Normal pressure hydrocephalus: diagnosis and treatment

Abstract

Normal pressure hydrocephalus (NPH) is a syndrome of gait dysfunction and enlarged cerebral ventricles in the absence of another cause. It is frequently accompanied by frontal and subcortical cognitive deficits and bladder detrusor overactivity. NPH is rare relative to other potential causes of these symptoms in the elderly, but timely diagnosis can lead to reversal of symptoms through ventricular shunting. There are many tests used to predict possible response to surgery, such as MRI of the brain, formalized neuropsychological and gait testing, large-volume lumbar puncture, and prolonged lumbar drainage, but no one test has been validated to rule out potential response to surgery.

Figure 1

MRI of a patient with probable idiopathic normal pressure hydrocephalus. The Evans ratio is the maximal ventricular width divided by the largest biparietal distance between the inner tables of the skull. In this case, the Evans ratio was 0.39. Ventriculomegaly is defined as an Evans ratio of 0.30 or greater.