Intracranial pressure parameters in idiopathic normal pressure hydrocephalus patients treated with ventriculo-peritoneal shunts

Acta Neurochir (Wien). 2006 Jan;148(1):21-9; discussion 29. doi: 10.1007/s00701-005-0654-8. Epub 2005 Nov 14.


Background: Although the mean intracranial pressure (ICP) is normal in patients with idiopathic normal pressure hydrocephalus (iNPH), there could possibly be alterations in their single ICP waves.

Method: Thirty-nine consecutive patients treated for iNPH with ventriculo-peritoneal shunts were followed prospectively with regard to clinical and radiological findings. Changes in clinical state 12 months after shunt surgery were assessed as change on a 15-3 score NPH Grading Scale, while the changes in ventricular size were assessed by linear measures. The ICP recordings were performed as part of routine pre-operative assessment, stored as raw data files, and analyzed retrospectively. The mean ICP as well as single ICP wave amplitudes were computed and analysed in consecutive 6 second time windows.

Findings: Twelve months after shunt surgery, changes in NPH score of 5 or more (very significant improvement) were observed in 12 patients (31%), of 3 to 4 (significant improvement) in 6 patients (15%), of 1 to 2 (slight improvement) in 9 patients (23%) and of -4 to 0 (non-responders) in 12 patients (31%). The ventricular size did not change in any of the outcome categories. While the pre-operative mean ICP was similar between outcome groups, the mean ICP wave amplitude was significantly higher in patients improving clinically as compared to the non-responders.

Conclusions: While pre-operative mean ICP was similar, the mean ICP wave amplitudes were significantly higher in iNPH patients improving clinically after shunt treatment as compared to the non-responders.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Follow-Up Studies
  • Humans
  • Hydrocephalus, Normal Pressure / physiopathology*
  • Hydrocephalus, Normal Pressure / surgery*
  • Intracranial Pressure / physiology*
  • Male
  • Middle Aged
  • Monitoring, Physiologic / methods
  • Retrospective Studies
  • Sensitivity and Specificity
  • Treatment Outcome
  • Ventriculoperitoneal Shunt*