title: Influence of stimulation location and posture on the reliability and comfort of the nociceptive flexion reflex.
abstract: BACKGROUND
  The lower limb nociceptive flexion reflex (NFR) is commonly used to assess the function of the nociceptive system. Currently, there is a lack of standardized stimulation procedures to determine the NFR threshold, making comparisons of thresholds across studies difficult.
  
  
  OBJECTIVE
  To assess and compare the within- and between-session reliability of NFR threshold when elicited from two common stimulation locations: the medial arch of the foot (while standing) and the sural nerve (while seated).
  
  
  METHODS
  A staircase procedure was used to determine NFR threshold in 20 healthy participants twice within one session and once more in a separate session approximately four days later. At both sessions, NFR threshold was determined from both medial arch and sural nerve stimulation. Comparisons of NFR threshold, reliability and participant discomfort ratings were made between the two stimulation locations.
  
  
  RESULTS
  NFR thresholds were statistically equivalent at the two stimulation locations, but there were more nonresponders and ratings of participant discomfort were significantly higher during stimulation over the sural nerve. Within-session reliability measures were superior for stimulation over the sural nerve; however, between-session measures were more reliable using stimulation over the medial arch of the foot.
  
  
  CONCLUSIONS
  The authors recommend stimulation over the medial arch of the foot while standing as the preferred location for eliciting the lower limb NFR, particularly if measurements are to be compared across multiple sessions.
authors.affiliation: Health and Research Institute, AUT University, Auckland, New Zealand. gwyn.lewis@aut.ac.nz
authors.forename: Gwyn N
authors.initials: GN
authors.lastname: Lewis
authors.forename: David A
authors.initials: DA
authors.lastname: Rice
authors.forename: Kathryn
authors.initials: K
authors.lastname: Jourdain
authors.forename: Peter J
authors.initials: PJ
authors.lastname: McNair
mesh_terms: D000328:Adult; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods / Q000592:standards; D005260:Female; D005528:Foot / Q000294:innervation; D006801:Humans; D007866:Leg / Q000294:innervation; D008297:Male; D059225:Nociception / Q000502:physiology*; D010147:Pain Measurement / Q000379:methods / Q000592:standards*; D017288:Pain Threshold / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D012018:Reflex / Q000502:physiology*; D015203:Reproducibility of Results; D013497:Sural Nerve / Q000502:physiology*; D055815:Young Adult