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Epileptic Seizures in Multiple Sclerosis May Suggest Shared Pathology

January 25, 2017

Patients with multiple sclerosis (MS) who experience seizures are more likely to be younger at the age of MS onset than patients with MS who do not have seizures, according to a study reported in Neurological Sciences by the Epilepsy Study Group of the Italian Neurological Society. The disease course also tended to be slightly more severe in patients with seizures.

It is not well understood, but previous studies have determined that there is an overlap between MS and epilepsy. The most common condition to show a higher incidence and prevalence in MS is epilepsy, estimated at 2-3%, compared to less than 1% of the general population.

The authors of the current meta-analysis, led by Sara Gasparini, MD, from the Magna Graecia University of Catanzaro in Italy, selected 9 studies conducted from 1996 to 2014 from a total of 668 articles available. Of those, 4 studies showed a younger age at onset of MS by a mean difference of nearly 5 and a half years.

Dr. Gasparini and colleagues found this pattern to be consistent with previous studies indicating a potentially more aggressive inflammatory process involved in early-onset MS, which may have a focus in the cerebral cortex.

Two studies pointed to an association between the presence of cortical lesions and seizures, although differences in the imaging techniques used did not allow for comparison between them. The first reported that a greater proportion of patients with MS with seizures had cortical lesions compared with patients with MS without seizures, and that both the quantity and size of the lesions was larger in the MS-with-seizures group. The second study also found a higher mean number of lesions in patients with MS who had seizures.

Another feature that was prominent in 5 of the 9 studies evaluated was a trend toward higher Expanded Disability Status Scale scores among patients with MS and epilepsy, even though it was not such a significant difference.

In addition, the meta-analysis did not reveal any relevant trends in sex distribution or clinical type of MS associated with the expression of seizures.

Despite the evidence above, authors were unable to draw any firm conclusions as to the potential causality of epilepsy in MS, citing suboptimal study data. They suggested that this comorbidity may be associated with poorer outcomes, as measured by Expanded Disability Status Scale scores, and that earlier onset of MS may increase the risk of developing seizures, but larger prospective studies will be necessary to support these findings.