Unexplained spikes in lamotrigine serum concentration: nonlinear elimination?

OBJECTIVES

The objective of this study was to evaluate possible nonlinear lamotrigine (LTG) pharmacokinetics at elevated concentration. LTG is reported to have linear kinetics, so that elimination rate is linearly proportional to blood concentration and a change in dose is accompanied by a proportionate change in serum concentration. We encountered patients in whom LTG serum concentration increased dramatically in response to minor or no change in LTG dose. We studied this phenomenon in patients with LTG toxicity in one clinic.

MATERIALS AND METHODS

Using electronic medical records from 1997 to 2014, we identified patients who developed clinical LTG toxicity with LTG serum concentrations >20 mg/l, after tolerating lamotrigine at lower serum concentrations. We reviewed LTG dose change and other changes that preceded the episode of toxicity.

RESULTS

Twenty-two patients had at least one episode of LTG toxicity with levels higher than 20 mg/l (of 922 patients with available levels). The peak serum concentration varied from 21.1 to 40.3 mg/l (mean 28.7). The increase in level was explained in three patients (post-delivery in one, addition of valproate in two). In the 18 others, the increase was not explained or it was disproportionate to an increase in LTG dose.

CONCLUSIONS

Spikes in LTG levels and associated clinical toxicity may occur unexpectedly, suggesting that elimination kinetics may be nonlinear in some individuals at serum concentrations in the upper range. Measurement and close monitoring of LTG levels is warranted for new symptoms that could be consistent with lamotrigine toxicity, particularly when the baseline serum concentration has been >10 mg/l.

Genetic variants in the IMPA2 gene do not confer increased risk of febrile seizures in Caucasian patients

Pathogenesis of febrile seizures (FS), causing the most common of types of seizures in children, remains unknown. Genetic factors appear to play a pivotal role and FS can be inherited as a monogenic or genetically complex disorder. Several risks factors have been proposed but many of the previously reported genetic associations were not replicated. Non-coding polymorphisms in the myo-inositol monophosphatase 2 gene (IMPA2) have been suggested as a susceptibility factor for FS in Japanese patients. It is unknown whether genetic variants in the same gene constitute a risk factor for FS in other ethnic groups because the frequency of FS is significantly higher in Japanese children than in Caucasian patients. We investigated the role of the IMPA2 gene in a cohort of 96 unrelated Caucasian subjects with a history of FS. We did not identify any significant differences in genotypes of cases and matched controls; no mutations or non-synonymous polymorphisms were detected in these individuals. Our data suggest that the genetic variants in the IMPA2 gene are not associated with a risk of FS in Caucasian patients and patients from various genetic groups are likely to have different genetic causes of FS.

Familial mesial temporal lobe epilepsy maps to chromosome 4q13.2-q21.3

PURPOSE

To report results of linkage analysis in a large family with autosomal dominant (AD) familial mesial temporal lobe epilepsy (FMTLE).

BACKGROUND

Although FMTLE is a heterogeneous syndrome, one important subgroup is characterized by a relatively benign course, absence of antecedent febrile seizures, and absence of hippocampal sclerosis. These patients have predominantly simple partial seizures (SPS) and infrequent complex partial seizures (CPS), and intense and frequent déjà vu phenomenon may be the only manifestation of this epilepsy syndrome. No linkage has been described in this form of FMTLE.

METHODS

We identified a four-generation kindred with several affected members meeting criteria for FMTLE and enrolled 21 individuals who gave informed consent. Every individual was personally interviewed and examined; EEG and MRI studies were performed on three affected subjects. DNA was extracted from every enrolled individual. We performed a genome-wide search using an 8 cM panel and fine mapping was performed in the regions with a multipoint lod score >1. We sequenced the highest priority candidate genes.

RESULTS

Inheritance was consistent with AD mode with reduced penetrance. Eleven individuals were classified as affected with FMTLE and we also identified two living asymptomatic individuals who had affected offspring. Seizure semiologies included predominantly SPS with déjà vu feeling, infrequent CPS, and rare secondarily generalized tonic-clonic seizures. No structural abnormalities, including hippocampal sclerosis, were detected on MRI performed on three individuals. Genetic analysis detected a group of markers with lod score >3 on chromosome 4q13.2-q21.3 spanning a 7 cM region. No ion channel genes are predicted to be localized within this locus. We sequenced all coding exons of sodium bicarbonate cotransporter (SLC4A) gene, which plays an important role in tissue excitability, and cyclin I (CCNI), because of its role in the cell migration and possibility of subtle cortical abnormalities. No disease-causing mutations were identified in these genes.

CONCLUSION

We report identification of a genetic locus for familial mesial temporal lobe epilepsy. The identification of a disease-causing gene will contribute to our understanding of the pathogenesis of temporal lobe epilepsies.

Familial genetic predisposition, epilepsy localization and antecedent febrile seizures

PURPOSE

The magnitude of genetic influence in epilepsy may vary in relation to epilepsy classification and localization and factors such as antecedent febrile seizures. We assessed this genetic influence in a large epilepsy population.

METHODS

Patients with established epilepsy diagnosis evaluated in the Vanderbilt Epilepsy Program were systematically questioned about family history of epilepsy and febrile seizures, prior febrile seizures and other risk factors for epilepsy.

RESULTS

A total of 1994 patients with epilepsy and reliable family history were identified. Patients with prior febrile seizures (FS) were more likely to have a family history of febrile seizures than those without prior FS (p<0.000001) and also had a greater proportion of relatives with febrile seizures. The groups did not differ with respect to family history of epilepsy. Patients with generalized epilepsy were more likely to have first and second degree relatives with epilepsy than those with partial epilepsy (40.2% versus 31.2%, p=0.001), and also had a greater proportion of affected first degree relatives (p<0.000001). The proportion of first degree relatives affected with epilepsy was higher than local published prevalence, for both groups.

CONCLUSION

Susceptibility for febrile seizures with subsequent epilepsy may be genetically distinct from susceptibility for afebrile seizures alone. Although family history of epilepsy was more likely with generalized epilepsy, a familial tendency was considerable in partial epilepsy.

Efficacy and tolerability of the new antiepileptic drugs I: treatment of new onset epilepsy: report of the Therapeutics and Technology Assessment Subcommittee and Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society

OBJECTIVE

To assess the evidence demonstrating efficacy, tolerability, and safety of seven new antiepileptic drugs (AEDs) (gabapentin, lamotrigine, topiramate, tiagabine, oxcarbazepine, levetiracetam, and zonisamide-reviewed in the order in which these agents received approval by the US Food and Drug Administration) in the treatment of children and adults with newly diagnosed partial and generalized epilepsies.

METHODS

A 23-member committee, including general neurologists, pediatric neurologists, epileptologists, and doctors in pharmacy, evaluated the available evidence based on a structured literature review including MEDLINE, Current Contents, and Cochrane library for relevant articles from 1987 until September 2002, with selected manual searches up until 2003.

RESULTS

There is evidence either from comparative or dose-controlled trials that gabapentin, lamotrigine, topiramate, and oxcarbazepine have efficacy as monotherapy in newly diagnosed adolescents and adults with either partial or mixed seizure disorders. There is also evidence that lamotrigine is effective for newly diagnosed absence seizures in children. Evidence for effectiveness of the new AEDs in newly diagnosed patients with other generalized epilepsy syndromes is lacking.

CONCLUSIONS

The results of this evidence-based assessment provide guidelines for the prescription of AEDs for patients with newly diagnosed epilepsy and identify those seizure types and syndromes where more evidence is necessary.

Efficacy and tolerability of the new antiepileptic drugs II: Treatment of refractory epilepsy: Report of the Therapeutics and Technology Assessment Subcommittee and Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society

OBJECTIVE

To assess the evidence demonstrating efficacy, tolerability, and safety of seven new antiepileptic drugs (AEDs) (gabapentin, lamotrigine, topiramate, tiagabine, oxcarbazepine, levetiracetam, and zonisamide) in the treatment of children and adults with refractory partial and generalized epilepsies.

METHODS

A 23-member committee including general neurologists, pediatric neurologists, epileptologists, and doctors in pharmacy evaluated the available evidence based on a structured literature review including MEDLINE, Current Contents, and Cochrane library for relevant articles from 1987 until March 2003.

RESULTS

All of the new AEDs were found to be appropriate for adjunctive treatment of refractory partial seizures in adults. Gabapentin can be effective for the treatment of mixed seizure disorders, and gabapentin, lamotrigine, oxcarbazepine, and topiramate for the treatment of refractory partial seizures in children. Limited evidence suggests that lamotrigine and topiramate are also effective for adjunctive treatment of idiopathic generalized epilepsy in adults and children, as well as treatment of the Lennox Gastaut syndrome.

CONCLUSIONS

The choice of AED depends upon seizure and/or syndrome type, patient age, concomitant medications, AED tolerability, safety, and efficacy. The results of this evidence-based assessment provide guidelines for the prescription of AEDs for patients with refractory epilepsy and identify those seizure types and syndromes where more evidence is necessary.

Intraventricular monitoring for temporal lobe epilepsy: report on technique and initial results in eight patients

OBJECTIVE AND IMPORTANCE

Resective surgery is an effective treatment for refractory temporal lobe epilepsy. In difficult cases, invasive monitoring may be needed to precisely lateralise and localise seizure foci of mesial temporal origin. The authors present a modified technique for image guided, endoscopic placement of an intraventricular electrode array (IVE) that abuts the amygdalo-hippocampal complex.

METHODS

Eight patients with suspected mesial temporal lobe epilepsy had placement of an IVE in conjunction with other invasive electrodes. Seven of these patients also had subdural grid or strip electrodes and four had foramen ovale electrodes. Frameless image guidance was used to place a custom 10-contact depth electrode through a rigid neuroendoscope within the atrium of the lateral ventricle. Once proper orientation towards the temporal horn was confirmed, the IVE array was advanced into the temporal horn to the temporal tip. The endoscope was removed and electrode placement was confirmed through an intraoperative lateral skull radiograph and on visual inspection at the time of resection in two cases.

RESULTS

The IVE was crucial for localisation in one patient and helped localisation in four others. Surgery was offered to seven patients. The only serious complication of IVE placement was a thalamic contusion presumably from an errant electrode tip. One electrode was inadvertently placed into the frontal horn. There were no deaths and no permanent morbidity associated with the procedure.

CONCLUSION

Endoscopically placed temporal horn, intraventricular electrodes provide an alternative to transcortical depth electrode placement. The technique hopefully can avoid complications associated with multiple depth electrode placements, especially when bilateral amygdalo-hippocampal electrical recordings are desired, although there may be a steep learning curve.

An open-label study of levetiracetam at individualised doses between 1000 and 3000 mg day(-1) in adult patients with refractory epilepsy

BACKGROUND

The novel antiepileptic drug (AED) levetiracetam (LEV, Keppra) is indicated as adjunctive therapy for partial epilepsy. The primary aim of this study was to measure the safety and tolerability of LEV individualised dosing in a heterogeneous refractory epilepsy population.

METHODS

LEV was evaluated in a 10- to 16-week open-label, multicentre study in adult patients with epilepsy refractory to previous treatment with at least two AEDs. Individualised LEV doses up to 3000 mg x day(-1) were determined in an initial up-titration phase, and optimal doses were administered as adjunctive treatment during an 8- to 10-week evaluation period. Concomitant AEDs and their doses could not be changed during the study. Safety and tolerability were monitored by expression of adverse events as well as by retention rate. The effect of LEV on concomitant AED concentration was also studied. Efficacy was assessed using global clinical evaluation (GCE) scores, seizure frequency, and >or=50% responder rate.

RESULTS

LEV therapy was initiated in 219 patients; 183 had localisation-related epilepsy and 37 had generalised epilepsy. In one patient, epileptic syndrome was defined as both localisation-related and generalised. About 81.7% (179/219) continued and completed treatment throughout the study, and 79% (172/219) chose to continue LEV in a follow-up study. The most common adverse events were asthenia, dizziness, and somnolence. Most adverse events occurred during up-titration. LEV treatment did not alter the concentration of concomitant AEDs. LEV improved GCE scores in 79.5% (152/191) of patients. LEV reduced the median total seizure frequency of all patients from a median of 2.25 seizures per week at baseline (n=219) to 1.10 seizures per week during the evaluation period (n=191 patients with at least one seizure count during evaluation). The >or=50% responder rate was 48.2% for all seizure types, 49.4% for partial-onset, and 51.4% for generalised-onset seizures. Throughout the evaluation period (i.e. from the start of the evaluation period until completion or early discontinuation), 26/191 (13.6%) had a 100% reduction in total seizure frequency, while in a follow-up study, 10.5% (18/172) were seizure-free for at least 6 months and 6.4% (11/172) were seizure-free for at least 1 year.

CONCLUSION

LEV was well tolerated, as evidenced by limited adverse event reporting and the high retention rate, and appeared effective in both generalised and partial epilepsy.

Partial and generalized epilepsy with febrile seizures plus and a novel SCN1A mutation

BACKGROUND

Generalized epilepsy with febrile seizures plus (GEFS+) is an autosomal dominant syndrome characterized by febrile seizures (FS) and a variety of afebrile generalized seizure types. GEFS+ has previously been linked to mutations in two genes encoding the voltage-gated sodium channel alpha-subunit (SCN1A) and beta1-subunit (SCN1B). We studied a large family with FS and partial as well as generalized seizure types.

METHODS

All but two living affected family members were interviewed and examined. Information on deceased affected family members was sought. EEG for 11 affected family members and one unaffected family member were obtained. Genetic linkage analysis and mutation screening of SCN1A were performed on blood samples from 16 affected individuals and their first-degree relatives.

RESULTS

There were 27 affected family members; 18 were alive at the time of the study. All affected family members had FS; seven had FS only, and 19 also had afebrile seizures. Eleven individuals continued to have FS beyond 6 years of age. FS were complex in 12 family members, usually with prolonged duration. The index patient had right temporal lobe epilepsy and hippocampal sclerosis. Four other patients had strong historical evidence of temporal lobe epilepsy, and three others had nonlocalizing evidence of partial epilepsy. Pedigree analysis indicated autosomal dominant transmission. All affected individuals who were tested and one asymptomatic individual had a sodium channel mutation of SCN1A, an A-->C transversion at nucleotide 3809 resulting in the substitution of lysine 1270 by threonine in the D3/S2 segment (designated as K1270T).

CONCLUSIONS

Our findings indicate that partial epilepsy preceded by FS can be associated with sodium channel mutations and may represent a variant of GEFS+.

Video-EEG in the diagnosis of paroxysmal events in children with mental retardation and in children with normal intelligence

Video-EEG monitoring was performed to evaluate 193 children (91 females, 102 males; mean age 9.6 years, SD 5.7) who presented with paroxysmal events of uncertain etiology. Diagnosis of the type of event, i.e. epileptic or non-epileptic, was successfully established in 130 of 193 patients (67.3%). Seventy children (36%) had mental retardation* (MR). Children with MR were more likely (p<0.05) than children without MR to have events during the studies. Children with and without MR had strikingly similar frequencies of epileptic and non-epileptic events. In participants who had events recorded and characterized, epileptic seizures were identified in 67 children (51.5%), non-epileptic events in 54 children (41.5%), and both epileptic and non-epileptic events in nine children (7%). Improved diagnosis prompted appropriate management. This should encourage more frequent use of video-EEG in children, especially in those with MR, to differentiate epilepsy from behavioral disturbances so that specific treatment can be provided.

Hashimoto's encephalopathy: documentation of mesial temporal seizure origin by ictal EEG

Hashimoto's encephalopathy is a chronic relapsing and remitting encephalopathy associated with antithyroid antibodies. Seizures are a frequent manifestation, but are not well characterized in the literature with respect to their onset. We describe a 48-year-old patient with recurrent encephalopathy and seizures, and elevated antithyroid antibodies. One seizure was documented with video-EEG monitoring using scalp and sphenoidal electrodes. The ictal discharge originated in the left mesial-basal temporal region. MRI showed an increased T2 signal in the white matter of the centrum semiovale, but no temporal pathology. Symptoms resolved after treatment with prednisone and azathioprine. Hashimoto's encephalopathy should be considered in patients with unexplained encephalopathy and seizures, including those originating in the temporal lobe.

Low-dose stereotactic radiosurgery is inadequate for medically intractable mesial temporal lobe epilepsy: a case report

The successful surgical treatment of medically refractory epilepsy is based on one of three different principles: (1) elimination of the epileptic focus, (2) interruption of the pathways of neural propagation, and (3) increasing the seizure threshold through cerebral lesions or electrical stimulation. Temporal lobe epilepsy, being the most common focal epilepsy, may ultimately require temporal lobectomy. This is a case report of a 36-year-old male with drug-resistant right mesial temporal lobe epilepsy who failed to obtain seizure control after stereotactic radiosurgery to the seizure focus. Complex-partial seizures occurred 6-7 times monthly, and consisted of a loss of awareness followed by involuntary movements of the right arm. EEG/CC TV monitoring indicated a right mesial temporal lobe focus, which was corroborated by decreased uptake in the right temporal lobe by FDG-PET and by MRI findings of right hippocampal sclerosis. Stereotactic radiosurgery was performed with a 4MV linac, utilizing three isocenters with collimator sizes of 10, 10, and 7 mm respectively. A dose of 1500 cGy (max dose 2535 cGy) was delivered in a single fraction to the patient's right amygdala and hippocampus. There were no acute complications. Following radiosurgery the patient's seizures were improved in both frequency and intensity for approximately 3 months. Antiepileptic medications were continued. Thereafter, seizures increased in both frequency and intensity, occurring 10-20 times monthly. At 1 year post radiosurgery, standard right temporal lobectomy including amygdalohippocampectomy was performed with subsequent resolution of complex-partial seizures. Histopathology of the resected temporal lobe revealed hippocampal cell loss and fibrillary astrocytosis, consistent with hippocampal sclerosis. No radiation-induced histopathologic changes were seen. We conclude that low-dose radiosurgery doses temporarily changed the intensity and character of seizure activity, but actually increased seizure activity long-term. If radiosurgery is to be an effective alternative to temporal lobectomy for medically intractable temporal lobe epilepsy, higher radiosurgery doses will be required. The toxicity and efficacy of higher-dose radiosurgery is currently under investigation.

Orbito-frontal epilepsy masquerading as temporal lobe epilepsy-a case report

Temporal lobectomy fails to control seizures in a considerable percentage of patients who do not have hippocampal sclerosis. One theoretical reason for failure of surgery is that some of these patients may in fact have extratemporal epilepsy. We present a 28-year-old woman with clinical and scalp electroencephalogram (EEG) evidence of right temporal lobe epilepsy (TLE) supported by functional imaging with interictal positron emission tomography (PET) and ictal single-photon emission computerized tomography (SPECT). An invasive EEG monitoring was prompted by the discovery of a small right orbito-frontal lesion on MRI. Monitoring documented seizure onset at the lesion, with rapid right temporal involvement. The patient was almost seizure-free after a lesionectomy. The index of suspicion of orbito-frontal epilepsy should be high in patients with apparent TLE when the scalp EEG and neuroimaging data are not congruent, or if temporal lobe pathology cannot be identified on structural imaging.

Adult myoclonic epilepsy: a distinct syndrome of idiopathic generalized epilepsy

The authors present 11 cases of idiopathic generalized epilepsy that began in adulthood at a mean age of 39 years. All patients had myoclonic jerks, five had absence seizures, and nine had infrequent generalized tonic-clonic seizures. A majority had a family history of seizures. EEG in all patients showed generalized epileptiform abnormalities, whereas neuroimaging and neurologic examination results were normal. This series appears to represent a previously undescribed idiopathic generalized epilepsy syndrome of adult myoclonic epilepsy.

Safety of long-term treatment with tiagabine

The aim of this study was to evaluate the safety of long-term treatment with tiagabine. We reviewed the case report forms of patients with refractory partial epilepsy who took tiagabine for longer than 6 months in two long-term studies. We classified all adverse events based on severity and persistence, and recorded the dose at onset of each adverse event. We then divided patients into those treated for 6-12 months, 12-24 months and > 24 months. We compared the adverse event profile and change in seizure frequency among the three groups. Forty-two patients took tiagabine for longer than 6 months. The mean duration of treatment was 22.6 months. The mean monthly seizure frequency was 12.7 at baseline and 8.1 at study termination (36% decrease). The most common adverse events were: tiredness (56%), headache (46%), dizziness (44%), visual symptoms (blurring, difficulty focusing, diplopia) (39%), altered mentation (32%), and tremor (31%). The adverse event profile was comparable among the three groups. Seizure frequency was significantly more improved in the > 24 months group. Long-term treatment with tiagabine is well tolerated. The most important predictor of long-term therapy with tiagabine was the degree of seizure improvement.

Levetiracetam for partial seizures: results of a double-blind, randomized clinical trial

OBJECTIVE

To evaluate the efficacy and safety of 500 mg bid and 1500 mg bid levetiracetam as adjunctive therapy for refractory partial seizures in a double-blind, randomized, placebo-controlled, parallel-group, multicenter trial.

METHODS

The authors studied patients with uncontrolled partial seizures (minimum 12 per 12 weeks), regardless of whether they became secondarily generalized, for 38 weeks. A 12-week baseline was followed by random assignment to adjunctive therapy with placebo (n = 95), levetiracetam 1000 mg/day (n = 98), or levetiracetam 3000 mg/day (n = 101). Upward titration over 4 weeks was followed by 14 weeks of fixed dose treatment, and concluded with an 8-week medication withdrawal period or entering a follow-up study.

RESULTS

Of 294 patients randomized, 268 completed the study. Partial seizure frequency during the entire evaluation period (primary efficacy variable) was lower with levetiracetam compared to placebo (p </= 0.001 for both groups). More patients responded (defined as minimum 50% reduction in partial seizure frequency) to levetiracetam than placebo, with rates of 33. 0% in the 1000 mg/day and 39.8% in the 3000 mg/day group, compared to 10.8% in the placebo group (p < 0.001). Of 199 patients receiving levetiracetam, 11 became seizure free; no patient became seizure free in the placebo group. Treatment-emergent adverse events (>/=10%), mostly mild to moderate in severity, with incidences higher than placebo were asthenia, dizziness, flu syndrome, headache, infection, rhinitis, and somnolence.

CONCLUSION

Adjunctive therapy with levetiracetam was effective and well tolerated in controlling partial seizures.

Adjunctive therapy with oxcarbazepine in children with partial seizures. The Oxcarbazepine Pediatric Study Group

OBJECTIVE

To evaluate the safety and efficacy of oxcarbazepine (OXC) as adjunctive therapy in children with inadequately controlled partial seizures on one or two concomitant antiepileptic drugs (AEDs).

BACKGROUND

OXC has shown antiepileptic activity in several comparative monotherapy trials in newly diagnosed patients with epilepsy, and in a placebo-controlled monotherapy trial in hospitalized patients evaluated for epilepsy surgery.

DESIGN

A total of 267 patients were evaluated in a multicenter, randomized, placebo-controlled trial consisting of three phases: 1) a 56-day baseline phase (patients maintained on their current AEDs); 2) a 112-day double-blind treatment phase (patients received either OXC 30-46 mg/kg/day orally or placebo); and 3) an open-label extension phase. Data are reported only from the double-blind treatment phase; the open-label extension phase is ongoing.

METHODS

Children (3 to 17 years old) with inadequately controlled partial seizures (simple, complex, and partial seizures evolving to secondarily generalized seizures) were enrolled.

RESULTS

Patients treated with OXC experienced a significantly greater median percent reduction from baseline in partial seizure frequency than patients treated with placebo (p = 0.0001; 35% versus 9%, respectively). Forty-one percent of patients treated with OXC experienced a > or =50% reduction from baseline in partial seizure frequency per 28 days compared with 22% of patients treated with placebo (p = 0.0005). Ninety-one percent of the group treated with OXC and 82% of the group treated with placebo reported > or =1 adverse event; vomiting, somnolence, dizziness, and nausea occurred more frequently (twofold or greater) in the group treated with OXC.

CONCLUSION

OXC adjunctive therapy administered in a dose range of 6 to 51 mg/kg/day (median 31.4 mg/kg/day) is safe, effective, and well tolerated in children with partial seizures.

Topiramate in the long-term management of refractory epilepsy. Topiramate YOL Study Group

PURPOSE

A total of 292 adult patients (mean age, 33 years) with partial and/or generalized seizures previously resistant to antiepileptic drug (AED) therapy (median baseline seizure rate, 12 seizures/month) were treated with open-label topiramate (TPM) in dosages of 100-1,600 mg/day.

METHODS

The mean duration of TPM treatment was 413 days (range, 84-804 days), and the mean TPM dosage was 503 mg/day (range, 100-1,600 mg/day; median TPM dosage, 300 mg/day). Seizure reduction was calculated from seizure counts during the last 3 months and last 6 months of TPM therapy compared with baseline.

RESULTS

Overall, >50% of patients achieved > or =50% seizure reduction. More important, 11% of patients were seizure-free for > or =3 months at the last visit; 10% of patients were seizure free for > or =6 months at the last visit. This robust therapeutic response was consistent for patients receiving TPM dosages >400 and <400 mg/day. The most commonly reported adverse events were related to the central nervous system. Over the 2.2-year treatment period, 19% of patients discontinued TPM therapy because of inadequate seizure control; 32% discontinued because of adverse events. Findings from this study show that TPM is a useful agent for long-term seizure control, with some patients becoming seizure free for extended periods despite failing previous AED therapy.

Absence seizures with evolution into generalized tonic-clonic activity: clinical and EEG features

PURPOSE

To report the clinical and electrographic features of absence seizures evolving into generalized tonic-clonic (GTC) activity in six patients with idiopathic generalized epilepsy.

METHODS

All patients were referred for evaluation of refractory seizures and underwent video-EEG monitoring after discontinuation of their antiepileptic drugs (AEDs). We analyzed the video-EEG recordings for seizure semiology as well as ictal and interictal activity. We also reviewed the initial clinical data in all patients.

RESULTS

All patients were women, with a mean age of 27 years (range, 14-43 years). The mean age at seizure onset was 12 years (range, 5-15 years). Family history was positive for epilepsy in four patients. All patients had recorded seizures with an onset that was characteristic of generalized absence clinically and electrographically, with evolution into GTC activity. The EEG onset was with generalized 2.5-to 5-Hz spike-and-wave discharges, with evolution into faster rhythmic activity. Interictal EEG recordings showed generalized 2-to 5-Hz spike-and-wave discharges. All had normal background activity. All patients were treated with divalproex monotherapy. Five patients have been seizure free, and one had a single breakthrough GTC seizure during a follow-up period of 12-36 months.

CONCLUSIONS

GTC activity may evolve from typical absence seizures. This seizure type should be included in the International Classification of Seizures. Its recognition and distinction from complex partial seizures with secondary generalization are important for appropriate therapy.

Statistically driven identification of focal metabolic abnormalities in temporal lobe epilepsy with corrections for tissue heterogeneity using 1H spectroscopic imaging

1H spectroscopic imaging of N-acetyl-aspartate, creatine, and choline has proven to be a sensitive indicator for the lateralization of seizure foci in temporal lobe epilepsy. Previous studies have used right-left comparisons to identify the epileptogenic tissue assuming that alterations due to the disease process outweigh the effects of tissue heterogeneity. To evaluate the effectiveness of tissue heterogeneity corrected analyses, we evaluated three criteria for lateralization of the seizure focus: 1) a statistically driven method adjusted for tissue composition, 2) a single valued threshold, and 3) a single global index of the hippocampus. The statistically driven analysis lateralized all eight patients correctly, whereas the single threshold method incorrectly lateralized one case and the global index failed to identify a significant difference in two cases. These findings indicate that increased accuracy and sensitivity can be obtained by correcting for tissue heterogeneity when analyzing spectroscopy studies of temporal lobe epilepsy.

Brief antiepileptic drug withdrawal prolongs interval to next seizure

OBJECTIVE

To evaluate the course of seizure control after reinstitution of antiepileptic drugs (AEDs) in patients whose AEDs were discontinued during inpatient EEG-video monitoring.

METHODS

The authors studied prospectively patients with intractable epilepsy admitted for EEG-video monitoring with AED withdrawal. They examined seizure diaries in the 2 months preceding admission and recorded the number of seizures during hospitalization and for 2 months after discharge. They also recorded the interval between the last two seizures preceding admission (S-S pre), from the last seizure to admission (S-A), from discharge to the first seizure after discharge (D-S), and between the first and the second seizures following discharge (S-S post).

RESULTS

Sixty patients qualified for the study. There was a significant decrease in seizure frequency in the 2 months after discharge compared with baseline (p = 0.02). For patients who had at least two seizures during follow-up, the mean D-S interval was significantly longer than mean S-S pre and S-S post (p < 0.005), whereas the latter two intervals were comparable. Prolongation of D-S was related to duration off AEDs and to the AED restarted, but not to the number or severity of seizures during monitoring.

CONCLUSION

Seizure improvement after reinstitution of antiepileptic drugs (AEDs) is due primarily to prolongation of the interval from reinstitution of AEDs to the next seizure. This may reflect increased patient responsiveness to AED therapy after a drug "holiday" and has implications for experimental AED testing in the setting of presurgical evaluation.

The generalized tonic-clonic seizure in partial versus generalized epilepsy: semiologic differences

PURPOSE

To study differences in the clinical manifestations of generalized tonic-clonic seizures (GTCS) of partial versus generalized onset.

METHODS

We studied 10 GTCSs in nine patients with idiopathic generalized epilepsy (IGE) and 10 GTCSs in 10 patients with temporal lobe epilepsy (TLE). Videotaped seizures were reviewed for all clinical features, focusing on asymmetries during different phases of each seizure.

RESULTS

In the IGE group, focal features were seen before generalized motor activity in seven seizures. The most common was adversive head turn (six seizures). One patient had opposite direction of head turning in two recorded seizures. The tonic phase was always symmetric. In the last generalized clonic phase, asymmetry or asynchrony of motor activity was seen transiently in three seizures. The TLE group showed focal features before generalization in all seizures. Adversive head turning occurred in nine patients and was always contralateral to the focus. Focal clonic activity occurred before generalization in three and was always contralateral to the focus. The generalized tonic phase was usually asymmetric, and in the last clonic phase, motor activity was asymmetric or asynchronous in eight seizures (p<0.05, IGE vs. TLE).

CONCLUSIONS

Brief focal features or asymmetry at onset are common in the GTCSs of IGE. However, asymmetry or asynchrony during the last clonic phase are uncommon in IGE, in contrast to TLE.

Limbic encephalitis and hyperactive foci on PET scan

Two cases of patients with paraneoplastic limbic encephalitis, difficult to control seizures, and unilateral hippocampal hypermetabolism on positron emission tomography (PET) are described. Two women aged 33 and 61 presented with uncontrolled complex partial seizures, profound memory loss and cognitive decline. One was later diagnosed with breast cancer and the other with lung cancer. Video-EEG on the first patient recorded multifocal sharp waves and bilateral independent seizure onsets. The second patient had no epileptiform discharges and bitemporal ictal onset, even though the clinical seizures suggested a right temporal onset. Magnetic resonance imaging (MRI) was normal in both patients. PET scans obtained in the interictal state showed right hippocampal hypermetabolism in both patients. In the second patient, the lung cancer was irradiated with resolution of seizures and improvement of memory function. A PET scan six months later was normal. Subsequent seizure recurrence and worsening of memory led to the discovery of widespread metastases. Limbic encephalitis should be considered in the differential diagnosis of intractable partial epilepsy, particularly if accompanied by severe memory loss and cognitive decline. Treatment of the underlying cancer may be lead to improved seizure control. Hippocampal hypermetabolism may be a common feature on PET, and may indicate subclinical seizure activity.

The value of combined ambulatory cassette-EEG and video monitoring in the differential diagnosis of intractable seizures

OBJECTIVE

To evaluate the ability of combined ambulatory cassette-EEG and video monitoring (ACV) to establish a diagnosis in patients with attacks of unknown nature and its impact on their treatment.

METHODS

We evaluated ACV in 125 consecutive patients with attacks of unknown nature. Most had intractable attacks suspected of being non-epileptic. Antiepileptic drugs (AEDs) were discontinued or reduced at the start of the procedure. The median duration of monitoring was 3 days (range 1-10). The ACV results and patient records were reviewed, and patients were called for additional follow-up when feasible.

RESULTS

Attacks were recorded in 101 patients. They were epileptic in 20 patients, psychogenic in 60, both in 3, and of unknown nature in 18 (usually subjective episodes). The study resulted in AED discontinuation at discharge in 46 patients with recorded psychogenic seizures and 6 with recorded attacks of unknown nature. Three-quarters of patients followed up were free of attacks or improved.

CONCLUSIONS

ACV was effective in providing a diagnosis in two-thirds of patients. If psychogenic seizures are suspected in patients on AEDs, ACV may provide the diagnosis and may help exclude epilepsy, without the need for standard EEG-CCTV, which can then be reserved for patients undergoing presurgical evaluation.

Visual field defects after temporal lobe resection: a prospective quantitative analysis

OBJECTIVE

To evaluate and quantify prospectively visual field changes in patients undergoing temporal lobe resections for intractable epilepsy.

BACKGROUND

Visual field abnormalities occur after temporal lobe resections for epilepsy; however, we have not encountered published reports using automated static visual field analysis.

METHODS

Humphrey visual fields (program 30-2) were obtained before and after partial temporal lobe resection in 32 consecutive patients with intractable epilepsy. A quantitative point-by-point analysis was made in the affected superior quadrant, and the defects were averaged for the whole patient group.

RESULTS

Thirty-one patients developed a visual field defect, but none was aware of the defect. The points nearest fixation were relatively spared. The defects were greatest in the sector closest to the vertical meridian in the eye ipsilateral to the resection. The ipsilateral and contralateral mean field defects also differed in both topography and depth. A significant correlation was found between the extent of lateral temporal lobe resection and the degree of the defect in the contralateral eye.

CONCLUSIONS

There are differences in the shape and depth of the ipsilateral and the contralateral field defects not previously reported. These findings demonstrate that certain fibers from the ipsilateral eye travel more anteriorly and laterally in Meyer's loop, and support the hypothesis that visual field defects due to anterior retrogeniculate lesions are relatively incongruous because of anatomic differences in the afferent pathways. Automated perimetry is a sensitive method of evaluating and quantifying visual field defects.

Generalized absence seizures with 10-15 Hz fast discharges

OBJECTIVE

To report clinical and EEG features in 5 adults with unusual, fast rhythmic discharges accompanying absence seizures.

DESIGN AND METHODS

The 5 patients presented with uncontrolled seizures. All had EEG-video monitoring with recorded seizures. Video seizures were reviewed and ictal as well as interictal epileptiform activity was analyzed. The patients were followed up after appropriate therapy for a minimum of 6 months.

RESULTS

There were 3 women and two men, with a mean age of 37 years (range: 23-59). Two patients had onset of absence seizures in childhood, one in adolescence and two after age 20. All patients also had generalized tonic-clonic seizures. Ictal EEG recordings showed generalized spike and wave (SW) discharges of variable dominant frequencies (2.5-6 Hz) and intermingled 10-15 Hz generalized rhythmic discharges which also occurred in isolation or as the dominant activity. Interictal recordings showed similar but shorter 2.5-6 Hz generalized SW discharges. The background activity was normal in 3 patients and mildly slow in two who had very frequent absence seizures during the recording period. Four patients became seizure free and one had 75% improvement on appropriate antiabsence therapy.

CONCLUSIONS

The fast 10-15 Hz rhythmic discharges that we report appear to occur mostly in adult patients with absence, as well as, generalized tonic-clonic seizures. They can occur in isolation or be embedded in more typical SW discharges accompanying typical absence seizures. Their presence does not imply a poor prognosis for seizure control.

EEG changes in intrathecal baclofen overdose: a case report and review of the literature

OBJECTIVE

To review the clinical and EEG manifestations of intrathecal baclofen overdose.

METHODS

We identified one patient who had received an overdose of intrathecal baclofen. Information about the clinical course was obtained by reviewing the patient's medical record. EEGs were recorded with the use of the standard 10-20 electrode placement system.

RESULTS

The patient received 30 mg baclofen intrathecally. Shortly after the injection he developed respiratory insufficiency and quadriparesis and later became comatose. The first EEG obtained 20 h after the injection showed very frequent quasiperiodic generalized epileptiform discharges. The patient gradually improved clinically and a second EEG obtained 24 h later showed only intermittent bursts of generalized slow wave activity. A repeat EEG study 1 week later was normal.

CONCLUSIONS

The EEG in intrathecal baclofen overdose can show quasiperiodic generalized epileptiform discharges. This does not necessarily indicate the presence of underlying potential epileptogenicity, and treatment with an antiepileptic medication is not necessary.

Meningoencephalitis: an atypical presentation of herpes simplex type 2 central nervous system infection

Encephalitis is the best recognized form of central nervous system (CNS) infection with the herpes simplex virus. We present a case of meningoencephalitis with a benign course caused by herpes simplex virus type 2. The patient had no focal abnormalities on either brain magnetic resonance imaging scan or electroencephalogram. The cerebrospinal fluid profile was that of aseptic meningitis, with a lymphocytic pleocytosis. The clinical spectrum of herpes simplex infections in the CNS is broad. Specifically, herpes simplex type 2 can cause a benign meningoencephalitis with scant focal findings, in addition to the known encephalitis and more recently recognized benign recurrent lymphocytic meningitis.

Epilepsy diagnosis and localization in patients with antecedent childhood febrile convulsions

PURPOSE

A history of febrile convulsions (FC) is often obtained in patients presenting for surgical treatment of temporal lobe epilepsy (TLE), but it is not clear that preferential temporal localization of epilepsy is associated with antecedent FC.

METHODS

We prospectively inquired about FC and their characteristics in all patients presenting to an epilepsy clinic through a patient questionnaire and interview. We studied the incidence of antecedent childhood febrile convulsions in relation to epilepsy diagnosis.

RESULTS

FC were reported by 133 of 1005 study patients (13.2%). TLE was more likely to be preceded by FC (78/310, 25.2%) than extratemporal epilepsy (ETE) (12/216, 5.6%) (p < 0.000001) or generalized epilepsy (GE) (16/146, 11.0%) (p < 0.001). Patients with GE were more likely than patients with TLE to have had simple FC (p < 0.00005). Prolonged duration was the most common FC complex feature in TLE patients.

CONCLUSIONS

We demonstrated a preferential association of FC with temporal lobe foci and a weaker association between FC and GE. FC does not appear to be a clear risk factor for ETE.

Conversion to high dose gabapentin monotherapy in patients with medically refractory partial epilepsy

PURPOSE

To evaluate the safety and efficacy of high dose gabapentin (GBP) monotherapy (3,000-4,800 mg/day) in patients with medically refractory partial epilepsy.

METHODS

GBP monotherapy at daily doses up to 4,800 mg was attempted in patients participating in the open-label phase of a double-blind, dose-controlled, GBP monotherapy trial. For those who achieved monotherapy, the types and severity of adverse events were assessed and the average seizure frequency per 28 days while maintained on the highest daily GBP dose was compared to the seizure frequency during the baseline phase of the double blind trial. Correlation analysis between GBP serum level, total daily dose, and percentage of seizure change from baseline was performed.

RESULTS

A total of 45 patients participated in the open-label phase of the trial and 23 (51%) were converted successfully to GBP monotherapy. In those patients, the average daily gabapentin dose was 3,900 mg and the mean length of follow-up was 252 days. Compared to baseline, there was a mean reduction of 54%, 43%, and 14% for simple partial, complex partial and secondarily generalized seizures respectively, while maintained on high-dose GBP monotherapy. A significant linear correlation between daily GBP dosage (2,400-4,800 mg) and resultant mean serum levels was found (r = 0.51; p < 0.01). There was no significant correlation between seizure frequency and total daily GBP dose or with serum levels. High-dose GBP monotherapy was well tolerated; only one patient exited the trial because of adverse events. The most common adverse event was tiredness/sleepiness and was not dose-related.

CONCLUSIONS

GBP monotherapy is well tolerated in daily doses of up to 4,800 mg and is effective in a subgroup of patients with medically refractory partial epilepsy.

Gabapentin monotherapy: II. A 26-week, double-blind, dose-controlled, multicenter study of conversion from polytherapy in outpatients with refractory complex partial or secondarily generalized seizures. The US Gabapentin Study Group 82/83

This study evaluated gabapentin monotherapy in 275 patients with medically refractory complex partial or secondarily generalized seizures who were taking one or two antiepileptic drugs (AEDs). Following an 8-week baseline, patients received randomized dosages of gabapentin (600, 1,200, or 2,400 mg/d) during a 26-week double-blind phase comprising 2 weeks gabapentin add-on therapy, an 8-week AED taper, and a 16-week gabapentin monotherapy period. Patients exited the study if they experienced a protocol-defined exit event. Results of outcome measures, including time to exit, completion rate, and mean time on monotherapy, showed no significant differences among dosage groups. Possible reasons for this lack of a dose-response relationship include withdrawal seizures and the limited range of gabapentin dosages studied. Overall, 20% of patients completed the study. Completion rates were higher among patients who had discontinued one AED (23%) than two AEDs (14%), and higher among patients who were not withdrawn from carbamazepine (27%) than among those who were (16%).

Occipital pole area and language dominance

A previous report demonstrated a relationship between asymmetries of occipital lobe length measured on magnetic resonance images (MRIs) and the hemisphere verified as dominant for language. This study sought to discern whether asymmetry in occipital pole area is more predictive of the hemisphere dominant for language. Language dominance was identified by the Wada test in 55 patients evaluated for surgical treatment of epilepsy. In a blinded fashion, an examiner measured bilateral occipital pole area on MRIs for each patient. Asymmetry of the occipital pole area on the MRI made at 10 mm above the tentorium was significantly related to language dominance. This two-dimensional analysis was better than previously described linear measurements in discriminating patients with left-hemisphere dominance for language.

Midsagittal corpus callosum area, intelligence, and language dominance in epilepsy

Alterations in midsagittal corpus callosum (CC) area and morphology have been suggested in several disease processes of the nervous system. In addition, some studies found a relation of CC area to handedness, language dominance, and gender. The relation of CC area to measures of intelligence and memory and the effect of epilepsy on CC area have received less attention. In this study CC area was measured on midsagittal magnetic resonance images in 48 patients undergoing presurgical evaluation of epilepsy and in 20 control subjects. All patients had the Wada test and formal neuropsychological testing. The mean CC area of the epilepsy group was significantly smaller than that of control subjects (p < 0.00001). CC area showed a positive correlation with presurgical performance IQ (p = 0.008) and full-scale IQ (p = 0.048), but not with memory scores or language dominance. There was no relation of CC area to location of epileptic focus, seizure types, age at onset, epilepsy duration, or etiology. The presence of an atrophic lesion was associated with a smaller CC area. The correlation of total CC area with performance and full-scale IQs may reflect axonal loss in patients with a low IQ resulting from the etiology of epilepsy or the epilepsy itself.

Significance of head turn sequences in temporal lobe onset seizures

We studied head turning in 239 complex partial seizures with or without generalization, in 32 patients with unilateral temporal lobe epilepsy. Head turns occurred in 73% of seizures that did not evolve to focal jerking or secondary generalization, and in all 41 seizures that secondarily generalized. In seizures without focal jerking or secondary generalization the most common pattern was that of single head turns (70%) which were ipsilateral to the focus in 94%. The next most common pattern was that of two or more head turns, with the first two turns in the same direction (19%), always ipsilateral to the focus. In seizures with secondary generalization, the most common sequence was that of two head turns contralateral to each other (59% of seizures). The first was always ipsilateral to the focus, associated with dystonic posturing in 96%, and was not tonic in character. The second was always contralateral, was tonic in character, and was still present within five seconds of secondary generalization or focal jerking. Our results suggest different patterns and sequences of head turning temporal lobe complex partial seizures without, and those with focal jerking or secondary generalization. Some sequences have powerful lateralizing value that can complement other lateralizing features.

The start-stop-start phenomenon in scalp-sphenoidal ictal recordings

The start-stop-start (SSS) phenomenon is an apparent abortive ictal onset separated from the main seizure discharge. It was previously described in seizures recorded with subdural electrodes. We have observed this phenomenon in scalp-sphenoidal ictal recordings as well. We retrospectively reviewed 435 seizures recorded with scalp-sphenoidal electrodes from 61 patients with temporal lobe epilepsy. We found SSS onset in 15 seizures of 8 patients, representing 26% of these patients' seizures. The first "start" usually had a narrow field, typically in the sphenoidal electrode. The mean duration of the first "start" was 11 sec and that of the stop 8 sec. The restart had a different morphology and frequency in 87% and had a wider field in 67% of seizures. The clinical onset followed the first start and preceded the restart in most of the seizures. In 1 patient, 1 seizure with SSS was correctly localized and lateralized, whereas 5 of 7 without SSS were falsely lateralized. The recognition of the SSS phenomenon may improve the accuracy of seizure localization in scalp-sphenoidal recordings.

Association of ipsilateral head turning and dystonia in temporal lobe seizures

We evaluated head turning in 239 complex partial seizures (CPS) with or without generalization in 32 patients with unilateral temporal lobe epilepsy (TLE). Head turns occurred in 187 seizures of 31 patients, more than once in 71 seizures. The first head turn was ipsilateral to the focus in 162 seizures (87%), with a mean latency of 22 s, as compared with 83 s for contralateral first head turns. Concomitant dystonic posturing of the arm occurred with 71% of all ipsilateral head turns and with 16% of all contralateral head turns. The mean difference in absolute latency between the first head turn and concomitant dystonic posturing was 6 s. Examination of all instances of concomitant head turning and dystonic posturing (160) showed them to be contralateral to each other in 154 (96%). Furthermore, the dystonia was contralateral and head turning was ipsilateral to the focus in 149 (93%). Forty-one seizures secondarily generalized, with transitional tonic head deviation contralateral to the focus in 35. Early head turning suggests an ipsilateral temporal seizures focus, particularly when associated with contralateral dystonic posturing. Similar mechanisms may account for both. Tonic head deviation preceding secondary generalization probably has a different mechanism.

Aphasia secondary to partial status epilepticus of the basal temporal language area

We present a patient with aphasia of several days' duration that was secondary to spontaneous partial status epilepticus arising from the left basal temporal region. Evidence from MRI, EEG, and PET confirmed the origin of the seizures in the basal temporal area. Both the seizure discharges and the aphasia resolved after antiepileptic therapy. This case, to our knowledge, is the first documented example of epileptic aphasia secondary to spontaneous partial status epilepticus originating from the basal temporal area.

The course of seizure disorders in patients with malignant gliomas

OBJECTIVE

To describe the morbidity associated with seizures and the efficacy of anticonvulsant therapy in adult patients with malignant gliomas (MGs).

STUDY DESIGN

A retrospective review of charts was performed to determine the occurrence of seizures at diagnosis, the frequency and character of subsequent seizures, and the use and toxic side effects of anticonvulsants.

PATIENTS

Sixty-five consecutive adult patients with supratentorial MGs who were examined in the neurooncology clinic at a university medical center were studied. The diagnosis was glioblastoma in 47 of the patients, and it was anaplastic astrocytoma in 18 patients. The mean age of the patients was 49.5 years. The median Karnofsky status score was 80. The median survival was 18 months.

RESULTS

Twenty-nine patients presented with seizures, and 21 of these had subsequent (eg, "recurrent") seizures while they were receiving anticonvulsant therapy. Ten of 36 patients who were free of seizures at diagnosis experienced seizures after diagnosis (eg, "late onset") while they were being treated with anticonvulsants, including five patients who had single seizures. Long-term seizure frequency in excess of one per month was observed in 13 patients. Ten patients had episodes of partial motor status epilepticus. Most recurrent and late-onset seizures occurred despite therapeutic anticonvulsant levels, and without evidence of tumor progression. Rash associated with anticonvulsants was observed in 26% of the patients. Other clinically important toxic side effects were observed in 14% of the patients who were receiving long-term anticonvulsant therapy.

CONCLUSIONS

Seizures contributed substantially to the neurologic morbidity of MGs in at least 25% of these patients. The occurrence of seizures at diagnosis was a strong predictor of subsequent seizures, and in many patients, seizures proved to be refractory to standard anticonvulsant therapy. Long-term anticonvulsant toxic side effects are relatively common in patients with MGs. The use of long-term seizure prophylaxis for patients with MGs who are free of seizures at presentation is not clearly beneficial and should be studied in a prospective trial.

Self-injury and incontinence in psychogenic seizures

Two patients who incurred significant injuries during psychogenic seizures prompted us to do a telephone survey of self-injury and incontinence in 102 consecutive patients diagnosed with psychogenic seizures by EEG-closed-circuit TV (EEG-CCTV) monitoring. Seventy-three patients (or a close family member or friend) were reached by telephone and responded to our survey. During typical attacks of psychogenic seizures, 40% reported injuries, 44% reporting tongue biting, and 44% reported urinary incontinence. Suicide attempts were reported by 32% and were more common in those with self-injury and urinary incontinence. We compared the results of patients with psychogenic seizures with those of 30 patients with refractory epilepsy documented by ictal recordings, using a similar telephone survey. Injuries of all types were more commonly reported by epilepsy patients. Burn injuries were reported only by patients with epilepsy. Suicide attempts were more commonly reported by the psychogenic seizure group. Self-injury and incontinence are commonly reported by psychogenic seizure patients. In view of their significant association with suicide attempts, they may indicate an underlying depression.

Inhibitory motor seizures: correlation with centroparietal structural and functional abnormalities

Six adults and 2 children with focal inhibitory motor seizures (ictal paralysis) were evaluated during a 4-year period. Paresthesias at seizure onset occurred during some seizures in all patients, and focal clonic activity followed paralysis in 4. EEG-CCTV recordings of the seizures in 2 patients showed that ictal paralysis coincided with an ictal discharge starting in one centroparietal area. MRI showed centroparietal structural lesions in six patients. One patient with a normal MRI scan had right centroparietal hypometabolism on PET. Inhibitory motor seizures must be differentiated from transient ischemic attacks and migraine. In our patients a centroparietal epileptogenic focus was suggested by neuroimaging studies, and in 2 instances by ictal EEG.

MRI asymmetries and language dominance

OBJECTIVE

To examine the relationship between language dominance, as measured by Wada testing, and hemispheric asymmetries on MR brain images.

BACKGROUND

A previous report that did not include verification of language dominance compared the length of the planum temporale with hemispheric asymmetries seen on CT and inferred that occipital lobe asymmetry is related to language dominance.

METHODS

Language dominance was identified by the Wada test in 57 patients evaluated for surgical treatment of epilepsy. Fifty-five had an MRI scan that allowed accurate measurement. In a blinded fashion, two examiners independently measured bilateral frontal, parietal, and occipital lobe lengths on MR scan for each patient. Measurements of asymmetries were compared with language dominance established by the Wada test.

RESULTS

Reliability of measurement between the examiners was 97%. Asymmetry of the occipital lobe length on MR scan 10 mm above the tentorium was the only measurement significantly related to language dominance (p < 0.01). Occipital lobe length was longer on the left in 19 (40%) and on the right in 10 (21%) patients with left dominance. The right lobe was longer in six of seven (86%) patients with bilateral dominance. One patient with right hemisphere dominance had a longer left lobe. None of the measurements significantly related to handedness.

CONCLUSION

Asymmetries of occipital lobe length relate to language dominance, but such dominance cannot be reliably identified by MR in an individual patient.

Differentiating clinical features of right and left temporal lobe seizures

We reviewed 127 seizures in 19 consecutive patients with temporal lobe epilepsy (TLE) documented by EEG/closed-circuit TV (EEG-CCTV) monitoring. Ten patients had seizure onset in the right temporal lobe (RTL, 54 seizures), and 9 had seizure onset in the left temporal lobe (LTL, 73 seizures). We compared the clinical characteristics in the two groups and analyzed the seizures for frequency of auras, seizures secondarily generalized, automatisms, tonic head deviation, focal posturing and jerking, ictal speech, and postical manifestations. Automatisms overall were more common in the RTL group, but individual categories (extremity, head and trunk, oroalimentary) were comparable among the two groups. Contralateral focal jerking and tonic head deviation were more common in LTL lobe seizures, as were secondarily generalized seizures. In addition to focal motor symptoms, three features were most statistically significant in distinguishing the two groups: Postictal aphasia occurred exclusively in the LTL group, whereas well-formed ictal speech and rapid return to baseline postictally were noted only in RTL seizures.

Global aphasia with seizure onset in the dominant basal temporal region

A 33-year-old right-handed woman had intractable simple and complex partial seizures (SPS, CPS) that began with global aphasia. EEG closed-circuit TV (EEG-CCTV) monitoring with sphenoidal electrodes showed left inferomesial temporal ictal onset of CPS. Subdural electrodes were implanted over the left frontotemporal convexity, subtemporally and subfrontally. Stimulation of the basotemporal cortex produced global aphasia. A posterolaterotemporal language area was also identified. Spontaneous SPS had focal onset in the basal temporal language area (BTLA). Ictal discharges did not involve the posterotemporal region. This case shows that aphasic speech arrest at seizure onset may be due to seizure discharge in the basotemporal region and that the BTLA is clinically relevant in seizure semiology.

Hemodynamic responses to shock in young trauma patients: need for invasive monitoring

OBJECTIVE

To determine whether early invasive monitoring is necessary in young trauma patients.

DESIGN

A prospective study.

SETTING

Surgical intensive care unit (ICU) at an inner-city, Level I trauma center.

PATIENTS

Thirty-nine patients < 40 yrs of age, who required operative therapy for penetrating trauma and who received > 6 units of intraoperative blood.

INTERVENTIONS

Invasive hemodynamic monitoring, with percutaneous insertion of arterial and pulmonary artery catheters. Vital signs, hemodynamic and oxygen transport values, and laboratory tests were obtained at 1, 8, and 24 hrs postoperatively. Oxygen delivery was increased until a normal serum lactate concentration and a state of nonflow-dependent oxygen consumption were achieved.

MEASUREMENTS AND MAIN RESULTS

Despite normal heart rate, blood pressure, and urine output, only five (15%) patients achieved an optimized state at 1 hr postoperatively. Of the other 34 patients, two patients achieved an optimized state with volume infusion alone and 32 (82%) patients required inotropes. Five (12%) patients never achieved an optimized state and died within hours of their arrival to the ICU. Two other patients achieved an optimized state but died of sepsis and organ failure. The other 32 (82%) patients achieved an optimized state within 24 hrs and survived. The hemodynamic values of survivors at 1 hr postoperatively showed a significantly lower pulmonary vascular resistance and serum lactate concentration, and a significantly higher oxygen delivery and mixed venous oxygen saturation, when compared with the values of nonsurvivors. At 24 hrs postoperatively, survivors also had a significantly lower pulmonary vascular resistance and serum lactate concentration, and significantly higher oxygen delivery than nonsurvivors. Survivors' oxygen consumption was also higher than the oxygen consumption of nonsurvivors.

CONCLUSIONS

Our data demonstrate that young trauma patients have substantial but clinically occult myocardial depression after shock, and most of these patients require inotropes to optimize and clear circulating lactate. Early invasive monitoring is necessary to precisely define the adequacy of the cardiac response and to individually tailor therapy. Patients who do not optimize and clear their lactate within 24 hrs may not survive.

Preferential neuronal loss in layer III of the entorhinal cortex in patients with temporal lobe epilepsy

We report a characteristic pattern of neuropathological change in the entorhinal cortex (EC) from four patients with temporal lobe epilepsy. Specimens of the EC were obtained during the surgical treatment of intractable partial seizures and were studied by light microscopy in Nissl-stained sections. A distinct loss of neurons was observed in the anterior portion of the medial EC in the absence of apparent damage to temporal neocortical gyri. Cell loss was most pronounced in layer III, but also noticed in layer II, particularly in the rostral field. A similar pattern of neurodegeneration in the EC was found in all specimens examined though the degree of neuronal loss varied between cases. These observations provide neuropathological evidence for an involvement of the EC in temporal lobe epilepsy. Since the EC occupies a pivotal position in gating hippocampal input and output, our results further support previous suggestions that dysfunction of this region may contribute, either independently or in concert with Ammon's horn sclerosis, to epileptogenesis in humans.

Psychogenic seizures in old age: a case report

Psychogenic seizures are unusual after age 60 years. A 73-year-old woman had onset of psychogenic seizures at age 69 years. Five to six attacks occurred each month, usually at night, characterized by an initial subjective sensation and headache followed by generalized stiffening and shaking. Continuous EEG-closed circuit television (EEG-CCTV) monitoring clearly showed these episodes to be nonepileptic. Discontinuation of antiepileptic drugs (AEDs) did not increase the frequency or severity of attacks. Epileptiform discharges were not recorded during the awake, drowsy, or sleeping states. Psychiatric evaluation identified significant turmoil in the patient's life and a history of childhood sexual and physical abuse. Psychogenic seizures may begin in old age and should be considered in the differential diagnosis of intractable seizures in the elderly. Predominantly nocturnal occurrence should not exclude the diagnosis.

Temporal lobe epilepsy after prolonged febrile convulsions: excellent outcome after surgical treatment

We studied 47 consecutive patients who underwent temporal resection for seizure control. Nineteen (40%) had febrile convulsions preceding onset of their habitual seizures. In 17 of 18 patients whose disease duration was known, the febrile convulsions were prolonged (mean 4 h). As compared with patients without preceding febrile convulsions, patients with antecedent febrile convulsions had a significantly higher prevalence of positive family history of febrile convulsions, an increased incidence of retrospectively identified gestational or perinatal complications, and no foreign tissue lesions. Pathologic studies showed gliosis and cell loss in mesiotemporal structures, usually moderate, in addition to usually mild gliosis in lateral temporal cortex. These patients had an excellent outcome after temporal resection: 84% were seizure-free, had residual auras only, or occasional convulsions with medication discontinuation. One patient (5%) had > 90% improvement. Two patients (11%) in whom the hippocampus was totally spared continued to have complex partial seizures: in both, seizures stopped after reoperation and hippocampal resection. Thus, 95% of these patients had an excellent result. Only 16% required invasive preoperative studies to confirm lateralization. These results were significantly better than those of the group without preceding febrile convulsions (p = 0.0013).