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Biomedical subjects

Frederick Andermann

Publications and source records attributed to Frederick Andermann.

At least 55 records · Page 3Linked to original sources
PubMed2003

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↗
PubMed2003

Nonsyndromic mental retardation and cryptogenic epilepsy in women with doublecortin gene mutations.

DCX mutations cause mental retardation in male subjects with lissencephalypachygyria and in female subjects with subcortical band heterotopia (SBH). We observed four families in which carrier women had normal brain magnetic resonance imaging (MRI) and mild mental retardation, with or without epilepsy. Affected male subjects had SBH or pachygyria-SBH. In two families, the phenotype was mild in both genders. In the first family, we found a tyr138his mutation that is predicted to result in abnormal folding in the small hinge region. In the second family, we found an arg178cys mutation at the initial portion of R2, in the putative beta-sheet structure. Carrier female subjects with normal MRI showed no somatic mosaicism or altered X-inactivation in lymphocytes, suggesting a correlation between mild mutations and phenotypes. In the two other families, with severely affected boys, we found arg76ser and arg56gly mutations within the R1 region that are predicted to affect DCX folding, severely modifying its activity. Both carrier mothers showed skewed X-inactivation, possibly explaining their mild phenotypes. Missense DCX mutations may manifest as non-syndromic mental retardation with cryptogenic epilepsy in female subjects and SBH in boys. Mutation analysis in mothers of affected children is mandatory, even when brain MRI is normal.

Adolescent↗
PubMed2003

alpha-[11C]-Methyl-L-tryptophan PET identifies the epileptogenic tuber and correlates with interictal spike frequency.

Epilepsy surgery has been successfully performed in patients with tuberous sclerosis complex (TSC) and seizures arising from a restricted epileptogenic area. The outcome of cortical excision depends on accurate pre-surgical identification of the epileptogenic tuber. [11C] alpha-methyl-L-tryptophan (alpha-MTrp) was originally developed to measure serotonin synthesis in vivo with positron emission tomography (PET). However in pathologic conditions its uptake may also depend on the synthesis of quinolinic or kynurenic acid via the kynurenine pathway. Increased levels of serotonin and quinolinic acid have been observed in epileptogenic lesions, raising the possibility that alpha-MTrp PET may localize the epileptogenic area. The aim of this study was to correlate alpha-MTrp PET uptake with the localization of the epileptogenic area and with interictal spike frequency in patients with TSC. alpha-MTrp uptake was measured in 8 patients (2 males, mean age 29.6+/-14.9 years, range 3-50 years) with intractable partial epilepsy due to TSC. All patients underwent scalp EEG monitoring during the PET scan. In four (50%), increased uptake of alpha-MTrp occurred in the epileptogenic area alone. Two (25%) patients showed multifocal abnormalities and the remaining two (25%) did not show focal changes. PET localization was mostly seen in patients with frequent interictal abnormalities on the EEG. Furthermore, there was a significant correlation between alpha-MTrp uptake and the frequency of interictal spikes (r=0.6; P<0.05). alpha-MTrp PET is a promising diagnostic tool in the localization of the epileptogenic area in patients with TSC.

Adolescent↗
PubMed2003

Automated detection of focal cortical dysplasia lesions using computational models of their MRI characteristics and texture analysis.

Focal cortical dysplasia (FCD), a malformation of cortical development, is a frequent cause of pharmacologically intractable epilepsy. FCD is characterized on Tl-weighted MRI by cortical thickening, blurring of the gray-matter/white-matter interface, and gray-level hyperintensity. We have previously used computational models of these characteristics to enhance visual lesion detection. In the present study we seek to improve our methods by combining these models with features derived from texture analysis of MRI, which allows measurement of image properties not readily accessible by visual analysis. These computational models and texture features were used to develop a two-stage Bayesian classifier to perform automated FCD lesion detection. Eighteen patients with histologically confirmed FCD and 14 normal controls were studied. On the MRI volumes of the 18 patients, 20 FCD lesions were manually labeled by an expert observer. Three-dimensional maps of the computational models and texture features were constructed for all subjects. A Bayesian classifier was trained on the computational models to classify voxels as cerebrospinal fluid, gray-matter, white-matter, transitional, or lesional. Voxels classified as lesional were subsequently reclassified based on the texture features. This process produced a 3D lesion map, which was compared to the manual lesion labels. The automated classifier identified 17/20 manually labeled lesions. No lesions were identified in controls. Thus, combining models of the T1-weighted MRI characteristics of FCD with texture analysis enabled successful construction of a classifier. This computer-based, automated method may be useful in the presurgical evaluation of patients with severe epilepsy related to FCD.

Adult↗
PubMed2003

fMRI activation in continuous and spike-triggered EEG-fMRI studies of epileptic spikes.

PURPOSE: To evaluate functional magnetic resonance imaging (fMRI) with simultaneous EEG for finding metabolic sources of epileptic spikes. To find the localizing value of activated regions and factors influencing fMRI responses. METHODS: Patients with focal epilepsy and frequent spikes were subjected to spike-triggered or continuous fMRI with simultaneous EEG. Results were analyzed in terms of fMRI activation, concordance with the location of EEG spiking and anatomic MRI abnormalities, and other EEG and clinical variables. In four patients, results also were compared with those of intracerebral EEG. RESULTS: Forty-eight studies were performed on 38 patients. Seventeen studies were not analyzed, primarily because no spikes occurred during scanning. Activation was obtained in 39% of 31 studies, with an activation volume of 2.55 +/- 4.84 cc. Activated regions were concordant with EEG localization in almost all studies and confirmed by intracerebral EEG in four patients. Forty percent of patients without an MRI lesion showed activation; 37.5% of patients with a lesion had an activation; the activation was near or inside the lesion. Bursts of spikes were more likely to generate an fMRI response than were isolated spikes (76 vs. 11%; p < 0.05). CONCLUSIONS: Combining EEG and fMRI in focal epilepsy yields regions of activation that are presumably the source of spiking activity. These regions are highly linked with epileptic foci and epileptogenic lesions in a significant number of patients. Activation also is found in patients with no visible MRI lesion. Intracerebral recordings largely confirm that these activation regions represent epileptogenic areas. It is still unclear why many patients show no activation.

Action Potentials↗
PubMed2003

Outcome of surgical treatment in familial mesial temporal lobe epilepsy.

PURPOSE: To describe postoperative outcome in patients with familial mesial temporal lobe epilepsy (FMTLE). METHODS: We studied FMTLE patients who underwent surgical treatment for refractory seizures. FMTLE was defined when at least two individuals in a family had a clinical EEG diagnosis of MTLE. Preoperative investigation included magnetic resonance imaging (MRI), interictal/ictal EEGs, and neuropsychological evaluation. We used Engel's classification for postoperative outcome. RESULTS: To date, 20 FMTLE patients have been operated on, with 1.6 to 9.8 years of follow-up (mean, 5.5 years). Hippocampal atrophy (HA) and other signs of mesial temporal sclerosis (MTS) were present in 18 patients (15 unilateral). Seizures were recorded in 19 patients. Seventeen (85%) patients are in class I. Two patients had normal hippocampal volumes (HcV): one (5%) is in class II and the other (5%) in class IV (extratemporal seizures developed after surgery). One (5%) patient had bilateral HA and is in class III. Qualitative histopathology showed MTS with different degrees of severity. CONCLUSIONS: Refractory FMTLE patients have good surgical outcome when unilateral or clearly asymmetric HA is identified. Preoperative investigation should be the same as that in patients with sporadic refractory MTLE.

Adult↗
PubMed2003

The effects of adjunctive topiramate on cognitive function in patients with epilepsy.

PURPOSE: We investigated possible cognitive effects of topiramate (TPM) in polypharmacy on patients with intractable epilepsy. METHODS: Study 1 evaluated 22 consecutively admitted patients whose antiepileptic drugs (AEDs) on admission to the Montreal Neurological Hospital included TPM. Performance on neuropsychological tests administered on and subsequently off TPM was analyzed. Four patients also were tested before taking TPM, allowing comparisons off, then on, and then off the drug again. Measures included intellectual function, verbal and nonverbal memory, language, word and design fluency, somatosensory sensitivity, and motor skills. In Study 2, 16 patients at the Minnesota Epilepsy Group were tested first off, then on TPM with nine cognitive tasks that measured concentration, verbal fluency, language, and psychomotor speed. RESULTS: In Study 1, significant (p < or = 0.01) improvements were observed off TPM on 13 measures including verbal and nonverbal fluency and certain verbal and perceptual tasks. Notably, verbal learning and memory were unaffected; a limited effect was observed on nonverbal memory. Patients tested 3 times scored better in both tests off TPM compared with on this drug. In Study 2, declines on TPM were observed on all measures, significantly (p < or = 0.05) for tests of fluency, sustained concentration, and visual motor processing speed. CONCLUSIONS: TPM was associated with declines in fluency, attention/concentration, processing speed, language skills, and perception; working memory but not retention was affected. As the two studies used an opposite order of testing on versus off TPM, our results clearly show a performance decrement while patients are taking TPM, without respect to which condition is tested first.

Adolescent↗
PubMed2003

Bilateral Rasmussen encephalitis: postmortem documentation in a five-year-old.

A case of Rasmussen encephalitis with bilateral involvement and onset at age 2 years is reviewed. Rasmussen encephalitis is a rare progressive disease that causes intractable seizures, cognitive decline, and inflammatory changes in the brain. The neurologic involvement is characteristically unilateral. Bilateral involvement in this case was suspected within 5 months of presentation and was confirmed by bilateral frontal lobe biopsies. The severity and progression of the disease in this case was remarkable and resulted in the patient's death by age 5 years, despite numerous attempted therapeutic interventions. Autopsy findings confirmed the diagnosis of Rasmussen encephalitis with bilateral involvement.

Atrophy↗
PubMed2003

Hypothalamic hamartoma and seizures: a treatable epileptic encephalopathy.

Hypothalamic hamartomas may be associated with gelastic seizures, focal seizures, and a generalized epileptic encephalopathy, with severe seizures and cognitive and behavior decline. Despite earlier views to the contrary, good evidence now exists that all these clinical features are caused, directly or indirectly, by the hamartoma. Resection of these lesions was long regarded as too hazardous and unlikely to benefit seizure control. It is now clear that hypothalamic hamartomas can be effectively treated with a variety of surgical approaches with sustained seizure control and often seizure freedom. Qualitative observations suggest that behavior and cognition also improve with treatment, but quantitative validation is required. The specific approach should be tailored according to the surgical anatomy of the lesion and the experience of the surgeon. Choices include a transcallosal approach (good for intraventricular lesions), a pterional approach (useful for interpeduncular lesions), a transventricular endoscopic approach, or destruction of the lesion with radiofrequency probes or gamma knife radiosurgery. The previously dismal outlook for children with severe seizures associated with this lesion has now dramatically changed. These insights may have implications for other epileptic encephalopathies of childhood.

Adolescent↗
PubMed2003

Entorhinal cortex MRI assessment in temporal, extratemporal, and idiopathic generalized epilepsy.

PURPOSE: We previously showed a reduction in the volume of the entorhinal cortex (EC) ipsilateral to the seizure focus in patients with intractable temporal lobe epilepsy (TLE). The purpose of this study was to examine the specificity of EC atrophy in epilepsy. METHODS: We performed volumetric measurement of the EC on high-resolution magnetic resonance imaging (MRI) in patients with TLE (n = 70), extratemporal lobe epilepsy (ETE; n = 18), and idiopathic generalized epilepsy (IGE; n = 20). EC volumes of epilepsy patients were compared with those of 48 age- and sex-matched normal controls. Within the TLE group, 63 patients were selected prospectively with hippocampal atrophy ipsilateral to the seizure focus. The remaining seven patients were chosen retrospectively based on normal volumetric MRI of the hippocampus and amygdale, as well as normal histopathologic examination of the resected tissue. RESULTS: Compared with normal controls, EC volume was smaller ipsilateral but not contralateral to the seizure focus in patients with TLE (p < 0.001). No difference in the EC volumes ipsilateral and contralateral to the seizure focus was seen in patients with ETE and IGE compared with normal controls. The individual analysis showed that the EC was atrophic in 73% of TLE patients with hippocampal atrophy. Three of the seven TLE patients with normal volumetric MRI of the hippocampus and amygdala and normal histopathologic examination had EC atrophy ipsilateral to the seizure focus. In no patient with ETE or IGE was the EC found to be atrophic. CONCLUSIONS: EC atrophy ipsilateral to the seizure focus appears to be specific to mesial temporal lobe structural damage associated with TLE.

Adolescent↗
PubMed2003

Psychiatric aspects of patients with hypothalamic hamartoma and epilepsy.

Uncontrolled rage, while long associated with hypothalamic hamartoma, has not been as extensively studied as the epilepsy. Rage can be more detrimental to quality of life than seizures. It is now realized that behavior and aggression improve after a complete resection of the hypothalamic hamartoma correlating with a good seizure control post-surgically. We report on the longitudinal psychiatric history of a patient with hypothalamic hamartoma and rage whose severe and refractory epilepsy was ultimately treated by thalamic and intrahamartoma chronic stimulation. Our patient did not exhibit sham rage typical of hypothalamic lesions, but rather multifactorial aggressive bouts typical of challenging behaviors seen with mental retardation. The anxious and social features of the aggression suggest that psychiatric interventions, which have been neglected as the emphasis has been on seizure control, are worthwhile in the overall management of this difficult case.

Adult↗
PubMed2002

Myoclonic status epilepticus: video presentation.

A young woman with juvenile myoclonic epilepsy had recurrent attacks of myoclonic status epilepticus related to a long history of limited compliance and irregular sleep. The diagnosis of this clinical pattern is based mainly on clinical description. A home video captured an attack.

Adult↗
PubMed2002

Is complete seizure control imperative?

Is complete control imperative? The answer depends on whether complete control is indeed possible, on the possibility of achieving modifications of lifestyle, and on the type of epilepsy, with particular reference to the presence of progressive dysfunction. This may be seen in patients with temporal lobe or other forms of focal epilepsy, in the epileptic encephalopathies such as West and Lennox Gastaut Syndromes and even in some patients with idiopathic generalized epilepsy. Progressive memory changes and global cognitive problems are examples. Progressive language deterioration, secondary epileptogenesis and phenomena analogous to kindling are also important issues. How long treatment should be continued depends on many factors, not least the preference of the patient and of the family. Weighing the benefits of complete control versus the side effects and risks of medication or surgery is crucial. There are obvious benefits to complete control; it is imperative if these benefits are greater than the cost.

Disease Progression↗
PubMed2002

Autism, macrocrania and epilepsy: how are they linked?

To evaluate the possible association of autistic disorder (AD), macrocrania and epilepsy, we performed a retrospective study comparing epileptic and non-epileptic AD patients with macrocrania, and AD patients with macrocrania to age- and sex-matched AD controls without macrocrania. We found macrocrania in 17.3% of 121 patients with AD. Epilepsy was not significantly more frequent in AD patients with macrocrania than in those without macrocrania. There were no significant differences in the other clinical characteristics studied except for epileptiform EEG abnormalities which were more often found in AD patients with epilepsy. AD with macrocrania and epilepsy is not a syndrome but may be a marker for a group of subjects with AD. A role for familial macrocrania needs further assessment.

Adolescent↗