title: PTA testing, the Westmead post traumatic amnesia scale and opiate analgesia: a cautionary note.
abstract: OBJECTIVE
  To assess the validity of the Westmead PTA scale in patients treated with opiate analgesia.
  
  
  METHODS
  Seventeen non-head injured, non-traumatic, electively hospitalized orthopaedic patients treated with opiate analgesia were tested on the Westmead PTA scale for a minimum of 2 consecutive days (n=17) to a maximum of 4 consecutive days (n=10).
  
  
  RESULTS
  Only 20% of participants tested over 4 days reached criteria of three consecutive 12/12 scores on the Westmead PTA scale. Daily failure rates on the 12 item scale ranged from 36-70%. All failures were on the 'new learning' items, orientation items were never failed.
  
  
  CONCLUSIONS
  The low pass rate of non-head injured patients treated with opiate analgesics indicates that the Westmead PTA scale is non-specific to traumatic brain injury and is probably an invalid measure of post-traumatic amnesia in patients actively treated with opiates. Implications for the measurement and accurate classification of traumatic brain injury patients are discussed.
authors: Department of Neuropsychology, Frenchay Hospital, Bristol, UK. rjmccarter@npsych.co.uk
authors: R J
authors: RJ
authors: McCarter
authors: N H
authors: NH
authors: Walton
authors: C
authors: C
authors: Moore
authors: A
authors: A
authors: Ward
authors: I
authors: I
authors: Nelson
mesh_terms: D000293:Adolescent; D000328:Adult; D000647:Amnesia / Q000175:diagnosis*; D000701:Analgesics, Opioid / Q000009:adverse effects* / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000592:standards*; D009985:Orthopedics; D010146:Pain / Q000188:drug therapy; D015203:Reproducibility of Results; D015599:Trauma Severity Indices
chemical_list: D000701:Analgesics, Opioid