Idiopathic normal pressure hydrocephalus: the CSF tap-test may predict the clinical response to shunting

Acta Neurol Scand. 1994 May;89(5):311-6. doi: 10.1111/j.1600-0404.1994.tb02640.x.


A follow-up study was performed in nine patients with idiopathic normal pressure hydrocephalus (NPH) 37 months (mean) after shunting and 10 non-operated controls with comparable degrees of ventricular enlargement, gait disorder, and dementia. Five operated patients vs. no controls reported sustained general improvement (p < 0.02). Objectively improved gait at follow-up (compared with preoperative status) was found in five of the six tested NPH-patients vs. none of the controls (p < 0.005). Improved gait and/or psychometric function was found in four of six NPH vs. none of eight control patients (p < 0.02) after drainage of 40 ml cerebrospinal fluid (CSF tap-test). Improved gait during the CSF tap-test predicted continued improvement at follow-up. Temporal horn size was the only radiological variable which showed a (moderate) positive correlation with resistance to CSF absorption and rate of pressure increase. The size of the third ventricle diminished in parallel with clinical improvement.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Cerebral Ventricles / surgery
  • Cerebrospinal Fluid Shunts*
  • Dementia / etiology
  • Female
  • Follow-Up Studies
  • Gait
  • Humans
  • Hydrocephalus, Normal Pressure / cerebrospinal fluid*
  • Hydrocephalus, Normal Pressure / complications
  • Hydrocephalus, Normal Pressure / surgery
  • Male
  • Middle Aged
  • Prognosis
  • Treatment Outcome