Attenuation of experimental pain by vibro-tactile stimulation in patients with chronic local or widespread musculoskeletal pain

Effects of focal muscle vibration on cervical pain in Parkinson's disease patients: a pilot study

Musculoskeletal pain is a common symptom of Parkinson's disease (PD) that is not adequately treated with current dopaminergic drugs. This pilot study sought to investigate the effect of focal muscle vibration (fMV) on a group of Parkinson's disease patients suffering from chronic cervical pain. In addition to conventional physiotherapy, twenty-two patients with idiopathic Parkinson's disease (Hoehn and Yahr stages II-III) received three weeks of bilateral focal musclevibration to the trapezius muscles. The Visual Analogue Scale (VAS), the Short-form McGill, and the Present PainIntensity scales were used to assess pain at baseline (T0), after three weeks of treatment (T1), one week after the last treatment session (T2), and three weeks after T2 (T3). Pain intensity decreased significantly from baseline to T1 across all pain scales (p < 0.0001). Furthermore, the beneficial effect of fMV on cervical pain lasted up to one month after treatment. Our findings show that fMV, in combination with conventional physiotherapy, is effective at reducing pain intensity in PD patients, with results visible even after a month of follow-up.

A novel theta-controlled vibrotactile brain-computer interface to treat chronic pain: a pilot study

Limitations in chronic pain therapies necessitate novel interventions that are effective, accessible, and safe. Brain-computer interfaces (BCIs) provide a promising modality for targeting neuropathology underlying chronic pain by converting recorded neural activity into perceivable outputs. Recent evidence suggests that increased frontal theta power (4-7 Hz) reflects pain relief from chronic and acute pain. Further studies have suggested that vibrotactile stimulation decreases pain intensity in experimental and clinical models. This longitudinal, non-randomized, open-label pilot study's objective was to reinforce frontal theta activity in six patients with chronic upper extremity pain using a novel vibrotactile neurofeedback BCI system. Patients increased their BCI performance, reflecting thought-driven control of neurofeedback, and showed a significant decrease in pain severity (1.29 ± 0.25 MAD, p = 0.03, q = 0.05) and pain interference (1.79 ± 1.10 MAD p = 0.03, q = 0.05) scores without any adverse events. Pain relief significantly correlated with frontal theta modulation. These findings highlight the potential of BCI-mediated cortico-sensory coupling of frontal theta with vibrotactile stimulation for alleviating chronic pain.

The Effect of Pre-Electroacupuncture on Nociceptive Discharges of Spinal Wide Dynamic Range Neurons in Rat

Purpose

Spinal wide dynamic range (WDR) neurons are well studied in pain models and they play critical roles in regulating nociception. Evidence has started to accumulate that acupuncture produces a good analgesic effect via activating different primary fibers with distinct intensities. The purpose of the present study was to compare the distinct intensities of pre-electroacupuncture (pre-EA) at local muscular receptive fields (RFs), adjacent or contralateral non-RFs regulating the nociceptive discharges of spinal WDR neurons evoked by hypertonic saline (HS).

Materials and Methods

Spinal segments of electrophysiological recording were identified by neural tracers applied at the left gastrocnemius muscle. The thresholds of Aβ (T_Aβ), Aδ (T_Aδ) and C (T_C) components of WDR neurons were measured to determine the intensity of pre-EA by extracellular recording. The discharges of WDR neurons induced by distinct intensities of pre-EA and 200 µL HS (6%) injection in left gastrocnemius muscle of rats were observed by extracellular recording.

Results

The spinal segments of WDR neurons were confirmed in lumbar (L)5-6 area according to the projective segments of dorsal root ganglion. T_Aβ, T_Aδ and T_C of WDR neurons was determined to be 0.5, 1, and 2 mA, respectively. The pre-EA with intensities of T_Aβ (P < 0.05), T_Aδ (P < 0.05), T_C (P < 0.05) or 2T_C (P < 0.01) at ipsilateral adjacent non-RFs significantly reduced the discharges of WDR neurons, while at local RFs only pre-EA of T_Aδ (P < 0.05), T_C (P < 0.05) and 2T_C (P < 0.01) could inhibit the nociceptive discharges. In addition, intensity of pre-EA at contralateral non-RFs should reach at least T_C to effectively inhibit the firing rates of WDR neurons (P < 0.01).

Conclusion

Pre-EA could suppress nociceptive discharges of WDR neurons and the inhibitory effects were dependent on the distinct intensities and locations of stimulation.

The Current View on the Paradox of Pain in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, which affects 1 in 44 children and may cause severe disabilities. Besides socio-communicational difficulties and repetitive behaviors, ASD also presents as atypical sensorimotor function and pain reactivity. While chronic pain is a frequent co-morbidity in autism, pain management in this population is often insufficient because of difficulties in pain evaluation, worsening their prognosis and perhaps driving higher mortality rates. Previous observations have tended to oversimplify the experience of pain in autism as being insensitive to painful stimuli. Various findings in the past 15 years have challenged and complicated this dogma. However, a relatively small number of studies investigates the physiological correlates of pain reactivity in ASD. We explore the possibility that atypical pain perception in people with ASD is mediated by alterations in pain perception, transmission, expression and modulation, and through interactions between these processes. These complex interactions may account for the great variability and sometimes contradictory findings from the studies. A growing body of evidence is challenging the idea of alterations in pain processing in ASD due to a single factor, and calls for an integrative view. We propose a model of the pain cycle that includes the interplay between the molecular and neurophysiological pathways of pain processing and it conscious appraisal that may interfere with pain reactivity and coping in autism. The role of social factors in pain-induced response is also discussed. Pain assessment in clinical care is mostly based on subjective rather than objective measures. This review clarifies the strong need for a consistent methodology, and describes innovative tools to cope with the heterogeneity of pain expression in ASD, enabling individualized assessment. Multiple measures, including self-reporting, informant reporting, clinician-assessed, and purely physiological metrics may provide more consistent results. An integrative view on the regulation of the pain cycle offers a more robust framework to characterize the experience of pain in autism.

Higher Pain Sensitivity Predicts Efficacy of a Wearable Transcutaneous Electrical Nerve Stimulation Device for Persons With Fibromyalgia: A Randomized Double-Blind Sham-Controlled Trial

OBJECTIVES

This study investigated the efficacy of a transcutaneous electrical nerve stimulation (TENS) device (Quell®) for persons with symptoms due to fibromyalgia (FM).

MATERIALS AND METHODS

One hundred nineteen (N = 119) subjects were randomly assigned to use an active (N = 62) or sham (N = 57) TENS for three months. All subjects completed baseline questionnaires and were administered quantitative sensory testing (QST). Subjects completed the Patients' Global Impression of Change (PGIC, primary outcome measure) and other mailed questionnaires (secondary outcome measures) at six weeks and three months.

RESULTS

The subjects averaged 50.4 ± 13.5 years of age, 93.3% were female, and 79.8% were Caucasian. Most showed benefit from using the TENS, but no differences between groups were found on the primary outcome measure after three months (active 3.87 ± 1.85, sham 3.73 ± 1.80, 95% confidence interval [CI] [-0.60, 0.88], p = 0.707). Those with more hypersensitivity showed most improvement on the PGIC at six weeks (0.22, 95% CI [0.01, 0.43], p = 0.042) and three months (0.20, 95% CI [0.00, 0.41], p = 0.049) and among those with higher sensitivity based on QST, the active TENS group showed the most benefit with TENS compared with the sham treatment (1.20, 95% CI [0.22, 2.18], p = 0.017). No TENS-related serious adverse events were reported. Subjects in the sham group correctly identified their treatment 87.5% of the time, while, surprisingly, subjects in the active group correctly identified their treatment only 17.4% of the time.

CONCLUSION

This study found no differences between those who were exposed to maximal-frequency active stimulation or minimal-frequency sham stimulation from a wearable TENS in reducing FM-related symptoms. However, those with greater hypersensitivity showed most benefit from TENS. Additional studies to help determine the role individual differences play in the use of TENS in managing FM-related symptoms are needed.

Effects of different vibration frequencies on spinal cord reflex circuits and thermoalgesic perception

OBJECTIVES

We studied the effect of different vibration frequencies on spinal cord excitability and heat pain perception. We hypothesized that the effects of vibration on spinal cord reflexes, and, also those on heat pain perception, depend on vibration frequency.

METHODS

In 9 healthy subjects, we applied vibration over the tibialis anterior muscle at three different frequencies (50, 150, or 250 Hz) on spinal cord reflex excitably, tested with the H reflex and the T wave in the soleus muscle, as well as on sensory and pain perception, tested by measuring warm perception (WT) and heat pain perception thresholds, (HPT) in sites rostral and caudal to vibration. Exams were carried out before, during, and after vibration.

RESULTS

The amplitude of the H reflex and T wave significantly decreased during vibration in comparison to baseline. Low frequencies (50 and 150Hz) induced greater reflex suppression than high frequency (250Hz). No significant changes were observed on WT and HPT.

CONCLUSIONS

The effects of vibratory stimulation can be summarized as frequency-related suppression of the spinal cord excitability without an effect on warm and heat pain perception. The present results may help to design vibration-related interventions intended to diminish spinal cord reflex excitability in spastic patients.

Evaluation of the Efficacy of Musical Vibroacupuncture in Pain Relief: A Randomized Controlled Pilot Study

OBJECTIVES

To investigate if skin vibration employing consonant frequencies emitted by skin transducers attached to a combination of acupuncture points and according to musical harmony (musical chord) produces more significant pain relief compared to just a single frequency.

MATERIALS AND METHODS

Skin vibrostimulation produced by five electromagnet transducers was applied at five acupoints traditionally used to pain relief and anxiety in 13 pain-free healthy volunteers using the cold pressor test (CPT). The study consisted of three randomized sessions conducted on alternate days, with participants receiving either simultaneous frequencies of 32, 48, and 64 Hz that equate those used in a musical chord, hereby defined as musical vibroacupuncture (MVA), a single frequency of 32 Hz, set as vibroacupuncture (VA) and sham procedure (SP). CPT scores for pain thresholds and pain tolerance were assessed using repeated-measures ANOVAs. Pain intensity was evaluated using a numerical rating scale (NRS), while sensory and affective aspects of pain were rated using the short-form McGill Pain Questionnaire (SF-MPQ) and State-Trait Anxiety Inventory (STAI) Y-Form.

RESULTS

Pain thresholds did not vary significantly between trials. Pain tolerance scores were markedly higher in MVA compared to baseline (p = 0.0043) or SP (p = 0.006) but not for VA. Pain intensity for MVA also differed significantly from the baseline (p = 0.007) or SP (p = 0.027), but not for VA. No significant differences were found in SF-MPQ and STAI questionnaires.

CONCLUSIONS

These results suggest that MVA effectively increased pain tolerance and reduced pain intensity when compared with all groups, although not significant to the VA group.

Neuromagnetic oscillations in the human sensory systems: A mini review of our series and literature

Oscillatory neuronal (electrical) activity in defined frequency ranges supports synchronous interactions between anatomically distinct regions of the human brain during cognitive tasks. Here, the author reviews our previous studies that focused on the neuromagnetic oscillations in the sensory systems in response to the external stimuli in normal healthy subjects and neurological disorders. A magnetoencephalography was applied to evaluate the neuromagnetic oscillations in humans. We have demonstrated that the oscillatory gamma synchronization binds the primary and secondary somatosensory areas (S1 and S2) in humans. This functional coupling is modulated by aging. In people who stutter, functional and structural reorganization of the right auditory cortex appears to be a compensatory mechanism for impaired left auditory cortex function. This may be partly caused by increased right hemispheric local phase synchronization and increased inter-hemispheric phase synchronization. We have also found that the hippocampus modulates auditory processing differently under normal conditions and in epileptic patients with hippocampal sclerosis. This indicates that altered neural synchronization may provide useful information about possible functional deterioration in patients with unilateral mesial temporal lobe epilepsy. Finally, supraspinal (cortical) mechanism is responsible for pain perception and pain relief via neural oscillations. Together, neuronal synchronization plays an important role in distributed cortico-cortical processing.

Testing the effects of gentle vibrotactile stimulation on symptom relief in fibromyalgia

Background

Sensory disturbances in fibromyalgia extend beyond nociception. It has been proposed that imbalance in the mutual competition between painful input and non-painful sensory activity may, to a significant extent, account for the augmented subjective perception of pain. In this context, non-nociceptive somatosensory stimulation could arguably attenuate fibromyalgia symptoms by restoring the sensory balance. We specifically tested the effect of vibrotactile stimulation on symptom relief in fibromyalgia patients with a randomized, double-blind, sham-controlled, crossover clinical trial.

Methods

Seventy-seven female patients were randomized and data from 63 valid cases were analyzed. Active intervention involved extensive body stimulation with gentle mechanical vibrations administered during 3 h at night for 3 weeks, and the placebo effect was controlled using identical instruments to simulate an alternative treatment option. The primary outcome measure combined pain, fatigue, and complaints of poor cognition.

Results

Vibrotactile stimulation was significantly superior to sham in alleviating fibromyalgia symptoms globally. However, univariate analyses showed that the effect was not universal. Benefits were perceived on unpleasant somatic sensations such as generalized pain and fatigue, but not on poor cognition, anxiety, and depression. Vibrotactile stimulation was notably well tolerated and sleep quality significantly improved despite the fact that vibrations were administered at night.

Conclusions

Results thus provide new evidence that non-nociceptive somatosensory stimulation may favorably act upon altered somatosensory balance in fibromyalgia. From a clinical perspective, both the degree of improvement and the easy application of our proposal would seem to support a potential role for vibrotactile stimulation in the symptomatic treatment of fibromyalgia.

Trial registration

ClinicalTrials.gov registration number NCT03227952. Registered 24 July, 2017.

The Use of the Buzzy, Jet Lidokaine, Bubble-blowing and Aromatherapy for Reducing Pediatric Pain, Stress and Fear Associated with Phlebotomy

PURPOSE

This study aimed to investigate the effects of the Buzzy, Jet lidokaine, bubble-blowing and inhalation aromatherapy with lavender essence on pain, stress and fear in children undergoing phlebotomy.

DESIGNS AND METHODS

This study was a prospective, randomized controlled trial. The sample was comprised of children aged 5 to 10 years requiring blood tests. Children were assigned to five subgroups through randomization performed using a computer program: the Buzzy group (n = 39), Jet lidokaine group (n = 39), bubble-blowing group (n = 39), inhalation aromatherapy with lavender essence group (n = 39) and control group (n = 39). The children's levels of pain were evaluated and reported by the parents, observers and the children, who self-reported using the Oucher Pain Scale. The children's fear levels were assessed using the Children's Fear Scale, and salivary cortisol analysis was conducted to evaluate stress levels.

RESULTS

A significant difference was found between the intervention and control groups in terms of levels of pain during and after phlebotomy in favor of the Buzzy group (p < 0.05). There was a significant difference between the fear scores of the children in the intervention and control groups before phlebotomy (p < 0.05). This difference was found to be caused by the bubble-blowing method. There was a significant difference between intervention and control groups fear levels in favor of the Buzzy group during phlebotomy (p < 0.05).

PRACTICE IMPLICATIONS

It is recommended that the Buzzy and bubble-blowing be used during phlebotomy in children to reduce the severity of their pain.

Outcome of a High-Frequency Transcutaneous Electrical Nerve Stimulator (hfTENS) Device for Low Back Pain: A Randomized Controlled Trial

OBJECTIVE

This controlled trial examined the benefit of a high-frequency transcutaneous electrical nerve stimulation (hfTENS) device (the Quell, NeuroMetrix, Inc., Waltham, MA, U.S.A.) for patients with chronic low back pain (CLBP).

METHODS

Thirty-five (n = 35) participants were randomly assigned to use the device each day for 3 months (experimental group) and were compared with 33 subjects without the device (treatment-as-usual control group). All patients were instructed to complete baseline questionnaires and were assessed on thresholds of pressure pain and mechanical temporal summation as part of standardized quantitative sensory testing (QST). The subjects also uploaded smartphone applications (apps) for tracking use of the hfTENS and for daily pain assessment. Each participant completed weekly phone interviews, was prompted to complete daily pain app assessments, and was asked to repeat the baseline questionnaires again after 6 weeks and 3 months.

RESULTS

Sixty percent of the subjects were female, 77.9% were Caucasian, and the average age was 46.2 years. Significant reductions in pain intensity (P < 0.01) and activity interference (P < 0.025) and significant improvements in pain catastrophizing (P < 0.025) were noted in the experimental group compared with the control group. No group differences were found on depression, anxiety, or pain-related disability. Older subjects with a longer duration of pain tended to use the hfTENS more often. Subjects who showed greater sensitivity based on QST results revealed increased use of the hfTENS (P < 0.025) and tended to believe that the hfTENS was more helpful in reducing their back pain, but these findings did not reach significance (P = 0.09).

CONCLUSION

These results suggest that hfTENS can have a moderate effect in reducing pain and improving quality of life in low back pain patients. Further trials designed to determine the mechanism of action of the hfTENS are needed.

Localized muscle vibration reverses quadriceps muscle hypotrophy and improves physical function: a clinical and electrophysiological study

Quadriceps weakness has been associated with knee osteoarthritis (OA). High-frequency localized muscle vibration (LMV) has been proposed recently for quadriceps strengthening in patients with knee OA. The purpose of this study was (a) to investigate the clinical effectiveness of high-frequency LMV on quadriceps muscle in patients with knee OA and (b) to disentangle, by means of surface electromyography (sEMG), the underlying mechanism. Thirty patients, aged between 40 and 65 years, and clinically diagnosed with knee OA were included in this randomized, controlled, single-blinded pilot study. Participants were randomly assigned to two groups: a study group treated with LMV, specifically set for muscle strengthening (150 Hz), by means of a commercial device VIBRA, and a control group treated with neuromuscular electrical stimulation. Clinical outcome was measured using the Western Ontario and McMaster Universities Osteoarthritis Index, Visual Analogue Scale, knee range of motion, Timed Up and Go test, and Stair climbing test. To assess changes in muscle activation and fatigue a subgroup of 20 patients was studied with the use of sEMG during a sustained isometric contraction. The LMV group showed a significant change in Western Ontario and McMaster Universities Osteoarthritis Index score, Visual Analogue Scale score, Timed Up and Go test, Stair Climbing Test, and knee flexion. These improvements were not significant in patients treated with neuromuscular electrical stimulation. sEMG analysis suggested an increased involvement of type II muscle fibers in the group treated with LMV. In conclusion, the present study supports the effectiveness of local vibration in muscle function and clinical improvement of patients with knee OA.

Mid-Air Tactile Stimulation for Pain Distraction

Using the human sense of touch, pain control has been studied for decades. With the rise of Virtual Reality (VR) and haptic technologies, creating VR and haptic sensations provide a unique opportunity for pain distraction. In this paper, we present an experimental study to test whether VR and mid-air ultrasound tactile stimulation reduce perceived pain simulated via the cold pressor test, i.e., submerging a human hand in cold water (2 C) for as long as the test subject can. Fifty right-handed subjects participated in the study and three tasks were considered: task 1 involved experiencing the cold pressor test with no distraction (considered as the control task), task 2 involved playing a simple VR game with no tactile feedback, and task 3 utilized the same VR game with tactile feedback; tasks 2 and 3 were assigned in random order after task 1. The tolerance time, perceived pain rating, and quality of experience were evaluated and compared for the three tasks. Results demonstrated that when a VR task involves physical (touch) interaction, tactile stimulation plays a significant role in increasing pain tolerance time. Furthermore, the study demonstrated that for high pain tolerance participants, tactile stimulation is more effective for pain distraction compared to low pain tolerance participants. Although there are no significant differences in perceived pain and quality of experience between VR and VR+Tactile tasks, there are significant differences in tolerance time (Wilcox signed rank test, p 0.05). It is presumed that VR and the tactile stimulation induces positive emotions when utilized (for both valence and arousal).

Low threshold unmyelinated mechanoafferents can modulate pain

Background

Human, hairy skin contains a subgroup of C-fibers, the C-low threshold mechanoreceptive afferents ((C-LTMR) C-tactile or C-touch (CT) fibers) that are linked with the signaling of affective aspects of human touch. Recent studies suggest an involvement of these afferents in the modulation of pain in healthy volunteers. Small fiber neuropathy (SFN) is associated with a damage of C-fibers. Therefore, an impairment of C-LTMRs can be assumed. We aimed to elaborate a possible role of CT-afferents in pain modulation by investigating healthy volunteers and SFN-patients.

Methods

Experiment I: 20 SFN-patients (12 women, median age 52.0 years) and 20 healthy controls (14 women, median age 43.0 years) participated in this prospective fMRI and psychophysical study. Heat-pain (HP), CT-targeted touch (slow brushing) and HP combined with CT-targeted touch were applied in randomized order to the left shank in a block design. The participants rated pain intensity on a visual analogue scale. Experiment II: We investigated a possible impact of pain intensity on CT induced pain modulation (10 healthy participants). The intensity of HP stimulation was chosen to induce pain intensity 50/100 (NRS). HP stimulation was applied with and without CT-targeted touch.

Results

Experiment I: CT-stimulation was sufficient to reduce heat pain in healthy participants (p = 0.016), but not in SFN-patients. HP induced pain intensity was significantly higher (32,2 vs 52,6) in SFN-patients. During HP, bold responses in pain associated areas were observed in both groups. Additional CT-stimulation elicited no significant difference of bold responses compared to HP. Experiment II: In healthy volunteers, we reproduced a significant reduction of HP intensity by CT-stimulation (p = 0.038).

Conclusions

CT input seems to be sufficient to modulate pain, independent of intensity of the pain stimulus. As a prerequisite, the CT fibers have to be intact as in healthy volunteers. If CT fibers are impaired – as in SFN -, CT-targeted touch does not modulate pain intensity. The location of CT-induced pain modulation might be attributed to the level of the dorsal horn since the cortical activation pattern of heat pain with and without CT-targeted touch did not differ in healthy subjects and in SFN-patients.

Pacinian Signals Determine the Direction and Magnitude of the Effect of Vibration on Pain

Although the ability of vibration to reduce pain has been extensively documented, an occasional participant reports that vibration increases pain. For pain patients, such reports may reflect pathophysiology, but this is unlikely in studies of experimental pain in healthy participants. In the present series of experiments on 27 pain-free individuals, we manipulated both the frequency (12, 50, and 80 Hz) and amplitude of vibration to more fully characterize vibratory pain modulation. The noxious stimulus was pressure applied to a finger, and vibration was delivered to the fleshy palmar pad at the base of the same finger. Subjects continuously reported pain on a Visual Analog Scale. Intermittent vibration was used to minimize peripheral vibratory adaptation. Pain records at 12 and 50 Hz were similar; pooling them revealed significant hypoalgesia at the highest amplitude. At 80 Hz, in contrast, the middle amplitude produced hypoalgesia, but a significant shift toward hyperalgesia occurred at the highest amplitude. The strong correlation ( r = .81) between the Pacinian-weighted power of a vibration and the absolute value of the pain modulation it produces indicates that the Pacinian system plays a key role in vibratory hypoalgesia or hyperalgesia.

Nonpainful wide-area compression inhibits experimental pain

Compression therapy, a well-recognized treatment for lymphoedema and venous disorders, pressurizes limbs and generates massive non-noxious afferent sensory barrages. The aim of this study was to study whether such afferent activity has an analgesic effect when applied on the lower limbs, hypothesizing that larger compression areas will induce stronger analgesic effects, and whether this effect correlates with conditioned pain modulation (CPM). Thirty young healthy subjects received painful heat and pressure stimuli (47°C for 30 seconds, forearm; 300 kPa for 15 seconds, wrist) before and during 3 compression protocols of either SMALL (up to ankles), MEDIUM (up to knees), or LARGE (up to hips) compression areas. Conditioned pain modulation (heat pain conditioned by noxious cold water) was tested before and after each compression protocol. The LARGE protocol induced more analgesia for heat than the SMALL protocol (P < 0.001). The analgesic effect interacted with gender (P = 0.015). The LARGE protocol was more efficient for females, whereas the MEDIUM protocol was more efficient for males. Pressure pain was reduced by all protocols (P < 0.001) with no differences between protocols and no gender effect. Conditioned pain modulation was more efficient than the compression-induced analgesia. For the LARGE protocol, precompression CPM efficiency positively correlated with compression-induced analgesia. Large body area compression exerts an area-dependent analgesic effect on experimental pain stimuli. The observed correlation with pain inhibition in response to robust non-noxious sensory stimulation may suggest that compression therapy shares similar mechanisms with inhibitory pain modulation assessed through CPM.

Towards an optimal therapy strategy for myogenous TMD, physiotherapy compared with occlusal splint therapy in an RCT with therapy-and-patient-specific treatment durations

BACKGROUND

Temporomandibular Disorders (TMD) may be characterized by pain and restricted jaw movements. In the absence of somatic factors in the temporomandibular joint, mainly myogenous, psychobiological, and psychosocial factors may be involved in the aetiology of myogenous TMD. An occlusal appliance (splint) is commonly used as a basic therapy of the dental practice. Alternatively, a type of physiotherapy which includes, apart from massage of sore muscles, aspects of cognitive-behavioural therapy might be a basic therapy for myogenous TMD. Treatment outcome of physiotherapy (Ph-Tx) was evaluated in comparison to that of splint therapy (Sp-Tx), using the index Treatment Duration Control (TDC) that enabled a randomized controlled trial with, comparable to clinical care, therapy-and-patient-specific treatment durations.

METHODS

Seventy-two patients were randomly assigned to either Ph-Tx or Sp-Tx, with an intended treatment duration between 10 and 21 or 12 and 30 weeks respectively. Using TDC, the clinician controlled treatment duration and the number of visits needed. A blinded assessor recorded anamnestic and clinical data to determine TDC-values following treatment and a 1-year follow-up, yielding success rate (SR) and effectiveness (mean TDC) as treatment outcomes. Cohen's d, was determined for pain intensity. Overall SR for stepped-care was assessed in a theoretical model, i.e. a second of the two studied therapies was applied if the first treatment was unsuccessful, and the effect of therapy sequence and difference in success rates was examined.

RESULTS

SR and effectiveness were similar for Ph-Tx and Sp-Tx (long-term SR: 51-60%; TDC: -0.512- -0.575). Cohen's d was 0.86 (Ph-Tx) and 1.39 (Sp-Tx). Treatment duration was shorter for Ph-Tx (on average 10.4 weeks less; p < 0.001). Sp-Tx needed 7.1 less visits (p < 0.001).

CONCLUSIONS

Physiotherapy may be preferred as initial therapy over occlusal splint therapy in stepped-care of myogenous TMD. With a similar SR and effectiveness, physiotherapy has a shorter duration. Thus patients whose initial physiotherapy is unsuccessful can continue earlier with subsequent treatment. The stepped-care model reinforces the conclusion on therapy preference as the overall SR hardly depends on therapy sequence.

TRIAL REGISTRATION

isrctn.com/ISRCTN17469828 . Retrospectively registered: 11/11/2016.

An Innovative and Portable Multimodal Pain Relief Device for the Management of Neuropathic Low Back Pain - a Study from Kashmir (Southeast Asia)

We developed a portable multimodal system with seven different mechanisms of pain relief incorporated into a lumbar belt called the Comfort-N-Harmony Belt (C&H belt).

Here, we describe the technical details of the system and also summarize the effects of this multimodal pain relieving technology as an adjuvant to analgesics versus analgesics alone, on the level of pain, improvement of psychological status, disability, and the quality of life in the patients with neuropathic low back pain (LBP).

We tracked the volunteers who were following up at a tertiary health care center for the complaints of neuropathic LBP of minimum three months duration and were on analgesics alone with no relief in the severity of the pain. Study group A (n = 45) consisted of volunteers with LBP on C&H belt therapy, along with the usually prescribed analgesic intake, and group B (n = 45) with LBP volunteers on analgesics, plus a similar looking but plain leather belt (placebo). For pain, the VAS (Visual Analogue Scale); for anxiety and depression, the (HADS) Hospital Anxiety-Depression Scale; for disability, the RMDQ (Roland Morris Disability Questionnaire); and for quality of life, (NHP) Nottingham-Health-Profile were used before and after the study period. 

There were no significant differences in demographic variables between the groups (p < 0.05). After the study period of one month, VAS, RMDQ, NHP-pain, NHP-physical activity, and HADS scores in both groups were significantly improved compared to the pre-treatment scores (p < 0.05). Group A also showed significant improvements in the scores of NHP-energy level and NHP-social isolation (p < 0.05). The post-treatment scores did not significantly show any difference between the two groups (p > 0.05). However, in comparison of pre- and post-treatment scores, the pre-treatment score values of RMDQ, NHP-pain, NHP-physical activity, and NHP-social isolation were much higher in group A compared to the group B, but still these scores were, in a statistically significant manner, improved in group A compared to the group B after the study period was over (p < 0.05).

Multiple pain relieving mechanisms in a portable device-based system, when used along with analgesics, are effective in relieving pain, improving function and quality of life, and help in relieving the associated anxiety and depression in patients with chronic neuropathic LBP than the analgesics alone in the Kashmiri (Southeast Asian) population.

Clinical features for diagnosis and management of patients with PRDM12 congenital insensitivity to pain

Background

Congenital insensitivity to pain (CIP) is a rare extreme phenotype characterised by an inability to perceive pain present from birth due to lack of, or malfunction of, nociceptors. PRDM12 has recently been identified as a new gene that can cause CIP. The full phenotype and natural history have not yet been reported.

Methods

We have ascertained five adult patients and report their clinical features.

Results

Based on our findings, and those of previous patients, we describe the natural history of the PRDM12-CIP disorder, and derive diagnostic and management features to guide the clinical management of patients.

Conclusions

PRDM12-CIP is a distinct and diagnosable disorder, and requires specific clinical management to minimise predictable complications.

A spatiotemporal signature of cortical pain relief by tactile stimulation: An MEG study

Recently, the cortical mechanisms of tactile-induced analgesia have been investigated; however, spatiotemporal characteristics have not been fully elucidated. The insular-opercular region integrates multiple sensory inputs, and nociceptive modulation by other sensory inputs occurs in this area. In this study, we focused on the insular-opercular region to characterize the spatiotemporal signature of tactile-induced analgesia using magnetoencephalography in 11 healthy subjects. Aδ (intra-epidermal electrical stimulation) inputs were modified by Aβ (mechanical tactile stimulation) selective stimulation, either independently or concurrently, to the right forearm. The optimal inter-stimulus interval (ISI) for cortical level modulation was determined after comparing the 40-, 60-, and 80-ms ISI conditions, and the calculated cortical arrival time difference between Aδ and Aβ inputs. Subsequently, we adopted a 60-ms ISI for cortical modulation and a 0-ms ISI for spinal level modulation. Source localization using minimum norm estimates demonstrated that pain-related activity was located in the posterior insula, whereas tactile-related activity was estimated in the parietal operculum. We also found significant inhibition of pain-related activity in the posterior insula due to cortical modulation. In contrast, spinal modulation was observed both in the posterior insula and parietal operculum. Subjective pain, as evaluated by the visual analog scale, also showed significant reduction in both conditions. Therefore, our results demonstrated that the multisensory integration within the posterior insula plays a key role in tactile-induced analgesia.

Distraction Using the BUZZY for Children During an IV Insertion

Needle pricks are rated by children as their most feared medical event resulting in acute pain, anxiety and distress, which negatively affects both the child and his/her parents.

OBJECTIVES

To investigate the effects of external cold and vibration via the "BUZZY" on pain ratings of children, their parents and nurses during peripheral IV insertion, to measure the time to a successful IV insertion and to assess the factors that are associated with pain perception of children.

METHODS

In this randomized control trial (RCT), children between the ages of 4 to 12years were assigned to either an intervention or a control group. The intervention group (n=25) had the "BUZZY" applied during IV insertion while the control group (n=23) did not have the "BUZZY". Children were asked to rate their pain along with their parents and nurses on the Wong-Baker FACES Pain Rating Scale. Time to successful IV insertion and background characteristic of children were assessed and compared.

RESULTS

Pain scores were significantly lower in the "BUZZY" group for children and the nurses. Time to a successful IV insertion did not differ between groups. Gender, age, previous hospitalization, diagnoses and analgesics were all factors associated with the children's pain scores. However, a multiple regression analysis found that only the "BUZZY" remained a significant predictor of pain scores in children.

CLINICAL IMPLICATIONS

The "BUZZY" may be an easily accessed, inexpensive ($39.95 each at $0.09 per 3 minute stick), and effective technique to control or reduce pain in young children undergoing IV insertion.

Effect of low frequency transcutaneous magnetic stimulation on sensory and motor transmission

Peripheral nerve injury diminishes fast conducting large myelinated afferent fibers transmission but enhances smaller pain transmitting fibers firing. This aberrant afferent neuronal behavior contributes to development of chronic post-traumatic peripheral neuropathic pain (PTP-NP). Non-invasive dynamic magnetic flux stimulation has been implicated in treating PTP-NP, a condition currently not adequately addressed by other therapies including transcutaneous electrical nerve stimulation (TENS). The current study assessed the effect of low frequency transcutaneous magnetic stimulation (LFTMS) on peripheral sensory thresholds, nerve conduction properties, and TENS induced fast afferent slowing effect as measured by motor and sensory conduction studies in the ulnar nerve. Results indicated sham LFTMS with TENS (Sham + TENS) significantly (P = 0.02 and 0.007, respectively) reduces sensory conduction velocity (CV) and increases sensory onset latency (OL), and motor peak latency (PL) whereas, real LFTMS with TENS (Real + TENS) reverses effects of TENS on sensory CV and OL, and significantly (P = 0.036) increases the sensory PL. LFTMS alone significantly (P < 0.05) elevates sensory PL and onset-to-peak latency. LFTMS appears to reverse TENS slowing effect on fast conducting fibers and casts a selective peripheral modulatory effect on slow conducting pain afferent fibers.

Enhancement of Analgesic Effect by Combination of Non-Noxious Stimulation and Noxious Stimulation in Humans

The aim of the this study was to investigate the combined effects of heterosegmental non-noxious and noxious stimulation on electrically induced tooth pain. The late component of somatosensory-evoked potentials (SEP), induced by electrical tooth stimulation and pain intensity, were examined under electrical stimulation to forearms. Noxious, non-noxious, and combined non-noxious and noxious electrical stimulation were applied to median nerves on the forearms. Four experimental sessions (ie, control session, combined non-noxious and noxious stimulation session, non-noxious stimulation session, and noxious stimulation session were performed for each subject at each 10-minute interval for 30 minutes. The amplitudes of the SEP and VAS scores in the combined stimulation session decreased significantly compared with those in the control session and the reduction rates were 51.1% (13.4 μV) and 41.0% (23.5 mm), respectively. These results show that the combined stimulation has a more potent analgesic effect than that of either the non-noxious or the noxious stimulation. It is suggested that a potent analgesia was produced by an activated central mechanism, including endogenous opioid and descending pain inhibitory systems due to combined non-noxious and noxious stimulation.

How does vibration reduce pain?

Cutaneous vibration is able to reduce both clinical and experimental pain, an effect called vibratory analgesia. The traditional explanation for this phenomenon is that it is mediated by lateral inhibition at the segmental (spinal cord) level, in pain-coding cells with center-surround receptive fields. We evaluated this hypothesis by testing for two signs of lateral inhibition-namely (1) an effect of the distance between the noxious and vibratory stimuli and (2) an inhibition-induced shift in the perceived location of the noxious stimulus. The experiment involved continuous ratings of the pain from pressure applied to the back of a finger, alone and in the presence of vibration delivered to sites on the palm of the hand both near to and far from the site of painful stimulation. Neither prediction of the segmental hypothesis was supported. There was also little evidence to support the view (widely held by subjects) that distraction is the primary mechanism of vibratory analgesia. The results are more consistent with a recently proposed theory of interactions between two cortical areas that are primarily involved in coding pain and touch, respectively.