title: Accuracy of the Babinski sign in the identification of pyramidal tract dysfunction.
abstract: BACKGROUND
  The extensor plantar response described by Joseph Babinski (1896) indicates pyramidal tract dysfunction (PTD) but has significant inter-observer variability and inconsistent accuracy. The goal of this study was to determine the accuracy of the Babinski sign in subjects with verified PTD.
  
  
  METHODS
  We studied 107 adult hospitalized and outpatient subjects evaluated by neurology. The reference standard was the blinded and independent diagnosis of an expert neurologist based on anamnesis, physical examination, imaging and complementary tests. Two neurologists elicited the Babinski sign in each patient independently, blindly and in a standardized manner to measure inter-observer variability; each examination was filmed to quantify intra-observer variability.
  
  
  RESULTS
  Compared with the reference standard, the Babinski sign had low sensitivity (50.8%, 95%CI 41.5-60.1) but high specificity (99%, 95%CI 97.7-100) in identifying PTD with a positive likelihood ratio of 51.8 (95%CI 16.6-161.2) and a calculated inter-observer variability of 0.73 (95%CI 0.598-0.858). The intraevaluator reliability was 0.571 (95%CI 0.270-0.873) and 0.467 (95%, CI 0.019-0.914) respectively, for each examiner.
  
  
  CONCLUSIONS
  The presence of the Babinski sign obtained by a neurologist provides valid and reliable evidence of PTD; due to its low sensitivity, absence of the Babinski sign still requires additional patient evaluation if PTD is suspected.
authors.affiliation: Facultad de Medicina, Universidad de Antioquia, Carrera 51d N° 62-29, Medellín 050010, Colombia. Electronic address: sandraisazaneuro@yahoo.com.
authors.forename: Sandra Patricia
authors.initials: SP
authors.lastname: Isaza Jaramillo
authors.affiliation: Facultad de Medicina, Universidad de Antioquia, Carrera 51d N° 62-29, Medellín 050010, Colombia; Hospital Universitario San Vicente Fundación, Calle 64N° 51d-154, Medellín 050010, Colombia; Neurologic institute of Colombia, Calle 55N° 46-36, Medellín 050010, Colombia.
authors.forename: Carlos Santiago
authors.initials: CS
authors.lastname: Uribe Uribe
authors.affiliation: Facultad de Medicina, Universidad de Antioquia, Carrera 51d N° 62-29, Medellín 050010, Colombia; Hospital Universitario San Vicente Fundación, Calle 64N° 51d-154, Medellín 050010, Colombia.
authors.forename: Francisco A
authors.initials: FA
authors.lastname: García Jimenez
authors.affiliation: Facultad de Medicina, Universidad de Antioquia, Carrera 51d N° 62-29, Medellín 050010, Colombia.
authors.forename: William
authors.initials: W
authors.lastname: Cornejo-Ochoa
authors.affiliation: Neurologic institute of Colombia, Calle 55N° 46-36, Medellín 050010, Colombia.
authors.forename: Juan Felipe
authors.initials: JF
authors.lastname: Alvarez Restrepo
authors.affiliation: Methodist Neurological Institute, 6560 Fannin Street, Suite 802, Houston, TX 77030, USA.
authors.forename: Gustavo C
authors.initials: GC
authors.lastname: Román
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011712:Pyramidal Tracts / Q000473:pathology*; D012372:ROC Curve; D001405:Reflex, Babinski / Q000502:physiology*; D012189:Retrospective Studies; D013118:Spinal Cord Diseases / Q000175:diagnosis*; D018709:Statistics, Nonparametric
keywords: Accuracy; Babinski sign; ROC curve; Sensitivity; Specificity