On the merits of non-invasive myelin imaging in epilepsy, a literature review

Myelin is a vital element of normal brain development and structure. Myelination is most prominent during the first two years of life and proceeds until the age of 30. Abnormal myelination is related to several neurological and neuropsychiatric disorders such as Alzheimer's disease and multiple sclerosis. Recently, abnormal myelin content has also been reported in children with epilepsy. Furthermore, more and more literature hints at a link between abnormal myelination and epilepsy, hence it is worthwhile to evaluate the benefits of non-invasive myelin imaging. In this literature review, we provide an overview of the current evidence of myelin abnormalities in epilepsy from imaging and histological studies. After preselection, 21 histological and 21 in vivo imaging studies were identified. Primarily, epilepsy is found to be associated with a reduced myelin content. This review shows that the currently available literature does not provide a complete view into the nature of myelin abnormalities in epilepsy. However, the reported literature is indicative of a relation between the pathophysiology of epilepsy and the myelin content. More studies that apply myelin-specific imaging techniques are needed to determine whether the myelin abnormalities are an underlying cause of epilepsy, or a consequence of the excessive activity in epilepsy.