Normal Pressure Hydrocephalus

Normal pressure hydrocephalus is a chronic communicating hydrocephalus typically affecting adults over 60 years of age. Despite ventriculomegaly on imaging, cerebrospinal fluid pressure measured on lumbar puncture is within normal range, hence the name.

The classic Hakim triad consists of magnetic gait with short shuffling steps and reduced foot clearance, urinary urgency or frank incontinence, and progressive cognitive decline including bradyphrenia, executive dysfunction and memory complaints. Gait disturbance is usually the earliest and most responsive symptom.

Diagnosis combines clinical features with MRI showing ventriculomegaly, callosal angle below 90 degrees and disproportionately enlarged subarachnoid space hydrocephalus pattern. Functional response is assessed with high-volume lumbar tap test or extended lumbar drainage. Patients showing significant improvement are candidates for ventriculoperitoneal shunting, which provides sustained benefit in carefully selected patients.