About the Neurobiological Foundations of the De-Qi — Stimulus-Response Relation

Objectivization study of acupuncture Deqi and brain modulation mechanisms: a review

Deqi is an important prerequisite for acupuncture to achieve optimal efficacy. Chinese medicine has long been concerned with the relationship between Deqi and the clinical efficacy of acupuncture. However, the underlying mechanisms of Deqi are complex and there is a lack of systematic summaries of objective quantitative studies of Deqi. Acupuncture Deqi can achieve the purpose of treating diseases by regulating the interaction of local and neighboring acupoints, brain centers, and target organs. At local and neighboring acupoints, Deqi can change their tissue structure, temperature, blood perfusion, energy metabolism, and electrophysiological indicators. At the central brain level, Deqi can activate the brain regions of the thalamus, parahippocampal gyrus, postcentral gyrus, insular, middle temporal gyrus, cingulate gyrus, etc. It also has extensive effects on the limbic-paralimbic-neocortical-network and default mode network. The brain mechanisms of Deqi vary depending on the acupuncture techniques and points chosen. In addition, Deqi 's mechanism of action involves correcting abnormalities in target organs. The mechanisms of acupuncture Deqi are multi-targeted and multi-layered. The biological mechanisms of Deqi are closely related to brain centers. This study will help to explore the mechanism of Deqi from a local-central-target-organ perspective and provide information for future clinical decision-making.

Applications of pain-related evoked potentials and short-latency somatosensory evoked potentials in acupuncture research: a narrative review

OBJECTIVE

To review and discuss the Chinese and English literature on the use of pain-related evoked potentials (PREP) and short-latency somatosensory EP (SLSEP) in acupuncture research.

METHODS

China National Knowledge Infrastructure Database and MEDLINE were searched for the following key words: acupuncture and PREP or SLSEP.

RESULTS

Thirty-seven articles were included in the review. Researchers usually use PREPs to study the analgesic effect of acupuncture, observe influential factors, or for mechanistic exploration. In the SLSEP studies, researchers focused on response characteristics of acupuncture, acupoint specificity, and influential factors of the treatment. There were some problems with the study design and conclusions.

CONCLUSION

Researchers could use PREP and SLSEP to objectively validate the effects of acupuncture and explore its mechanisms using nerve electrophysiology. Further studies can benefit from observing more acupoints' effects using PREPs or SLSEPs and investigating the placebo effect of acupuncture.

Neuroimaging and Neuromonitoring Effects of Electro and Manual Acupuncture on the Central Nervous System: A Literature Review and Analysis

The aim of this review is to provide an overview of the different effects of manual and electroacupuncture on the central nervous system in studies with different neuroimaging interventions. The Database PubMed was searched from 1/1/2000 to 1/6/2014 with restriction to human studies in English language. Data collection for functional magnetic resonance (fMRI) studies was restricted to the period from 1/1/2010 to 1/6/2014 due to a recently published review which included all published randomized and nonrandomized controlled clinical studies as well as observational studies with control groups, no blinding required. Only studies comparing manual or electroacupuncture with sham acupuncture were eligible. All participants were healthy adult men and women. A majority of 25 studies compared manual versus sham, a minority of 7 trials compared electro versus sham and only 1 study compared electro versus manual acupuncture. In 29 out of 33 studies verum acupuncture results were found to present either more or different modulation effects on neurological components measured by neuroimaging and neuromonitoring methods than sham acupuncture. Only four studies reported no effects of verum in comparison to sham acupuncture. Evaluation of the very heterogeneous results shows evidence that verum acupuncture elicits more modulation effects on neurological components than sham acupuncture.

Characterization of deqi sensation and acupuncture effect

Acupuncture stimulation elicits deqi, a composite of unique sensations. According to traditional Chinese medicine (TCM), deqi experienced by patients is often described as suan (aching or soreness), ma (numbness or tingling), zhang (fullness, distention, or pressure), and zhong (heaviness) and is felt by the acupuncturists (needle grasping) as tense, tight, and full. It is believed that deqi may be an important variable in the studies of the mechanism and efficacy of acupuncture treatment. In recent years, great efforts have been made to understand deqi, which include a couple of questionnaires to qualify and quantify deqi sensations, neuroimaging studies of deqi and acupuncture, physiological mechanisms of deqi, and the relation between deqi and clinical efficacy. However, many problems need to be resolved, and more researches are required to be made in the future.

The effect of acupuncture duration on analgesia and peripheral sensory thresholds

Background

Acupuncture provides a means of peripheral stimulation for pain relief. However, the detailed neuronal mechanisms by which acupuncture relieves pain are still poorly understood and information regarding optimal treatment settings is still inadequate. Previous studies with a short burst of unilateral electroacupuncture (EA) in the Tendinomuscular Meridians (TMM) treatment model for pain demonstrated a transient dermatomally correlated bilateral analgesic effect with corresponding peripheral modality-specific sensory threshold alterations. However, the impact of EA duration on the analgesic effect in this particular treatment model is unknown. To obtain mechanistically and clinically important information regarding EA analgesia, this current prospective cross-over study assesses the effects of EA duration on analgesia and thermal sensory thresholds in the TMM treatment model.

Methods

Baseline peripheral sensory thresholds were measured at pre-marked testing sites along the medial aspects (liver and spleen meridians) of bilateral lower extremities. A 5-second hot pain stimulation was delivered to the testing sites and the corresponding pain Visual Analog Scale (VAS) scores were recorded. Three different EA (5Hz) stimulation durations (5, 15 and 30 minutes) were randomly tested at least one week apart. At the last 10 seconds of each EA session, 5 seconds of subject specific HP stimulation was delivered to the testing sites. The corresponding pain and EA VAS scores of de qi sensation (tingling) during and after the EA were recorded. The measurements were repeated immediately, 30 and 60 minutes after the EA stimulation. A four-factor repeat measures ANOVA was used to assess the effect of stimulation duration, time, location (thigh vs. calf) and side (ipsilateral vs. contralateral) of EA on sensory thresholds and HP VAS scores.

Results

A significant (P < 0.01) main effect of time and location with warm, cold and hot pain thresholds at the four testing sites without any significant difference in duration effect was observed. Similar time and location effects were observed with HP VAS with the longer durations (15 and 30 minutes) of stimulation showed a slower onset, but a more sustainable bilateral analgesic benefit than the short stimulation duration (5 minutes). The 15-minute stimulation resulted in an earlier onset of analgesic effect than the 30-minute stimulation paradigm.

Conclusion

Longer durations of EA stimulation provide a more sustainable analgesic benefit to hot noxious stimulation than a shorter duration of stimulation. The increase of cold threshold with sustained warm threshold temperature elevation as observed in the longer durations of EA suggests that as the duration of EA lengthened, there is a gradual shifting from an initial predominantly spinally mediated analgesic effect to a supraspinally mediated modulatory mechanism of thermal pain. The 15-minute stimulation appeared to be the optimal setting for treating acute pain in the lower extremities.

The Electrophysiology of De Qi Sensations

OBJECTIVE

The objective was to investigate the effect of three different modes of stimulation on: (1) the electrical conductance of a known acupuncture point (AP) and a point with no known acupuncture function (NP); and (2) the corresponding characteristics of de qi sensations.

DESIGN

The design was prospective. SETTINGS AND LOCATIONS: Healthy subjects were recruited for the study at the University of California, San Diego Medical Center. Subjects and Study Interventions: Fifteen subjects were enrolled. Two locations of the subjects' nondominant hand were marked: (1) AP (Li4); and (2) NP, a control location with no known acupuncture function. The following different stimulation paradigms were applied to the testing sites in a randomized fashion: (1) transcutaneous electrical stimulation via an ECG electrode; (2) manual stimulation via an acupuncture needle; and (3) electrical stimulation via an acupuncture needle. All electrical stimulation was provided at 12 V and 5 Hz for 30 seconds.

OUTCOME MEASURES

The conductance before and after each stimulation were measured. The subjects were asked to choose four most predominant descriptors of the de qi sensation after the stimulation and to rate the corresponding intensity on a linear VAS.

RESULTS

The conductance values at the AP site are generally a bit higher than conductance values at the NP site for each given stimulation type. The de qi VAS score increased significantly after needle electrical stimulation (EA) in comparison to electrode or manual stimulation at both sites. The most predominant (incidence >30%) de qi sensation with electrical stimulation in either electrode or needle electrical stimulation was tingling, whereas in the manual stimulation, aching was the most predominant sensation of de qi.

CONCLUSIONS

The de qi sensation appears to be qualitatively and quantitatively different between manual and electrical stimulation. The observed difference in transcutaneous electrical conductance between.

The Effect of Ting Point (Tendinomuscular Meridians) Electroacupuncture on Thermal Pain: A Model for Studying the Neuronal Mechanism of Acupuncture Analgesia

OBJECTIVE

The aim of this study was to characterize the role of Ting points (TP) in acute pain management and its potential use in functional imaging studies by quantitatively assessing: (1) the change in peripheral thermal thresholds before and after the electroacupuncture (EA); and (2) the corresponding behavioral feedback of thermal pain stimulation and the de qi sensation of EA.

DESIGN

The study design was prospective.

SETTINGS/LOCATION

Healthy subjects were recruited for the study at the University of California, San Diego Medical Center.

SUBJECTS/INTERVENTIONS

Thirteen (13) healthy subjects were studied. Baseline thermal thresholds (cold and warm sensations and cold and hot pain) were measured at premarked testing sites along the medial aspects of bilateral lower extremities. Five (5) seconds of hot pain (HP) was delivered to the testing sites and the corresponding pain visual analog scale (VAS) scores were recorded. Thirty (30) seconds of EA was delivered via the SP1 and LR1 on the left lower extremities at 5 Hz via a 6-V square-wave stimulator.

OUTCOME MEASURES

The VAS scores of the HP and de qi sensation (tingling) during the EA were recorded. The thermal thresholds and VAS scores for the HP and de qi were obtained immediately and both 30 and 60 minutes after the EA. Adaptation testing was also carried out to assess the change in thermal thresholds and the VAS scores of HP without EA.

RESULTS

The warm thresholds of bilateral medial calves significantly increased (p < 0.01) after 30 seconds of EA stimulation. The HP VAS score reduced significantly at the ipsilateral calf during EA in comparison to preacupuncture and postacupuncture (p < 0.01) measurements. No significant change in thermal thresholds was noted in the adaptation paradigm.

CONCLUSIONS

EA at the TP has an inhibitory effect on the C-fiber afferents. The analgesic benefit observed is most likely A-delta afferent mediated. Further correlation studies in functional imaging may provide defining data for the observed analgesic mechanism.