title: A psychophysical investigation of the facial action coding system as an index of pain variability among older adults with and without Alzheimer's disease.
abstract: OBJECTIVE
  Reflexive responses to pain such as facial reactions become increasingly important for pain assessment among patients with Alzheimer's disease (AD) because self-report capabilities diminish as cognitive abilities decline. Our goal was to study facial expressions of pain in patients with and without AD.
  
  
  METHODS
  We employed a quasi-experimental design and used the Facial Action Coding System (FACS) to assess reflexive facial responses to noxious stimuli of varied intensity. Two different modalities of stimulation (mechanical and electrical) were employed.
  
  
  RESULTS
  The FACS identified differences in facial expression as a function of level of discomforting stimulation. As expected, there were no significant differences based on disease status (AD vs control group).
  
  
  CONCLUSIONS
  This is the first study to discriminate among FACS measures collected during innocuous and graded levels of precisely measured painful stimuli in seniors with (mild) dementia and in healthy control group participants. We conclude that, as hypothesized, FACS can be used for the assessment of evoked pain, regardless of the presence of AD.
authors.affiliation: Department of Psychology and Center on Aging and Health, University of Regina, Regina, Canada.
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Lints-Martindale
authors.forename: Thomas
authors.initials: T
authors.lastname: Hadjistavropoulos
authors.forename: Bruce
authors.initials: B
authors.lastname: Barber
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Gibson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000523:psychology*; D004558:Electric Stimulation; D005149:Facial Expression; D005260:Female; D006801:Humans; D008297:Male; D010147:Pain Measurement / Q000379:methods*; D017288:Pain Threshold; D010812:Physical Stimulation