Background As a new technology, electronic wrist‐ankle acupuncture (E‐WAA) combines the advantages of wrist‐ankle acupuncture and transcutaneous electrical nerve stimulation, but the analgesic effect and mechanism need to be clarified. The purpose of this study was to identify the pain modulation caused by E‐WAA by evaluating the response of the prefrontal cortex (PFC) from the perspective of neurophysiology. Methods Fifty male volunteers (age 25.00 ± 1.05 years) with trapezius myofascial pain syndrome were randomly allocated into intervention group (E‐WAA treatment) or sham control group at a 1:1 ratio. An outcome evaluation system was used to induce tenderness on the Jianjing point and record the pain value. A multichannel functional near‐infrared spectroscope was used to detect the PFC activation during tenderness before and after treatment to demonstrate the neuromodulation mechanism. A general linear model and t‐test (p < 0.05) were used to analyze the difference in the oxyhemoglobin (HbO) concentration and pain value. Results In the intervention group, the pain value of volunteers decreased significantly (p = 0.017) after E‐WAA treatment, whereas there was no statistical difference (p = 0.082) in the sham group. Before treatment, the frontopolar (FP) and dorsolateral prefrontal cortex (DLPFC) were the activation areas of the PFC. The E‐WAA treatment then suppressed the activation of the two areas. The HbO concentration of the FP and DLPFC changed from a sharp rise during tenderness to not changing with tenderness stimulation. Conclusion The results demonstrated that the E‐WAA have a great analgesic effect. The FP and DLPFC were relative to the analgesia neuromodulation induced by the E‐WAA.

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Objective Transcutaneous electrical nerve stimulation (TENS) based on wrist-ankle acupuncture has been shown to relieve pain levels in patients with myofascial pain syndrome (MPS). However, its efficacy is highly subjective. The purpose of this study was to evaluate the feasibility and effectiveness of TENS based on wrist-ankle acupuncture for pain management in patients with MPS from the perspective of cerebral cortex hemodynamics. Design, setting, participants and interventions We designed a double-blind, randomized, controlled clinical trial. Thirty-one male patients with MPS were randomly assigned to two parallel groups. The experimental group (n = 16) received TENS based on wrist-ankle acupuncture for analgesic treatment, while the control group (n = 15) did not. The pain was induced by mechanically pressurized at acupoint Jianjing. The multichannel functional near-infrared spectroscopy (fNIRS) equipment was utilized for measuring oxyhemoglobin (HbO) levels in the cerebral cortex during the tasks. Results After the intervention, visual analog scale (VAS), the activation degree and activation area of pain perception cortices were significantly reduced in the experimental group compared to the baseline values (P&lt;0.05). Particularly, Frontopolar Area (FPA), and Dorsolateral Prefrontal Cortex (DLPFC) are highly involved in the pain process and pain modulation. Conclusion Compared to no intervention, TENS based on wrist-ankle acupuncture can be effective in relieving pain in patients with MPS in terms of cerebral cortical hemodynamics. However, further studies are necessary to quantify the analgesic effect in terms of cerebral hemodynamics and brain activation. Trial registration The study was registered in the Chinese Trial Registry (No. ChiCTR2200056394).

Background: Determining an objective measure for pain is one of the most significant challenges in neuroscience and clinical medicine. The response of the cerebral cortex to noxious stimuli/pain can be detected by functional near infrared spectroscopy (fNIRS). The study aimed to examine the law of pain relief and cerebral blood volume dynamics based on the wrist-ankle acupuncture (WAA) analgesic bracelet, and determined the reliability of the cortical activation patterns as objective measurements of pain. Methods: Tenderness was performed on the left point Jianyu of volunteers (age, 23.9 ± 1.9 years, mean ± SD) suffering from the cervical-shoulder syndrome (CSS) as tasks. A transcutaneous electrical nerve stimulation analgesic bracelet based on WAA in traditional Chinese medicine (TCM) was used for treatment. A 24-channel fNIRS system was used for measuring cerebral oxygenated hemoglobin (Oxy-Hb) levels. Oxy-Hb concentration changes in each channel were determined by calculating the differences of Oxy-Hb levels between task and rest. Paired t-tests (p< 0.05) were used to assess the difference in data during tasks and rest. Results: A significant increase in Oxy-Hb was found in all 12 channels of the participants’ right hemisphere during the three tenderness tasks. The mean ± SD of Oxy-Hb levels changes in three tenderness were 0.50±1.22 mM mm, 0.28±1.36 mM mm, 0.09±0.81 mM mm, respectively, and the amount of the change gradually decreased with the participation of the analgesic bracelet. Group analysis of the three tenderness tasks showed that the main activation channels of the cerebral cortex for tenderness were CH6, CH11, CH12, and cortical regions response to tenderness were the frontopolar area, dorsolateral prefrontal cortex, and includes frontal eye fields. With the participation of the analgesic bracelet, the activation area of the cerebral cortex for tenderness gradually decreases. Conclusions: These findings describe the cerebral blood volume dynamics and cortical activation patterns during shoulder tenderness measured by fNIRS, which can not only be used to assess patients with CSS and other shoulder pain, but also to determine the reliability of the cerebral blood volume dynamics and cortical activation patterns pain assessment indicators. Further, this research explores the objective evaluation of the efficacy of an analgesic bracelet based on WAA in TCM for the first time, and provides a new research direction for further pain relief. Trial registration: Chinese Clinical Trial Registry, ChiECRCT20200243. Registered 12 May 2020.

IntroductionEstablishing an accurate way to quantify pain is one of the most formidable tasks in neuroscience and medical practice. Functional near-infrared spectroscopy (fNIRS) can be utilized to detect the brain’s reaction to pain. The study sought to assess the neural mechanisms of the wrist-ankle acupuncture transcutaneous electrical nerve stimulation analgesic bracelet (E-WAA) in providing pain relief and altering cerebral blood volume dynamics, and to ascertain the reliability of cortical activation patterns as a means of objectively measuring pain.MethodsThe participants (mean age 36.6 ± 7.2 years) with the cervical-shoulder syndrome (CSS) underwent pain testing prior to, 1 min following, and 30 min after the left point Jianyu treatment. The E-WAA was used to administer an electrical stimulation therapy that lasted for 5 min. A 24-channel fNIRS system was utilized to monitor brain oxyhemoglobin (HbO) levels, and changes in HbO concentrations, cortical activation areas, and subjective pain assessment scales were documented.ResultsWe discovered that HbO concentrations in the prefrontal cortex significantly increased when CSS patients were exposed to painful stimuli at the cerebral cortex level. The second pain test saw a considerable decrease in the average HbO change amount in the prefrontal cortex when E-WAA was applied, which in turn led to a reduction in the amount of activation and the size of the activated area in the cortex.DiscussionThis study revealed that the frontal polar (FP) and dorsolateral prefrontal cortex (DLPFC) were linked to the analgesic modulation activated by the E-WAA.

IntroductionMusic interventions have been proposed in recent years as a treatment for chronic pain. However, the mechanisms by which music relieves pain are unclear, and the effects of music intervention on physiological indicators in patients with chronic pain remain to be explored. This study aimed to explore whether a music intervention would have effects on subjective pain ratings, heart rate variability, and functional connectivity of the cerebral cortex in patients with chronic pain.MethodsA randomized controlled study was conducted on 37 pain patients aged 18–65 years, with the control group receiving usual care, and the intervention group receiving music intervention (8–150 Hz, 50–70 dB) for 30 min before bedtime for 7 days on top of usual care. Pain visual analog scale and heart rate variability were used as subjective and objective physiological indices before and after the music intervention, respectively. Changes in oxyhemoglobin and deoxyhemoglobin concentrations in the cerebral cortex were measured by functional near-infrared spectroscopy, and whole-brain correlation analysis was used to quantify the connectivity of prefrontal brain regions associated with the pain response.ResultsResults showed that patients with chronic pain in the intervention group had significantly lower visual assessment scale scores, as well as significantly lower overall voluntary mobility during pain episodes, resulting in relatively higher vagal innervation compared to the control group. In addition, connections between the bilateral dorsolateral prefrontal cortex (BA9, BA46) and frontal areas (BA10) were significantly higher in the intervention group.DiscussionThis study demonstrates the effectiveness of the combined application of music interventions with usual care in reducing pain levels in patients with chronic pain and provides insight into the pathological mechanisms of music interventions for analgesia, providing direction for new baseline indicators for quantitative clinical assessment of pain. The study was registered in the Chinese Clinical Trial Registry (No. ChiCTR2100052993).Clinical trial registration[https://www.chictr.org.cn/showproj.aspx?proj=136268], identifier [ChiCTR2100052993].

ObjectThis study measured cerebral blood oxygen changes in patients with myofascial pain syndrome (MPS) using functional near-infrared spectroscopy (fNIRS). The aim was to investigate the effect of music intervention on pain relief in MPS patients.Materials and methodsA total of 15 patients with MPS participated in this study. A self-controlled block task design was used to collect the oxy-hemoglobin ([HbO2]) and deoxy-hemoglobin ([HbR]) concentrations in the prefrontal cortex (PFC) and motor cortex using fNIRS. The cerebral cortex response and channel connectivity were further analyzed. In the experiment, the therapist was asked to apply compression of 3–4 kg/cm2 vertically using the thumb to induce pain. Soothing synthetic music with frequencies of 8–150 Hz and 50–70 dB was used as the audio for the music intervention.ResultCompared to the group without music intervention, the activation of brain regions showed a decreasing trend in the group with music intervention under the onset of pain. The results of paired t-tests showed that nine of the data were significantly different (p &lt; 0.05). It was also found that with music intervention, inter-channel connectivity was diminished. Besides, their dorsolateral prefrontal cortex (dlPFC) was significantly correlated with the anterior prefrontal cortex (aPFC) for pain response (r = 0.82), and weakly correlated with the premotor cortex (r = 0.40).ConclusionThis study combines objective assessment indicators and subjective scale assessments to demonstrate that appropriate music interventions can be effective in helping to relieve pain to some extent. The analgesic mechanisms between relevant brain regions under music intervention were explored in depth. New insights into effective analgesic methods and quantitative assessment of pain conditions are presented.