Normal Pressure Hydrocephalus

Cerebrospinal fluid

The cavity within which the brain and spinal cord are contained has a volume of approximately 1500 ml. About 200 ml of this volume is cerebrospinal fluid (CSF). The function of the CSF is to nourish the central nervous system and protect it against chemical and physical injury. A disturbance in the CSF system may lead to development of the disorder Normal Pressure Hydrocephalus (NPH).

Symptoms

NPH is a neurological condition which mainly occurs in people that are 55 years and older. The main clinical features of NPH are balance and gait disturbance, dementia and urinary incontinence. Since these symptoms are common in the normal ageing process, and similar to the symptoms of Alzhemer’s or Parkinson’s disease, NPH is often difficult to diagnose. The most common diagnostic tools are CT-scans or MRI as well as a thorough clinical assessment.

Predictive tests

To determine whether a patient is likely to improve from shunt surgery or not, there are several additional tests which can be performed. Here the infusion test, for assessment of CSF-dynamical parameters, including resting ICP and absorption of CSF, is an important test which can be performed with the Likvor instrument.

Shunt surgery

The most common treatment of patients with NPH is shunt surgery. A shunt system is surgically placed from the ventricles of the brain to the abdominal cavity, to drain excess CSF from the brain. About 70 % of the patients operated on improve after surgery. Today hydrocephalus shunt surgery is the most frequent operation performed at many neurosurgical centers, with nearly 70 000 shunts implanted yearly in the developed countries.