Normal-Pressure Hydrocephalus

Normal-pressure hydrocephalus is characterized by neurological symptoms of dementia and awkwardness of movement, cerebrospinal fluid pressure in the normal range, and ventricular enlargement without cortical atrophy. Pneumoencephalograms reveal enlarged ventricles with failure of air to pass over the cerebral convexities. The cisternographic abnormalities are the presence of radioactivity in the enlarged ventricles, abnormality of movement of the injected radioactivity over the cerebral hemispheres, and failure of the radioactivity to concentrate in the sagittal area on delayed scans (24 or 48 hours). Since normal-pressure hydrocephalus is a treatable form of dementia, accurate diagnosis based on clinical manifestations, findings from lumbar puncture, pneumoencephalography, and cisternography is mandatory.