Normal Pressure Hydrocephalus: Understanding Gait Issues, Cognitive Changes, and Shunt Treatment

Imagine waking up one day and realizing you can’t walk like you used to. Your steps feel stuck, like your feet are glued to the floor. Then, you start forgetting names, struggling to plan your day, or losing control of your bladder. You think, “I’m just getting older.” But what if this isn’t aging? What if it’s something treatable? That’s the reality for many people with normal pressure hydrocephalus-a condition that mimics dementia but can often be reversed with surgery.

What Is Normal Pressure Hydrocephalus?

Normal pressure hydrocephalus, or NPH, happens when too much cerebrospinal fluid (CSF) builds up in the brain’s ventricles. Unlike other forms of hydrocephalus, the pressure inside the skull stays within the normal range-between 70 and 245 mm H₂O. That’s why it’s called “normal pressure.” The fluid doesn’t rush in suddenly; it accumulates slowly over months or years. This slow buildup stretches the brain tissue, especially around the ventricles, and disrupts how signals move through key areas that control walking, thinking, and bladder function.

NPH mostly affects people over 60. In fact, about 0.4% of everyone over 65 has it. Among nursing home residents, that number jumps to nearly 6%. Yet, most doctors miss it. Studies show up to 60% of NPH cases are misdiagnosed as Alzheimer’s or Parkinson’s. That’s not because the symptoms aren’t clear-they are. It’s because they look too much like normal aging.

The Three Classic Signs: Gait, Cognition, and Bladder Control

NPH doesn’t come with one symptom. It shows up as a trio-and they don’t always appear together. But if you see two of them, especially in someone over 65, NPH should be on the radar.

The first and most consistent sign is gait disturbance. People describe it as a magnetic walk-like their feet are stuck to the ground. They take small, shuffling steps, stand with their feet wide apart for balance, and struggle to turn. Their arms don’t swing normally. In studies, 100% of diagnosed NPH patients show this symptom. It’s often the first thing noticed by family members, long before memory problems show up.

The second is cognitive impairment. This isn’t the memory loss you see in Alzheimer’s, where people forget names or recent events. In NPH, it’s more about slowed thinking, trouble planning, difficulty focusing, and losing track of conversations. Neuropsychological tests show problems with executive function-like doing a task that requires switching between steps. Up to 73% of patients have this type of cognitive decline. But here’s the key: it doesn’t get worse every day. It creeps in slowly, and it can improve-sometimes dramatically-after treatment.

The third sign is urinary incontinence. This usually comes later. Only about one-third of patients have it at diagnosis. But when it does show up, it’s often a major source of embarrassment and social isolation. Many people delay seeking help because they think it’s just a normal part of aging. But in NPH, it’s not about weak muscles-it’s about the brain losing its ability to signal when the bladder is full.

How Is NPH Diagnosed?

There’s no single blood test or scan that confirms NPH. Diagnosis requires putting together pieces from several tests.

First, doctors look at brain imaging. A CT scan or MRI will show enlarged ventricles. The key measurement is Evan’s index-how wide the ventricles are compared to the brain. If it’s above 0.3, that’s a red flag. MRI can also show signs of fluid pressure on brain tissue, like bright spots around the ventricles (periventricular hyperintensities) or a “flow void” in the aqueduct, which means CSF is moving abnormally.

Next comes a CSF tap test. This is the most important diagnostic step. A doctor removes 30 to 50 milliliters of spinal fluid with a needle in the lower back. Then, they measure walking speed, balance, and mental performance before and after. If the person walks 10% faster or scores better on a memory test within an hour, there’s a strong chance a shunt will help. Studies show this test predicts shunt success with 82% accuracy.

Some hospitals use a more advanced version called external lumbar drainage, where a small tube stays in the back for 2-3 days to drain fluid continuously. This gives a clearer picture of how the brain responds over time.

Neuropsychological testing is also key. Tests like the Trail Making Test B or Digit Symbol Substitution Test reveal the specific type of thinking problems seen in NPH-slowed processing and poor planning-not the memory loss seen in Alzheimer’s.

Shunt Surgery: The Only Treatment

There’s no medication that fixes NPH. The only proven treatment is surgery: placing a ventriculoperitoneal shunt.

This device has two thin tubes connected by a valve. One tube goes from the brain’s ventricle to the abdomen. The other sits in the belly. The valve controls how much fluid drains out-usually set between 50 and 200 mm H₂O. The fluid is absorbed naturally by the body in the abdomen.

The surgery takes about an hour under general anesthesia. Most people go home in 2 to 3 days. Recovery takes 6 to 12 weeks. But here’s the surprising part: many patients feel better within 48 hours. One man on a patient forum said his 10-meter walk time dropped from 28 seconds to 12 seconds after surgery. Another reported regaining bladder control after 18 months of incontinence.

Success rates are high-70% to 90% of carefully selected patients improve. But not everyone benefits. About 20% to 30% of shunts don’t help, even if the tap test looked good. Why? Sometimes, the brain has already been damaged too long. Or the person has another condition like Alzheimer’s mixed in.

Who Benefits Most from Shunt Surgery?

Not every person with enlarged ventricles needs a shunt. Doctors look for specific signs that surgery will work.

The best candidates:

• Have clear gait problems as the first symptom
• Show improvement after a CSF tap test (10%+ improvement in walking or thinking)
• Have no major brain damage on MRI beyond ventricular enlargement
• Are under 80 years old
• Have had symptoms for less than a year

Delay matters. Research shows that if surgery is delayed more than 12 months after symptoms start, the chance of improvement drops by 30%. That’s why early diagnosis is so critical.

Risks and Complications

Shunt surgery is generally safe, but it’s not risk-free.

Common complications:

• Shunt malfunction (15.3% within two years)-the tube gets blocked or disconnected
• Infection (8.5% overall, up to 21% in patients over 80)
• Subdural hematoma (5.7%)-bleeding between the brain and skull
• Over-drainage-too much fluid removed, causing headaches or dizziness

Many people need at least one revision surgery. About 32% of patients require a shunt adjustment or replacement within a few years. But even with that, most say the benefits outweigh the risks.

Why Is NPH So Often Missed?

NPH is called “the great masquerader.” It looks like other diseases:

• Alzheimer’s: Both cause memory problems, but Alzheimer’s starts with forgetting recent events, while NPH starts with walking trouble.
• Parkinson’s: Parkinson’s has tremors and stiffness; NPH has a wide-based, shuffling gait without tremor.
• Vascular dementia: This comes after strokes, with step-by-step decline. NPH is gradual and steady.

MRI can help tell them apart. NPH shows enlarged ventricles with periventricular swelling, while Alzheimer’s shows shrinking of the hippocampus. The Alzheimer’s Disease Neuroimaging Initiative found MRI can distinguish NPH from Alzheimer’s with 87% accuracy.

But here’s the catch: 25% to 30% of NPH patients have both NPH and Alzheimer’s. That makes diagnosis harder. New tools like the iNPH Diagnostic Calculator app use 12 clinical factors to predict shunt success with 85% accuracy. That’s helping doctors make better decisions.

What’s Next for NPH Treatment?

Research is moving fast. In 2022, the FDA approved a new device called the Radionics® CSF Dynamics Analyzer. It measures how well the brain drains fluid-giving doctors a clearer idea of whether a shunt will work before surgery.

Three clinical trials are testing blood or spinal fluid biomarkers that could one day replace the tap test. Early results show 92% accuracy in detecting NPH. If these work, diagnosis could become as simple as a blood draw.

Meanwhile, shunt technology keeps improving. New programmable valves let doctors adjust pressure non-invasively using a magnet-no more surgery just to tweak settings.

Real Stories, Real Outcomes

A 72-year-old man in Ohio went from needing a walker to walking unassisted after his shunt. He started gardening again. He drove himself to church.

A 68-year-old woman in Florida had a positive tap test but no improvement after surgery. She developed chronic headaches and needed a valve adjustment. She still feels frustrated-but says she’d do it again if she knew what she knows now.

The Hydrocephalus Association’s 2022 survey of 457 patients found:

• 76% improved in walking
• 62% improved in thinking
• 58% regained bladder control
• 89% were satisfied with their treatment

The average time from first symptom to diagnosis? 14.3 months. That’s over a year of missed opportunity.

What Should You Do If You Suspect NPH?

If you or a loved one is showing signs of gait trouble, slowed thinking, or bladder control issues-especially after 65-don’t assume it’s just aging.

Start with your primary doctor. Ask for a referral to a neurologist. Request a brain MRI and a CSF tap test. If they say “it’s too late” or “nothing can be done,” get a second opinion from a center that specializes in hydrocephalus.

Shunt surgery isn’t magic. It doesn’t work for everyone. But for many, it’s life-changing. It’s the only dementia-like condition that can be reversed with a simple operation. Don’t let a missed diagnosis steal back years of independence.