Normal-pressure hydrocephalus is associated with ventricular enlargement and symptoms that may involve walking, cognition and bladder control. Idiopathic NPH means there is no identified preceding cause; secondary NPH can follow a known neurological injury such as hemorrhage or meningitis. These categories should not be conflated with all adult hydrocephalus. The term “normal pressure” does not establish that symptoms are harmless or that assessment is unnecessary.1

More than a classic triad

The three familiar symptom domains do not have to appear together, and they are not specific to NPH. Other neurological, mobility and urinary disorders can create similar difficulties; comorbid disease can coexist. Clinicians assess the time course, examination and function alongside imaging. The aim is to understand whether a CSF disorder contributes enough to make treatment appropriate.2

The Japanese guideline discusses DESH, an imaging pattern involving a characteristic distribution of enlarged and narrowed CSF spaces. It contributes to interpretation but is not a home scan-reading rule. Absence of DESH or a negative tap test does not by itself exclude potential shunt benefit. CSF testing must be interpreted by the clinical team with attention to what was measured and when. No positive or negative single test supplies certainty for every person.1

What PENS adds

PENS studied 99 selected iNPH participants whose gait responded to temporary CSF drainage. Everyone received a shunt, randomized to an open or placebo valve setting. At three months, gait speed and a gait/balance measure favored open shunting. Cognitive and bladder secondary measures did not show significant between-group improvement at that time. Enrollment stopped after a planned interim analysis, and the report does not establish long-term results.3

The trial also recorded harms, including more bleeding and positional headache in the open group and more falls in the placebo group. Its selected participants do not represent every person with dementia or enlarged ventricles. Chronic anticoagulation and secondary hydrocephalus were excluded, among other restrictions. The result cannot justify a general promise of dementia reversal or guarantee benefit for an individual.3

Questions for a consultation

Ask which findings support iNPH, which alternative causes remain possible, and what improvement is realistically being targeted. Walking, cognition, bladder symptoms and independence should be considered as separate goals. Ask how the team weighs operative risk, monitors results and manages complications, including when another condition may limit improvement.

Hamilton and colleagues' 2025 article reviews guideline development. It isn't a new society guideline replacing the 2021 recommendations.4

For someone already treated, new concerning symptoms need professional assessment rather than assumptions based on the diagnosis name. Severe deterioration calls for local emergency care.5

References

  1. Nakajima M et al. Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus (Third Edition). Neurol Med Chir. 2021;61:63–97. doi:10.2176/nmc.st.2020-0292. Source ↩
  2. NHS. Hydrocephalus: Diagnosis. Source ↩
  3. Luciano MG et al. A Randomized Trial of Shunting for Idiopathic Normal-Pressure Hydrocephalus. N Engl J Med. 2025;393:2198–2209. doi:10.1056/NEJMoa2503109. Source ↩
  4. Hamilton MG, Williams MA, Edwards S, Tullberg M. Guidelines for Diagnosis and Management of Idiopathic Normal Pressure Hydrocephalus. Neurosurg Clin N Am. 2025;36:199–205. doi:10.1016/j.nec.2024.12.006. PubMed ↩
  5. NHS. Hydrocephalus: Complications. Source ↩