Normal Pressure Hydrocephalus (NPH): Symptoms, Diagnosis, and How It Differs from Dementia

Understanding Normal Pressure Hydrocephalus

When a parent or spouse begins struggling to walk steadily, forgetting familiar things, or losing bladder control, it is natural to feel concerned. Many families in Singapore assume these changes are signs of dementia or simply the unavoidable effects of ageing.

In some cases, however, the cause is a condition called Normal Pressure Hydrocephalus (NPH). Unlike most forms of dementia, NPH is one of the few conditions that can often be improved or reversed with appropriate treatment.

What Is Normal Pressure Hydrocephalus?

Normal Pressure Hydrocephalus (NPH) is a neurological condition in which cerebrospinal fluid (CSF), the clear liquid that cushions and nourishes the brain and spinal cord, accumulates in the brain’s fluid-filled cavities (called ventricles). This build-up causes the ventricles to enlarge and press on surrounding brain tissue, even though the pressure within the fluid system measures at a seemingly normal level. That last detail is what makes NPH particularly easy to miss.

Think of the brain’s fluid system like a household drainage pipe. Under normal circumstances, fluid flows in, circulates, and drains away at a steady rate. In NPH, the drainage slows down, so fluid gradually backs up, and the pipes expand, placing pressure on the surrounding structures, even if the water pressure gauge does not read as dangerously high.

NPH most commonly affects adults over the age of 60. It is not a normal part of ageing, but the gradual, subtle way it develops means its symptoms are frequently attributed to getting older, which can lead to delays in diagnosis and treatment.

Who Is at Risk of Developing NPH?

NPH can develop without any identifiable cause. This is called idiopathic NPH, and it is the most common form. In other cases, a known underlying event or condition may disrupt the normal flow and absorption of cerebrospinal fluid. Known risk factors include:

• Age over 60: The risk increases with advancing age.
• Previous brain haemorrhage: Bleeding in or around the brain can affect how fluid drains.
• Meningitis or other brain infections: Inflammation can scar the tissues responsible for fluid absorption.
• Traumatic head injury: Significant head trauma may alter the brain’s fluid dynamics over time.
• Prior brain surgery: Surgical changes to brain structures can occasionally affect CSF flow.

Having one or more of these risk factors does not mean you or your loved one will develop NPH. Many people with these histories never develop the condition at all.

Recognising the Symptoms of Normal Pressure Hydrocephalus

NPH presents with a characteristic set of three symptoms, often referred to as the “classic triad.” These symptoms tend to develop slowly and progressively, making it easy to attribute them to normal ageing or other conditions. Recognising the pattern, rather than any single symptom in isolation, is important.

Difficulty with Walking and Balance

The most common and often the earliest noticeable symptom of NPH is a change in the way a person walks. The gait (walking pattern) in NPH has a distinctive quality: steps become short and shuffling, the feet may appear almost stuck to the floor (sometimes described as “magnetic gait”), and turning becomes difficult. Balance is often affected, increasing the risk of falls.

Families frequently notice this before the person does. If someone who was previously steady on their feet has gradually become hesitant, shuffling, or unsteady without a clear musculoskeletal cause, this is worth discussing with a healthcare professional.

Memory and Thinking Changes

Cognitive changes in NPH tend to differ from the memory loss seen in Alzheimer’s disease. Rather than a severe inability to recall recent events, NPH typically causes a general slowing of thought, difficulty concentrating, reduced motivation, and mild forgetfulness. Processing information takes longer. Responses in conversation may become slower or less detailed.

These changes can be subtle enough that they are dismissed as stress or tiredness, especially in the earlier stages. Over time, however, they may become more apparent and can affect daily functioning.

Loss of Bladder Control

Urinary urgency (a sudden, strong need to urinate) and urinary incontinence (accidental leakage) are the third component of the classic triad. This symptom tends to appear later than walking and cognitive changes. It is often a source of embarrassment, and many people do not mention it to their doctor without being asked directly.

When urinary incontinence occurs alongside walking difficulties and cognitive slowing in someone over 60, the combination is worth discussing with a specialist, rather than being attributed solely to ageing.

How Does NPH Differ from Dementia and Parkinson’s Disease?

NPH shares symptoms with both Alzheimer’s disease and Parkinson’s disease, which is why it is frequently misdiagnosed. In some cases, NPH symptoms may improve with treatment.

Why Misdiagnosis Happens

Alzheimer’s disease causes memory loss, cognitive decline, and changes in behaviour. Parkinson’s disease causes movement difficulties, including shuffling gait and balance problems. NPH overlaps with both, which is why patients are sometimes assessed for dementia or Parkinson’s before NPH is considered.

The combination and sequence of symptoms, the appearance of the brain on imaging, and the potential response to treatment are among the factors that help distinguish NPH from other conditions. A specialist evaluation, including brain imaging and specific diagnostic tests, is needed to reliably distinguish these conditions.

The comparison below is a simplified reference only. A definitive diagnosis requires clinical assessment by a neurosurgeon or neurologist with experience in NPH.

NPH as a Reversible Cause of Dementia-Like Symptoms

NPH is considered a potentially treatable cause of dementia-like symptoms. When diagnosed accurately and managed with the appropriate procedure, many patients may experience improvements in walking, thinking, and bladder control. Outcomes vary by individual and depend on several factors, including the timing of diagnosis and the patient’s overall condition.

How Is NPH Diagnosed in Singapore?

Diagnosing NPH requires a careful, stepwise evaluation. No single test confirms the diagnosis on its own. A combination of clinical assessment, brain imaging, and fluid drainage tests is typically used to build a complete picture.

Clinical Assessment and Gait Analysis

The diagnostic process begins with a detailed clinical history and physical examination. A neurosurgeon or neurologist will ask about the nature, onset, and progression of symptoms, and will observe the patient walking. Gait analysis, sometimes recorded on video, helps document the characteristic shuffling, wide-based, or magnetic walking pattern associated with NPH. Cognitive screening tests may also be performed at this stage to assess the degree of thinking and memory changes.

MRI and CT Brain Imaging

Brain imaging is an important part of the diagnostic process. An MRI (Magnetic Resonance Imaging) scan, which creates detailed images of the brain using magnetic fields, is the preferred imaging tool. It allows the specialist to assess the size of the ventricles, look for evidence of fluid build-up, and evaluate the surrounding brain tissue. Enlarged ventricles alongside a relatively preserved cerebral cortex (the outer layer of the brain) are a hallmark finding in NPH.

A CT (Computed Tomography) scan may be used when MRI is not available or suitable. While CT provides less detail than MRI, it can still identify ventricular enlargement.

Lumbar Puncture Tap Test and Extended Lumbar Drainage

The lumbar puncture tap test is a key step in the diagnostic process. In this procedure, a needle is inserted into the lower back to withdraw a measured amount of cerebrospinal fluid. The patient’s gait and cognitive function are assessed before and after the procedure. If walking or thinking improves noticeably after fluid removal, this suggests that a permanent drainage procedure (a shunt) may be beneficial.

For patients whose response to a single tap test is unclear, extended lumbar drainage may be recommended. This involves draining cerebrospinal fluid continuously over several days via a small catheter (tube) in the lower back, providing a more prolonged and measurable assessment of how the patient responds to fluid removal.

Treatment Options for Normal Pressure Hydrocephalus

The primary treatment for NPH is surgical: the insertion of a shunt, a small device that diverts excess cerebrospinal fluid away from the brain to another part of the body where it can be absorbed. In selected cases, an alternative procedure called endoscopic third ventriculostomy (ETV) may be considered.

Ventriculoperitoneal (VP) Shunt Surgery

A ventriculoperitoneal (VP) shunt is a commonly used treatment for NPH. During the procedure, the neurosurgeon places a thin, flexible tube (catheter) into one of the brain’s ventricles. This tube connects to a pressure-sensitive valve, which then leads to a second catheter tunnelled under the skin to the abdomen (the peritoneal cavity), where the drained fluid is absorbed naturally by the body.

The valve regulates how much fluid drains, helping to manage both over-drainage and under-drainage. Some shunts use programmable valves, meaning the drainage rate can be adjusted non-invasively after surgery using an external device, allowing the neurosurgeon to modify the system as the patient’s condition evolves.

VP shunt surgery is performed under general anaesthesia. It is a well-established procedure, and some patients may begin to notice improvements, particularly in walking, within days to weeks after surgery. Individual outcomes vary.

Endoscopic Third Ventriculostomy

Endoscopic third ventriculostomy (ETV) is a procedure in which a small camera (endoscope) is used to create a small opening in the floor of the brain’s third ventricle. This opening allows cerebrospinal fluid to bypass a blockage and flow more freely, reducing pressure on the brain without an implanted device.

ETV is more commonly used for obstructive hydrocephalus (where a physical blockage prevents fluid from flowing) and is less frequently the first-choice treatment for NPH. However, in carefully selected patients, it may be a suitable alternative to a shunt.

What to Expect During Recovery

Recovery after shunt surgery varies between individuals. Some patients may notice an improvement in walking within the first few weeks. Cognitive improvements may take longer to become apparent, sometimes over several months. The medical team will schedule follow-up appointments to monitor progress, assess whether the shunt valve settings need adjustment, and watch for any complications.

What Results Can Patients Expect After Treatment?

NPH treatment can produce meaningful improvements in quality of life, though outcomes vary depending on how long symptoms have been present, the patient’s overall health, and how well the underlying brain tissue has been preserved.

In general:

• Walking and balance tend to show the most noticeable improvement after shunt surgery, often within weeks, though individual results vary.
• Cognitive symptoms may improve partially in some patients; the degree of improvement is less predictable and tends to be more gradual.
• Bladder control may improve in some patients, though this is the least consistent of the three areas.

Earlier diagnosis and treatment are generally associated with better outcomes. When NPH is identified and treated before the brain tissue has been under prolonged pressure, there may be more potential for recovery.

Shunt surgery does not cure NPH permanently. Ongoing follow-up with a neurosurgeon is important to monitor the shunt’s function and make adjustments as needed over time.

Taking an Active Role in Your Loved One’s Care

As a caregiver or family member, your observations are genuinely valuable to the diagnostic process. Here are practical steps you can take:

• Keep a symptom diary: Note when changes in walking, memory, or bladder control first appeared and how they have progressed.
• Record gait changes on video: A short video of your loved one walking, taken on a smartphone, can provide the specialist with information that is difficult to capture in a clinic setting.
• Note patterns: Does your loved one shuffle more at certain times of day? Have there been falls?
• Bring your notes to appointments: A clear timeline of symptom progression helps the specialist make a more accurate assessment.

When to Seek Professional Help

• Progressive difficulty walking or unexplained balance problems in someone over 60, without a clear musculoskeletal cause
• Gradual cognitive slowing, reduced motivation, or mild memory changes that are worsening over time
• New urinary urgency or incontinence occurring alongside changes in walking or thinking
• Any combination of two or more of the above symptoms developing together

Because NPH is a potentially treatable condition, early evaluation is worth considering. A healthcare professional can help determine whether symptoms warrant further investigation.

Commonly Asked Questions

Is normal pressure hydrocephalus curable?

NPH is not curable in the traditional sense, but it is treatable. Shunt surgery may significantly improve or stabilise symptoms in many patients. The goal of treatment is to relieve the build-up of cerebrospinal fluid and reduce its impact on brain function. Many patients experience a meaningful improvement in quality of life after treatment, particularly when NPH is diagnosed and managed early.

How long does it take to see improvement after shunt surgery?

Improvement in walking is often the first noticeable change, and many patients begin to see this within days to weeks of surgery. Cognitive improvements tend to emerge more gradually, sometimes over several months. The timeline varies between individuals, and follow-up appointments allow the neurosurgeon to assess progress and adjust the shunt valve settings if needed.

Can NPH come back after treatment?

NPH itself does not recur in the way an infection might, but shunt-related issues can develop over time. Shunts may occasionally become blocked, malfunction, or require valve adjustments as the patient’s needs change. Regular follow-up with a neurosurgeon is important to ensure the shunt continues to function as intended and that any issues are identified and addressed promptly.

What are the risks of shunt surgery?

As with any surgical procedure, shunt surgery carries potential risks. These include infection, bleeding, over-drainage or under-drainage of cerebrospinal fluid, and the possibility that the shunt may require revision in the future. A neurosurgeon will discuss the specific risks and benefits in detail before any procedure, taking into account individual health circumstances.

How is NPH different from other types of hydrocephalus?

NPH specifically refers to hydrocephalus in adults where cerebrospinal fluid accumulates despite pressure readings appearing normal, and where the cause is often unknown. Other forms of hydrocephalus, such as obstructive hydrocephalus, occur when a physical blockage prevents fluid from flowing normally and may present at any age, including in children and infants. The treatment approach and underlying causes differ between types, which is why specialist evaluation is important.

Next Steps

If you recognise the symptoms described in this article, whether in yourself or someone close to you, you may wish to seek a specialist evaluation. A neurosurgeon with experience in hydrocephalus management can guide you through the diagnostic process, interpret imaging and tap test results, and discuss the most appropriate course of action. You do not need to have all three symptoms of the classic triad to seek an opinion.

Learn More About Hydrocephalus Treatment in Singapore

If you would like to learn more about normal pressure hydrocephalus, the diagnostic process, or surgical treatment for hydrocephalus in Singapore, you are welcome to reach out to the team at the clinic. A consultation with Dr Teo Kejia may provide guidance relevant to your specific situation and concerns.