Entitlement to service connection for hydrocephalus as secondary to service-connected Parkinson's disease is granted.

Board reasoning

The Board found that the Veteran's hydrocephalus was aggravated by his service-connected Parkinson's disease, resolving all doubt in his favor. It reasoned there is evidence of a current hydrocephalus disability separate from Parkinson's and that while the record does not clearly show which condition started first, the record supports aggravation by the Parkinson's disease, with no contrary medical opinion. The Board applied the benefit-of-the-doubt doctrine and determined secondary service connection is warranted.