Periventricular Leukomalacia (PVL) and Myelination

In Reply.— The hypothesis of our study was that periventricular-intraventricular hemorrhage may damage the glia precursors in the subependymal germinal layer, the site of origin of the hemorrhage. Our results showed that glia precursors in the subependymal germinal layer are not so severely damaged that the subsequent production of myelin by oligodendroglia is impaired.1 Our prime goal was not to study the local effects of a `parenchymal extension' of the hemorrhage. Volpe2 suggests that parenchymal extension of an intraventricular hemorrhage as described by Papile et al3 is not merely an extension of the hemorrhage but a hemorrhagic infarction secondary to obstruction of venous flow by a large quantity of intraventricular blood.