The fluid builds up, enlarging the ventricles (fluid-filled chambers) inside the brain. As the chambers expand, they can compress and damage nearby tissue.

The “normal pressure” refers to the fact that the spinal fluid pressure often, although not always, falls within the normal range on a spinal tap.

Symptoms of NPH

• Difficulty walking.

• Loss of bladder control.

• Mental decline, usually involving an overall slowing in processing and reacting to information. A person’s responses are delayed, but they tend to be accurate and appropriate to the situation when they finally come.

Treatment of NPH

• NPH can occasionally be treated by surgically inserting a long thin tube called a shunt to drain fluid from the brain to the abdomen.

• Certain television broadcasts and commercials have portrayed NPH as a highly treatable condition that is often misdiagnosed as Alzheimer’s, another dementia or Parkinson’s disease. However, most experts believe it is unlikely that significant numbers of people diagnosed with Alzheimer’s or Parkinson’s actually have NPH that could be treated with surgery.

• NPH is rare, and it looks different from Alzheimer’s, another dementia or Parkinson’s to a physician with experience in assessing brain disorders.

• When shunting surgery is successful, it tends to help more with walking and bladder control than with mental decline.

• Brain imaging by itself cannot diagnose normal pressure hydrocephalus. Many disorders that cause dementia, including Alzheimer’s disease, cause the brain to shrink, making the fluid-filled chambers appear larger.