Analgesic Effect of Vibro-acupuncture – Quantitative Sensory Testing on Healthy Humans and Chronic Pain Patients
Student thesis: Master thesis (including HD thesis)
- Dennis Boye Larsen
4. term, Medicine with Industrial Specialisation, Master (Master Programme)
Background & Aims: Acupuncture treatment has attained an important role in Western medicine, and its analgesic benefits are rapidly being accepted for pain alleviation in several disorders. Vibration therapy is an-other treatment modality that has been investigated throughout the last two decades, and its pain relieving effects is possibly mediated by Aβ-fibers, which inhibits nociceptive transmission at a segmental and central level. A combination of both (vibro-acupuncture; VA) has to our knowledge not yet been attempted. Therefore, the current study aimed to test a novel acu-vibrator device, capable of delivering high-frequency vibration into the deep muscle through acupuncture needles. The effects of the novel VA was compared to manual acupunc-ture (MA) and placebo acupuncture (PA), to elucidate possible differences on pain and sensory responses in human subjects.
Methods: A subjects- and outcome assessor-blinded, randomized, placebo-controlled cross-over study was conducted, including 30 healthy subjects (21 men; 9 women) and 11 chronic elbow pain subjects (six men; five women). The full battery of quantitative sensory testing (QST) was employed for testing sensory responses to VA in comparison with PA and MA on thermal, mechanical, and pain parameters. Moreover, subjective sensa-tion scales McGills Pain Questionnaire (MPQ), the MGH acupuncture sensation scale (for Deqi sensations), and the visual analogue scale (VAS) were used to describe the acupuncture sensation, and pain in the affected arm of chronic pain subjects.
Results: The primary findings of the current study were: Significantly elevated vibration detection threshold following treatment with VA compared to PA and MA (p = 0.004) in healthy subjects; time-dependent increases in thermal parameters cold and warm detection thresholds (p < 0.0001 and 0.029, respectively), and decreases in cold and heat pain thresholds (p = 0.032 and < 0.00001, respectively) for healthy subjects and chronic elbow pain subjects. For mechanical parameters, a time-dependent decrease for mechanical pain threshold was found (p < 0.0001) together with increased pressure pain thresholds in the left arm (p = 0.019) and tibialis (p = 0.016) for healthy subjects. In addition, double-blinding was assessed based on indication percentage for each treat-ment, and was considered unsuccessful. Several descriptors associated with Deqi was increasingly reported dur-ing treatment with MA and VA compared to PA, together with vibration. MPQ data showed increased pain qual-ity for MA and VA compared to PA (p < 0.001 for both comparisons) for healthy subjects. Corroborating data from VAS ratings showed significantly elevated pain associated with MA and VA, compared to PA (p = 0.003 and < 0.0001, respectively). Lastly, chronic elbow pain subjects described their pain quality (MPQ) and intensity (VAS) as being significantly lower following treatment for all three treatments.
Conclusions: The current study showed treatment and time-specific changes in local sensory responses for both thermal and mechanical QST parameters, suggesting an impact on all three main primary afferent nerve fibers involved in exteroception. Similar responses for MA and VA with regards to Deqi descriptors, pain quality, and pain intensity were found, suggesting an applicability of VA in future acupuncture trials. Moreover, pain was in general rated lower by chronic elbow pain subjects following each of the three treatments, warranting further investigation. Unravelling the analgesic potential of VA may introduce a novel approach to treating chronic pain in several disorders and provide insight into segmental and central effects of the proposed combi-nation.
Language | English |
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Publication date | 4 Jun 2015 |
Number of pages | 49 |