Epileptic aphasia: a consequence of regional hypometabolic encephalopathy?

A series of 25 children, 13 females and 12 males, who had an acquired communication disorder together with epilepsy, but did not fulfil the strict criteria of the Landau-Kleffner syndrome, was studied. All children had a clinical neurological evaluation, speech and language assessment, an awake and sleep EEG, cranial MRI, SPET scan, and audiometry. Clinical seizures were most often polymorphic in type (17 of 25). Atypical absences were the commonest individual seizure type occurring in 15 cases. All patients had an unequivocal epileptiform EEG. Normal sleep phenomena were only observed in 10 cases, enhancement of epileptiform activity in sleep was seen in 16. Cranial MRI was abnormal in six and normal in 19 cases. The SPET scans were abnormal in 22 of 25 children. The language deficits were classified neurologically as receptive aphasia, 24 of 25; expressive aphasia, 20 of 25; nominal aphasia, eight of 25; articulatory dyspraxia, 10 of 25; and auditory agnosia, nine of 25. It is hypothesized that the loss of communication skills is due to an encephalopathy secondary to the persistent epileptic discharge and manifests as a hypometabolic area on the SPET scan.     

Semiological seizure classification

We propose an epileptic seizure classification based exclusively on ictal semiology. In this semiological seizure classification (SSC), seizures are classified as follows: a. Auras are ictal manifestations having sensory, psychosensory, and experiential symptoms. b. Autonomic seizures are seizures in which the main ictal manifestations are objectively documented autonomic alterations. c. "Dialeptic" seizures have as their main ictal manifestations an alteration of consciousness that is independent of ictal EEG manifestations. The new term "dialeptic" seizure has been coined to differentiate this concept from absence seizures (dialeptic seizures with a generalized ictal EEG) and complex partial seizures (dialeptic seizures with a focal ictal EEG). d. Motor seizures are characterized mainly by motor symptoms and are subclassified as simple or complex. Simple motor seizures are characterized by simple, unnatural movements that can be elicited by electrical stimulation of the primary and supplementary motor area (myoclonic, tonic, clonic and tonic-clonic, versive). Complex motor seizures are characterized by complex motor movements that resemble natural movements but that occur in an inappropriate setting ("automatisms"). e. Special seizures include seizures characterized by "negative" features (atonic, astatic, hypomotor, akinetic, and aphasic seizures). The SSC identifies in detail the somatotopic distribution of the ictal semiology as well as the seizure evolution. The advantages of a pure SSC, as opposed to the current classification of the International League Against Epilepsy (ILAE), which is actually a classification of electroclinical syndromes, are discussed.     

Botulinum toxin injections in the internal anal sphincter for the treatment of chronic anal fissure: long-term results after two different dosage regimens

OBJECTIVE: To determine whether the recently published guidelines on neuroimaging in patients with new-onset seizures are applicable to children. METHODS: We carried out a retrospective analysis of 107 neurologically normal children (excluding children with simple febrile seizures) who had undergone neuroimaging when they presented to the emergency department with a possible "first seizure." RESULTS: Eight of the 107 children had nonepileptic events (gastroesophageal reflux, syncopal event, rigor). Of the remaining 99 children, 49 had provoked seizures (complicated febrile seizure, meningo-encephalitis, toxic or metabolic abnormalities), and 50 had unprovoked seizures. A total of 19 children had brain abnormalities identified on computed tomography (CT) scan; 7 received further investigation or intervention as a result of CT scan findings (2 with tumors, 3 with vascular anomalies, 1 with cysticercosis, and 1 with obstructive hydrocephalus). CT scan abnormalities requiring treatment or monitoring were more frequently seen in children with their first unprovoked seizure (P < .01) and in those children whose seizure onset had been focal or who had focal abnormalities identified on postictal neurologic examination (P < .04). CONCLUSION: In a child, a seizure in the setting of a fever rarely indicates the presence of an unexpected CT scan lesion requiring intervention.     

EEG findings in frontal lobe epilepsies

As a group, epilepsies of frontal lobe origin are thought to be poorly localized using surface EEG recordings. This finding may depend on the specific areas of frontal lobe from which the seizures originate or the pathologic substrate. We reviewed the presurgical surface EEGs of patients with frontal lobe epilepsy who underwent epilepsy surgery. The specific area of the frontal lobe where seizures originated was determined by 1) intracranial ictal EEG recordings, or 2) the presence of a structural lesion, identified by imaging studies in patients who achieved complete seizure control following surgery. We differentiated patients whose seizures began in the dorsolateral frontal convexity from those whose seizures began in the medial frontal region, and we correlated EEG findings in the interictal, postictal, and ictal states with seizure semiology, pathologic substrate, and surgical outcome. Four of nine patients had seizures originating in the dorsolateral frontal convexity and five had medial frontal onset seizures. Patients whose seizures originated from the dorsolateral convexity had focal interictal epileptiform abnormalities that localized to the region of seizure onset. Patients whose seizures began in the medial frontal region had either no interictal epileptiform abnormality or had multifocal epileptiform discharges. Patients whose seizures began in the dorsolateral convexity showed focal electrographic seizure activity that was localizing. This rhythmic fast activity did not appear to be substrate-specific. Patients whose seizure onset localized to the medial frontal region did not show focal electrographic seizure at clinical onset. We conclude that the scalp EEG recordings of frontal lobe epilepsies contain features that enable differentiation of seizures originating from two different regions of the frontal lobe.     

Fluorometric assessments of acrosomal integrity and viability in cryopreserved bovine spermatozoa

It is widely agreed that after two or more seizures patients should be given antiepileptic treatment, but there is still controversy about the treatment of patients after a first unprovoked seizure. In a multicenter, randomized, open trial, patients with a first tonic-clonic seizure were randomized to immediate treatment (carbamazepine, phenytoin, phenobarbital, or sodium valproate) or to treatment only after another seizure. Fifty-two (24%) of the 215 patients randomized to immediate treatment and 85 (42%) of the 204 randomized to delayed treatment experienced seizure recurrence during follow-up. Age, acute treatment of the seizure with benzodiazepines, remote etiologic factors, and EEG abnormalities were significant predictors of relapse. Of the immediately treated patients, 87% had no seizures for a year and 68% had no seizures for 2 years, whereas only slightly fewer initially untreated patients (83% and 60%) achieved these endpoints. Patients treated after the first seizure and those treated after seizure relapse had the same time-dependent probability of achieving 1 and 2 seizure-free years. None of the variables that were prognostic predictors of relapse was significantly associated with the probability of having 1 or 2 years of seizure control. Anticonvulsants in patients presenting a first tonic-clonic seizure reduce the risk of relapse; however, 50% of patients who are not treated will never experience a second seizure. Moreover, the probability of long-term remission is not influenced by treatment of the first seizure.     

Prognostic factors for recurrence of a first seizure during childhood

This study was designed with the objective of evaluating the chance of recurrence in our area and to answer questions regarding prognostic factors capable of helping in the management of the first seizure in childhood. One hundred and thirty six children from 1 month to 12 years of age seen at the Pediatric Emergency Division of Hospital de Clínicas de Porto Alegre because of a first seizure with or without triggering factors were included in the study. The follow-up included 121 children. We concluded that family history of seizures, presence of triggering factors at first event, seizure type, seizure duration and paroxysmal electroencephalographic abnormalities were predictive factors for seizure recurrence. The recurrence in this sample was 36.36% during the study. Cumulative recurrence risks were 14.88%, 23.14%, 28.93%, 33.06% and 35.54% to 3, 6, 9, 12 and 15 months, respectively.     

Prognostic factors for seizure recurrence after withdrawal of antiepileptic drugs in patients with neurocysticercosis

We tapered antiepileptic drugs in 40 patients with epilepsy due to neurocysticercosis who had been free of seizures for 2 years. All patients previously received a course of albendazole that resulted in complete destruction of brain cysts. We followed the patients prospectively from the time of diagnosis until 12 months after antiepileptic drug withdrawal. We evaluated the following prognostic factors for seizure recurrence: sex, number of seizures before control, type of seizures, number of parenchymal brain cysts before albendazole therapy, EEG findings, and CT findings after albendazole therapy. In the univariate analysis of prognostic factors for seizure recurrence, the development of brain calcifications caused by albendazole was the only factor associated with a significantly higher rate of relapse (p = 0.004). The multivariate analysis showed that patients who had both recurrent seizures and multiple brain cysts also had a higher risk of relapse than those with single seizures or single cysts (p = 0.05). This study suggests that the prognosis of epilepsy due to neurocysticercosis is not as benign as previously thought. Patients with residual calcifications and those with both recurrent seizures and multiple cysts before albendazole therapy have the highest rate of relapse after withdrawal of antiepileptic drugs.     

Need for electroencephalogram video confirmation of atypical absence seizures in children with Lennox-Gastaut syndrome

Children with childhood epileptic encephalopathy (Lennox-Gastaut syndrome) frequently have both multiple seizure types and nonepileptic stereotyped events that are difficult to differentiate. We hypothesize that electroencephalogram (EEG) video monitoring is essential for correct identification of atypical absence seizures in this population. All video/EEG monitoring records on patients with confirmed Lennox-Gastaut syndrome between September 1992 and December 1996 were reviewed for clinical events and EEG changes. A subset of patients with suspected atypical absence seizures during the video/EEG formed the cohort for analysis. Thirty-eight patients had 48 monitoring periods ranging from 1 to 4 days (mean, 2.2 days). Twenty-six monitoring periods captured suspected atypical absence seizures and formed the study cohort. Suspected atypical absence seizures were epileptic seizures in only 27% (7 of 26) of the study cohort. By contrast, parents reliably and correctly identified tonic, atonic, and tonic-clonic seizures in the study cohort. Reliable diagnosis and subsequent counting of atypical absence seizures in patients with Lennox-Gastaut syndrome cannot be made on the basis of observation and/or history alone. Future outpatient studies of investigational anticonvulsant medications for patients with Lennox-Gastaut syndrome should consider parental counts of atypical absence seizures unreliable. We recommend that video/EEG monitoring be done on all Lennox-Gastaut syndrome patients with suspected atypical absence seizures not controlled by medication.     

Problematic standards: improving organizational performance through the assess and improve phases

Since 1987, we have diagnosed 10 patients, 4 males and 6 females, aged 2-11 years at the last evaluation, who all met the following criteria of severe myoclonic epilepsy in infancy (SMEI): generalized or unilateral long-lasting febrile clonic seizures in the first year of life; the subsequent appearance of myoclonic seizures and other types of seizure (partial seizures, atypical absences and convulsive status epilepticus); and neuropsychological deterioration for a certain period. Family histories of epilepsy and febrile seizures could be traced in 1 and 3 cases, respectively. None of them had previous personal history of brain insult. Electroencephalographic (EEGic) recordings in febrile seizure stage were normal; and continuous prophylaxis with phenobarbital failed to prevent the recurrence of febrile seizures. EEG studies in myoclonic stage showed generalized spike-and-waves, polyspike-and-waves, focal abnormalities and/or photosensitivity. The seizures were highly resistant to antiepileptic drugs. Our experiences suggested that comedication of valproic acid, clonazepam and carbamazepine may be most effective in treatment of the diverse seizures including myoclonic seizures, myoclonic-tonic-clonic seizures, atypical absences and partial seizures. Myoclonic seizures and atypical absences diminished in parallel to a clear-cut decrease in generalized abnormalities on EEG in 4 cases aged more than 7 years. However, the partial seizures, secondarily generalized seizures and status epilepticus were still present. Further investigations should aim to identify the underlying etiology and to search more effective treatment.     

Seizures involving the supplementary sensorimotor area in children: a video-EEG analysis

Most reports of supplementary sensorimotor seizures have been of adults with medically refractory epilepsy. Typically, supplementary sensorimotor seizures have onset in childhood. We describe the electroclinical features in 12 children. Cases were selected from an EEG laboratory population in whom video-EEG was performed routinely on all children. Supplementary sensorimotor seizures were diagnosed when there was bilateral tonic posturing of the upper or lower extremities, preserved consciousness, and lack of postictal confusion. Sensory auras were reported by 8 of 9 children aged > 3 years who had daytime seizures. Speech arrest occurred in all patients in whom it could be assessed, and abnormal vocalization was observed in 7 children. Interictal EEGs were often normal (49% of recordings), and ictal EEG changes could be subtle. An etiology was demonstrated in only 2 children, and brain imaging studies were normal in the other 10 patients. Seizures were controlled with antiepileptic drugs (AEDs) in 6 of the 12 children. The clinical manifestations of supplementary sensorimotor seizures in children are similar to those reported in adults; misdiagnosis is common at all ages.     

Effects of aspirin treatment on survival in non-insulin-dependent diabetic patients with coronary artery disease. Israeli Bezafibrate Infarction Prevention Study Group

We studied seizures that occur during the acute phase of aseptic and bacterial meningitis in childhood. Of the 108 children with aseptic meningitis, five had seizures (4.7%). Four patients developed them within 24 hours of the onset of the initial symptom (fever in 3 cases), and three had repeated seizures on the first day. One case had SIADH complication, but another neurologic abnormalities were not observed. On the 18 children with bacterial meningitis, three cases (16.7%) had seizure, which occurred on the second day of illness. Disturbance of consciousness and cerebral hypertension were observed in 2 cases each, and abnormal cerebral CT findings in all the three. The NSE level in the cerebrospinal fluid was elevated in 2 cases. Thus, seizures occurring in the acute phase of aseptic meningitis may reflect transient cerebral functional abnormality accompanying fever or SIADH, whereas those in bacterial meningitis may result from neural tissue damage due to encephalopathy or angitis. In aseptic and bacterial meningitis, the presence of seizures in the acute phase was not correlated with the neurological outcome.     

Dynamic cerebral autoregulation during sevoflurane anesthesia: a comparison with isoflurane

OBJECTIVE: To study the incidence and pattern of epilepsy in patients with periventricular leukomalacia (PVLM) in two specialty clinic settings. BACKGROUND: Motor and cognitive deficit as well as epilepsy are common in patients with PVLM. With modern imaging techniques, PVLM is now easily recognized. METHODS: Epileptic seizures and syndromes as well as motor and cognitive deficits were correlated with MRI findings. Two patient populations were studied: Group A-children with cerebral palsy and PVLM presenting to a center for children with motor disability (n = 19); and Group B-epileptic patients with PVLM presenting to a tertiary epilepsy center (n = 12). A single patient with PVLM and epilepsy who underwent extensive investigations, including intracranial EEG telemetry, is reported. RESULTS: In Group A, 47% of patients had epilepsy (9/19). PVLM was found in 1.27% of patients investigated for epilepsy at a tertiary epilepsy center (12/942). The majority of patients in both groups had multiple seizure types, with complex partial seizures being most common. Of patients with seizures (Groups A and B), 85.7% had intractable epilepsy (18/21). Intracranial EEG in the illustrative case demonstrated a multifocal epileptic process with occipitotemporal predominance. CONCLUSIONS: PVLM was an uncommon underlying cause in patients presenting with epilepsy (Group A); however, patients presenting with motor disability and PVLM (Group B) had a high incidence of seizures. PVLM in epileptic patients is associated with multiple seizure types and medically refractory disease.     

Ofloxacin-induced seizure

OBJECTIVE: To describe a possible case of ofloxacin-induced generalized tonic-clonic seizure. Although the etiology is unknown, ofloxacin most likely precipitated this patient's seizure threshold because of sepsis or secondary to drug accumulation due to the patient's compromised renal function. CASE SUMMARY: A 69-year-old white woman with non-small-cell lung cancer and a history of central nervous system metastatic disease treated with radiation therapy presented to the emergency department with symptoms of urosepsis. Because of multiple drug allergies she was started on ofloxacin (hospital formulary quinolone). After 4 days of therapy she developed a generalized tonic-clonic seizure. A computed tomography scan of the head with and without contrast was negative. The ofloxacin was discontinued and aztreonam therapy was started. Phenytoin therapy was instituted and, despite serum concentrations below the conventional therapeutic range, there was no recurrence of seizure. Subsequent discontinuation of phenytoin did not result in a seizure for this patient. DISCUSSION: Seizures induced by the fluoroquinolones are uncommon. The histopathologic features of this phenomenon are currently unknown. In this patient, imaging studies were negative for structural defects, ruling out metastasis as the cause of the seizure. Therefore, an investigation of drug-related causes ensued. The most likely offending agent was ofloxacin. Ofloxacin has been reported in the literature as a cause of seizures in patients with compromised renal function. CONCLUSIONS: This case and other reports indicate that fluoroquinolones, including ofloxacin, may contribute to seizure development in patients with or without a history of epilepsy. Fluoroquinolone therapy should be used with caution in patients with risk factors for the development of drug-induced seizures.     

Temperature, age, and recurrence of febrile seizure

OBJECTIVE: Prediction of a recurrent febrile seizure during subsequent episodes of fever. DESIGN: Study of the data of the temperatures, seizure recurrences, and baseline patient characteristics that were collected at a randomized placebo controlled trial of ibuprofen syrup to prevent febrile seizure recurrences. SETTING: Two pediatric hospitals in the Netherlands. PATIENTS: A total of 230 children with an increased risk of febrile seizure recurrence. MAIN OUTCOME MEASURE: Seizure recurrence during a subsequent fever episode. RESULTS: A total of 509 episodes of fever were registered with 67 recurrences; 35 (52%) recurrences within the first 2 hours after fever of onset had a lower median temperature (39.3 degrees C) than 32 (48%) after more than 2 hours of fever (40.0 degrees C, P<.001). Poisson regression analysis resulted in 3 univariably significant (P<.05) predictors of a recurrence of seizure during a subsequent episode of fever. In a multivariable model, they were corrected for their correlation: interval between the last previous seizure and fever of onset less than 6 months (relative risk= 1.3 [95% confidence interval: 0.8-2.4]), age at fever of onset (relative risk=0.7 [95% confidence interval: 0.5-1.0] per year increase) and temperature at fever of onset (relative risk = 1.7 [95% confidence interval: 1.1-2.8] per degree Celsius increase). CONCLUSIONS: Half of the recurrent seizures occur in the first 2 hours after fever of onset of a subsequent fever episode. If seizure recurs at a later time, the temperature at seizure is higher compared with recurrences occurring in the first 2 hours of fever. Young age at fever of onset, high temperature at fever of onset, and high temperature during the episode of fever are associated with an increased risk of a recurrent febrile seizure at the moment that a child with a history of febrile seizures has fever again.     

Adolescent onset of idiopathic photosensitive occipital epilepsy after remission of benign rolandic epilepsy

PURPOSE: We describe 2 girls, aged 19 years, who experienced a rolandic seizure at ages 4 and 5, respectively, together with the interictal EEG features of benign rolandic epilepsy (BRE). In adolescence both patients developed photosensitive occipital seizures accompanied by spontaneous and photic-induced occipital EEG paroxysms. METHODS: We have been following 33 patients with a history of BRE, between ages 12 and 28 years (mean 17 years). Twenty-one of these patients had experienced their last rolandic seizure before the age of 10 years and 9 of them had been without treatment since age 11 or earlier. In 2 of these 9 patients, other types of seizures recurred after remission of BRE. Clinical, EEG, and evoked potential findings on these 2 patients are presented. RESULTS: After having experienced BRE, both patients suffered partial seizures from age 12, with elementary visual hallucinations, visual blurring, slow head turning, cephalic pain, epigastric discomfort, unresponsiveness, and vomiting. Seizure onset was related to watching TV or exposure to bright light. EEG showed interictal occipital spikes, and a photoparoxysmal response limited to the occipital lobes. Visual evoked potentials were greatly increased in amplitude. One patient had two visual attacks only and remained seizure free after 4 years of follow-up, while the other had seizures controlled by an association of valproate and carbamazepine. CONCLUSIONS: Clinical and neurophysiological characteristics suggest that these two patients may have presented different age-related expressions within the spectrum of a benign seizure susceptibility syndrome rather than sharply distinct epilepsy syndromes.     

Paediatric pain management--the next step?

Congenital bilateral perisylvian syndrome (CBPS) is a recently described, neuronal migration disorder, characterized by pseudobulbar palsy, epilepsy and mental retardation and bilateral perisylvian dysplasia. A 15-year-old boy was diagnosed with CBPS according to the typical clinical, and magnetic resonance imaging (MRI) features. The patient was suffering from atypical absence seizures, repeating daily in spite of antiepileptic drug therapy, since age 7 years. He had also experienced rare generalized tonic-clonic seizures and complex partial seizures. Neurological examination showed severe restriction of tongue movements, severe dysarthria, dysphagia, facial diplegia, mild pyramidal signs and moderate mental retardation. A computed tomographic (CT) scan demonstrated bilateral perisylvian enlargement. The diagnosis was corrected with MRI after six years. Frequent irregular generalized spike and wave abnormalities and focal sharp and slow waves over the posterior regions of both hemispheres were shown by electroencephalograms (EEG). The patient was treated with Na-Valproate, carbamazepine and lamotrigine but did now show any significant change in seizure frequency in the eight-year follow-up period. Intractable seizures, mental retardation and particularly congenital pseudobulbar palsy suggest this congenital entity. Those patients who exhibit these typically clinical features, must have MRI.     

Surgical treatment of extratemporal epilepsy: clinical, radiologic, and histopathologic findings in 60 patients

PURPOSE AND METHODS: The aim of this study was to analyze clinical, radiologic, and histopathologic findings in 60 consecutive patients with medically intractable extratemporal epilepsy who were operated on between November 1987 and May 1993. RESULTS: Histologically, there were distinct structural abnormalities in 50 (83%) of the surgical specimens. Signal abnormalities on magnetic resonance imaging (MRI) were present in all patients with neoplastic lesions (n = 17) and in 94% of patients with nonneoplastic focal lesions (n = 32). Overall, structural abnormalities were detected by MRI in 47 (96%) of 49 patients with focal lesions. During a mean follow-up of 4 years, 30 (54%) patients remained completely seizure free, 11 (20%) had < or = 2 seizures per year, seven (12%) showed a seizure reduction of > or = 75%, and eight (14%) had < 75% reduction in seizure frequency. The fraction of seizure-free patients was 12 (80%) of 15 in patients with neoplastic lesions, 16 (52%) of 31 in patients with nonneoplastic focal lesions, and two (20%) of 10 for those without histopathologic abnormalities. The differences in seizure outcome between patients with and without focal lesions were statistically significant (p < 0.05), if seizure-free outcome was compared with persistent seizures. CONCLUSIONS: Focal lesions and particularly neoplasms are associated with improved postoperative seizure control compared with patients without histopathologic abnormalities. We advise caution in considering surgery to treat extratemporal epilepsy in patients who have normal MRI scans, because the outcome with the approach described in this study is poor in such cases.     

Clinical and electrographic manifestations of lesional neocortical temporal lobe epilepsy

To determine whether lesional neocortical temporal lobe epilepsy (NTLE) can be differentiated from mesial temporal lobe epilepsy (MTLE) during the noninvasive presurgical evaluation, we compared the historical features, seizure symptomatology, and surface EEG of 8 patients seizure free after neocortical temporal resection with preservation of mesial structures and 20 patients after anterior temporal lobectomy for MTLE. Seizure symptomatology of 107 seizures (28 NTLE, 79 MTLE) was analyzed. One hundred one ictal EEGs (19 NTLE, 82 MTLE) were reviewed for activity at seizure onset; presence, distribution, and frequency of lateralized rhythmic activity (LRA); and distribution of postictal slowing. Seizure symptomatology and EEG data were compared between groups, and sensitivity, specificity, and positive and negative predictive values were determined for variables that differed significantly. Multiple logistic regression was used to determine whether patients could be correctly classified as having MTLE or NTLE. MTLE patients were younger at onset of habitual seizures and more likely to have a prior history of febrile seizures, CNS infection, perinatal complications, or head injury. NTLE seizures lacked features commonly exhibited in MTLE, including automatisms, contralateral dystonia, searching head movements, body shifting, hyperventilation, and postictal cough or sigh. NTLE ictal EEG recordings demonstrated lower mean frequency of LRA that frequently had a hemispheric distribution, whereas LRA in MTLE seizures was maximal over the ipsilateral temporal region. We conclude that it may be possible to differentiate lesional NTLE from MTLE on the basis of historical features, seizure symptomatology, and ictal surface EEG recordings. This may assist in the identification of patients with medically refractory nonlesional NTLE who frequently require intracranial monitoring and more extensive or tailored resections.     

Effects of intracerebroventricular injection of histamine on memory deficits induced by hippocampal lesions in rats

This review was conducted to evaluate the long-term prognosis of children responding to vigabatrin by examining the incidence of increased seizure frequency, loss of efficacy, and appearance of new seizures in a cohort of 196 children (mean age, 68.2 months; range, 2 months to 19 years) with drug-resistant epilepsy, who had received vigabatrin as add-on treatment in clinical trials. The results indicate that an increase in seizure frequency was uncommon, occurring in only 10% of children with highly drug-resistant epilepsy and that it usually appears shortly after the initiation of treatment. It was clearly not dose-dependent and most often occurred in patients with nonprogressive myoclonic epilepsy. No specific seizure type was specially involved and usually the problem reversed on discontinuing vigabatrin. Loss of efficacy was also uncommon (12% of patients), and again no specific seizure type was found to be associated. Epilepsy syndrome does seem to be a better predictor of loss of efficacy because it occurred most often in symptomatic generalized epilepsies and cryptogenic infantile spasms. A total of 21 patients (11%) developed genuinely new types of seizures. Fifteen of these patients developed new partial seizures that had little impact on the patients' overall clinical improvement. The new partial seizures were better tolerated than the initial seizure type which in most cases had disappeared. Approximately 3% of patients experienced new generalized seizures that aggravated their initial condition. These occurred most often in patients with nonprogressive myoclonic epilepsy; therefore vigabatrin should be used with particular caution in such patients.     

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

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