Correlations between abnormalities on brain SPECT scan and interictal EEG-foci in children with 'intractable' partial epilepsy

SPECT scanning with Tc99mHM-PAO was performed on 40 children with 'intractable' partial epilepsy; 27 patients had abnormalities on SPECT images consisting of areas of decreased cerebral blood flow. In 18 of these 27 subjects there was a good correlation between site of the abnormalities on SPECT scan and interictal EEG foci. 12 patients with regionally decreased CBF had also neuroimaging (C.T. and/or R.M.I.) abnormalities. The brain SPECT provides more precise detection of epileptogenic foci, when used to complement EEG, also in childhood-onset epilepsy.     

Tooth-brushing epilepsy: a report of a case with structural and functional imaging and electrophysiology demonstrating a right frontal focus

Patients with reflex epilepsies may provide insights into cerebral pathophysiology. We report a patient with an unusual form of reflex epilepsy in whom seizures are induced by tooth brushing. Magnetic resonance imaging (MRI) demonstrated a right posterior frontal low-grade tumor predominantly involving the precentral gyrus. Video-telemetry demonstrated right-sided epileptiform activity during a typical induced complex partial seizure. An ictal single photon emission computed tomography (SPECT) scan showed an area of hyperfusion that corresponded to the MRI lesion on coregistration with a surface-matching technique. A subsequent coregistered interictal SPECT scan demonstrated hypoperfusion in the same region. Ours is the first report to demonstrate a structural focus in this unusual form of reflex epilepsy. Possible mechanisms to explain the induction of the seizures are discussed.     

Direct isolation, phenotyping and cloning of low-frequency antigen-specific cytotoxic T lymphocytes from peripheral blood

A 21-year-old male presented with temporal lobe epilepsy associated with a venous angioma in the ipsilateral frontal lobe, presenting as intractable complex partial seizures. Neuroimaging showed a cerebral venous angioma in the right dorsolateral and opercular frontal lobe, and atrophy of the right hippocampus. As the ictal electroencephalogram (EEG) obtained with subdural electrodes indicated spike discharges initiating from the right mesial temporal lobe, temporal lobectomy was performed. The patient was seizure-free after the operation. Patients with epilepsy who have a cerebral venous angioma require precise analysis of the seizure pattern and an ictal EEG because of cerebral venous angioma may be associated with an another epileptogenic lesion which is surgically treatable.     

Gallium scanning in cerebral and cranial disorders

Gallium scanning of cranial and cerebral abnormalities is a complex topic in which neither the mechanism of gallium accumulation or the clinical utility can be clearly defined. In the tests available to the neurologist, neurosurgeon, or practitioner, the gallium brain scan, computed tomographic brain scan, or other noninvasive studies are inconclusive. Its use as a primary localization test for CNS tumors does not appear to be warranted in view of the high sensitivity reported for conventional nuclide brain scanning, as well as computed tomography. In selected cases, the use of a gallium brain scan has been helpful in the differentiation of CNS lesions, as well as the early detection of intracerebral infection. New techniques involving 67Ga may eventually prove useful in the evaluation of CNS disorders, especially in the area of quantitating the amount of abnormal brain tissue removed following craniotomy.     

De novo epileptic confusional status in a patient with cobalamin deficiency

A 80-year-old man with cobalamin deficiency and no history of epilepsy developed a partial complex epileptic confusional status (ECS) unresponsive to acute i.v. diazepam. Brain CT scan and MRI investigation ruled out a focal cerebral lesion. Therapy with high doses (10,000 micrograms i.m. daily) of cobalamin alone was started, and the patient fully recovered in the following 72-hour. Control EEGs repeatedly performed days and weeks later showed progressive disappearance of the frontal interictal spiking, while the patient was on monotherapy with cobalamin (5,000 micrograms i.m. weekly). A month later the patient unfortunately discontinued replacement therapy and 13 weeks later he developed a fatal convulsive epileptic status. To our knowledge the association of ECS and cobalamin deficiency has not been previously reported.     

Preictal SPECT in temporal lobe epilepsy: regional cerebral blood flow is increased prior to electroencephalography-seizure onset

Peri-ictal SPECT provides unique information on the dynamic changes in regional cerebral blood flow (rCBF) that occur during seizure evolution and, thus, could be useful in clarifying the poorly understood interplay of the interictal and ictal states in human focal epilepsy. The regional hyperperfusion observed on ictal SPECT is generally believed to be a consequence of electrical seizure activity. However, recent studies using invasive long-term cortical CBF monitoring have demonstrated that rCBF changes occur up to 20 min prior to ictal electroencephalography (EEG) onset. Because of apparent technical difficulties, no preictal SPECT studies have been reported so far. Therefore, we present our results on two patients with temporal lobe epilepsy in whom preictal SPECT scans were performed fortuitously under continuous video-EEG monitoring control. METHODS: Technetium-99m-hexamethyl propyleneamine oxime was injected 11 min (Patient 1) and 12 min (Patient 2) before clinical and EEG seizure onset, as documented from simultaneous video-EEG monitoring in two patients with temporal lobe epilepsy. We obtained accurate anatomical reference of CBF changes visible on SPECT by a special coregistration technique of MRI and SPECT. RESULTS: Whereas interictal SPECT showed a hypoperfusion of the temporal lobe ipsilateral to the seizure focus, on preictal SPECT, a significant increase in rCBF in the epileptic temporal lobe could be observed. These rCBF changes were not accompanied by any significant changes of the ongoing EEG. CONCLUSION: Our study provides evidence that rCBF is increased in the epileptic temporal lobe several minutes before EEG seizure onset. Thus, rCBF changes observed on peri-ictal SPECT scan cannot be considered a mere consequence of EEG seizure activity but may rather reflect a change in neuronal activity precipitating the transition from the interictal to the ictal state.     

Ictal cerebral blood flow in seizures originating in the posterolateral cortex

In selecting patients for epilepsy surgery, it is important to distinguish mesial temporal seizures from seizures originating in the posterolateral cortex. We studied ictal cerebral perfusion in five patients with complex partial seizures with clear posterior EEG ictal onsets and clinical seizures semiology suggesting seizure origin in the posterolateral cortex. METHODS: Ictal SPECT was performed during video EEG monitoring using 99mTc-HMPAO as a cerebral perfusion tracer and a rotating gamma camera to acquire images. RESULTS: Three patterns of ictal hyperperfusion were seen: pattern A = temporoparieto-occipital junction extending into the lateral temporal cortex, involving the mesial temporal cortex and basal ganglia to a lesser degree and a small area of hyperperfusion in the contralateral parietal cortex (two patients); pattern B = pattern A but with no hyperperfusion of the mesial temporal cortex (one patient); and pattern C = localized hyperperfusion in the area of the temporoparieto-occipital junction (two patients). CONCLUSION: Our results suggest distinct patterns of ictal perfusion in seizures with posterolateral ictal EEG onsets. Ictal SPECT may be useful in distinguishing such seizures.     

Merosin-negative congenital muscular dystrophy, occipital epilepsy with periodic spasms and focal cortical dysplasia. Report of three Italian cases in two families

We report clinical, EEG and neuroimaging findings of three patients in two Italian families with merosin-negative congenital muscular dystrophy (CMD), drug-resistant occipital epilepsy, diffuse persistent cerebral white matter changes and focal cortical dysplasia. Clinical and epilepsy histories, EEG and neuroimaging findings were very similar in all patients. Seizures started in childhood and mainly consisted of periodic spasms, a particular type of partial seizure characterized by clusters of epileptic spasms. The motor expression of the spasms was very mild so that they had been frequently missed or misinterpreted as non-convulsive generalized absence seizures. Interictal EEG showed occipital spike-waves and bilateral synchronous slow spike-wave discharges. Ictal EEG showed prolonged periodic sequences of slow waves with associated fast rhythm complexes, characteristic of periodic spasms. Two patients had normal intelligence, one patient presented moderate mental retardation. Focal cortical dysplasia in the posterior areas of the brain, in addition to marked diffuse white matter alterations, was detected in the magnetic resonance images of all patients. Findings in these patients indicate that in merosin-negative CMD brain involvement can include cortical dysplasia, in addition to white matter changes. In such cases the brain damage can lead to a childhood-onset localization-related symptomatic occipital epilepsy. Epileptic seizures and cortical dysplasia can be, however, difficult to detect in CMD. The clinical semiology of epileptic seizures may in fact be modified because of muscular weakness. This implies that epilepsy may be misdiagnosed or even missed and EEG-polymyographic recordings may be necessary to identify it. Similarly, cortical dysplasia may be very localized and visible by neuroimaging only if it is carefully investigated on the basis of epileptological and EEG-polymyographic findings.     

Quantitative MRI in outpatient childhood epilepsy

PURPOSE: In adult studies, MRI volumetrics is a proven technique in presurgical assessment of epilepsy. Hippocampal volume loss is maximal in the syndrome of mesial temporal lobe epilepsy. We aimed (a) to validate this methodology in a pediatric outpatient epilepsy population (b) to determine the relationship of hippocampal asymmetry (HA) to epileptic syndromes and risk factors. METHODS: Two neurologists classified the epileptic syndrome in 79 pediatric outpatients, according to the International Classification of Epilepsies and Epileptic Syndromes (ILAE). Hippocampal volumetrics were performed in all patients. HA was defined according to adult control values. RESULTS: Inter-rater variability on measurement of HA was very small (Correlation of test retest of 0.97 on 17 children <3 years old). The rate of HA was 44/79 (57%). In 21 patients, (27%) potentially epileptogenic lesions (other than HA) were identified (cerebral dysgenesis n = 11). HA was present in 9/15 (60%) of temporal lobe epilepsy and in 15/28 (54%) extratemporal onset epilepsy and 5/11 (46%) of generalized symptomatic epilepsy. Analysis confined to <13 years also showed HA was not specific for epileptic syndrome. There was no significant association of febrile convulsions (13%) with HA or temporal lobe epilepsy. CONCLUSIONS: There is a high incidence of HA in childhood epilepsy. HA was not confined to clinically defined temporal lobe epilepsy. The poor correlation of epileptic syndrome to quantitative MRI findings may be due to the inadequacies of epilepsy classification in the younger child, with the clinical semiology providing misleading localizing information. Normative childhood data for hippocampal volumes and symmetry is needed.     

Posthyperventilatory steal response in chronic cerebral hemodynamic stress: a positron emission tomography study

BACKGROUND AND PURPOSE: The alteration of regional cerebral blood flow (CBF) during and after hyperventilation was measured using positron emission tomography (PET) to determine the circulatory response induced by daily respiratory changes in the cerebral area under chronic hemodynamic stress. METHODS: Three normal volunteers and 12 patients with an obstruction of major cerebral arteries underwent PET measurements of the CBF after an injection of H2(15)O: (1) in the resting condition, (2) during hyperventilation (HV scan), (3) 1 to 3 minutes after hyperventilation (post-HV scan), (4) during the inhalation of 5% CO2, and (5) after an injection of acetazolamide. Eleven patients also underwent a 15O gas study to measure CBF, oxygen extraction fraction (OEF), and cerebral blood volume (CBV). RESULTS: (1) In 9 patients, the CBF value in the post-HV scan was lower than that in the HV scan in 1 or more regions in the area of the obstructed arteries, although the PaCO2 level during the post-HV scan was higher than that during the HV scan in all patients. All control regions in the patients and in the normal volunteers showed an elevated CBF in the post-HV scan compared with the HV scan. (2) The negative post-HV response (posthyperventilatory steal) was prominent in 4 patients with moyamoya vessels and in another 5 patients with atherosclerotic disease who had PET evidence of hemodynamic stress (elevated CBV or OEF). (3) The regional pre- to post-HV change in CBF was significantly correlated with the CBF responses to acetazolamide and CO2. CONCLUSIONS: Vasodilatation after the termination of hyperventilation in the normal areas induces a steal response in the cerebral area suffering from hemodynamic stress and may cause profound hypoperfusion in everyday situations. This phenomenon may be important to our understanding of the clinical symptoms and the natural course of chronic cerebral occlusive disease bearing hemodynamic stress.     

Incidence of lesions described by magnetic resonance imaging in the clarification of focal epilepsy of frontal and temporal origin

AIM: Today, MRI is an integral part of the presurgical evaluation of patients suffering from partial epilepsy. These patients frequently show focal morphological abnormalities with potential epileptogenic character and surgical resection of these lesions is associated with superior postsurgical outcome as to seizure frequency. Apart from easily detectable defects, such as post-traumatic lesions or cerebral infarction, as wide variety of mainly small abnormalities can be detected using MRI. METHODS: In this study, 484 patients suffering from partial epilepsy of temporal or frontal onset were evaluated for the incidence of different lesions in this population. RESULTS: All lesions found were included without evaluating their potential epileptogenicity, which remains to be proven using other procedures (EEG, SPECT, PET, etc.). Involvement of the hippocampal formation was a major finding in temporal lobe epilepsy, which could be detected as sclerosis (T2w-images), atrophy (T2w-TSE or T1w-IR-images) or both (15%). In addition and in declining frequency various tumors (14%), post-traumatic lesion (-5%), and focal cortical dysplasia or other disturbances of cortical integrity (-4%) were found. These lesions are detectable with best contrast on different sequences. As a consequence it is suggested to acquire sequences in 3 dimensions including a T1w-SE, two (coronal and axial) double-echo-SE sequences and similarly two T1w-IR-sequences. The application of contrast media can be restricted to special questions, derived either from the first imaging results or from the patients history. CONCLUSION: Using qualitative data for interpretation, the sensitivity as to the detection of any focal pathology of a recent-generation MRI in this population was 75%, with 79% for temporal lobe epilepsies and 67% for frontal lobe epilepsies. Quantitative measurements of hippocampal volume or signal seem to be able to increase the sensitivity of the method.     

FDG-PET and volumetric MRI in the evaluation of patients with partial epilepsy

We performed interictal FDG-PET- and MRI-based hippocampal volumetric measurements on 18 adult patients with complex partial epilepsy of temporal lobe origin in whom we had identified their ictal focus by video-telemetry EEG. Sixteen patients (89%) had regional hypometabolism, 11 (61%) had focal 1.5-tesla T2-weighted MRI (two structural abnormalities, nine hippocampal formation [HF] increased T2 signal), and nine (50%) had absolute HF atrophy ipsilateral to the temporal ictal focus. Ten (55%) had abnormal L/R HF ratios, nine ipsilateral to the EEG focus. All patients with abnormal MRI volumetric studies had focal PET abnormalities. Only seven had both abnormal HF volume ratios and T2 MRI (all increased HF T2 signal). There was a significant correlation between hippocampal volume and inferior mesial and lateral temporal lobe cerebral metabolic rate of glucose asymmetry index (p < 0.01), suggesting that hypometabolism may reflect hippocampal atrophy. PET is more sensitive than MRI volumetry in identifying the ictal focus but does not provide additional information when HF atrophy is present.     

In vivo cerebral metabolism and central benzodiazepine-receptor binding in temporal lobe epilepsy

Positron emission tomography measured interictal cerebral glucose metabolism with [18F]fluorodeoxyglucose and central benzodiazepine-receptor binding with [11C]flumazenil in 10 mesial temporal lobe epilepsy (TLE) patients and in normal subjects. Eight TLE patients had mesial temporal, lateral temporal, and thalamic hypometabolism ipsilateral to EEG ictal onsets, with additional extratemporal hypometabolism in four. One had unilateral anterior mesial temporal hypometabolism only, and one had normal metabolism. Each patient had decreased benzodiazepine-receptor binding in the ipsilateral anterior mesial temporal region, without neocortical changes. Thus, interictal metabolic dysfunction is variable and usually extensive in TLE, whereas decreased central benzodiazepine-receptor density is more restricted to mesial temporal areas. Metabolic patterns in TLE may reflect diaschisis, while benzodiazepine-receptor changes may reflect localized neuronal and synaptic loss that is specific to the epileptogenic zone. [11C]Flumazenil imaging may be useful in presurgical evaluation of refractory complex partial seizures.     

Neuropsychologie de l'épilepsie infantile.

From a neuropsychological standpoint, epilepsy is a very heterogeneous condition. Epilepsies are divided into two categories (focal and generalized) that are differentiated by the neuropsychological symptoms that are present. Cognitive difficulties present in children suffering from focal epilepsy are usually specific to the cerebral area involved, while generalized epilepsies are linked to a diffuse neuropsychological deficit profile as well as to a more limited intellectual functioning. The aim of this article was to establish a neuropsychological profile of the various syndromes of focal and generalized epilepsy, and to outline the psychological and social effects of epilepsy among children with this condition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Active epilepsy in mentally retarded children. I. Prevalence and additional neuro-impairments

A population-based study of active epilepsy was conducted in 6-13-year-old mentally retarded children born between 1975 and 1986. The population at risk comprised 48,873 children. Ninety-eight children were identified, 35 mildly and 63 severely retarded. The prevalence was 2.0 per 1000; 0.7 per 1000 for mildly and 1.3 per 1000 for severely retarded children. Sixty-nine children had at least one additional neuroimpairment. Cerebral palsy was found in 42 children with a majority of spastic/dystonic tetraplegias; visual impairment was present in 24 and autism in 24. Thirty-three children had only a mild or no gross motor disability and mild mental retardation, while 23 had IQs < 20 and a very severe gross motor disability. This study underlines the fact that active epilepsy in mentally retarded children is often associated with additional neuroimpairments, especially a combination of severe cerebral palsy and severe visual impairment.     

Diffusion-weighted imaging in hyperacute stroke--gold standard?

Diffusion-weighted imaging (DWI) is more sensitive than CT and conventional T2-weighted MR imaging in the detection of early cerebral ischemia and infarction. In this case report, we present a case of a 79-year-old woman with symptoms of acute stroke, clinically and radiologically documented progression to complete stroke with an initial negative diffusion-weighted scan.     

Seizure disorders in the dog. 1. Clinical features and differential diagnosis

For differential diagnosis, therapy, and prognosis of seizures in dogs it is recommended to distinguish between two groups of diseases: 1. Epilepsy is diagnosed if seizures occur repeatedly without an active, underlying disorder. Idiopathic epilepsy occurs most commonly. A hereditary component has been demonstrated in several breeds. Symptomatic epilepsy results from previous resolved forebrain disorders, which cause epileptic seizures through scar formation. 2. Seizures are caused by active structural forebrain disease or metabolic-toxic imbalances. Upon initial presentation of the dog, a preliminary classification may be achieved with the seizure history, clinical and neurological examination, and routine laboratory evaluation. The diagnosis of idiopathic epilepsy is based on typical seizure history and exclusion of structural forebrain disease and metabolic-toxic imbalances with special laboratory testing, CSF examination, and brain scanning procedures.     

Imaging epileptogenic tubers in children with tuberous sclerosis complex using alpha-[11C]methyl-L-tryptophan positron emission tomography

Several reports have indicated that cortical resection is effective in alleviating intractable epilepsy in children with tuberous sclerosis complex (TSC). Because of the multitude of cortical lesions, however, identifying the epileptogenic tuber(s) is difficult and often requires invasive intracranial electroencephalographic (EEG) monitoring. As increased concentrations of serotonin and serotonin-immunoreactive processes have been reported in resected human epileptic cortex, we used alpha-[11C]methyl-L-tryptophan ([11C]AMT) positron emission tomography (PET) to test the hypothesis that serotonin synthesis is increased interictally in epileptogenic tubers in patients with TSC. Nine children with TSC and epilepsy, aged 1 to 9 years (mean, 4 years 1 month), were studied. All children underwent scalp video-EEG monitoring, PET scans of glucose metabolism and serotonin synthesis, and EEG monitoring during both PET studies. [11C]AMT scans were coregistered with magnetic resonance imaging and with glucose metabolism scans. Whereas glucose metabolism PET showed multifocal cortical hypometabolism corresponding to the locations of tubers in all 9 children, [11C]AMT uptake was increased in one tuber (n=3), two tubers (n=3), three tubers (n=1), and four tubers (n=1) in 8 of the 9 children. All other tubers showed decreased [11C]AMT uptake. Ictal EEG data available in 8 children showed seizure onset corresponding to foci of increased [11C]AMT uptake in 4 children (including 2 with intracranial EEG recordings). In 2 children, ictal EEG was nonlocalizing, and in 1 child there was discordance between the region of increased [11C]AMT uptake and the region of ictal onset on EEG. The only child whose [11C]AMT scan showed no regions of increased uptake had a left frontal seizure focus on EEG; however, at the time of his [11C]AMT PET scan, his seizures had come under control. [11C]AMT PET may be a powerful tool in differentiating between epileptogenic and nonepileptogenic tubers in patients with TSC.     

A particular type of epilepsy in patients with congenital hemiparesis associated with polymicrogyria or unilateral pachygyria

INTRODUCTION: Magnetic resonance has permitted the recognition of cortical dysplasias in patients with congenital hemiparesia and epilepsy. OBJECTIVE: To study the clinic-EEG characteristics and course of epilepsy in patients with congenital hemiparesia and unilateral polymicrogyria. METHODS AND RESULTS: We analyzed the clinical histories of 11 patients seen between 1990 and 1996. We studied 6 girls and 5 boys aged between 5 and 13 years, with a follow-up period of from 1 to 6 years. The epilepsy began at between 1 and 6 years old with partial motor seizures. On EEG there were frontotemporal spikes in 9 cases, temporooccipital in 1 and parieto-occipital in another. All 11 patients had hemiparesia, with slight mental retardation in 9 patients and moderate mental retardation in 2. The CT/MR brain scan showed unilateral polymicrogyria. At between 2 and 8 years of age, all 11 patients developed subintrant atonic crises with a pseudo-ataxic gait, absences in 7 patients and myoclonia in 3. Awake EEG showed bilateral asymmetrical spikes. During sleep 7 patients had continuous spikewave discharges and 4 had frequent asymmetrical bilateral spikes. Four patients relapsed. Five patients are free of crises, five have sporadic crises and one continues to have daily crises. CONCLUSIONS: These patients had hemiparetic cerebral paralysis, slight mental retardation and epilepsy. At about the age of 6 a peculiar electro-clinical condition developed. Response to treatment was satisfactory, although the follow-up period is still not long.     

Roles of glutamate receptor in c-fos gene expression and epilepsy susceptibility in rats

We use NMDA to induce expression of c-fos mRNA as a marker to observe the activity of NMDA receptor in neurons during development, and compare the activity of NMDA receptor between audiogenic epilepsy -prone (P77PMC) and audiogenic epilepsy resistant rats brain. In primary culture of rats cerebral cortical neurons NMDA induced c-fos mRNA expression exhibits dose and time-dependent changes, which can be prevented by antagonists. During the development of neurons, the NMDA -induced c-fos mRNA expression reaches a maximum at day 24. NMDA-induced c-fos mRNA expression of P77PMC rats is higher than that of controls during 6 to 24 days in vitro with significant difference (P < 0.05) at day 18. To present changes in c-fos mRNA expression induced by NMDA in cultured P77PMC rat cortical neurons may be one of the factors related to susceptibility of epilepsy in P77PMC rats.