Epidemiology of Idiopathic Normal Pressure Hydrocephalus: A Systematic Review of the Literature

• Published in: World neurosurgery Vol. 84; no. 6; pp. 2002 - 2009
• Main Authors: Martín-Láez, Rubén, Caballero-Arzapalo, Hugo, López-Menéndez, Luis Ángel, Arango-Lasprilla, Juan Carlos, Vázquez-Barquero, Alfonso
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.2015
• Subjects: Epidemiology; Health Surveys; Humans; Hydrocephalus, Normal Pressure - epidemiology; Idiopathic normal pressure hydrocephalus; Incidence; Neurosurgery; Prevalence; Review; Shunt-responsive hydrocephalus; Ventriculomegaly; Prevalence; Shunt-responsive hydrocephalus; Ventriculomegaly; MRI; AVIM; MeSH; Review; Epidemiology; iNPH; THC; Idiopathic normal pressure hydrocephalus; Incidence; Asymptomatic ventriculomegaly with features of normal pressure hydrocephalus; Tight high convexity without ventriculomegaly; Magnetic resonance imaging; Medical Subject Headings
• ISSN: 1878-8750; 1878-8769
• DOI: 10.1016/j.wneu.2015.07.005

Idiopathic normal pressure hydrocephalus (iNPH) is an important cause of gait disturbance and cognitive impairment in elderly adults. However, the epidemiology of iNPH is relatively unknown, largely as a result of the paucity of specifically designed population studies. This systematic review aims to assess the prevalence and incidence of iNPH. A systematic literature review on the epidemiology of iNPH was conducted using MEDLINE/PubMed searching for articles published up to June 2014. The inclusion criteria were met by 21 studies. Of the studies, 12 were specifically designed for detecting cases of iNPH; however, only 4 were prospective. In people >65 years old, pooled prevalence obtained from specific population studies was 1.3%, which was almost 50-fold higher than that inferred from door-to-door surveys of dementia or parkinsonism. Prevalence may be higher in assisted-living and extended-care residents, with 11.6% of patients fulfilling the criteria for suspected iNPH and 2.0% of patients showing permanent improvement after cerebrospinal fluid diversion. The only prospective population-based survey that reported iNPH incidence estimated 1.20 cases/1000 inhabitants/year, 15-fold higher than estimates obtained from studies based on hospital catchment areas. The incidence of shunt surgery for iNPH and shunt-responsive iNPH obtained from incident cases of hospital catchment areas appears to be <2 cases/100,000 inhabitants/year and 1 case/100,000 inhabitants/year, respectively. No population-based study reporting the real values for these 2 parameters could be found. iNPH appears to be extremely underdiagnosed. Properly designed and adequately powered population-based studies are required to characterize the epidemiology of this disease accurately.