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Vagus nerve stimulation for medication-resistant generalized epilepsy. E04 VNS Study Group.

We treated 24 generalized epilepsy patients with vagus nerve stimulation (VNS), comparing seizure rates during a 1-month baseline with 3 months of VNS. Median seizure rate reduction was -46%. Sixteen of the 24 patients had better than a -30% reduction and 11 of the 24 patients had better than a -50% reduction in seizure rate. A mild cough during stimulation occurred in six patients. Patients with higher baseline seizure rates and later ages at epilepsy onset had the best responses to VNS. Our findings suggest VNS is an effective treatment for medication-resistant generalized epilepsy even in patients as young as 4 years.

Adolescent↗

Association of HLA class II alleles in patients with juvenile myoclonic epilepsy compared with patients with other forms of adolescent-onset generalized epilepsy.

Reports have suggested an association of juvenile myoclonic epilepsy (JME) with an HLA-DR allele. We examined the HLA-DR and DQ frequencies in two populations of epilepsy patients: (1) JME patients and (2) patients with other forms of adolescent-onset, idiopathic generalized epilepsy (IGE). We did DNA-based HLA typing on 24 JME patients and 24 patients with non-JME forms of adolescent-onset IGE, forms that are clinically similar to JME. In typing the HLA region, we paid particular attention to the alleles contributing to the HLA-DR13 type and also to the DQB1 locus alleles that are in linkage disequilibrium with the alleles that comprise the DR13 type. We also examined the HLA-AP locus, which is centromeric to the DR locus. The frequency of DR13 was significantly higher in JME compared with the non-JME patients. Nine JME patients, compared with two non-JME patients, carried that type (chi 2 = 5.78 [p < 0.017, 1 df]). The odds ratio was 6.6. Furthermore, the DQB1 alleles in linkage disequilibrium with the alleles contributing to the DR13 type were also more frequent in JME than in non-JME epilepsy patients. The chi 2 is highly significant (8.1, p < 0.005) with an odds ratio of 13.8. These results confirm that JME is an HLA-associated form of epilepsy. They also show that the JME locus probably lies within the HLA region, most likely between the HLA-DP and HLA-B loci. The association studies also confirm linkage results showing that JME is genetically different from some other IGEs and emphasize that careful diagnosis is critical to genetic studies of the epilepsies.

Adolescent↗

Polygenic control of idiopathic generalized epilepsy phenotypes in the genetic absence rats from Strasbourg (GAERS).

PURPOSE: Generalized nonconvulsive absence seizures are characterized by the occurrence of synchronous and bilateral spike-and-wave discharges (SWDs) on electroencephalographic recordings, concomitant with behavioral arrest. The GAERS (genetic absence rats from Strasbourg) strain, a well-characterized inbred model for idiopathic generalized epilepsy, spontaneously develops EEG paroxysms that resemble those of typical absence seizures. The purpose of this study was to investigate the genetic control of SWD variables by using a combination of genetic analyses and electrophysiological measurements in an experimental cross derived from GAERS and Brown Norway (BN) rats. METHODS: SWD subphenotypes were quantified on EEG recordings performed at both 3 and 6 months in a cohort of 118 GAERS x BN F2 animals. A genome-wide scan of the F2 progenies was carried out with 146 microsatellite markers that were used to test each marker locus for evidence of genetic linkage to the SWD quantitative traits. RESULTS: We identified three quantitative trait loci (QTLs) in chromosomes 4, 7, and 8 controlling specific SWD variables in the cross, including frequency, amplitude, and severity of SWDs. Age was a major factor influencing the detection of genetic linkage to the various components of the SWDs. CONCLUSIONS: The identification of these QTLs demonstrates the polygenic control of SWDs in the GAERS strain. Genetic linkages to specific SWD features underline the complex mechanisms contributing to SWD development in idiopathic generalized epilepsy.

Action Potentials↗

Tonic status epilepticus in patients with idiopathic generalized epilepsy.

RATIONALE: Tonic status epilepticus (TSE) in patients with idiopathic generalized epilepsy (IGE) is not well recognized. The objective of this study is to report episodes of TSE in patients with IGE. METHODS: We retrospectively reviewed the clinical and EEG evaluation of three IGE patients who presented TSE. RESULTS: The three patients had mainly clinical features of IGE, but had developed, in addition, focal discharges, diffuse EEG abnormalities and some focal or diffuse neuropsychological dysfunction. The tonic attacks eventually responded to treatment, but were not completely controlled in any of the patients. DISCUSSION: The continuum between IGE and secondary generalized epilepsy is demonstrated in these patients. Most of their clinical and EEG features are however, in keeping with an idiopathic generalized epileptic process with additional focal and diffuse components. Recognition of the significance of TSE in such patients has important therapeutic and prognostic implications. [Published with video sequences].

Adult↗

Magnetic stimulation of the brain in generalized epilepsy: reversal of cortical hyperexcitability by anticonvulsants.

Observations on experimental models suggest that diffuse cortical hyperexcitability is an important abnormality in the generalized epilepsies. We used the threshold for transcranial magnetic stimulation as an index of motor cortical excitability in 89 neurologically normal control subjects and 56 patients with idiopathic generalized epilepsy (20 untreated and 36 chronically treated with anticonvulsants). Magnetic stimulation was repeated in 10 patients after valproate monotherapy had been commenced and in 23 control subjects. The threshold intensity was significantly lower in the untreated patients (46 +/- 5% [mean +/- 95% confidence interval]) than in the control subjects (56 +/- 2%). Treated patients had significantly higher thresholds (64 +/- 4%) than did untreated patients and control subjects. A significant increase in threshold intensity (8 +/- 2%) occurred in patients retested after starting valproate; there was no significant change in retested control subjects (-1 +/- 2%). Threshold intensity was positively correlated with plasma valproate levels (rs = 0.37). The findings suggest that cortical excitability is increased in idiopathic generalized epilepsy and is reduced following anticonvulsant treatment. Transcranial magnetic stimulation is of use in examining the pathophysiology of generalized epilepsy. Furthermore, changes in threshold intensity in response to anticonvulsant treatment may prove useful in guiding therapy.

Adolescent↗

EEG-fMRI of idiopathic and secondarily generalized epilepsies.

We used simultaneous EEG and functional MRI (EEG-fMRI) to study generalized spike wave activity (GSW) in idiopathic and secondary generalized epilepsy (SGE). Recent studies have demonstrated thalamic and cortical fMRI signal changes in association with GSW in idiopathic generalized epilepsy (IGE). We report on a large cohort of patients that included both IGE and SGE, and give a functional interpretation of our findings. Forty-six patients with GSW were studied with EEG-fMRI; 30 with IGE and 16 with SGE. GSW-related BOLD signal changes were seen in 25 of 36 individual patients who had GSW during EEG-fMRI. This was seen in thalamus (60%) and symmetrically in frontal cortex (92%), parietal cortex (76%), and posterior cingulate cortex/precuneus (80%). Thalamic BOLD changes were predominantly positive and cortical changes predominantly negative. Group analysis showed a negative BOLD response in the cortex in the IGE group and to a lesser extent a positive response in thalamus. Thalamic activation was consistent with its known role in GSW, and its detection in individual cases with EEG-fMRI may in part be related to the number and duration of GSW epochs recorded. The spatial distribution of the cortical fMRI response to GSW in both IGE and SGE involved areas of association cortex that are most active during conscious rest. Reduction of activity in these regions during GSW is consistent with the clinical manifestation of absence seizures.

Adolescent↗

EEG features in idiopathic generalized epilepsy: clues to diagnosis.

PURPOSE: To investigate the EEG profile and its contribution for diagnosis and management in a group of patients with a clinical diagnosis of idiopathic generalized epilepsy (IGE) who were referred to a tertiary hospital. METHODS: We retrospectively studied clinical and EEG features of 180 consecutive patients with IGE. Eighty patients were diagnosed with juvenile myoclonic epilepsy (JME), 35 had absence epilepsy (AE), 13 had generalized tonic-clonic seizures on awakening (GTCS-A), 28 had generalized tonic-clonic seizures only (TCS), and 24 had adult-onset idiopathic generalized epilepsy (AIGE). The EEGs were classified in typical (synchronous generalized spike or polyspikes-and-wave discharges with normal background), atypical (with clear focalities or asymmetries), and normal. RESULTS: The 493 EEG exams were analyzed. The first EEG was normal in 45% of the 180 patients, and only 33% had typical abnormalities. AE had a higher proportion of typical examinations and needed fewer sequential examinations to register a typical abnormality compared with the other groups. By contrast, the serial EEG profile of TCS and AIGE showed a higher proportion of normal and atypical EEG findings. CONCLUSIONS: These findings support previous recommendations that IGE patients should be treated with appropriate therapy based on clinical history. Waiting for a typical abnormal EEG pattern can generate an unacceptable delay in the correct diagnosis and treatment of these patients. In patients with long-term epilepsy, the diagnosis may be difficult. Furthermore, serial EEGs can help to elucidate the syndromic diagnosis, especially in patients with TCS and AIGE.

Adolescent↗

[Persistence of point-waves in the encephalogram (EEG) in idiopathic generalized epilepsy and therapeutic decisions].

We reviewed the literature on the following issues in idiopathic generalized epilepsy, is there a correlation between the persistence of seizures and electroencephalographic anomalies? Do point-waves observed in well-controlled patients constitute a factor predicting relapse? Do changes in paroxysmal anomalies during the disease course mean poor prognosis? Actually, there is very little literature on these issues and some disagreement in those data which have been published. Documented studies have been conducted in search of factors predicting relapse at treatment withdrawal, but little has been published concerning the role of the EEG. Few studies specifically mention idiopathic generalized epilepsy. In terms of the syndrome studied, they concern heterogeneous groups of patients. Generally, it is accepted that the EEG helps predict clinical course in idiopathic generalized epilepsy as it does in other epilepsies, given the characteristic EEG signs. This is true in patients under treatment and after treatment withdrawal. Risk errors were not however reported. II would appear reasonable to assume that no one EEG anomaly is determinant outside the clinical context.

Electroencephalography↗

Absence epilepsy with fast rhythmic discharges during sleep: an intermediary form of generalized epilepsy?

PURPOSE: To describe a particular form of absence epilepsy (AE) characterized by an atypical EEG pattern (fast rhythmic discharges) during sleep and an unfavorable course with the persistence of seizures at a late age and drug resistance. METHODS: We reviewed the medical files of 31 patients diagnosed with AE at our institution been 1995 and 1999 for whom an EEG during sleep had been recorded. Patients with fast rhythmic discharges during sleep were selected for the study. RESULTS: Five patients showed the usual criteria of childhood absence epilepsy (CAE) or juvenile absence epilepsy (JAE), but with fast discharges of rhythmic spikes (10-15 Hz) during sleep. such as those typically observed in Lennox-Gastaut syndrome. Four patients were of adult age at the time of the last examination. Intellectual capacities were "borderline" in each case, with visible social and learning handicaps. Absences were the initial seizure event in all patients, but four patients developed generalized tonic-clonic seizures during the course of the disease. Treatment using a combination of antiabsence drugs such as valproate and lamotrigine led to only marginal improvement. CONCLUSIONS: These findings illustrate the utility of sleep EEG in detecting the fast rhythmic discharges that are markers of drug resistance in AE and suggest the existence of transitional forms of AE that are intermediate between idiopathic and cryptogenic/symptomatic generalized epilepsies.

Adult↗

MRI volumetry of the thalamus in temporal, extratemporal, and idiopathic generalized epilepsy.

OBJECTIVE: To examine the specificity of thalamic atrophy in epilepsy. METHODS: Thalamic volume measurements were carried out using high-resolution MRI in 40 patients with pharmacologically intractable temporal lobe epilepsy (TLE), 16 patients with extratemporal lobe epilepsy (ETE), and 17 with idiopathic generalized epilepsy (IGE). Thalamic volumes of patients were compared with those of 21 neurologically normal control subjects. Volumes were correlated with duration of epilepsy. The effect of prolonged febrile seizures and generalized seizures on thalamic volumes was examined. RESULTS: Compared with normal control subjects, patients with TLE had a reduction in thalamic volume ipsilateral to the seizure focus. Thalamic volumes in patients with ETE and IGE were not significantly different from those of normal control subjects. In TLE patients, thalamic volumes ipsilateral to the seizure focus were negatively correlated with duration of epilepsy. Patients with a history of prolonged febrile seizures had more severe thalamic atrophy ipsilateral to the seizure focus than those without febrile seizures. CONCLUSIONS: Thalamic atrophy ipsilateral to the seizure focus is found in TLE but not in other forms of focal epilepsy or IGE. In TLE, thalamic atrophy is correlated with duration of disease. Patients with a history of prolonged febrile seizures had smaller thalamic volumes ipsilateral to the seizure focus than those without.

Adolescent↗

Lamotrigine associated with exacerbation or de novo myoclonus in idiopathic generalized epilepsies.

Five patients with idiopathic generalized epilepsies (IGE) treated with lamotrigine (LTG) experienced exacerbation or de novo appearance of myoclonic jerks (MJ). In three patients, LTG exacerbated MJ in a dose-dependent manner with early aggravation during titration. MJ disappeared when LTG dose was decreased by 25 to 50%. In two patients, LTG exacerbated MJ in a delayed but more severe manner, with myoclonic status that only ceased after LTG withdrawal.

Adult↗

Time modulation of spike-and-wave activity in generalized epilepsy.

Nineteen patients aged 4 to 44 years with generalized epilepsy and generalized 3 Hz spike-and-wave activity, were monitored for 24 or 36 hours on one to nine occasions to determine the time distribution of ictal and interictal electroencephalographic discharges and the consistency of the time patterns observed. Two patients with a low incidence of spike-and-wave activity had a random pattern of occurrence; the other 17 showed one of three types of time modulation. The latter can be explained by the interaction of two modulative processes, one with a period of about 100 minutes and the other of approximately 24 hours. The pattern observed depends on the phase angle of the two cyclic processes. Treatment with ethosuximide altered the pattern of time modulation, and eventually, when the spike-and-wave activity was reduced to a low level, the time distribution became random.

Adolescent↗

Autism in several members of a family with generalized epilepsy with febrile seizures plus.

The neurobiologic basis for autism is not well understood. In contrast, there have been several recent discoveries into the genetics of generalized epilepsy with febrile seizures plus, a group of epilepsy syndromes characterized by multiple seizure phenotypes. Here we describe a family with generalized epilepsy with febrile seizures plus and variably expressed autism spectrum disorder that does not show linkage to any of the four known generalized epilepsy with febrile seizures plus loci. A relationship between these two disorders has not previously been described.

Adult↗

The thalamic commissure in generalized epilepsy.

In selected patients callosotomy usually dramatically improves disabling generalized epilepsy, but it also may be without any effect. This paradox might be due to the anatomical variability of the thalamic commissure, which interconnects thalamic nuclei essential to the dynamics of seizures. The commissure may be as thick as a finger or absent.

Animals↗

Genome scan of idiopathic generalized epilepsy: evidence for major susceptibility gene and modifying genes influencing the seizure type.

Idiopathic generalized epilepsy (IGE) is a common, complex disease with an almost exclusively genetic etiology but with variable phenotypes. Clinically, IGE can be divided into different syndromes. Varying lines of evidence point to the involvement of several interacting genes in the etiology of IGE. We performed a genome scan in 91 families ascertained through a proband with adolescent-onset IGE. The IGEs included juvenile myoclonic epilepsy (JME), juvenile absence epilepsy (JAE), and epilepsy with generalized tonic clonic seizures (EGTCS). Our linkage results support an oligogenic model for IGE, with strong evidence for a locus common to most IGEs on chromosome 18 (lod score 4.4/5.2 multipoint/two-point) and other loci that may influence specific seizure phenotypes for different IGEs: a previously identified locus on chromosome 6 for JME (lod score 2.5/4.2), a locus on chromosome 8 influencing non-JME forms of IGE (lod score 3.8/2.5), and, more tentatively, two newly discovered loci for absence seizures on chromosome 5 (lod scores 3.8/2.8 and 3.4/1.9). Our data also suggest that the genetic classification of different forms of IGE is likely to cut across the clinical classification of these subforms of IGE. We hypothesize that interactions of different combinations of these loci produce the related heterogeneous phenotypes seen in IGE families.

Adolescent↗