According to the Spina Bifida Association there's no studies related to this specific topic, and I couldn't find much information outside of that site and a similar site. This is something that I sort of realized that was Hydrocephalus in at least Middle School, a few years before I started looking more into my condition (Hydrocephalus). It's not something that everyone with Hydrocephalus experience but it's common, and I've met many others online who have Hydrocephalus who deal with it. The sources I found refer to it as something people with shunts deal with, so it seems like it's something that has to do with the shunt specifically. Both sites that I found have to do with Spina Bifida instead of Hydrocephalus though. The two most common noises according to the sources I found are high pitched and loud noises. There is a range of reactions to noises that people can have, and for those that have seizures it can be a seizure trigger. There is no known treatment for those that have it as a side effect to Hydrocephalus but in general audiologists and ENT physicians can use a desensitization technique. Personally I've had sensitivity to high pitched noises since at least around the 4th or 5th grade and probably longer but I can't remember any specific situations having to do with it before that point. Except for being skittish I wasn't really sensitive to loud noises until I was an adult and now I'm sensitive to most noises. Especially with high pitched noises my reaction has always been anxiety, but in a way where it's not really noticed. Thanks for reading, I'm planning on writing about similar subjects or asking others to do it in the near future.