The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
The Influence of Opioids on Transcutaneous Electrical Nerve Stimulation Effects in Women with Fibromyalgia.
Transcutaneous electrical nerve stimulation (TENS) uses endogenous opioids to produce analgesia, and effectiveness can be reduced in opioid-tolerant individuals'. We examined TENS effectiveness (primary aim), and differences in fibromyalgia symptoms (secondary aim), in women with fibromyalgia regularly taking opioid (RTO) medications compared with women not- regularly taking opioids (not-RTO). Women (RTO n = 79; not-RTO not-n = 222) with fibromyalgia with daily pain levels ≥4 were enrolled and categorized into RTO (taking opioids at least 5 of 7 days in last 30 days) or not-RTO groups. ⋯ Clinical Trial Registration Number: NCT01888640. PERSPECTIVE: Individuals treated with mixed frequency TENS at a strong but comfortable intensity that was taking prescription opioid analgesics showed a significant reduction in movement-evoked pain and fatigue. These data support the use of TENS, using appropriate parameters of stimulation, as an intervention for individuals with fibromyalgia taking opioid analgesics.
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Interhemispheric inhibition between primary sensory cortices is not influenced by acute muscle pain.
Bilateral deficits in sensorimotor function have been observed in unilateral musculoskeletal pain conditions. Altered interhemispheric inhibition (IHI) between primary sensory cortices (S1s) is one mechanism that could explain this phenomenon. However, IHI between S1s in response to acute muscle pain, and the relationship between IHI and pressure pain sensitivity in the unaffected limb have not been examined. ⋯ These findings suggest IHI between S1s is unaffected by acute, short-lasting muscle pain, despite the development of increased sensitivity to pressure in the unaffected APB muscle. PERSPECTIVE: IHI from the affected S1 (contralateral to the side of pain) to unaffected S1 is unaltered following the resolution of acute muscle pain. This finding suggests that IHI between S1s may not be relevant in the development of bilateral sensorimotor symptoms in unilateral pain conditions.
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Observational Study
The histamine-induced axon-reflex response in people with type 1 diabetes with and without peripheral neuropathy: A clinical, observational study.
Small nerve fibres are important when studying diabetic peripheral neuropathy (DPN) as they could be first affected. However, assessing their integrity and function adequately remains a major challenge. The aim of this study was to investigate the association between different degrees of DPN, the presence of neuropathic pain, and the intensity of the axon-reflex flare response provoked by epidermal histamine. ⋯ The method can distinguish between groups with and without diabetes and with and without DPN but cannot distinguish between groups with and without painful DPN. PERSPECTIVE: This study describes how diabetes attenuates the axon-reflex response, and how it is affected by neuropathy and pain clarifying previous findings. Furthermore, the study is the first to utilize histamine when evoking the response, thus providing a new and fast alternative for future studies into the pathophysiology of neuropathic pain.
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This ecological momentary assessment (EMA) study examined the extent of pain intensity variability among 140 individuals with chronic low back pain and explored predictors of such variability and psychosocial and health care utilization outcomes. Individuals completed momentary pain intensity reports (0-10 numeric rating scale) several times daily for two periods of seven consecutive days, one month apart. Participants also completed online questionnaires at baseline which tapped into pain characteristics, pain-related catastrophization, kinesiophobia, activity patterns, and depression and anxiety symptoms. ⋯ Future EMA studies should replicate and extend current findings. PERSPECTIVE: This study provides evidence indicating that there is substantial variability in momentary reports of pain intensity among individuals living with chronic low back pain. However, risk and protective factors for greater lability of pain are elusive as is evidence that greater pain intensity variability results in differential health care utilization.
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Recent studies suggest that the COVID-19 pandemic can serve as a unique psychosocial stressor that can negatively impact individuals with chronic pain. Using a large online sample in the U. S., the present study sought to investigate the impact of the pandemic on the trajectories of pain severity and interference, emotional distress (ie, anxiety and depressive symptoms), and opioid misuse behaviors across one year. ⋯ Nevertheless, interventions that target improvement of pain acceptance may help individuals with chronic pain be resilient during the pandemic. PERSPECTIVE: Individuals with chronic pain overall did not experience significant exacerbation of pain, emotional distress, and opioid misuse across one year during the COVID-19 pandemic. Individuals with higher pain acceptance showed greater improvement in pain severity and depressive symptoms over time during the pandemic.