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Hyperalgesia and allodynia are frequent in neuropathic pain. Some pain questionnaires like the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) and the Neuropathic Pain Scale (NPS) include self-assessment or bedside-testing of hyperalgesia/allodynia. The aim of this study was to determine to what extent LANSS and NPS data are congruent with findings upon quantitative Sensory Testing (QST).Self-reported presence of dynamic mechanical allodynia (DMA) and descriptors of hot, cold or deep ongoing pain (NPS, LANSS) as well as bedside findings of mechanical allodynia (LANSS) were compared to signs of DMA and thermal hyperalgesia upon QST in 617 neuropathic pain patients.Self-reported abnormal skin sensitivity (LANSS) showed a moderate concordance with DMA during bedside test (67.9%, k=0.391) or QST (52.8%, k=0.165). Receiver operating curve analysis for self-reported DMA yielded similar area-under-the-curve values for LANSS (0.65, CI: 0.59-0.97%) and NPS (0.71, CI: 0.66-0.75%) with high sensitivity but low specificity. Self-reported deep pain intensity was higher in patients with blunt pressure hyperalgesia, but not in patients with DMA or thermal hyperalgesia. No correlations were observed between self-reported hot or cold pain quality and thermal hyperalgesia upon QST.Self-reported abnormal skin sensitivity has a high sensitivity to identify patients with DMA, but its low specificity indicates that many patients mean something other than DMA when reporting this symptom. Self-reported deep pain is related to deep-tissue hypersensitivity, but thermal qualities of ongoing pain are not related to thermal hyperalgesia. Questionnaires mostly evaluate the ongoing pain experience while QST mirrors sensory functions. Therefore, both methods are complementary for pain assessment.
Learn More >Self-regulatory (SR) ability is an important resource for managing pain, but chronic pain patients experience chronic self-regulatory fatigue even when they are not in pain. Pressure pain thresholds (PPT) and pain inhibition are two mechanisms that differentiate people with and without chronic pain. It was hypothesized that trait SR ability would be associated with higher PPT and better pain inhibition and that PPT and pain inhibition would be lower following high versus low SR fatigue. Three studies tested these hypotheses. Study 1 had 240 pain-free undergraduates complete measures of trait SR ability and PPT; 122 also provided data on pain inhibition. Study 2 had 38 of Study 1's participants return for two additional sessions in which they underwent PPT testing under conditions of high or low SR fatigue (within-person, counterbalanced). Study 3 repeated these procedures with pain inhibition as the outcome (n = 39). Results revealed that individual differences in SR ability were not associated with PPT or pain inhibition (all ps > 0.05). Within people, neither PPT (F(1, 36) = 1.57, p = 0.22) nor pain inhibition (F(1, 37) = 1.79, p = 0.19) were significantly different under conditions of low versus high SR fatigue. Results do not support the hypotheses that PPT or pain inhibition associate with individual differences in trait SR ability or transient changes in state SR fatigue in the absence of pain. Instead, the SR deficits in chronic pain patients may arise from the experience of chronic pain.
Learn More >Migraine is one of the most disabling and prevalent of all disorders. To improve understanding of migraine mechanisms and to suggest a new therapeutic target, we investigated whether opening of ATP-sensitive potassium channels (KATP) would cause migraine attacks. In this randomized, double-blind, placebo-controlled, crossover study, 16 patients aged 18-49 years with one to five migraine attacks a month were randomly allocated to receive an infusion of 0.05 mg/min KATP channel opener levcromakalim and placebo on two different days (ClinicalTrials.gov number, NCT03228355). The primary endpoints were the difference in incidence of migraine attacks, headaches and the difference in area under the curve (AUC) for headache intensity scores (0-12 h) and for middle cerebral artery blood flow velocity (0-2 h) between levcromakalim and placebo. Between 24 May 2017 and 23 November 2017, 16 patients randomly received levcromakalim and placebo on two different days. Sixteen patients (100%) developed migraine attacks after levcromakalim compared with one patient (6%) after placebo (P = 0.0001); the difference of incidence is 94% [95% confidence interval (CI) 78-100%]. The incidence of headache over the 12 h observation period was higher but not significant after levcromakalim (n = 16) than after placebo (n = 7) (P = 0.016) (95% CI 16-71%). The AUC for headache intensity was significantly larger after levcromakalim compared to placebo (AUC0-12h, P < 0.0001). There was no change in mean middle cerebral artery blood flow velocity after levcromakalim compared to placebo (AUC0-2hP = 0.46). Opening of KATP channels caused migraine attacks in all patients. This suggests a crucial role of these channels in migraine pathophysiology and that KATP channel blockers could be potential targets for novel drugs for migraine.
Learn More >The purpose of this cross-sectional, descriptive study was to assess differences in neuropathic symptoms, physical and emotional well-being, and quality of life in cancer patients at the end of life compared to those without neuropathic symptoms. Neuropathic symptoms were defined as numbness and tingling in the hands and/or feet. A secondary analysis of data from two hospices in Central Florida was performed. Adults (n = 717) with a cancer diagnosis, an identified family caregiver, and who were receiving hospice services, were eligible. The prevalence of numbness/tingling in the hands or feet was 40% in this sample of hospice patients with cancer. Participants with neuropathic symptoms of numbness/tingling had a significantly higher prevalence of pain (76.7% vs. 67.0%; p = .006), difficulty with urination (29.4% vs. 20.3%; p = .007), shortness of breath (64.9% vs. 54.1%; p = .005), dizziness/lightheadedness (46.0% vs. 28.2%; p < .001), sweats (35.5% vs. 20.3%; p < .001), worrying (50.7% vs. 37.3%; p = .001), feeling irritable (38.5% vs. 28.7%; p = .008), feeling sad (48.2% vs. 37.8%; p = .008), and difficulty concentrating (46.2% vs. 32.5%; p < .001). They also reported significantly higher overall symptom intensity and symptom distress scores (p = < .001), higher pain severity (p = .001) and pain distress (p = .002), and decreased quality of life (p = .002) compared to those without numbness/tingling. Neuropathic symptoms are emotionally distressing at the end of life and associated with higher symptom burden and diminished quality of life.
Learn More >Failed back surgery syndrome (FBSS) is a pain condition refractory to therapy, and is characterised by persistent low back pain after spinal surgery. FBSS is associated with severe disability, low quality of life and high unemployment. We are currently unable to identify patients who are at risk of developing FBSS. Patients with chronic low back pain may display signs of central hypersensitivity as assessed by quantitative sensory tests (QST). This can contribute to the risk of developing persistent pain after surgery.
Learn More >We termed chronic neuropathic pain (NeP) in patients with diseases associated with spinal cord damage as "spinal cord-related pain syndrome". We conducted a survey of patients with the syndrome to assess the type and severity of NeP and its effect on QOL, and treatment modalities.
Learn More >People with whiplash associated disorders (WAD) report difficulty with quick head movements and cervico-ocular dysfunctions. Changes in coordination between eye movement and neck muscle activity may be involved.
Learn More >We conducted a cohort study of adult patients presenting for orthopaedic trauma surgery at a statewide trauma centre, with the aims of determining (i) the incidence and risk factors for severe acute pain in the PACU, and (ii) the incidence and risk factors for persistent post-surgical pain at 3 months.
Learn More >Inconsistent reporting of outcomes in clinical trials of treatments for Whiplash Associated Disorders (WAD) hinders effective data pooling and conclusions that can be drawn about the effectiveness of tested treatments. The aim of this study was to provide recommendations for core outcome domains that should be included in clinical trials of WAD.
Learn More >To describe the frequency, intensity, and duration of urologic chronic pelvic pain syndrome symptom exacerbations ("flares"), as well as risk factors for these features, in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain Epidemiology and Phenotyping longitudinal study.
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