Exploring amplitude in transcutaneous electroacupuncture stimulation - PowerPoint PPT Presentation

Exploring amplitude in transcutaneous electroacupuncture stimulation (TEAS) AACP Leeds Conference, Principal Met Hotel, Leeds 13 October 2018 David F Mayor MA, BAc, MBAcC, Hon member AACP Acupuncture practitioner and Visiting Fellow, School of Health and Social Work, University of Hertfordshire, UK 1

Background – the study data This presentation is based on data, gathered during 2015-16, during an experimental study into the effects of TEAS on the brain brain (using electroencephalography, EEG) and heart heart (assessing heart and pulse rate variability, HRV, PRV). With minor adjustments, our findings are likely to be applicable to electroacupuncture (EA) as well as TEAS. 2

Contents of this presentation slides 1. Background [ 2,4 -8] 2. Study objectives [9] 3. Materials and methods [9-20] 4. Main findings – amplitude & frequency [21-30] 5. Factors affecting amplitude (& freq.) [31-39] 6. Subjective responses [40-43] 7. Effects on mood [44-52] 8. Factors affecting mood [53] 9. Some conclusions [54-60] 10. Breaking news ... ! [61] 3 2

Background – EA and TEAS parameters EA and TEAS parameters fall into two main families: ‘low frequency (LF), high intensity’(ALS) ‘high frequency (HF), low intensity’ (TLS). Sometimes the label ALS is restricted to ‘burst’ stimulation (brief LF trains of HF pulses). In addition, there is a middle range, of around 10-20 pps. LF: Low frequency, 2-6 pps HF: High frequency, 50-200 pps ALS: Acupuncture-like TLS: TENS-like pps: Pulses per second 4

PPS vs frequency (cycles per second, Hz) Equinox: alternating monophasic pulses PPS = 2 x Hz 5

Background – ‘Strong but Comfortable’ (SbC) Literature review: Literature review: Most authorities recommend that TENS,TEAS and EA should be experienced as ‘strong but strong but comfortable comfortable’ (SbC), or at the most as ‘non-painful’ and tolerable. In addition, for LF (or burst) stimulation, ‘SbC’ tolerable muscle twitches should be elicited. In TENS/TEAS, A- β afferent fibres are mostly involved. EA is also likely to activate A- δ fibres. In either case, if stimulation is strong, C (or type IV) nociceptive (pain) fibres will start to fire, and stress mechanisms may become involved. Stimulation at close to sensory threshold (ST) is unlikely to be clinically effective. 6

Background – what we told our participants STIMULATION SENSATION SHOULD FEEL ‘STRONG BUT COMFORTABLE’ ST: Sensory SbC Threshold None Some Strong Painful Max possible So aim for a sensation between ‘Strong’ and ‘Painful’ 7

Background – data from an online database www.electroacupunctureknowlege.com is a comprehensive open-access online database of a information from more than 8,000 EA, TENS/TEAS and related clinical studies published before 2004. Modality All studies ‘comfort*’ % total ‘Toler*’ % total EA 3880 148 3.8% 907 23.4% TEAS 450 22 4.9% 89 19.8% TENS 1170 107 9.1% 126 10.8% Studies including the words ‘comfort*’ or ‘toler* under treatment parameters. Parameters were described in terms of ‘comfort comfort*’ in relatively more TENS TENS than EA/TEAS studies, and in terms of ‘toler toler*’ in relatively more EA/TE EA/TEAS than TENS studies. 1 8

Study objectives To investigate amplitude settings for sensory threshold (ST) and ‘strong but comfortable’ (SbC) responses in our study participants – what affects these, and what do they affect? Materials and methods 66 participants were recruited. They attended for four sessions, a week or more apart, in which TEAS was applied for 20 minutes to each hand between the acupuncture points LI4 ( hegu ) and the ulnar border (JR Worsley’s location for SI3, houxi ). 9

TEAS Stimulation at 2.5 pps

Study protocol In each session, TEAS was delivered at a SbC intensity and at either 2.5, 10 or 80 pps. In the fourth session, for sham sham TEAS, amplitude was set at zero and frequency at 160 pps. The order of sessions in which each frequency was used was varied in a balanced manner. Four participants dropped out after their first session, and a fifth after the third session. 2.5 pps 65 sessions 10 pps 64 sessions 80 pps 61 sessions Sham 61 sessions Total Total 251 sessions 11

Online initial questionnaire Online initial questionnaire Session – time line 8 x 5-minute slots Baseline Stim1 Stim2 Stim3 Stim4 Post1 Post2 Post3 Physiological measurements (EEG, HRV, PRV, temp, head movement) Room Room Room Room temp temp temp temp Online debriefing questionnaire 12

Online initial questionnaire Online initial questionnaire e.g. past EA or TENS lifestyle … Session – time line 8 x 5-minute slots Baseline Stim1 Stim2 Stim3 Stim4 Post1 Post2 Post3 Physiological measurements (EEG, HRV, PRV, temp, head movement) Online debriefing questionnaire which session: most/least change most/least intense most/least pleasant 13

Online initial questionnaire Online initial questionnaire PSS Initial session Post session NRS‐M (month) questionnaires scales Sleep/tired Rate intensity/pleasantness 8 x 5-minute slots Baseline Stim1 Stim2 Stim3 Stim4 Post1 Post2 Post3 Physiological measurements (EEG, HRV, PRV, temp, head movement) Online debriefing questionnaire 14

NRS for Mood (NRS-M) Used for ‘how you have felt in general over the past month’ and ‘how you feel right now’ 15

Online initial questionnaire Online initial questionnaire ST 1  SbC 1 ST 2  SbC 2 (R  L) (R  L) 8 x 5-minute slots Baseline Stim1 Stim2 Stim3 Stim4 Post1 Post2 Post3 Physiological measurements (EEG, HRV, PRV, temp, head movement) Online debriefing questionnaire ST: Sensory threshold SbC: Strong but Comfortable 16

Online initial questionnaire Online initial questionnaire Initial session Post session questionnaires scales 8 x 5-minute slots Baseline Stim1 Stim2 Stim3 Stim4 Post1 Post2 Post3 Physiological measurements (EEG, HRV, PRV, temp, head movement) NRS-M 1 NRS-M 2 NRS-M 3 NRS-M 4 BRUMS 1 BRUMS 2 Online debriefing questionnaire NRS-M NRS-M Numerical rating scale for mood Chan Change ge: : NRS 3 – NRS 1 BRUMS Brunel Mood Scale BRUM Chan Change ge: : BRUMS 2 – BRUMS 1 Outcome measures 17

Brunel Mood Scale (BRUMS) Used for ‘how you feel right now’ 18

Online initial questionnaire Online initial questionnaire Initial session Post session questionnaires scales 8 x 5-minute slots Baseline Stim1 Stim2 Stim3 Stim4 Post1 Post2 Post3 Physiological measurements (EEG, HRV, PRV, temp, head movement) RT RT RT RT NRS-M 1 NRS-M 2 NRS-M 3 NRS-M 4 BRUMS 1 BRUMS 2 Online debriefing questionnaire NRS-M Numerical rating scale for mood NRS-M Change Chan ge: : NRS 3 – NRS 1 BRUMS Brunel Mood Scale BRUM Chan Change ge: : BRUMS 2 – BRUMS 1 Outcome measures 19

Statistics Almost all our data was not ‘normally distributed’ 2 Therefore ‘nonparametric’ methods of analysis were used: Simple change counts, and medians and quartiles rather than averages and standard deviations. Nonparametric methods used for differen differences ces Wilcoxon and Sign tests (for pairs of repeated measures) • Mann-Whitney U test (for pairs of unrelated samples) • Friedman test (to compare >2 repeated measures) • Kruskal-Wallis test (to compare >2 unrelated samples) • Binomial test (to compare counts counts of pairs: M/F, or +/-) • Nonparametric method used for similarities similarities Correlation using Spearman’s ρ • Limitati Limitations ons: Multilevel modelling methods and post hoc corrections were not used. 20

Main findings 1. Stimulation amplitudes vary with frequency frequency Median amplitudes were higher at 2.5 pps than at 10 pps, and these in turn were higher than at 80 pps, for both SbC and (most) ‘sensory threshold’ (ST) levels. Level (0‐10) 2.5 pps (N=63) 10 pps (N=64) 80 pps (N=61) Amplitude median range median range median range 2.5 pps ( N =63) 2.5 pp 63) 10 pps pps ( N =64 =64) 80 pps ( N =61 80 pp =61) L ST 1 2.9 3.1 2.3 3.2 2.0 3.9 R 2 L 2 L SbC 1 4.1 7.9 3.6 8.1 3.0 6.1 Level Level median range median range median range R 1 R ST 1 2.9 4.3 2.7 2.9 2.1 2.5 L 1 L ST L ST 1 2.9 3.1 2.3 3.2 2.0 3.9 R SbC 1 4.5 7.6 3.9 6.3 3.1 5.5 L Sb L SbC 1 4.1 7.9 3.6 8.1 3.0 6.1 L ST 2 3.1 4.8 2.9 3.8 2.5 3.0 R ST 1 R ST 2.9 4.3 2.7 2.9 2.1 2.5 L SbC 2 5.0 8.5 4.0 7.8 3.2 6.5 R ST 2 3.1 4.2 2.9 3.2 2.9 3.7 R SbC 1 R Sb 4.5 7.6 3.9 6.3 3.1 5.5 R SbC 2 5.1 8.4 4.0 7.1 3.6 6.1 L ST 2 L ST 3.1 4.8 2.9 3.8 2.5 3.0 L Sb L SbC 2 5.0 8.5 4.0 7.8 3.2 6.5 R ST R ST 2 3.1 4.2 2.9 3.2 2.9 3.7 R Sb R SbC 2 5.1 8.4 4.0 7.1 3.6 6.1 21