The journal of pain : official journal of the American Pain Society
-
Some studies suggest that women with primary dysmenorrhea have distinct emotional or personality features. For example, they might exaggerate their responses to external stimuli, such as to intensity-increasing auditory stimuli. ⋯ Regarding the IDAEP generation, the source inversion of N1 and P2 disclosed the activated bilateral superior temporal gyri, medial and superior prefrontal gyri in all participants, and additionally, the middle frontal gyri in dysmenorrhea patients. We report a pronounced IDAEP in primary dysmenorrhea, which indicates the decreased cerebral serotonergic innervations and points to increased activations in the prefrontal and frontal areas in the disorder.
-
Spontaneous pain and function-associated pain are prevalent symptoms of multiple acute and chronic muscle pathologies. We established mouse models for evaluating spontaneous pain and bite-evoked pain from masseter muscle, and determined the roles of transient receptor potential cation channel subfamily V member 1 (TRPV1) and the contribution of TRPV1- or neurokinin 1 (NK1)-dependent nociceptive pathways. Masseter muscle inflammation increased Mouse Grimace Scale scores and face-wiping behavior, which were attenuated by pharmacological or genetic inhibition of TRPV1. ⋯ Furthermore, ablation of neurons expressing NK1 receptor in trigeminal subnucleus caudalis also prevented both types of muscle pain. Our results suggest that TRPV1 differentially contributes to spontaneous pain and bite-evoked muscle pain, but TRPV1-expressing afferents and NK1-expressing second-order neurons commonly mediate both types of muscle pain. Therefore, manipulation of the nociceptive circuit may provide a novel approach for management of acute or chronic craniofacial muscle pain.
-
Randomized Controlled Trial Comparative Study
Comparison of two lumbar manual therapies on temporal summation of pain in healthy volunteers.
The purpose of this study was to compare the immediate change in temporal summation of heat pain (TSP) between spinal manipulation (SMT) and spinal mobilization (MOB) in healthy volunteers. Ninety-two volunteers (24 male; 23.8 ± 5.3 years) were randomized to receive SMT, MOB, or no treatment (REST) for 1 session. Primary outcomes were changes in TSP, measured at the hand and foot, immediately after the session. A planned subgroup analysis investigated effects across empirically derived TSP clusters. For the primary outcome there were no differences in the immediate change in TSP measured at the foot between SMT and MOB, however, both treatments were superior to the REST condition. In the subgroup analysis the response to a standard TSP protocol was best characterized by 3 clusters: 52% no change (n = 48, 52%); facilitatory response (n = 24, 26%), and inhibitory response (n = 20, 22%). There was a significant Time × Treatment group × Cluster interaction for TSP measured at the foot. The inhibitory cluster showed the greatest attenuation of TSP after SMT and MOB compared with REST. These data suggest lumbar manual therapies of different velocities produce a similar localized attenuation of TSP, compared with no treatment. Attenuation of localized pain facilitatory processes by manual therapies was greatest in pain-free individuals who show an inhibitory TSP response. ⋯ The attenuation of pain facilitatory measures may serve an important underlying role in the therapeutic response to manual therapies. Identifying patients in pain who still have an inhibitory capacity (ie, an inhibitory response subgroup) may be useful clinically in identifying the elusive "manual therapy" responder.
-
In response to increases in harms associated with prescription opioids, opioid prescribing has come under greater scrutiny, leading many health care organizations and providers to consider or mandate opioid dose reductions (tapering) for patients with chronic pain. Communicating about tapering can be difficult, particularly for patients receiving long-term opioids who perceive benefits and are using their medications as prescribed. Because of the importance of effective patient-provider communication for pain management and recent health system-level initiatives and provider practices to taper opioids, this study used qualitative methods to understand communication processes related to opioid tapering, to identify best practices and opportunities for improvement. Up to 3 clinic visits per patient were audio-recorded, and individual interviews were conducted with patients and their providers. Four major themes emerged: 1) explaining-patients needed to understand individualized reasons for tapering, beyond general, population-level concerns such as addiction potential, 2) negotiating-patients needed to have input, even if it was simply the rate of tapering, 3) managing difficult conversations-when patients and providers did not reach a shared understanding, difficulties and misunderstandings arose, and 4) nonabandonment-patients needed to know that their providers would not abandon them throughout the tapering process. ⋯ Although opioid tapering can be challenging, helping patients to understand individualized reasons for tapering, encouraging patients to have input into the process, and assuring patients they would not be abandoned all appear to facilitate optimal communication about tapering.
-
The aim of this case-control study was to examine differences in neural correlates of pain facilitatory and inhibitory mechanisms between acute low back pain (LBP) patients and healthy individuals. Pressure pain tolerance, electrical pain detection thresholds, pain ratings to repetitive suprathreshold electrical stimulation (SES) and conditioned pain modulation (CPM) were assessed in 18 patients with acute LBP and 18 healthy control participants. Furthermore, event-related potentials (ERPs) in response to repetitive SES were obtained from high-density electroencephalography. Results showed that the LBP group presented lower pressure pain tolerance and higher pain ratings to SES compared with the control group. ⋯ Both groups presented similar reductions in ERP amplitudes during CPM, but ERP responses to repetitive SES were significantly larger in the LBP group. In conclusion, acute LBP patients presented enhanced pain facilitatory mechanisms, whereas no significant changes in pain inhibitory mechanisms were observed. These results provide new insight into the central mechanisms underlying acute LBP.