title: Improvement in executive subfunctions following cerebrospinal fluid tap test identifies idiopathic normal pressure hydrocephalus from its mimics.
abstract: OBJECTIVE
  Patients with idiopathic normal pressure hydrocephalus (iNPH) present cognitive deficits that overlap with other neurological conditions such as Parkinson's disease or vascular dementia, therefore mimicking iNPH. This prospective study aimed to compare cognitive performances between iNPH and iNPH mimics before and after cerebrospinal fluid (CSF) tapping.
  
  
  METHODS
  A total of 57 patients with suspicion of iNPH (75.84 ± 6.42 years; 39% female) were included in this study (37 iNPH and 20 iNPH mimics). Neuropsychological assessments were performed before and 24 h after CSF tapping of 40 ml. Multivariate logistic regressions were used to examine the association between iNPH and cognitive functions, adjusted for age, education, baseline cognitive assessment and disease duration.
  
  
  RESULTS
  Both groups presented the same baseline cognitive performances. After CSF tapping, iNPH patients improved their semantic (P = 0.001) and phonemic verbal fluencies (P = 0.001), whereas iNPH mimics presented similar performances to before CSF tapping. The phonemic verbal fluency (odds ratio 1.43, 95% confidence interval 1.05; 1.96) and the Color Trails Test (odds ratio 0.10, 95% confidence interval 0.01; 0.76) improvements were the two discriminative cognitive tests that identified iNPH from iNPH mimics.
  
  
  CONCLUSIONS
  Improvement in executive subfunctions after CSF tapping identified iNPH patients from other neurological conditions that mimic iNPH. These findings respond to clinical issues encountered on a daily basis and would improve the diagnostic process of iNPH.
authors.affiliation: Department of Clinical Neurosciences, Division of Neurology, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Laidet
authors.affiliation: Department of Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: F R
authors.initials: FR
authors.lastname: Herrmann
authors.affiliation: Department of Clinical Neurosciences, Division of Neurosurgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Momjian
authors.affiliation: Department of Clinical Neurosciences, Division of Neurology, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Assal
authors.affiliation: Department of Clinical Neurosciences, Division of Neurology, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.|Department of Neurology, Division of Cognitive and Motor Aging, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, USA.
authors.forename: G
authors.initials: G
authors.lastname: Allali
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002555:Cerebrospinal Fluid; D003937:Diagnosis, Differential; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000175:diagnosis*; D008297:Male; D011446:Prospective Studies; D011597:Psychomotor Performance / Q000502:physiology*; D013129:Spinal Puncture
keywords: cerebrospinal fluid; cerebrospinal fluid tap test; dementia; executive functions; idiopathic normal pressure hydrocephalus; mimics; neuropsychology