title: Practice guideline: Idiopathic normal pressure hydrocephalus: Response to shunting and predictors of response: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology.
abstract: OBJECTIVE
  We evaluated evidence for utility of shunting in idiopathic normal pressure hydrocephalus (iNPH) and for predictors of shunting effectiveness.
  
  
  METHODS
  We identified and classified relevant published studies according to 2004 and 2011 American Academy of Neurology methodology.
  
  
  RESULTS
  Of 21 articles, we identified 3 Class I articles.
  
  
  CONCLUSIONS
  Shunting is possibly effective in iNPH (96% chance subjective improvement, 83% chance improvement on timed walk test at 6 months) (3 Class III). Serious adverse event risk was 11% (1 Class III). Predictors of success included elevated Ro (1 Class I, multiple Class II), impaired cerebral blood flow reactivity to acetazolamide (by SPECT) (1 Class I), and positive response to either external lumbar drainage (1 Class III) or repeated lumbar punctures. Age may not be a prognostic factor (1 Class II). Data are insufficient to judge efficacy of radionuclide cisternography or aqueductal flow measurement by MRI.
  
  
  CONCLUSIONS
  Clinicians may choose to offer shunting for subjective iNPH symptoms and gait (Level C). Because of significant adverse event risk, risks and benefits should be carefully weighed (Level B). Clinicians should inform patients with iNPH with elevated Ro and their families that they have an increased chance of responding to shunting compared with those without such elevation (Level B). Clinicians may counsel patients with iNPH and their families that (1) positive response to external lumbar drainage or to repeated lumbar punctures increases the chance of response to shunting, and (2) increasing age does not decrease the chance of shunting being successful (both Level C).
authors.affiliation: From the Overlook Medical Center (J.J.H., R.K.), Atlantic Neuroscience Institute, Summit, NJ; Department of Neurosurgery (J.M.S., M.D.C.), Henry Ford Medical Group, West Bloomfield, MI; Division of Neurosurgery (M.D.C.), St. Michael's Hospital, University of Toronto, Canada; Department of Neurology (G.G.), University of Kansas Medical Center, Kansas City; and Department of Neurology (D.G.), Geisinger Medical Center, Danville, PA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Halperin
authors.affiliation: From the Overlook Medical Center (J.J.H., R.K.), Atlantic Neuroscience Institute, Summit, NJ; Department of Neurosurgery (J.M.S., M.D.C.), Henry Ford Medical Group, West Bloomfield, MI; Division of Neurosurgery (M.D.C.), St. Michael's Hospital, University of Toronto, Canada; Department of Neurology (G.G.), University of Kansas Medical Center, Kansas City; and Department of Neurology (D.G.), Geisinger Medical Center, Danville, PA.
authors.forename: Roger
authors.initials: R
authors.lastname: Kurlan
authors.affiliation: From the Overlook Medical Center (J.J.H., R.K.), Atlantic Neuroscience Institute, Summit, NJ; Department of Neurosurgery (J.M.S., M.D.C.), Henry Ford Medical Group, West Bloomfield, MI; Division of Neurosurgery (M.D.C.), St. Michael's Hospital, University of Toronto, Canada; Department of Neurology (G.G.), University of Kansas Medical Center, Kansas City; and Department of Neurology (D.G.), Geisinger Medical Center, Danville, PA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Schwalb
authors.affiliation: From the Overlook Medical Center (J.J.H., R.K.), Atlantic Neuroscience Institute, Summit, NJ; Department of Neurosurgery (J.M.S., M.D.C.), Henry Ford Medical Group, West Bloomfield, MI; Division of Neurosurgery (M.D.C.), St. Michael's Hospital, University of Toronto, Canada; Department of Neurology (G.G.), University of Kansas Medical Center, Kansas City; and Department of Neurology (D.G.), Geisinger Medical Center, Danville, PA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Cusimano
authors.affiliation: From the Overlook Medical Center (J.J.H., R.K.), Atlantic Neuroscience Institute, Summit, NJ; Department of Neurosurgery (J.M.S., M.D.C.), Henry Ford Medical Group, West Bloomfield, MI; Division of Neurosurgery (M.D.C.), St. Michael's Hospital, University of Toronto, Canada; Department of Neurology (G.G.), University of Kansas Medical Center, Kansas City; and Department of Neurology (D.G.), Geisinger Medical Center, Danville, PA.
authors.forename: Gary
authors.initials: G
authors.lastname: Gronseth
authors.affiliation: From the Overlook Medical Center (J.J.H., R.K.), Atlantic Neuroscience Institute, Summit, NJ; Department of Neurosurgery (J.M.S., M.D.C.), Henry Ford Medical Group, West Bloomfield, MI; Division of Neurosurgery (M.D.C.), St. Michael's Hospital, University of Toronto, Canada; Department of Neurology (G.G.), University of Kansas Medical Center, Kansas City; and Department of Neurology (D.G.), Geisinger Medical Center, Danville, PA.
authors.forename: David
authors.initials: D
authors.lastname: Gloss
mesh_terms: D000047:Academies and Institutes / Q000592:standards*; D002557:Cerebrospinal Fluid Shunts / Q000592:standards*; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery*; D009462:Neurology / Q000379:methods / Q000592:standards*; D017410:Practice Guidelines as Topic / Q000592:standards*; D011237:Predictive Value of Tests; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology