Normal pressure hydrocephalus (NPH) is an accumulation of cerebrospinal fluid (CSF) that causes the ventricles in the brain to become enlarged, sometimes with little or no increase in intracranial pressure (ICP). In most cases of NPH, the cause of blockage to the CSF absorptive pathways is unclear. The name for this condition, ’normal pressure hydrocephalus,‘ originates from Dr. Salomon Hakim’s 1964 paper describing certain cases of hydrocephalus in which a triad (a group of three) of neurologic symptoms occurred in the presence of ’normal‘ CSF pressure – gait disturbances, dementia, and impaired bladder control. These findings were observed before continuous pressure-recording techniques were available. The phrase ‘normal pressure’ is misleading as many patients experience fluctuations in CSF pressure that range from high to low and are variable within those parameters. However, normal pressure hydrocephalus (NPH) continues to be the common name for the condition.
Who develops Normal Pressure Hydrocephalus?
NPH is most commonly seen in older adults.
- It is estimated that more than 700,000 Americans have NPH, but less than 20% receive an appropriate diagnosis.
- Without appropriate diagnostic testing, NPH is often misdiagnosed as Alzheimer’s disease or Parkinson’s disease, or the symptoms are attributed to the aging process.
- 1% – 5% of the diagnoses of dementia are estimated to actually be NPH.
- NPH has come to be known as the “treatable dementia,” as it is one of the few causes of dementia that can be controlled or reversed with treatment.