What mean if sulci gyri inter hemisperic fissure and both sylvian fissures are prominent?

Significant prominence of the sulci, gyri and fissures are indicative of a probable dementia process (such as Alzheimer's type, vascular type and many others). However, further testing would be needed to confirm this - and this type of testing is best done by a neuropsychologist (including interview, and several pencil and paper type tests).