Is normal pressure hydrocephalus a valid concept in 2002? A reappraisal in five questions and proposal for a new designation of the syndrome as "chronic hydrocephalus".

The authors question the current validity of the traditional concept of normal pressure hydrocephalus (NPH) as it was described by Adams and Hakim in 1965. The classic features of the disease are addressed. It is concluded that most of the historical statements made three decades ago need to be revised. Especially, the term "normal pressure" hydrocephalus probably does not match the actual manometric profile of patients with NPH. Similarly, the terms"curable"and "reversible" dementia are inadequate to designate the mental alterations of NPH. That NPH is non-specific to the adult population is also stressed, since it may be not uncommonly encountered in paediatrics, especially in an implanted shunt malfunction. The term "chronic hydrocephalus" without reference to cerebrospinal fluid pressure and to the age of the patient is proposed instead of NPH, which seems out of step with current knowledge of the pressure profile and with the diagnosis and decision making context in patients with so called NPH.