Increased intracranial pressure in so-called 'normal-pressure hydrocephalus'.

Five patients exhibited an apparently communicating hydrocephalus -- type of disorder, with ventricular reflux on the cisternograms, lack of air-encephalographic parasagittal air-filling and clearly enlarged temporal horns. The group seemed heterogeneous, with regard to age distribution; possible etiological factors and duration of the hydrocephalic process. In all 5 patients increased intracranial/intrathecal pressure was observed: in 2 patients, only with intrathecal measurement in the lumbar area, but in the remaining 3 patients with epidural/ventricular fluid pressure monitoring. Continuously increased pressure extending over 1 or more days was observed in these patients. This pressure increase may seem different from the episodic pressure increase previously reported in normal-pressure hydrocephalus. These patients seem to be cases of so-called normal-pressure hydrocephalus according to the commonly accepted criteria. It is therefore suggested that the term normal-pressure hydrocephalus should be abandoned, and replaced by, e.g., low-pressure hydrocephalus, malresorptive or malabsorptive hydrocephalus.