Spinal cord neural activity of patients with fibromyalgia and healthy controls during temporal summation of pain: an fMRI study

“Windup” and its behavioral correlate “temporal-summation-of-second pain” (TSSP) represent spinal cord mechanisms of pain augmentation associated with central sensitization and chronic pain. Fibromyalgia (FM) is a chronic pain disorder, where abnormal TSSP has been demonstrated. We used fMRI to study spinal cord and brainstem activation during TSSP. We characterized the time course of spinal cord and brainstem BOLD activity during TSSP which showed abnormal brainstem activity in patients with FM, possibly due to deficient pain modulation.

Impact of Music on First Pain and Temporal Summation of Second Pain

Passive music listening has shown its capacity to soothe pain in several clinical and experimental studies. This phenomenon—known as music-induced analgesia—could partly be explained by the modulation of pain signals in response to the stimulation of brain and brainstem centers. We hypothesized that music-induced analgesia may involve inhibitory descending pain systems. We assessed pain-related responses to endogenous pain control mechanisms known to depend on descending pain modulation: peak of first pain (PP), temporal summation (TS), and diffuse noxious inhibitory control (DNIC). Twenty-seven healthy participants (14 men, 13 women) were exposed to a conditioned pain modulation paradigm during a 20-minute relaxing music session and a silence condition. Pain was continually measured with a visual analogue scale. Pain ratings were significantly lower with music listening (p < .02). Repeated measures ANOVA indicated significant differences between conditions within PP and TS (p < .05) but not in DNIC. Those findings suggested that music listening could strengthen components of the inhibitory descending pain pathways operating at the dorsal spinal cord level.

Enhanced Pronociceptive and Disrupted Antinociceptive Mechanisms in Nonspecific Chronic Neck Pain

Objective Evidence suggests altered pronociceptive and antinociceptive mechanisms in many chronic pain conditions. Knowledge about these mechanisms in nonspecific chronic neck pain (NSNP) would improve understanding of the causes and the design of more effective treatments. Pressure pain threshold (PPT) is often used to assess presence of altered nociceptive processing in NSNP; however, its usefulness to detect this is yet to be established. The purpose of this study was to determine the functional status of temporal summation of second pain (TSSP) and conditioned pain modulation (CPM) in NSNP and to characterize the association of both measures with PPT and clinical features of NSNP. Methods Thirty-two participants with NSNP (mean [SD] age = 44 [11] y; 27 female) and 32 age and sex matched healthy controls were recruited. TSSP was assessed using an electrical stimulus at the dorsum of the hand, and CPM was evaluated with the Cold Pressor Test. PPT was assessed bilaterally at the neck and tibialis anterior muscles. Results Participants with NSNP showed greater TSPP (mean difference = 0.23; 95% CI = 0.46-0.01; Cohen d = 0.51) and lower CPM (mean difference = 19.44; 95% CI = 10.42-28.46; Cohen d = 1.09). Pooled data from all participants showed lower PPTs at the neck than the tibialis anterior. However, PPT measures did not differ between groups at either location. PPT measures were not correlated with CPM and TSP. Conclusion NSNP is associated with enhanced pronociceptive and impaired antinociceptive mechanisms, which may explain long-lasting pain and failure of some treatments to resolve symptoms. However, due to the observational nature of this study, a clear cause-effect relationship cannot be established. Normal PPT values in the clinic should not be interpreted as absence of altered nociceptive processing. Impact This study fills in some gaps in knowledge. Changes in central nociceptive processing may explain persistent and recurrent symptoms in NSNP and failure of treatments to obtain long-lasting relief. Further research is required to ascertain if TSSP and CPM assessment in the clinic may help predict physical therapy treatment outcome. Whether symptomatic relief with physical therapy is mediated by an improvement in TSSP and CPM should also be explored. PPTs were unaltered in participants with NSNP despite evidence of impairment in the central pain modulatory systems. Normal PPTs should not be interpreted as evidence of unaltered central pain-related processing.

Predictors of effective management of acute pain in children within a UK ambulance service: a cross-sectional study

Introduction: Pre-hospital pain management in children is poor, with very few children in pain receiving analgesia. Without effective pain treatment, children may suffer long-term changes in stress hormone responses and pain perception and are at risk of developing posttraumatic stress disorder. We aimed to identify predictors of effective management of acute pain in children in the pre-hospital setting.Methods: A retrospective cross-sectional study using electronic clinical records from one large UK ambulance service between 1 October 2017 and 30 September 2018 was performed using multi-variable logistic regression. We included all children < 18 years suffering acute pain. Children with a Glasgow Coma Scale of < 15, no documented pain or without a second pain score were excluded. The outcome measure was effective pain management (abolition or reduction of pain by ≥ 2 out of 10 using the numeric pain rating scale, Wong and Baker FACES® scale or Face, Legs, Activity, Crying and Consolability (FLACC) scale).Results: A total of 2312 patients were included for analysis. Median (IQR) age was 13 (9‐16), 54% were male and the cause of pain was trauma in 66% of cases. Predictors of effective pain management include children who were younger (0‐5 years) compared to older (12‐17 years) (adjusted odds ratio (AOR) 1.57; 95% confidence interval (CI) 1.21‐2.03), administered analgesia (AOR 2.35; CI 1.94‐2.84), attended by a paramedic (AOR 1.39; CI 1.13‐1.70) or living in an area of medium deprivation (index of multiple deprivation (IMD) 4‐7) compared to children in an area of high deprivation (IMD 1‐3) (AOR 1.41; CI 1.10‐1.79). Child gender, type of pain, transport time and clinician experience were not significant.Conclusion: These predictors highlight disparity in effective pre-hospital management of acute pain in children. Qualitative research is needed to help explain these findings.

The effect of spinal manipulative therapy on heart rate variability and pain in patients with chronic neck pain: a randomized controlled trial

Background Recent experimental research has suggested that spinal manipulative therapy (SMT) may reduce pain through modulation of the ascending pain signals and/or the central pain-regulating mechanisms. People with persistent neck pain (NP) have also been found to have disturbances in autonomic nervous system (ANS) regulation. A common way to study the ANS is to measure heart rate variability (HRV). It is not known whether deviations in HRV are related to changes in pain perception or to the treatment response to SMT. Commonly, an individual in pain will experience pain reduction when exposed to a second pain stimulus, a mechanism known as conditioned pain modulation (CPM). Patients with persistent pain have been found to have a reduced CPM reaction. It is not known whether this is predictive of treatment response to SMT. The aim of the study is to examine the effects of SMT on HRV and pain. Further, a secondary aim is to test whether a CPM test can be used to predict treatment response in a population of patients with recurrent and persistent NP. Method/design A multicentre randomized controlled clinical trial will be carried out in multidisciplinary primary care clinics. This setting is chosen to minimize bias resulting from patient preference for the treatment modality and provider. The subjects are either self-referred or referred from other health care practitioners locally. The treatment modalities are two well-known interventions for NP; SMT and stretching exercises compared to stretching exercises alone. HRV will be measured using a portable heart monitor. The subjective pain experience will be investigated by assessing pain intensity and the affective quality of pain. CPM will be measured with a standardized cold pressor test. Measurements will be performed three times during a 2-week treatment series. Discussion The study will utilize normal clinical procedures, which should aid the transferability and external validity of the results. The study will provide knowledge regarding the underlying mechanisms of the effects of SMT. Furthermore, the study will examine whether a CPM test is predictive of treatment outcome in a population of patients with recurrent and persistent NP. Trial registration ClinicalTrials.gov, NCT03576846. Registered on 3 July 2018.

The effect of Spinal Manipulative Therapy on Heart Rate Variability and pain in patients with chronic neck pain: A Randomized Controlled trial

Background Recent experimental research has suggested that Spinal Manipulative Therapy (SMT) may reduce pain through modulation of the ascending pain signals and/or the central pain regulating mechanisms. People with persistent neck pain (NP) have also been found to have disturbances in Autonomic Nervous System (ANS) regulation. A common way to study ANS is to measure heart rate variability (HRV). It is not known if deviations in HRV are related to changes in pain perception or to the treatment response to SMT. Commonly, an individual in pain will experience pain reduction when exposed to a second pain stimulus, a mechanism known as Conditioning Pain Modulation (CPM). Patients with persistent pain have been found to have a reduced CPM reaction. It is not known if this is predictive of treatment response to SMT. The aim of the study is to examine the effects of SMT on HRV and pain and to test if a CPM test can be used to predict treatment response, in a population of patients with recurrent and persistent NP. Method/Design A multicentre randomized controlled clinical trial will be carried out in multidisciplinary primary care clinics. This setting is chosen to minimize bias resulting from patient preference to treatment modality and provider. The subjects are either self-referred or referred from other health care practitioners locally. The treatment modalities are two well-known interventions for NP; SMT and stretching exercises compared to stretching exercises alone. The subjective pain experience will be investigated by assessing pain intensity and the affective quality of pain. HRV will be measured using a portable heart monitor and CPM will be measured with a standardized cold-pressor-test. Measurements will be performed at baseline, prior to the third treatment and after the fourth treatment. Discussion The study will utilize normal clinical procedures, which should aid transferability and external validity of the results. The study will provide knowledge regarding the underlying mechanisms of the effects of SMT. Furthermore, the study will examine if a CPM test is predictive of treatment outcome in a population of patients with recurrent and persistent NP.

The effect of Spinal Manipulative Therapy on Heart Rate Variability and pain in patients with chronic neck pain: A Randomized Controlled trial

Background Recent experimental research has suggested that Spinal Manipulative Therapy (SMT) may reduce pain through modulation of the ascending pain signals and/or the central pain regulating mechanisms. People with persistent neck pain (NP) have also been found to have disturbances in Autonomic Nervous System (ANS) regulation. A common way to study ANS is to measure heart rate variability (HRV). It is not known if deviations in HRV are related to changes in pain perception or to the treatment response to SMT. Commonly, an individual in pain will experience pain reduction when exposed to a second pain stimulus, a mechanism known as Conditioning Pain Modulation (CPM). Patients with persistent pain have been found to have a reduced CPM reaction. It is not known if this is predictive of treatment response to SMT. The aim of the study is to examine the effects of SMT on HRV and pain and to test if a CPM test can be used to predict treatment response, in a population of patients with recurrent and persistent NP. Method/Design A multicentre randomized controlled clinical trial will be carried out in multidisciplinary primary care clinics. This setting is chosen to minimize bias resulting from patient preference to treatment modality and provider. The subjects are either self-referred or referred from other health care practitioners locally. The treatment modalities are two well-known interventions for NP; SMT and stretching exercises compared to stretching exercises alone. The subjective pain experience will be investigated by assessing pain intensity and the affective quality of pain. HRV will be measured using a portable heart monitor and CPM will be measured with a standardized cold-pressor-test. Measurements will be performed at baseline, prior to the third treatment and after the fourth treatment. Discussion The study will utilize normal clinical procedures, which should aid transferability and external validity of the results. The study will provide knowledge regarding the underlying mechanisms of the effects of SMT. Furthermore, the study will examine if a CPM test is predictive of treatment outcome in a population of patients with recurrent and persistent NP.

The effect of Spinal Manipulative Therapy on Heart Rate Variability and pain in patients with chronic neck pain: A Randomized Controlled trial

Background Recent experimental research has suggested that Spinal Manipulative Therapy (SMT) may reduce pain through modulation of the ascending pain signals and/or the central pain regulating mechanisms. People with persistent neck pain (NP) have also been found to have disturbances in Autonomic Nervous System (ANS) regulation. A common way to study ANS is to measure heart rate variability (HRV). It is not known if deviations in HRV are related to changes in pain perception or to the treatment response to SMT. Commonly, an individual in pain will experience pain reduction when exposed to a second pain stimulus, a mechanism known as Conditioning Pain Modulation (CPM). Patients with persistent pain have been found to have a reduced CPM reaction. It is not known if this is predictive of treatment response to SMT. The aim of the study is to examine the effects of SMT on HRV and pain and to test if a CPM test can be used to predict treatment response, in a population of patients with recurrent and persistent NP. Method/Design A multicentre randomized controlled clinical trial will be carried out in multidisciplinary primary care clinics. This setting is chosen to minimize bias resulting from patient preference to treatment modality and provider. The subjects are either self-referred or referred from other health care practitioners locally. The treatment modalities are two well-known interventions for NP; SMT and stretching exercises compared to stretching exercises alone. The subjective pain experience will be investigated by assessing pain intensity and the affective quality of pain. HRV will be measured using a portable heart monitor and CPM will be measured with a standardized cold-pressor-test. Measurements will be performed at baseline, prior to the third treatment and after the fourth treatment. Discussion The study will utilize normal clinical procedures, which should aid transferability and external validity of the results. The study will provide knowledge regarding the underlying mechanisms of the effects of SMT. Furthermore, the study will examine if a CPM test is predictive of treatment outcome in a population of patients with recurrent and persistent NP.