Cerebellar volumes in newly diagnosed and chronic epilepsy

Cerebellar atrophy is assumed to be a common finding in patients suffering from epilepsy. Anticonvulsants as well as seizure activity itself have been considered to be responsible for it but many studies have addressed these questions in specialised centres for epilepsy thus having a referral bias towards patients with severe epileptic syndromes. The purpose of this study was: 1. To develop a quantitative method on 3D-MRI data to achieve volume or planimetric measurements (of cerebrum, cerebellum and cerebellar substructures). 2. To investigate the prevalence of cerebellar atrophy (and substructure atrophy) in a prospectively investigated population-based cohort of patients with newly diagnosed and chronic epilepsy. 3. To quantify cerebellar atrophy in clinic-based patients, who had had atrophy previously diagnosed on routine visual MRI assessment. 4. To correlate the measures of atrophy with clinical features in both patient groups. A total of 57 patients with either newly diagnosed or chronic active epilepsy and 36 control subjects were investigated with a newly developed semiautomated method for cerebral as well as cerebellar volume measurements and substructure planimetry, corrected for intracranial volume. We did not find any significant atrophy in the population-based cohort of patients with newly diagnosed epilepsy or with chronic epilepsy. Visually diagnosed cerebellar atrophy was mostly confirmed and quantified by volumetric analysis. The clinical data suggested a correlation between cerebellar atrophy and the duration of the seizure disorder and also the total number of lifetime seizures experienced and the frequency of generalised tonic-clonic seizures per year. Volumetry on 3D-MRI yields reliable quantitative data which shows that cerebellar atrophy might be common in severe and/or longstanding epilepsy but not necessarily in unselected patient groups. The results do not support the proposition that cerebellar atrophy is a predisposing factor for epilepsy but rather are consistent with the view that cerebellar atrophy is the aftermath of epileptic seizures or anticonvulsant medication.

A descriptive survey of long-term residents with epilepsy and intellectual disability at the Chalfont Centre: is there a relationship between maladaptive behaviour and magnetic resonance imaging findings?

The advent of high-resolution magnetic resonance imaging (MRI) has facilitated the identification of subtle, aetiologically relevant structural brain abnormalities in a significant proportion of patients with epilepsy and negative standard neuro-imaging. In the present study of people with intellectual disability (ID), the authors show that a high frequency of cerebral structural abnormalities (72.4%) can be demonstrated by high-resolution MRI in patients with epilepsy and ID. Malformations of cortical development (MCD) were found in 8.7% of people without profound ID. An earlier age of onset of habitual seizures was associated with more severe ID and more severe seizures in adulthood. There was no obvious association between this finding and maladaptive behaviour, but a past history of febrile convulsions was associated with increased irritability and agitation. Since there was no obvious association between a history of febrile convulsions and MRI abnormalities, the reason for the above finding remains unclear. Inevitably, any residential epilepsy centre population is subject to selection biases. The population studied was highly skewed, with only one-third of the sample being female and 80% having mild ID. Thus, the findings of the present study cannot necessarily be generalized to all people with ID.

Classification of the epilepsies: time for a change? A critical review of the International Classification of the Epilepsies and Epileptic Syndromes (ICEES) and its usefulness in clinical practice and epidemiological studies of epilepsy

The Commission on Classification and Terminology of the International League against Epilepsy (ILAE) first devised a comprehensive classification for the epilepsies and epileptic syndromes nearly 30 years ago. Despite subsequent revisions, the classification remains too complicated to be of utility in clinical practice and epidemiological research. Recent developments in neuro-imaging and neurogenetics have also contributed to the limited usefulness of the current International Classification of the Epilepsies and Epileptic Syndromes (ICEES). This review examines the evolution, advantages, and notable disadvantages of the ICEES and assesses its previous application in several population-based studies of epilepsy. The important need for a new, simplified, and aetiologically orientated classification which is amenable to use outside of the tertiary epilepsy centre is discussed.

Magnetic resonance imaging in epilepsy with a fast FLAIR sequence

OBJECTIVE

To assess the diagnostic value of the fast FLAIR sequence in patients with epilepsy.

METHODS

One hundred and twenty eight patients with epilepsy and 10 control subjects were scanned with the fast FLAIR sequence with 5 mm slices, a coronal gradient echo (GRE) T1 weighted sequence with 1.5 mm slices and spin echo (SE) or fast spin echo (FSE) proton density and T2 weighted sequences with 5 mm slices. All images were compared by an unblinded neuroradiologist and neurologist. Fast FLAIR images of patients with hippocampal sclerosis (HS) and normal control subjects were also evaluated by two blinded independent raters.

RESULTS

Fast FLAIR provided a high conspicuity of neocortical damage, hamartomas, dysembryoplastic neuroepithelial tumours, and clear cut hippocampal sclerosis. However, the same information could be obtained from the coronal T1 and T2 weighted images. In three patients fast FLAIR showed a clearly abnormal signal when SE T2 weighted images had not been definitely abnormal. Heterotopia was less conspicuous on fast FLAIR than GRE T1 weighted images. The two blinded raters detected all but one of the patients with clear cut hippocampal sclerosis on fast FLAIR images but missed all borderline cases of hippocampal atrophy and there were two false positives. Clear cut hippocampal sclerosis was more conspicuous on fast FLAIR images than on SE T2 weighted images in most patients, but additional patients were not identified.

CONCLUSION

Fast FLAIR has the advantage of identifying neocortical lesions and definite hippocampal sclerosis with a short scanning time and may also demonstrate lesions when other sequences are normal in a limited number of cases. The technique was not useful, however, for identifying mild hippocampal sclerosis or heterotopia.