Idiopathic normal-pressure hydrocephalus. Results of shunting in 62 patients.

Of 62 patients given shunts for normal-pressure hydrocephalus of idiopathic type, 46.8% showed some improvement and 27.4% enjoyed virtually complete recovery. The best clinical predictor of good response was the complete triad of memory difficulty, gait disorder, and urine incontinence; 61.2% of patients with this combination of symptoms improved. Gait disturbance alone was also accompanied by improvement in two of three patients. An "obstructive" cisternographic radioisotope pattern was not significantly different from a "normal" pattern in predicting a response to shunting. Computerized tomography (CT) showing large ventricles and little atrophy predicted improvement in 11 out of 13 patients. There were five deaths within 3 months of shunting. The complication rate was 35.4%; subdural collections, shunt malfunction, and postoperative seizures constituted the most frequent complications. These data suggest that continued investigation for better predictions of shunt response is important, but that in the meantime the clinical pattern and cranial CT pattern are the most satisfactory guides to improvement after shunting.