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Biomedical subjects

Frederick Andermann

Publications and source records attributed to Frederick Andermann.

At least 19 recordsLinked to original sources
PubMed2006

Early onset Rasmussen's syndrome: a malignant, often bilateral form of the disorder.

Early onset of Rasmussen's syndrome, chronic encephalitis and epilepsy, is associated with a greater tendency to bilateral disease. A cluster of such children is described. This form has a poor prognosis and is usually fatal. This may be related to immaturity of the immune system. Bilateral involvement, as distinct from bilateral epileptic discharges, has also been described in adults but seems to have a more favourable prognosis. Isolated patients treated with immune modulating agents may also have bilateral disease but the significance of the treatment accounting for the contralateral spread requires further observations.

Age of Onset↗
PubMed2006

Unusually mild tuberous sclerosis phenotype is associated with TSC2 R905Q mutation.

OBJECTIVE: To report the clinical manifestations and functional aspects of Tuberous Sclerosis Complex (TSC), resulting from Codon 905 mutations in TSC2 gene. METHODS: We performed a detailed study of the TSC phenotype and genotype in a large French-Canadian kindred (Family A). Subsequently, clinical and molecular data on 18 additional TSC families with missense mutations at the same codon of TSC2 were collected. Functional studies were performed on the different missense changes and related to the phenotype. RESULTS: A 2714G>A (R905Q) mutation was identified in Family A. The TSC phenotype in this family was unusually mild and characterized by hypomelanotic macules or focal seizures that remitted spontaneously or were easily controlled with medication. Diagnostic criteria were met in only a minority of mutation carriers. Other families with the R905Q mutation were found to have a similar mild phenotype. In contrast, patients with a 2713C>T (R905W) or a 2713C>G (R905G) mutation had more severe phenotypes. Although all three amino acid substitutions were pathogenic, the R905W and R905G substitutions affected tuberin function more severely than R905Q. INTERPRETATION: Codon 905 missense mutations in TSC2 are relatively common. The TSC2 R905Q mutation is associated with unusually mild disease, consistent with functional studies. Combined with previous reports, it is apparent that certain TSC2 missense mutations are associated with a mild form of tuberous sclerosis, which in many patients does not meet standard diagnostic criteria. These findings have implications for the large number of patients with limited clinical features of TSC and for genetic counseling in these families.

Adolescent↗
PubMed2006

Temporal and extratemporal BOLD responses to temporal lobe interictal spikes.

PURPOSE: Simultaneous EEG and functional MRI (fMRI) allows measuring metabolic changes related to interictal spikes. Our objective was to investigate blood oxygenation level-dependent (BOLD) responses to temporal lobe (TL) spikes by using EEG-fMRI recording. METHODS: We studied 35 patients who had a diagnosis of temporal lobe epilepsy (TLE) and active TL spiking on routine scalp EEG recording. Two-hour sessions of continuous EEG-fMRI were recorded, and spikes were identified after offline artifact removal and used as events in the fMRI analysis. Each type of spike was analyzed separately, as one EEG-fMRI study. We determined significant (p < 0.05) positive (activation) and negative (deactivation) BOLD responses for each study. RESULTS: Twenty-seven patients had spikes during scanning (19 unilateral and eight bilateral). From a total of 35 fMRI studies, 29 (83%) showed BOLD responses: 14 had both activations and deactivations; 12, activations only; and three, deactivations only. Six (17%) showed no responses. Nineteen studies had mainly neocortical TL activation: Sixteen (84%) of 19 concordant with spikes, 12 of 16 with concomitant activation of the contralateral TL, and 16 of 19 with additional extratemporal activation; few showed exclusively mesial TL activation. Seventeen studies showed deactivation, either extratemporal plus temporal (n = 8) or exclusively extratemporal (n = 9). CONCLUSIONS: BOLD responses to TL spikes occurred in 83% of studies, predominated in the spiking temporal lobe, and manifested as activation or deactivation. Responses often involved the contralateral homologous cortex at the time of unilateral spikes and were frequently observed in extratemporal regions, suggesting that TL epileptic spikes can affect neuronal activity at a distance through synaptic connections.

Adult↗
PubMed2006

Seizure outcome after resection of cavernous malformations is better when surrounding hemosiderin-stained brain also is removed.

PURPOSE: Considering the epileptogenic effect of cavernoma-surrounding hemosiderin, assumptions are made that resection only of the cavernoma itself may not be sufficient as treatment of symptomatic epilepsy in patients with cavernous malformations. The purpose of this study was to test the hypothesis whether seizure outcome after removal of cavernous malformations may be related to the extent of resection of surrounding hemosiderin-stained brain tissue. METHODS: In this retrospective study, 31 consecutive patients with pharmacotherapy-refractory epilepsy due to a cavernous malformation were included. In all patients, cavernomas were resected, and all patients underwent pre- and postoperative magnetic resonance imaging (MRI). We grouped patients according to MRI findings (hemosiderin completely removed versus not/partially removed) and compared seizure outcome (as assessed by the Engel Outcome Classification score) between the two groups. RESULTS: Three years after resection of cavernomas, patients in whom hemosiderin-stained brain tissue had been removed completely had a better chance for a favorable long-term seizure outcome compared with those with detectable postoperative hemosiderin (p=0.037). CONCLUSIONS: Our study suggests that complete removal of cavernoma-surrounding hemosiderin-stained brain tissue may improve epileptic outcome after resection of cavernous malformations.

Adolescent↗
PubMed2006

Efficacy of and morbidity associated with stereoelectroencephalography using computerized tomography--or magnetic resonance imaging-guided electrode implantation.

OBJECT: The purpose of this paper was to define the general efficacy of and morbidity associated with stereoelectroencephalography using modem methods of imaging and to particularize the risks related to specific lobes of the brain. METHODS: All patients admitted to the Montreal Neurological Institute who had undergone either computerized tomography- or magnetic resonance imaging-guided electrode implantation by one surgeon (A.O.) were reviewed. The procedure was considered efficient if the obtained information was sufficient to make a decision either in support of or against surgery. Two hundred seventeen patients underwent 224 implantations with 3022 electrodes. Complications related to each lobe were as follows: temporal lobe, two abscesses (0.54%); frontal lobe, one abscess and three hematomas (1.4%); and occipital lobe, one hypointense lesion found 1 week after electrode explantation (2.6%). Significant risk factors associated with hematomas were implantation in the frontal lobe (p < 0.05) and the use of four or more implanted electrodes (p < 0.025). General complications included the following: 26 patients, psychiatric symptoms during monitoring; one patient, meningitis; four patients, scalp cellulitis; and two patients, hemiparesis during angiography in the early 1980s. One of these latter patients maintained a mild hemiparesis and represents the only case of permanent neurological sequela in the entire series. Data obtained during recordings supported an indication for surgery in 178 patients (79.5%), excluded a surgical option in 37 patients (16.5%), and were unsatisfactory in nine patients (4%). Thus, the overall efficacy as defined previously was 96%. CONCLUSIONS: Stereoelectroencephalography is an efficient procedure with low associated morbidity. Bilateral exploration of the temporal lobes has a morbidity rate of approximately 1%. A higher risk of hematomas occurs with the implantation of four or more electrodes in the frontal lobes.

Adult↗
PubMed2006

Post-ictal forceful yawning in a patient with nondominant hemisphere epilepsy.

Yawning has been rarely described in association with seizures and not previously documented by video-EEG. We present a 48-year-old woman with a long history of non-dominant for speech hemisphere seizures and post-ictal yawning. Yawning was irresistible, forceful and often repetitive. We reviewed the few similar epileptic cases described in the literature and discussed the possible mechanisms. [Published with video sequences].

Electroencephalography↗
PubMed2005

Identification of a VPS13A founder mutation in French Canadian families with chorea-acanthocytosis.

Mutations in VPS13A cause chorea-acanthocytosis (ChAc), an autosomal recessive neurodegenerative disorder. VPS13A is located in a tail-to-tail arrangement with GNA14 on chromosome 9q21. ChAc shows substantial allelic heterogeneity, with no single VPS13A mutation causing the majority of cases. We examined 11 patients in four French Canadian ChAc pedigrees for mutations in VPS13A. Affected members of three families were homozygous for a 37-kb deletion of the four terminal exons of VPS13A (EX70_EX73del). This deletion also encompasses the two terminal exons of GNA14. Two affected females in family 4 were homozygous for the splicing mutation 4242+1G>T. Remarkably, the affected males in this highly consanguineous pedigree were compound heterozygotes for EX70_EX73del and 4242+1G>T. PCR analysis of the deletion breakpoint junction revealed that an additional patient with French Canadian ancestry was heterozygous for the EX70_EX73del allele. The identification of a common 9q21 haplotype associated with EX70_EX73del in at least four apparently unrelated ChAc families implies that ChAc shows a founder effect in French Canadians, and that routine testing for EX70_EX73del in suspected ChAc cases may therefore be worthwhile in this population. The deletion breakpoint PCR described here will enable rapid identification of both homozygous and heterozygous carriers of EX70_EX73del.

Age of Onset↗
PubMed2005

Cortical triggers in generalized reflex seizures and epilepsies.

Activation of specific cortical territories by sensory stimuli or of less restricted areas of the brain by cognitive stimuli is known to induce apparently generalized seizures in predisposed patients; this is clinically and electroencephalographically distinct from reflex triggering of partial seizures. Photosensitive patients may have seizures when exposed to environmental stimuli producing appropriate flickering light or geometric patterns. Some children with benign myoclonic epilepsy in infancy have seizures triggered by unexpected touch or noise. Seizures induced by thinking have been reported in response to non-verbal higher mental activity such as mental arithmetic. Praxis-induced seizures are triggered by similar mental activities accompanied by the use of the hands. Language-induced seizures are usually triggered by verbal higher mental activity. Functional imaging and other methods have contributed to understanding how these seizures arise. Patients with these generalized reflex seizures appear to have regions of cortical hyperexcitability overlapping or coinciding with areas physiologically activated during specific sensory stimulations and cognitive or motor activities. When these areas receive appropriate afferent volleys and a critical mass of cortex is activated, an epileptic activity is produced that ultimately involves cortico-reticular or cortico-cortical pathways resulting in a generalized or bilateral epileptic event.

Cerebral Cortex↗
PubMed2005

The role of periventricular nodular heterotopia in epileptogenesis.

A temporal resection in patients with periventricular nodular heterotopia (PNH) and intractable focal seizures yields poor results. To define the role of heterotopic grey matter tissue in epileptogenesis and to improve outcome, we performed stereoencephalography (SEEG) recordings in eight patients with uni- or bilateral PNH and intractable focal epilepsy. The SEEG studies aimed to evaluate the most epileptogenic areas and included the allo- and neocortex and at least one nodule of grey matter. Interictal spiking activity was found in ectopic grey matter in three patients, in the cortex overlying the nodules in five and in the mesial temporal structures in all. At least one heterotopion was involved at seizure onset in six patients, synchronous with the overlying neocortex or ipsilateral hippocampus. Two patients had their seizures originating in the mesial temporal structures only. Six patients had surgery and the resected areas included the seizure onset, with follow-up from 1 to 8 years. An amygdalo-hippocampectomy was performed in two (Engel class Id and III), an amygdalo-hippocampectomy plus removal of an adjacent heterotopion in two (class Ia), and a resection of two contiguous nodules plus a small rim of overlying occipital cortex in one patient (class Id). One patient with bilateral PNH had three adjacent nodules resected and an ipsilateral amygdalo-hippocampectomy resulting in a reduction of the number of seizures by 25-50%. The best predictor of surgical outcome is the presence of a focal epileptic generator; this generator may or may not include the PNH. Invasive recording is required in patients with PNH; it improves localization and is the key to better outcome.

Adolescent↗
PubMed2005

Cognitive functioning in bilateral perisylvian polymicrogyria (BPP): clinical and radiological correlations.

Bilateral perisylvian polymicrogyria (BPP) is a malformation of cortical development, frequently associated with severe dysarthria or anarthria. BPP patients are therefore often labeled as severely retarded, but a detailed neuropsychological profile has not been reported to date. In a series of 14 patients, we demonstrated that only a minority had extremely low intelligence, and that some aspects of cognitive function correlated with the extent of the cortical disorganization. Early age at seizure onset correlated positively with Performance IQ scores (P<0.05) and negatively with the extent of the lesion (P<0.01), reflecting that patients with more severe BPP are more likely to have early seizure onset, resulting in greater interference with ongoing cognitive development. Receptive and expressive language skills were found to be equally poor. Frontal lobe function and memory abilities were relatively well preserved, suggesting that the observed cognitive profiles were related, at least in part, to specific areas of cortical dysfunction and not only to global dysfunction.

Adult↗
PubMed2005

Resolution of periodic alternating nystagmus after decompression for Chiari malformation.

CASE REPORT: A 20-year-old female presented with horizontal jerk nystagmus, blurred vision, severe headaches, unsteady gait, and paresthesia. Magnetic resonance imaging revealed Chiari malformation I. Symptoms resolved after decompression of the posterior cranial fossa and removal of the right cerebellar tonsil. COMMENTS: Conditions associated with acquired periodic alternating nystagmus and ocular disorders associated with Chiari malformation are discussed. To our knowledge, this case is the first to report the resolution of periodic alternating nystagmus after neurosurgical decompression.

Adult↗
PubMed2005

Transient edematous lesions of the splenium in epileptic patients.

BACKGROUND: Transient focal lesions in the splenium of the corpus callosum (SCC) have been previously described in patients with epilepsy or without epilepsy but receiving antiepileptic drugs (AED). CASE REPORTS: Two epileptic patients were admitted to our long-term monitoring unit. Antiepileptic drugs were completely discontinued a few days later. One patient had no seizures. The other had three attacks, the last of which occurred two days before a brain magnetic resonance imaging (MRI) was performed. In both cases brain MRI showed a lesion in the SCC characterized by high signal on T2-weighted images and no enhancement after Gadolinium infusion. The patients were discharged with their pre-admission medications. A follow-up MRI five weeks later showed resolution of the SCC lesions. CONCLUSIONS: The pathogenesis of transient SCC lesions in epileptic patients is still unclear. In our patients, either the sudden AED withdrawal or the seizures activity may be presumed to be the cause, though an individual susceptibility must also be considered.

Adult↗
PubMed2005

Mechanisms, genetics, and pathogenesis of juvenile myoclonic epilepsy.

PURPOSE OF REVIEW: This review addresses the mechanisms, genetics and pathogenesis of juvenile myoclonic epilepsy (JME, Janz syndrome). RECENT FINDINGS: Although JME is a well defined clinical syndrome among the idiopathic generalized epilepsies (IGEs), recent studies suggest that JME is distinct from other IGE syndromes and must be considered separately for the purposes of genetic studies. Clinical, morphological and metabolic data suggest a preferential role for frontal regions in this syndrome. However, JME is clinically and genetically heterogeneous. Although several major genes for JME have been identified and pathogenetic mechanisms suggested based on these findings, these genes account for only a small proportion of JME cases, suggesting multifactorial or complex inheritance in most. The roles played by other major genes, susceptibility genes and environmental factors in the pathogenesis of JME remain to be defined. SUMMARY: JME is clinically and genetically heterogeneous and should be considered separately from other IGE syndromes. Proposed mechanisms, such as those involving microdysgenesis or altered neuronal inhibition, may be related to different genetic abnormalities in different patients. Major genes account for relatively few cases, and most cases appear to involve multifactorial or complex inheritance.

Child↗
PubMed2005

Cortical resection with electrocorticography for intractable porencephaly-related partial epilepsy.

PURPOSE: We evaluated the results of cortical resection of epileptogenic tissue for treatment of intractable porencephaly-related epilepsy. METHODS: We examined clinical features, electrophysiological data, surgical findings, and seizure outcomes after cortical resection in eight patients with intractable epilepsy related to porencephalic cysts. RESULTS: All eight patients had hemiparesis. Five retained motor function in the hemiparetic extremities; six retained visual fields. All had partial seizures, six with secondary generalization. Seven patients had simple and three had complex partial seizures (CPSs); two also had drop attacks. Four patients had multiple seizure types. Long-term scalp video-EEG (LVEEG) localized interictal epileptic abnormalities that anatomically corresponded to the cyst location in three patients. LVEEG recorded ictal-onset zones in five; these anatomically corresponded to the cyst location in three of the five. EEG recorded generalized seizures in two patients, hemispheric in one, and multifocal in two. Intraoperative electrocorticography (ECoG) revealed interictal epileptic areas extending beyond the margins of the cyst in seven patients. We resected ECoG-localized interictal epileptic areas completely in five patients and partially in two. Cortical resection was based on seizure semiology and LVEEG in one patient whose ECoG showed no epileptiform discharges. After a minimum follow-up of 1 year, six patients had excellent seizure outcome (Engel class I), and two had a >90% seizure reduction (Engel class III) without complications. CONCLUSIONS: Cortical resection guided by ECoG allows preservation of motor function and visual field and provides an effective surgical procedure for treatment of intractable epilepsy secondary to porencephaly.

Adolescent↗
PubMed2005

Genetic focal epilepsies: state of the art and paths to the future.

The concept of genetic focal epilepsies is relatively new as compared to awareness of the importance of genetic factors in the generalized epilepsies. However, in the past decade, there has been increasing recognition of families with dominantly inherited partial epilepsies. Better definition of the phenotypes allows identification of distinct syndromes. The main familial focal epilepsies are autosomal-dominant nocturnal frontal lobe epilepsy (ADNFLE), familial mesial TLE (FMTLE), familial lateral TLE (FLTLE), and familial partial epilepsy with variable foci (FPEVF). The only genes identified so far are those for ADNFLE and FLTLE. In these disorders, functional studies are the next step and could provide advances leading to clarification of the pathophysiology as well as to new therapeutic strategies. At present, we can provide genetic counseling and a more accurate prognosis for most of the familial focal epilepsies. Greater awareness of the genetic basis in this group of disorders by the treating physicians is essential for identification of new families. This will allow further linkage studies, candidate gene screening, and identification of new genes, which will hopefully result in genetically based prevention and treatment.

Adolescent↗
PubMed2005

Antimyoclonic efficacy of piracetam in idiopathic generalized epilepsy.

Piracetam, a derivative of gamma-aminobutyric acid (GABA), has been used extensively for treatment of myoclonus in a variety of conditions, but not in patients with idiopathic generalized epilepsy (IGE). We have treated a patient with juvenile myoclonic epilepsy who had frequent and inconvenient morning myoclonus with 3,200 mg of piracetam daily. She had had only two generalized tonic-clonic seizures, with the last seizure 10 years earlier. Her obesity precluded the use of sodium valproate. She had a dramatic response to piracetam with sustained cessation of myoclonus and no side effects during 1.5 years' follow-up. Further trials of piracetam for control of myoclonus in patients with IGE are justified.

Comorbidity↗