Memory Digest

Normal Pressure Hydrocephalus

Normal pressure hydrocephalus is a buildup of fluid in the brain that causes walking trouble, bladder problems and thinking changes—and it can sometimes be improved with treatment.

Last reviewed: October 2026

Normal pressure hydrocephalus (NPH) is a brain disorder in which extra cerebrospinal fluid (CSF)—the clear fluid that cushions the brain and spinal cord—builds up in the brain's fluid-filled chambers, called ventricles. As the ventricles enlarge, they press on nearby brain tissue.

It is called "normal pressure" because, despite the extra fluid, the pressure measured during a spinal tap is usually normal or only slightly raised. The fluid builds up slowly enough that the brain adapts, according to the National Institute of Neurological Disorders and Stroke (NINDS).

NPH matters to families because it is one of the few causes of dementia-like symptoms that can sometimes be controlled or reversed with treatment. It is also easy to miss.

Who gets it?

NPH mainly affects people in their 60s and 70s. The Hydrocephalus Association estimates that nearly 700,000 American adults have NPH, and the Alzheimer's Association notes that fewer than 20 percent of people with the condition are properly diagnosed. It is often mistaken for Alzheimer's or Parkinson's disease, or simply blamed on "getting older."

Sometimes NPH follows a head injury, bleeding in the brain, infection or brain surgery. In many older adults, no clear cause is found.

The three classic symptoms

Doctors look for a pattern of three problems:

1. Walking difficulty – often the first and most noticeable sign. Steps become short and shuffling, the feet may seem "stuck" or magnetized to the floor, turning is hard, and falls become more common.
2. Bladder problems – needing to urinate often or urgently, or losing bladder control.
3. Thinking changes – slowed thinking, apathy, trouble with attention and planning, and forgetfulness.

Medical students sometimes learn these as "wet, wobbly and wacky," but real life is less tidy. In a Mayo Clinic study described by the Alzheimer's Association, all 41 older adults with suspected NPH had trouble walking, but only 12 had all three symptoms. A walking problem plus memory or bladder changes is a reason to ask about NPH.

How NPH is diagnosed

There is no single test. A typical evaluation includes:

• Medical history and neurological exam, with close attention to walking and balance
• Brain imaging (CT or MRI) to look for enlarged ventricles out of proportion to brain shrinkage
• Cognitive testing – see Cognitive Screening Tests (MMSE, MoCA)
• A spinal tap (lumbar puncture), often removing a larger amount of fluid (a "tap test"). Walking is measured before and after. If walking clearly improves for hours or days, the person is more likely to benefit from surgery.
• Sometimes a few days of external lumbar drainage or other specialized fluid tests

Because Alzheimer's, Parkinson's, vascular disease and NPH can overlap in older adults, an experienced neurologist or neurosurgeon is important. See Getting a Diagnosis and Mixed Dementia.

Treatment: the shunt

The main treatment is surgery to place a shunt—a thin tube that drains extra CSF from the brain (or lower spine) to another part of the body, usually the abdomen, where it is absorbed. A valve controls how much fluid drains.

What families should know:

• Walking is the symptom most likely to improve. Thinking changes and bladder control are less likely to improve, according to the Alzheimer's Association.
• Results vary. NINDS notes that some people recover almost completely and have a good quality of life, while others improve only a little.
• Earlier treatment may work better, before symptoms have been present for a long time.
• Shunts need follow-up. They can become blocked or infected, drain too much or too little, and sometimes need to be adjusted or replaced. Regular checkups are important.

Warning signs of a shunt problem can include headache, nausea or vomiting, sleepiness, fever, redness along the shunt tract, or a return of the original symptoms. Contact the surgical team promptly if these appear.

Questions to ask the doctor

• Could these walking, bladder and memory changes be NPH?
• Do the brain scans show enlarged ventricles?
• Would a tap test or lumbar drain help predict whether a shunt would help?
• What are the risks of surgery for this person, given their other health conditions?
• What improvements are realistic—walking, bladder, thinking?
• Who will monitor and adjust the shunt afterward?

Living with NPH

Whether or not surgery is chosen, practical steps help:

• Fall-proof the home—remove loose rugs, add grab bars and good lighting. See Home Safety.
• Ask about physical therapy for walking and balance.
• Plan bathroom routines, such as scheduled trips and easy-off clothing.
• Use memory supports like calendars and checklists—see Memory Aids and Tools.
• Support the caregiver—see Caregiver Stress and Burnout.

Bottom line

Normal pressure hydrocephalus is under-recognized, and it is one of the few dementia-like conditions that treatment can sometimes improve. If an older person develops a shuffling, unsteady walk along with memory or bladder changes, ask a doctor whether NPH has been considered. Only a medical team can decide whether testing or surgery is right for an individual.

Sources

1. Alzheimer's Association: Normal Pressure Hydrocephalus (NPH)
2. NINDS: Hydrocephalus
3. Hydrocephalus Association: Normal Pressure Hydrocephalus

Not medical advice. This article is general information, not a diagnosis or treatment plan for any individual. Talk with a doctor about your situation.

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