Normal-pressure hydrocephalus.

Normal-pressure hydrocephalus is a treatable form of dementia in which the patient presents with memory difficulty, slowing of thought and action, gait disturbance and urinary incontinence. Although normal-pressure hydrocephalus is usually idiopathic, it can occur with subarachnoid hemorrhage, head injury, tumors of the third ventricle or posterior fossa, intracranial surgery, meningitis or congenital anomalies. Treatment consists of insertion of ventriculoperitoneal or ventriculoatrial shunt.