IDIOPATHIC NORMAL-PRESSURE HYDROCEPHALUS - THE CSF TAP-TEST MAY PREDICT THE CLINICAL-RESPONSE TO SHUNTING

A follow-up study was performed in nine patients with idiopathic norma l pressure hydrocephalus (NPH) 37 months (mean) after shunting and 10 non-operated controls with comparable degrees of ventricular enlargeme nt, gait disorder, and dementia. Five operated patients vs. no control s reported sustained general improvement (p < 0.02). Objectively impro ved gait at follow-up (compared with preoperative status) was found in five of the six tested NPH-patients vs. none of the controls (p < 0.0 05). Improved gait and/or psychometric function was found in four of s ix NPH vs. none of eight control patients (p < 0.02) after drainage of 40 ml cerebrospinal fluid (CSF tap-test). Improved gait during the CS F tap-test predicted continued improvement at follow-up. Temporal horn size was the only radiological variable which showed a (moderate) pos itive correlation with resistance to CSF absorption and rate of pressu re increase. The size of the third ventricle diminished in parallell w ith clinical improvement.