title: Are physiological changes experienced by healthy subjects during acu-TENS associated with acupuncture point sensations?
abstract: BACKGROUND
  Transcutaneous electrical nerve stimulation over acupuncture points (acu-TENS) has been reported to improve clinical outcomes. The objectives of the present study were to investigate whether acupuncture point sensations were experienced during acu-TENS, and whether such sensations were associated with any concomitant changes in autonomic nervous system activity.
  
  
  METHODS
  This study adopted a single-blinded, randomised, controlled trial methodology. A total of 36 healthy subjects were randomly assigned to an experimental group (acu-TENS on right LI4 and LI11 points); control group (acu-TENS to bilateral kneecaps); or placebo group (sham acu-TENS on right LI4 and LI11 points). Heart rate (HR), mean arterial blood pressure (MAP), SD of the NN interval (SDNN) and low frequency to high frequency ratio (LF/HF) were measured before, during and after intervention. The Hong Kong Chinese version of the Massachusetts General Hospital Acupuncture Sensation Scale (C-MMASS) index was used for quantifying the acupuncture point stimulation sensations.
  
  
  RESULTS
  The experimental group showed a significant increase in HR (mean (SD) 73.5 (6.3) to 75.9 (6.7) bpm, p=0.027), MAP (88.5 (4.5) to 91.0 (4.1) mm Hg, p=0.004), SDNN (143.36 (8.58) to 153.69 (7.64) ms, p=0.002) and LF/HF (1.26 (0.19) to 1.31 (0.21), p=0.037) during the intervention. The control group showed a significant increase in SDNN (140.21 (8.72) to 143.39 (9.47) ms, p=0.009) and LF/HF (1.21 (0.09) to 1.23 (0.12), p=0.033). There were no significant physiological changes in the placebo group. Overall C-MMASS indices for the experimental, control and placebo groups were 3.23 (0.3), 2.14 (0.6) and 0.29 (0.32), respectively. The between-group difference was statistically significant (F=139.24, df=2, p<0.05). However, correlation analysis did not support any association between sensation intensity and physiological responses in any groups (γ ranged from -0.36 to 0.25).
  
  
  CONCLUSIONS
  This study showed that 'acupuncture point sensations' were experienced during acu-TENS to LI4 and LI11, but such sensations were not associated with physiological responses induced during the stimulation.
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, , Hong Kong, China.
authors.forename: David T W
authors.initials: DT
authors.lastname: Yu
authors.forename: Alice Y M
authors.initials: AY
authors.lastname: Jones
mesh_terms: D015669:Acupuncture Points; D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D012677:Sensation; D004561:Transcutaneous Electric Nerve Stimulation
keywords: PHYSIOTHERAPY