Main features of normal pressure hydrocephalus 1. Typical triad of dementia (memory loss), gait disturbance, and urinary incontinence; 2. CT or MRI showing traffic hydrocephalus; 3. Normal pressure on multiple lumbar punctures; 4. Symptoms may be relieved after cerebrospinal fluid shunts; 5. Age usually greater than 65 years, slightly more in men. Common etiology: after subarachnoid hemorrhage, after trauma, after meningitis, after posterior cranial fossa surgery, tumor, Alzheimer’s disease. Lumbar puncture: normal lumbar puncture opening pressure should be less than 180 mmH2O. Treatment: ventriculoperitoneal shunt is preferred, with an adjustable pressure shunt tube preferred. The symptom most likely to improve after shunt is urinary incontinence, followed by gait disturbance, and the least likely to recover is dementia. Possible complications include: subdural hematoma or edema; shunt infection; intracerebral parenchymal hemorrhage; and epilepsy. Late complications: shunt obstruction or disruption.