Normal Pressure Hydrocephalus (NPH)

Normal pressure hydrocephalus is a buildup of cerebrospinal fluid (CSF) in the brain's fluid chambers — the ventricles — in older adults. The fluid is made and absorbed continuously; in NPH the balance drifts, the ventricles slowly enlarge, and the stretched brain tissue around them begins to malfunction. Because it happens gradually and the measured pressure is often normal, the name — and the diagnosis — can be confusing.

The classic triad is walking trouble (slow, short-stepped, feet "glued to the floor"), cognitive slowing, and urinary urgency or incontinence. Not every patient has all three, and each symptom is easy to attribute to something else — aging, Parkinson's disease, dementia. That is exactly why NPH matters: among the causes of decline in older adults, it is one of the few that is genuinely treatable.

The evaluation starts with the story, an exam focused on gait, and brain imaging showing enlarged ventricles out of proportion to the brain's overall aging. But imaging alone does not make this diagnosis — plenty of older brains have large ventricles without NPH.

The pivotal step is a trial drainage: a lumbar puncture (or a few days of drainage through a temporary lumbar catheter) removes a volume of CSF, and we formally measure your walking before and after. If your gait measurably improves when fluid is removed, that is strong evidence a shunt will help. If it does not, we have spared you an operation unlikely to work.

We test before we operate — it is the whole philosophy of this diagnosis. Families are part of the evaluation too; they often see the changes, and the improvements, before anyone else does.

When the diagnosis is confirmed and the trial drainage shows real improvement, the treatment is a VP (ventriculoperitoneal) shunt — a thin tube under the skin that drains excess fluid to the abdomen, with a programmable valve we can adjust in clinic without further surgery.

Gait usually responds first and most; bladder symptoms and thinking often follow more gradually. An honest expectation: a shunt treats NPH, not every cause of decline that may coexist with it — which is why the up-front testing, and plain talk about what to expect, matter so much.