Answer:
Break it down into less intimidating portions:
Frontal cortical- front half of the brain
Sylvan fissures- these particular "wrinkles" in the brain seperates the frontal and temporal lobes
Effectively the front portion of the brain is wasting away and there is an uneveness in the brain in the area that seperates the front and back portions.
Best of luck for you and yours. That's a fairly rough Dx.