In adults, the causes of hydrocephalus include brain damage due to stroke or injury, Alzheimer's disease, or obstruction of the ventricles. Often, the cause is unknown.
Hydrocephalus results when more fluid enters the brain than leaves.
A blockage or swelling can stop fluid from draining.
According to the NIH,
The majority of cases of NPH are idiopathic...
The Stuttering Foundation of America has information for all ages at www.stutteringhelp.org. I personally have met one individual who never stuttered until after having a stroke. I expect the stroke...