for hippocampal sclerosis in individuals with RTLE. Results suggest that while both the spatial and figural aspects of nonverbal memory are sensitive to right hippocampal dysfunction, figural memory may be less vulnerable to the effects of RTLE.

Adult↗