title: An examination of the validity of the standardized field sobriety test in detecting drug impairment using data from the Drug Evaluation and Classification program.
abstract: OBJECTIVE
  The purpose of this study is to assess the validity of the 3 components of the Standardized Field Sobriety Test (SFST), including the Horizontal Gaze Nystagmus (HGN), One Leg Stand (OLS), and Walk and Turn (WAT) tests, in identifying impairment among suspected drug-impaired drivers using data recorded during drug evaluation and classification (DEC) evaluations.
  
  
  METHODS
  Data from 2142 completed DEC evaluations of central nervous system (CNS) stimulants, CNS depressants, narcotic analgesics, cannabis, or no drugs were analyzed using multinomial logistic regression.
  
  
  RESULTS
  All drug categories were significantly associated with impaired performance. On the HGN, users of CNS depressants were significantly more likely to experience lack of smooth pursuit and distinct nystagmus at maximum deviation compared to non-drug users. On the OLS, users of all drug classes were significantly more likely to sway while balancing and use their arms to maintain balance but significantly less likely to hop compared to drug-free cases. Users of CNS depressants, CNS stimulants, and narcotic analgesics were significantly more likely to put their raised foot down during the test. On the WAT, users of CNS depressants, CNS stimulants, and narcotic analgesics were significantly less likely to keep their balance while listening to test instructions compared to those who had not used drugs. Users of CNS depressants were less likely to touch heel-to-toe while walking, whereas individuals who had used narcotic analgesics were less likely to take the correct number of steps.
  
  
  CONCLUSIONS
  These findings provide support for the use of the SFST as a screening tool for law enforcement to identify impairment in persons who have used CNS stimulants, CNS depressants, cannabis, or narcotic analgesics.
authors.affiliation: a Canadian Centre on Substance Abuse , Ottawa , Ontario , Canada.
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Porath-Waller
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Beirness
mesh_terms: D001334:Automobile Driving / Q000331:legislation & jurisprudence*; D002188:Cannabis; D002492:Central Nervous System Depressants / Q000494:pharmacology; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D016208:Databases, Factual; D006801:Humans; D009294:Narcotics / Q000494:pharmacology; D009759:Nystagmus, Pathologic / Q000139:chemically induced; D016495:Police; D004856:Postural Balance / Q000187:drug effects; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000379:methods / Q000592:standards*; D019966:Substance-Related Disorders / Q000175:diagnosis*; D016138:Walking / Q000502:physiology
chemical_list: D002492:Central Nervous System Depressants; D000697:Central Nervous System Stimulants; D009294:Narcotics