Normal pressure hydrocephalus (NPH) is a gradual accumulation of cerebrospinal fluid (CSF) that causes the ventricles of the brain to enlarge. The condition occurs with a normal or slightly elevated CSF pressure. NPH is characterized by a classic triad of dementia, gait disturbance (magnetic gait), and urinary incontinence. The magnetic gait abnormality consists of very short steps with the appearance of the patient’s feet being stuck to the floor. MRI or CT scan of the brain demonstrates ventricular enlargement disproportionate to cortical atrophy. Lumbar puncture with removal of 30 to 50 mL of CSF helps to identify patients likely to respond to a shunt placement. These patients may have a noticeable improvement in gait, continence, and cognition after lumbar puncture. Treatment with shunting allows the diversion of CSF from the brain. A ventriculoperitoneal shunt consists of a catheter placed in the lateral ventricle of the brain, run underneath the skin, and deposited into the abdomen. Source
