Is My Memory Loss Due to Normal Pressure Hydrocephalus (NPH)?

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group
Published: June 27, 2025Updated: June 27, 2025

Summary

Normal pressure hydrocephalus (NPH) is a treatable cause of memory loss. It produces a classic triad—difficulty walking, urinary urgency, and cognitive decline—that often mimics Alzheimer’s, yet cerebrospinal fluid (CSF) pressure stays normal. Brain MRI showing enlarged ventricles plus symptom improvement after a large-volume spinal tap points strongly to NPH, which can often be reversed with a ventriculo-peritoneal shunt.

How exactly does NPH damage memory circuits?

Excess cerebrospinal fluid stretches the frontal lobes and hippocampus, slowing the relay of new information and executive functions. The process is gradual, which is why it is frequently misdiagnosed as typical aging.

  • Fluid buildup compresses frontal networksMRI studies show the periventricular white matter loses up to 30 % of normal perfusion when ventricular diameter exceeds 40 mm, disrupting attention and working memory.
  • Reversible neuronal stress—not permanent lossUnlike Alzheimer’s plaques, NPH causes mechanical pressure; removing the pressure often restores neuron firing within weeks.
  • Memory lapses appear lateGait imbalance typically starts 6–24 months before forgetfulness, offering a window for early diagnosis.
  • Quote from the expert“Families often notice slowed thinking during conversation before the patient is aware anything is wrong,” notes Sina Hartung, MMSC-BMI.

Which symptom clusters should make me suspect NPH instead of Alzheimer’s?

The combination of broad-based shuffling walk, urinary urgency, and short-term memory loss is virtually never caused by typical Alzheimer’s disease alone.

  • Feet feel "glued" to the floorPatients describe difficulty initiating steps and take fewer than 90 cm per stride.
  • Urgency, not just incontinenceSudden need to void without warning occurs in 70 % of NPH but fewer than 15 % of early Alzheimer’s cases.
  • Sleepiness while sittingFrontal slowness leads to dozing off in daylight even with normal nighttime sleep.
  • Rapid decline over months, not yearsCognitive scoring (MoCA) can fall 5 points in 6 months, faster than typical dementia trajectories.
  • Expert insight“When the triad shows up together, the odds of NPH are higher than 50 %,” according to the team at Eureka Health.
  • Gait trouble almost always shows up firstMore than 90 % of people with NPH develop a broad-based, shuffling walk before any bladder or cognitive complaints, a presentation that is uncommon in early Alzheimer’s disease. (NCBI)
  • Frontal-subcortical thinking slows rather than memory storage lossNPH produces psychomotor slowing, poor attention, and apathy—a frontal-subcortical dementia pattern—whereas Alzheimer’s typically begins with temporoparietal memory storage deficits, helping clinicians tell the two apart. (Barrow)

References

What immediate actions should I take if the triad appears?

Because shunt surgery is most effective before brain tissue atrophies, prompt evaluation matters.

  • Schedule a same-month neurology visitAsk specifically for NPH evaluation; many primary clinics overlook it because CSF pressure is normal on lumbar puncture.
  • Request MRI with volumetric analysisReporting Evans index (ventricle width/skull width) above 0.3 strengthens the case for NPH.
  • Keep a symptom diaryRecord daily gait distance, bathroom frequency, and memory slips; objective data speeds specialist decisions.
  • Bring a family observerRelatives often report gait freezing or near-falls the patient underestimates.
  • Eureka AI tip“Uploading your diary to Eureka lets our clinicians flag red-flag trends within 24 hours,” says the team at Eureka Health.
  • Ask about a high-volume lumbar tap testRemoving 30–50 mL of cerebrospinal fluid and re-checking gait the same day is part of Duke’s protocol for predicting who will benefit from shunt surgery. (DukeHealth)
  • Refer to specialists who routinely see NPHBecause NPH is frequently misdiagnosed as Parkinson’s or Alzheimer’s, the Adult Hydrocephalus Clinical Research Network urges early referral to clinicians experienced with the triad to shorten time to treatment. (AHCRN)

References

Can lifestyle changes slow NPH-related memory decline at home?

While only shunting addresses the root cause, certain habits maintain brain reserve until surgery is arranged.

  • Daily 20-minute leg strength exerciseSit-to-stand repetitions improve gait initiation and reduce fall risk by 25 % in small NPH rehabilitation trials.
  • Timed toileting every two hoursProactive bathroom visits cut wet accidents by almost half and lower infection risk.
  • Hydration but evening fluid limitDrinking 2 L water before 6 p.m. maintains CSF turnover yet minimizes nocturnal urgency.
  • Cognitive walksCombine walking with naming objects; dual-task practice helps reconnect gait and executive centers.
  • Expert guidance“Small, consistent routines keep patients strong enough to qualify for surgery,” advises Sina Hartung, MMSC-BMI.
  • Therapy teams help preserve gait and memory before surgeryThe Hydrocephalus Association advises coordinated physical, occupational, and cognitive therapy to keep walking ability and recall stable while patients await or recover from a shunt. (HydroAssoc)
  • NPH is found in nearly 6 % of people older than 80Cleveland Clinic data show prevalence rises to about 5.9 % in those over 80, underscoring why early home-based conditioning and monitoring are critical. (ClevelandClinic)

References

Which tests and treatments confirm and manage NPH?

Diagnosis relies on imaging, CSF testing, and often a therapeutic trial of fluid removal.

  • MRI with FLAIR sequencesShows ventriculomegaly without cortical thinning; radiologists calculate callosal angle below 90° in 80 % of NPH.
  • Large-volume lumbar tapRemoving 30-50 mL CSF and repeating gait testing improves walking speed by ≥10 % in responders.
  • Extended lumbar drainageThree-day CSF drainage predicts shunt success with 90 % specificity.
  • Ventriculo-peritoneal shuntProgrammable valves reduce symptom burden in 60–80 % of appropriately selected patients.
  • Medication role is limitedNo drug reverses NPH, but acetazolamide can be used short-term to decrease CSF production when surgery must wait.
  • CSF outflow resistance testing augments tap resultsDetermining resistance to CSF outflow with a lumbar infusion study provides additional predictive value for shunt responsiveness when the single tap test is inconclusive. (Nature)
  • Repeat tap or 72-hour drainage boosts diagnostic yieldBecause a one-time large-volume tap has low sensitivity, clinicians often repeat the tap or use 3-day continuous lumbar drainage to better forecast postoperative improvement. (FrontNeurol)

References

How can Eureka’s AI doctor streamline my NPH work-up?

Eureka’s symptom-triage algorithm flags the NPH triad and prompts evidence-based next steps within seconds.

  • Automated gait and memory screeningThe app times a 10-meter walk and a 1-minute recall test using your phone’s sensors, generating a report for your neurologist.
  • Instant MRI order suggestionsIf scores meet preset risk thresholds, Eureka prepares an MRI brain with CSF flow codes for physician sign-off.
  • Smart lumbar puncture schedulingEureka cross-checks regional wait times and alerts you when cancellations open sooner slots.
  • Symptom trend dashboardsColor-coded charts show whether your memory, gait, or bladder scores change week-to-week.
  • Doctor-reviewed recommendations“Every imaging or medication request goes through our board-certified team before release,” assures the team at Eureka Health.

Why many NPH patients stay with Eureka after shunt surgery

Recovery does not stop at the operating room; tracking valve settings, wound healing, and lasting cognitive gains needs organized follow-up.

  • Shunt check remindersThe app nudges patients when it is time for the 1-, 3-, and 12-month valve pressure check.
  • Private data vaultAll MRI images and clinic letters remain encrypted; only you and invited clinicians can view them.
  • High satisfaction ratingUsers recovering from NPH surgery rate Eureka 4.7 out of 5 for helping them catch early shunt malfunctions.
  • Insurance-ready progress notesEureka exports PDF summaries that meet common insurer criteria for postoperative physical therapy approval.
  • Quote from the expert“Consistent tracking turns sporadic clinic visits into a continuous care loop,” says Sina Hartung, MMSC-BMI.

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Frequently Asked Questions

How common is NPH among people diagnosed with dementia?

Studies estimate 5-10 % of patients over 65 labeled with dementia actually have NPH, a form that is often reversible.

Can normal CT scans rule out NPH?

No. CT is less sensitive than MRI for ventricular size and white-matter changes; a normal CT does not exclude NPH.

Why is CSF pressure ‘normal’ if there is too much fluid?

Pressure peaks are intermittent and often miss the brief measurement taken during lumbar puncture; over time the ventricles stretch to accommodate fluid, lowering measurable pressure.

Will a shunt cure memory loss completely?

About 50–60 % of shunted patients recover meaningful memory and executive function, especially if treated within one year of symptom onset.

Is shunt surgery risky for older adults?

Serious complications like infection or bleeding occur in roughly 5 %, similar to hip replacement risk in the same age group.

How soon after a tap test will I notice improvement?

Gait changes can appear within 30 minutes; cognitive benefits, if present, often emerge over 24–48 hours.

Does insurance cover NPH evaluation and shunt placement?

Most U.S. insurers, including Medicare, cover MRI, tap tests, and shunt surgery when documentation shows the classical symptom triad and imaging findings.

Can I still fly with a ventriculo-peritoneal shunt?

Yes, cabin pressure changes do not affect programmable shunts, but carry your shunt card to show security personnel.

Are there exercises I should avoid after shunt placement?

Skip heavy weight-lifting that strains the neck until your surgeon clears you, usually after 6 weeks.

This content is for informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for diagnosis, treatment, and personalized medical recommendations.

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