title: Idiopathic normal pressure hydrocephalus: diagnostic and predictive value of clinical testing, lumbar drainage, and CSF dynamics.
abstract: OBJECTIVE The aim of the study was to analyze the diagnostic and predictive values of clinical tests, CSF dynamics, and intracranial pulsatility tests, compared with external lumbar drainage (ELD), for shunt response in patients with idiopathic normal pressure hydrocephalus (iNPH). METHODS Sixty-eight consecutive patients with suspected iNPH were prospectively evaluated. Preoperative assessment included clinical tests, overnight intracranial pressure (ICP) monitoring, lumbar infusion test (LIFT), and ELD for 24-72 hours. Simple and multiple linear regression analyses were conducted to identify predictive parameters concerning the outcome after shunt therapy. RESULTS Positive response to ELD correctly predicted improvement after CSF diversion in 87.9% of the patients. A Mini-Mental State Examination (MMSE) value below 21 was associated with nonresponse after shunt insertion (specificity 93%, sensitivity 67%). Resistance to outflow of CSF (ROut) > 12 mm Hg/ml/min was false negative in 21% of patients. Intracranial pulsatility parameters yielded different results in various parameters (correlation coefficient between pulse amplitude and ICP, slow wave amplitude, and mean ICP) but did not correlate to outcome. In multiple linear regression analysis, a calculation of presurgical MMSE versus the value after ELD, ROut, and ICP amplitude quotient during LIFT was significantly associated with outcome (p = 0.04). CONCLUSIONS Despite a multitude of invasive tests, presurgical clinical testing and response to ELD yielded the best prediction for improvement of symptoms following surgery. The complication rate of invasive testing was 5.4%. Multiple and simple linear regression analyses indicated that outcome can only be predicted by a combination of parameters, in accordance with a multifactorial pathogenesis of iNPH.
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Cynthia V
authors.initials: CV
authors.lastname: Mahr
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Markus
authors.initials: M
authors.lastname: Dengl
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Ulf
authors.initials: U
authors.lastname: Nestler
authors.affiliation: Neuroradiology, University Hospital Leipzig; and.
authors.forename: Martin
authors.initials: M
authors.lastname: Reiss-Zimmermann
authors.affiliation: Mathematical Institute, Justus-Liebig University Gießen, Germany.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Eichner
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Matthias
authors.initials: M
authors.lastname: Preuß
authors.forename: Jürgen
authors.initials: J
authors.lastname: Meixensberger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002555:Cerebrospinal Fluid / Q000502:physiology*; D004322:Drainage; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies
keywords: AMP Q = ICP amplitude quotient; CSF dynamics; ELD = external lumbar drainage; ETV = endoscopic third ventriculostomy; ICP = intracranial pressure; LIFT = lumbar infusion test; MMSE = Mini–Mental State Examination; OVM = overnight ICP monitoring; RAP = correlation coefficient between pulse amplitude and ICP; ROC = receiver operating characteristic; ROut = resistance to outflow of CSF; SLHS = Stein and Langfitt Hydrocephalus Score; VP = ventriculoperitoneal; iNPH = idiopathic normal pressure hydrocephalus; mRS = modified Rankin Scale; normal pressure hydrocephalus; pulsatility; ∆Kiefer = change in Kiefer score