Valid and reliable biomarkers can play an important role in clinical trials as indicators of biological or pathogenic processes or as a signal of treatment response. Currently, there are no biomarkers for pain qualified by the US Food and Drug Administration or the European Medicines Agency for use in clinical trials. This article summarizes an Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) meeting in which 3 potential biomarkers were discussed for use in the development of analgesic treatments: (1) sensory testing, (2), skin punch biopsy, and (3) brain imaging.
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Tuesday, February 28, 2017
A brief tool to differentiate factors contributing to insomnia complaints.
Objective: A complaint of insomnia may have many causes. A brief tool examining contributing factors may be useful for nonsleep specialists. This study describes the development of the Insomnia Symptoms Assessment (ISA) for examining insomnia complaints. Method: ISA questions were designed to identify symptoms that may represent 1 of 8 possible factors contributing to insomnia symptoms, including delayed sleep phase syndrome (DSPS), shift work sleep disorder (SWSD), obstructive sleep apnea (OSA), mental health, chronic pain, restless leg syndrome (RLS), poor sleep hygiene, and psychophysiological insomnia (PI). The ISA was completed by 346 new patients. Patients met with a sleep specialist who determined primary and secondary diagnoses. Results: Mean age was 45 (18–85) years and 51% were male. Exploratory factor analysis (n = 217) and confirmatory factor analysis (n = 129) supported 5 factors with good internal consistency (Cronbach’s alpha), including RLS (.72), OSA (.60), SWSD (.67), DSPS (.64), and PI (.80). Thirty percent had 1 sleep diagnosis with a mean of 2.2 diagnoses per patient. No diagnosis was entered for 1.2% of patients. The receiver operating characteristics were examined and the area under the curves calculated as an indication of convergent validity for the primary diagnosis (N = 346) were .97 for SWSD, .78 for OSA, .67 for DSPS, .54 for PI, and .80 for RLS. Conclusion: The ISA demonstrated good internal consistency and corresponds well to expert diagnoses. Next steps include setting sensitivity/specificity cutoffs to suggest initial treatment recommendations for use in other settings. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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Monday, February 27, 2017
Thursday, February 23, 2017
Measures of upper limb function for people with neck pain. A systematic review of measurement and practical properties
There is a strong relationship between neck pain (NP) and upper limb disability (ULD). Optimal management of NP should incorporate upper limb rehabilitation and therefore include the use of an ULD measure in the assessment and management process. Clear guidance regarding the suitability of available measures does not exist. The aim of this study was to identify all available measures of ULD for populations with NP, critically evaluate their measurement properties and finally recommend a list of suitable measures.
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An Improved Rodent Model of Trigeminal Neuropathic Pain by Unilateral Chronic Constriction Injury of Distal Infraorbital Nerve (dIoN-CCI)
The number of studies on trigeminal nerve injury using animal models remains limited. A rodent model of trigeminal neuropathic pain was first developed in the 1994, in which chronic constriction injury is induced by ligation of the infraorbital nerve (IoN-CCI). This animal model has served as a major tool to study trigeminal neuropathic pain. Unfortunately, the surgical procedure in this model is complicated and far more difficult than ligation of peripheral nerves (e.g. sciatic nerve). The aim of this study was to improve on the current surgical procedure of IoN ligation to induce trigeminal neuropathic pain in rats.
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Opposite patterns of change in perception of imagined and physically induced pain over the course of repeated thermal stimulations
Abstract
Background
Individuals frequently show habituation to repeated noxious heat. However, given the defensive function of human pain processing, it is reasonable to assume that individuals anticipate that they would become increasingly sensitive to repeated thermal pain stimuli. No previous studies have, however, been addressed to this assumption. Therefore, in the current study, we investigated how healthy human individuals imagine the intensity of repeated thermal pain stimulations, and compared this with the intensity ratings given after physically induced thermal pain trials.
Methods
Healthy participants (N = 20) gave pain intensity ratings in two conditions: imagined and real thermal pain. In the real pain condition, thermal pain stimuli of two intensities (minimal and moderate pain) were delivered in four consecutive trials. The duration of the peak temperature was 20 s, and stimulation was always delivered to the same location. In each trial, participants rated the pain intensity twice, 5 and 15 s after the onset of the peak temperature. In the imagined pain condition, participants were subjected to a reference pain stimulus and then asked to imagine and rate the same sequence of stimulations as in the induced pain condition.
Results
Ratings of imagined pain and physically induced pain followed opposite courses over repeated stimulations: Ratings of imagined pain indicated sensitization, whereas ratings for physically induced pain indicated habituation. The findings were similar for minimal and moderate pain intensities.
Conclusions
The findings suggest that, rather than habituating to pain, healthy individuals imagine that they would become increasingly sensitive to repeated thermal pain stimuli.
Significance
This study identified opposite patterns of change in perception of imagined pain (sensitization) and physically induced pain (habituation). The findings show that individuals anticipate that they would become increasingly sensitive to repeated pain stimuli, which might also have clinical implications.
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Age-related changes in pain sensitivity in healthy humans: A systematic review with meta-analysis
Abstract
Literature suggests that pain perception diminishes in old age. The most recent review used search strategies conducted over a decade ago and concluded that study findings were equivocal. The aim of this systematic review, with meta-analysis, was to determine age-related changes in pain sensitivity in healthy pain-free adults, children and adolescents. A search of PubMed, Science Direct, and PsycINFO identified studies that compared pain sensitivity response to noxious stimuli at different time points in the lifespan of healthy individuals. Selected studies were assessed for methodological quality and data pooled and meta-analysed. Publication bias was tested using Funnel plots. Twelve studies were included in the review (study sample sizes 30–244 participants). Seven of nine studies found statistically significant differences in pain sensitivity response between old (mean ± SD 62.2 ± 3.4 to 79 ± 4 years) and younger adults (22 ± 1.5 to 39.1 ± 8.8 years), but the direction of change was inconsistent. Meta-analysis found that pressure pain threshold was lower in old adults compared with younger adults (p = 0.018, I2 = 60.970%). There were no differences in contact heat pain thresholds between old and younger adults (p = 0.0001, I2 = 90.23%). Three studies found that younger children (6–8.12 years) were more sensitive to noxious stimuli than older children (9–14 years). Methodological quality of studies was high, with a low risk of publication bias. There was substantial statistical and methodological heterogeneity. There is tentative evidence that pressure pain threshold was lower in old adults compared with younger adults, with no differences in heat pain thresholds. Further studies are needed.
Significance
There is tentative evidence that old adults may be more sensitive to mechanically-evoked pain but not heat-evoked pain than young adults. There is a need for further studies on age-related changes in pain perception.
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The development and assessment of the Worry About Pain Questionnaire
Abstract
Background
Worry can be conceptualized as a cognitive–affective automatic process initiated in order to address uncertainty and potential personal inadequacies that could result in negative outcomes. The purpose of the current study was to develop a measure of pain-specific worry – the Worry About Pain Questionnaire (WAPQ).
Method
In study 1, responses of 335 pain-free participants were used to complete an item analysis and exploratory factors analysis to develop and assess the internal structure of the WAPQ. Study 2 included 224 pain-free participants who completed the WAPQ in order to confirm its factor structure, and to examine its relation to the experience of acute experimental pain. In study 3, 137 individuals with persistent pain were asked to complete the WAPQ as well as measures of pain and depressive symptoms.
Results
The resulting 15-item measure assesses uncertainties and potential negative outcomes related to the experience of pain. The results of the exploratory and confirmatory factor analyses showed a two-factor structure. Across all studies, the WAPQ was found to be related to measures of pain in clinical and non-clinical samples, acute experimental pain stimuli, as well as pain anxiety, pain catastrophizing, fear of pain, rumination and depressive symptomatology.
Conclusions
The results suggest that the WAPQ is a reliable and valid measure for the assessment of worry about pain that can be used to understand how pain-specific worries are related to the experience and impact of pain across different populations.
Significance
Worry has been assessed in pain populations using measures that assess worry in general. The current study shows a relationship between pain-specific worry and the experience of pain. Further, worry about pain is related to but not synonymous with pain catastrophizing.
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Tuesday, February 21, 2017
The power and the pain of adolescents’ digital communication: Cyber victimization and the perils of lurking.
Many adolescents are heavily engaged with social media and text messaging (George & Odgers, 2015; Lenhart, 2015), yet few psychologists have studied what digital communication means for adolescents’ relationships and adjustment. This article proposes that psychologists should embrace the careful study of adolescents’ digital communication. We discuss theoretical frameworks for understanding adolescents’ involvement with social media, present less widely recognized perils of intense involvement with social media, and highlight positive features of digital communication. Coconstruction theory suggests that adolescents help to create the content of digital communication that shapes their lives, and that there may be strong continuity between adolescents’ offline and online lives (Subrahmanyam, Smahel, & Greenfield, 2006). However, psychological theories and research methods could further illuminate the power and the pain of adolescents’ digital communication. Psychologists need to understand more about subtle but potentially serious risks that adolescents might face: The agony of victimization by even a single episode of cyberbullying and the pain of social exclusion and comparison resulting from vast amounts of time reading large social media feeds and seeing friends doing things without you and comparing your inner emotional experience to everyone else’s highly groomed depictions of their seemingly marvelous lives. If we seek to understand developmental psychopathology and to help youth at risk, psychologists need to embrace careful study of the content of adolescents’ online communication, parents need to talk with their children about their own online experiences and become familiar with social media themselves, and clinicians need to address adolescents’ online social lives in prevention and treatment programs. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
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from American Psychologist - Vol 72, Iss 2 http://ift.tt/2l4vl40
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Skype programme is effective for people with chronic knee pain
An internet delivered programme produced meaningful improvements in pain and function among patients with chronic knee pain, research published in the Annals of Internal Medicine...
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Long-term pain and recovery after major pediatric surgery: A qualitative study with teens, parents, and perioperative care providers
Research developing targeted treatment focused on coping with children’s long-term pain after surgery is needed due to the high prevalence of chronic pain after surgery. This qualitative study aimed to 1) understand the child’s and family’s experiences of pain over the course of their surgical experience, and 2) gather stakeholder input regarding potential barriers and facilitators of perioperative intervention delivery. Fifteen children ages 10-18 years who underwent recent major surgery, their primary caregivers, and 17 perioperative healthcare providers were interviewed.
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Friday, February 17, 2017
Mild social stress in mice produces opioid-mediated analgesia in visceral but not somatic pain states
Visceral pain has a greater emotional component than somatic pain. To determine if the stress-induced analgesic response is differentially expressed in visceral versus somatic pain states, we studied the effects of a mild social stressor in either acute visceral or somatic pain states in mice. We show that the presence of an unfamiliar conspecific (stranger) in an adjacent cubicle of a standard transparent observation box produced elevated plasma corticosterone levels compared to mice tested alone, suggesting that the mere presence of a stranger is stressful.
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Challenges of managing chronic pain
Chronic pain is an individualised experience with multifactorial aetiology.1 It can cause unexpectedly prolonged suffering when, for example, an initial injury evolves into a complex disease state. A...
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Is this back pain killing me? All-cause and cardiovascular-specific mortality in older Danish twins with spinal pain
Abstract
Background
Few studies have examined the potentially reduced life expectancy associated with spinal pain (i.e. low back and neck pain) in an ageing population, particularly after controlling for familial factors, including genetics.
Methods
We investigated whether spinal pain increased the rate of all-cause and disease-specific cardiovascular mortality in older Danish twins aged ≥70 years. Data from 4391 participants collected at baseline were linked with the Danish Cause of Death Registry with the study ending on 31 December 2014. Two crude and adjusted Cox proportional hazards regression analyses determined the rate of all-cause and disease-specific cardiovascular mortality by baseline spinal pain exposure; unpaired (total sample analysis) and twin pair (intra-pair analysis). Analyses were also adjusted for confounders; baseline physical functional ability and depressive symptoms. Competing risk regression models determined the rate of cardiovascular mortality, adjusting for similar confounders and using the total sample only.
Results
Spinal pain was associated with an increased rate of all-cause mortality, hazard ratio (HR): 1.13 [95% confidence interval (CI): 1.06–1.21]. There was no association between spinal pain and cardiovascular disease mortality, sub-distribution hazard ratio (SHR): 1.08 [95% CI 0.96–1.21]. After adjusting for confounders (physical functional ability and depressive symptoms), the association became non-significant. All intra-pair analyses were statistically non-significant, although greater in magnitude for monozygotic twins.
Conclusions
Older people reporting spinal pain have 13% increased risk of mortality per years lived but the connection is not causal. We found no association between spinal pain and cardiovascular-specific mortality. The influence of shared familial factors is unlikely.
Significance
Older people reporting spinal pain have 13% increased risk of mortality per year lived. However, this association is not likely to be causal, with the relevant confounders contributing to this relationship. Thus, pain in the spine may be part of a pattern of poor health, which increases mortality risk in the older population.
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Histaminergic and non-histaminergic elicited itch is attenuated in capsaicin-evoked areas of allodynia and hyperalgesia: A healthy volunteer study
Abstract
Background
Chronic pain patients with sensitization may exhibit decreased sensitivity to normally pruritogenic sensory stimuli and moreover occasionally perceive these as painful. This study explored the relationship between itch and pain, by evaluating histaminergic and non-histaminergic itch evoked in capsaicin-induced allodynic and hyperalgesic areas.
Methods
In 28 healthy volunteers, capsaicin (100 μg/0.1 mL) was injected intradermally in the volar forearm to establish secondary dysesthesias. After the capsaicin-induced pain subsided, the areas of allodynia and hyperalgesia were mapped and itch was provoked inside these areas by histamine (10 mg/mL) and cowhage (25–40 spicules). The evoked itch and pain were recorded on a visual analogue scale (VAS 0–10 cm). Contralateral injection of 0.1 mL isotonic saline served as a control.
Results
Histaminergic and non-histaminergic evoked itch were significantly decreased when provoked in allodynic skin (p < 0.05). The area-under-the-curve of the evoked itch was reduced −43% from 18.0 ± 2.6 cm10 min in normal skin to 10.3 ± 1.8 cm10 min in allodynic skin (p < 0.01) for cowhage and −56% from 20.0 ± 3.5 cm10 min in normal skin to 8.8 ± 2.3 cm10 min allodynic skin (p < 0.001) for histamine. The pain responses to the pruritogens were not significantly altered between the areas of allodynia and normal skin (p > 0.1). An additional experiment showed that pinprick hyperalgesia in the absence of allodynia was sufficient to evoke the observed reduced sensitivity to itch stimuli.
Conclusions
Cutaneous sensitization (secondary allodynia and hyperalgesia) reduced itch responses regardless of the type of itch model applied and without attenuation of the associated pruritogen-induced pain responses. This could explain the decreased sensitivity to itch provocations previously observed in patients with chronic pain.
Significance
This study shows that the neuronal sensitization processes underlying the development secondary hyperalgesia involve significant gating of histaminergic as well as non-histaminergic pruriceptive transmission. Because these itch provocations normally target specific subpopulations of C-nociceptors they could be of relevance for exploratory purposes in pain patients.
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Thursday, February 16, 2017
Skin conductance as a pain assessment tool during chest tube removal: An observational study
Abstract
Background
Skin conductance variability to assess pain has shown varying results. Skin conductance responses per second (SCR) during a standardized painful stimulus in awake adults may give further understanding of the method's validity. The purpose of this study was to validate the SCR with the visual analogue scale (VAS) for pain (P-VAS) and anxiety (A-VAS) during chest tube removal (CTR).
Methods
Ninety-five patients receiving epidural or non-epidural treatment, scheduled for CTR, were studied. Pain or anxiety was considered when VAS > 30 mm; the SCR cut-off value reflecting pain was ≥0.2 SCR.
Results
SCR values could not be recorded in eight cases before CTR, six cases during CTR and seven cases after CTR. CTR induced increases in SCR, P-VAS and A-VAS (p < 0.001). Seventy-seven percent of all pairs of P-VAS and SCR values were well-classified; P-VAS ≤ 30 mm and SCR < 0.2 or P-VAS > 30 mm and SCR ≥ 0.2. SCR obtained before CTR differentiates between patients with and without pain during CTR in all patients (p = 0.04) and in the subgroup of non-anxious patients (p = 0.02), but not in the subgroup of anxious patients. SCR obtained during CTR had similar values in patients with and without pain in all patients and in the subgroup of anxious patients, but in the subgroup of non-anxious patients SCR during CTR differentiates patients with and without pain (p = 0.009).
Conclusions
SCR increases during painful procedures. Preprocedural SCR may help predict reported pain in patients exposed to painful procedures. SCR during CTR differentiates between patients with and without pain only in non-anxious patients.
Significance
Preprocedural SCR may help predict reported pain in patients exposed to painful procedures. Procedural SCR accuracy improves in a subgroup of non-anxious patients. P-VAS is influenced by anxiety different from SCR.
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Age-related changes in laser-evoked potentials following trigeminal and hand stimulation in healthy subjects
Abstract
Objective
This study aimed to evaluate age-related changes in laser-evoked potential (LEP) features, including habituation, via trigeminal and hand stimulation in a large group of healthy volunteers.
Methods
We recorded the LEPs by right-hand stimulation in 237 healthy subjects and by stimulation of the right supraorbital zone in 170 cases. The subjects ranged in age from 7 to 72 years and were divided into six groups by age.
Results
At the trigeminal level, the N2 and P2 latencies were significantly shorter and the N2–P2 amplitude was significantly larger in the 7–17 age group than in the other groups. The N2–P2 amplitude of the responses evoked by hand stimulation was significantly larger in the 7–40 age range than in the older subjects. The N1 amplitude and latency were not significantly different among the groups. The N2–P2 habituation increased with age, but no significant changes among groups were revealed by the Bonferroni test.
Conclusions
Trigeminal vertex LEPs have greater amplitudes and appear earlier in children, while a progressive age-related amplitude decrease characterizes the N2–P2 waves associated with hand stimulation. The N2–P2 habituation increases in older people. The N1 latency and amplitude seem to remain stable during ageing and are therefore potentially reliable and useful patterns for nociceptive system examination.
Significance
Standardization of age-related changes in trigeminal and hand LEPs is possible and should improve their reliability in the objective assessment of pain pathways.
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Wednesday, February 15, 2017
Non-drug therapies should be first line treatment for low back pain, US guidance says
New guidelines from the American College of Physicians recommend that physicians avoid prescribing drugs, particularly opioids, to treat acute and subacute low back pain and should instead emphasize...
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Tuesday, February 14, 2017
Saturday, February 11, 2017
Preschool Needle Pain Responding: Establishing ‘Normal’
The current study sets forth to provide both descriptive data for preschool vaccination pain responding and examine longitudinal relationships over early childhood. Growth mixture modeling (GMM) was first used to describe stable subgroups of preschoolers based on their pain response patterns over 2-minutes post-needle. Secondly, a parallel-process growth curve model was used to assess the stability of acute pain responding from 12-months of age to preschool age. Specifically, we examined whether preschool pain-related distress or regulation could be predicted from 12-month acute pain responding.
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Friday, February 10, 2017
Do depression and anxiety profiles over time predict persistent post-surgical pain? A study in cardiac surgery patients
Abstract
Background
Rates of depression and anxiety in cardiac surgery patients are higher than in the general population. The development of persistent post-surgical pain (PPSP) in this population is also concerning. The objectives of this study were to (1) identify anxiety and depression trajectories of cardiac surgery patients over a 2-year period; (2) examine demographic and clinical characteristics associated with trajectory memberships and (3) determine if anxiety and/or depression trajectories predict PPSP.
Methods
A total of 1071 patients completed questionnaires before cardiac surgery and 7 days, 3, 6, 12 and 24 months thereafter. Models were run using growth mixture modelling.
Results
Both anxiety and depression models yielded a 3-trajectory solution. A minority of patients (< 10%) had unremitted major depression, almost one-third of patients had remitted minor depression and the remaining patients had no depression over the 2-year period. < 10% of patients had unremitted elevated anxiety, almost 40% of patients had unremitted mild anxiety symptoms, whereas half of patients did not experience anxiety over the same time period. Patients with unremitted elevated anxiety were more likely to report PPSP; the association between depression and PPSP was not significant.
Conclusions
The results' novelty lies in the identification of a homogeneous patient subgroup presenting with unremitted elevated anxiety which predicted the presence of PPSP up to 2 years following cardiac surgery. Unlike anxiety, depression subgroups were not predictive of PPSP status.
Significance
This article presents the relationship between anxiety and depression profiles over 2 years in cardiac surgery patients and persistent post-surgical pain. These results suggest the importance of evaluating how early identification and treatment of high-risk patients could prevent PPSP. These results provide potential detection and prevention avenues of chronic pain for high-risk patients based on their anxiety trajectory.
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Thursday, February 9, 2017
Ankyrin-rich membrane spanning protein as a novel modulator of transient receptor potential vanilloid 1-function in nociceptive neurons
Abstract
Background
The ion channel TRPV1 is mainly expressed in small diameter dorsal root ganglion (DRG) neurons, which are involved in the sensation of acute noxious thermal and chemical stimuli. Direct modifications of the channel by diverse signalling events have been intensively investigated, but little is known about the composition of modulating macromolecular TRPV1 signalling complexes. Here, we hypothesize that the novel adaptor protein ankyrin-rich membrane spanning protein/kinase D interacting substrate (ARMS) interacts with TRPV1 and modulates its function in rodent DRG neurons.
Methods
We used immunohistochemistry, electrophysiology, microfluorimetry and immunoprecipitation experiments to investigate TRPV1 and ARMS interactions in DRG neurons and transfected cells.
Results
We found that TRPV1 and ARMS are co-expressed in a subpopulation of DRG neurons. ARMS sensitizes TRPV1 towards capsaicin in transfected HEK 293 cells and in mouse DRG neurons in a PKA-dependent manner. Using a combination of functional imaging and immunocytochemistry, we show that the magnitude of the capsaicin response in DRG neurons depends not only on TRPV1 expression, but on the co-expression of ARMS alongside TRPV1.
Conclusion
These data indicate that ARMS is an important component of the signalling complex regulating the sensitivity of TRPV1.
Significance
The study identifies ARMS as an important component of the signalling complex regulating the sensitivity of excitatory ion channels (TRPV1) in peripheral sensory neurons (DRG neurons) and transfected cells.
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Tissue mechanics during temporal summation of sequentially cuff pressure-induced pain in healthy volunteers and patients with painful osteoarthritis
Abstract
Background
The phenomenon of temporal summation to repetitive pressure pain stimuli is an important central neural mechanism for pain intensity encoding. This study evaluated the time-dependent behaviour of mechanical characteristics of soft tissue during repeated cuff stimulation used for eliciting temporal summation of cuff pressure-evoked pain. Such information of tissue mechanics is important for the interpretation of the pain response evoked during sequential stimulations.
Methods
Temporal summation was assessed in 16 subjects separated into two groups (healthy controls and severe knee osteoarthritis patients) using a visual analogue scale during 10 repetitive painful cuff stimuli (1-s duration, 1-s break) of the lower leg. The geometry of the lower leg was constructed based on magnetic resonance image (MRI) data. The loading boundary condition of the finite element model was defined according to the parabolic pattern of the interface pressure around the limb and the time-dependent profile of the cuff pressure during repetitive stimuli.
Results
The pain intensity significantly increased with an increasing number of stimuli (p < 0.001), and facilitated temporal summation of pain was observed in patients compared with healthy controls (p < 0.001). The maximal deep tissue stress and strain during stimuli 1–4 varied 43% and 9%, respectively. No variation was observed for stimuli 5–10.
Conclusions
The study concludes that the temporal summation of pain response during sequential cuff pressure is not explicable by a specific time-dependent behaviour of stress and strain in the activated deep tissue and hence not due to changes in tissue biomechanics.
Significance
The temporal summation of pain during sequential cuff stimulation is inexplicable by the time-dependent response of mechanical stress and strain in soft tissue.
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Intermittent haematuria and left flank pain
A 68 year old woman presented with a six month history of intermittent haematuria and pain in the left flank. The results of cystoscopy and renal ultrasonography were both negative. Abdominal and...
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Wednesday, February 8, 2017
Sustainability: Growing pains
Sustainability: Growing pains
Nature 542, 7640 (2017). doi:10.1038/542162a
Author: Richard B. Norgaard
Richard B. Norgaard is troubled by the incrementalism of Jeffrey Sachs's modest new plan for the US economy.
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Tuesday, February 7, 2017
Safety, Pharmacokinetic and Pharmacodynamic Study in Healthy Subjects of Oral NEO6860, a Modality Selective TRPV1 Antagonist
Most previous TRPV1 antagonist programs have been put on hold, mainly due on-target adverse events: hyperthermia and impaired noxious heat sensation. NEO6860 is a TRPV1 antagonist, blocking capsaicin activation of the target, with little or no effect against pH or heat activation. The hypothesis is that this pharmacological profile will translate into analgesia without undesired effects on the body temperature or heat-pain threshold.This phase I, double blind, placebo controlled, ascending dose study, included 64 subjects.
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Psychological and endocrine factors and pain after mastectomy
Abstract
Background
This prospective study was designed to examine the associations of demographic, clinical, psychological and neuroendocrine factors with acute and chronic post-operative pain following partial mastectomy.
Methods
Sixty-four female patients scheduled for partial mastectomy were enrolled. Pre-operative anxiety/depression was assessed, using the Hospital Anxiety and Depression Scale (HADS). Pre-operative 24-h urinary cortisol levels were measured 2 days before surgery. Post-operative pain was examined using a visual analog scale (VAS) for acute pain on 0–2 post-operative day (POD), and a short-form McGill Pain Questionnaire for chronic pain at 6 months after surgery. In the last 29 subjects, post-operative 24-h urinary cortisol levels were also measured on 0 POD and were subjected to correlation analysis.
Results
Multivariate logistic regression analysis revealed that lower pre-operative cortisol secretion and greater pre-operative anxiety were significantly associated with an increased risk of moderate to severe acute post-operative pain [Odds Ratio (95% Confidence Interval); 0.96 (0.92–0.98), and 1.24 (1.04–1.54)], and that patients with greater pre-operative anxiety and moderate to severe acute pain were more likely to develop chronic post-operative pain [OR (95% CI); 1.63 (1.23–2.40), and 5.07 (1.30–24.6)]. Correlational analysis demonstrated that the post-operative cortisol level was inversely correlated with pre-operative anxiety and the intensity of acute post-operative pain (r = −0.40, p < 0.05, and r = −0.50, p < 0.01), but not with the intensity of chronic pain.
Conclusions
This study confirms that pre-operative anxiety is associated with both acute and chronic post-operative pain after partial mastectomy. It also suggests that lower perioperative cortisol secretion might be associated with greater acute post-operative pain.
Significance
Although the associations between psychological stress/stress hormone levels and chronic post-operative pain remain to be determined, pre-operative psychological stress and perioperative cortisol levels are correlated with acute post-operative pain.
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Endogenous analgesic effect of pregabalin: A double-blind and randomized controlled trial
Abstract
Background
Conditioned pain modulation (CPM) is widely used to measure endogenous analgesia, and a recent study indicated that drugs that act on endogenous analgesia are more effective in individuals with lower CPM. Recent animal studies have indicated that pregabalin activates endogenous analgesia by stimulating the descending pain inhibitory system. The present study examined whether the analgesic effect of pregabalin is greater in individuals with lower original endogenous analgesia using CPM.
Methods
Fifty-nine healthy subjects were randomly assigned to either a pregabalin group or a placebo group, and 50 of them completed the study. CPM was measured before and after pregabalin or placebo administration. The correlation of initial CPM to change in CPM was compared between the pregabalin and placebo groups.
Results
Initial CPM was significantly correlated with the change in CPM in the pregabalin group (r = −0.73, p < 0.0001) but not in the placebo group (p = 0.56) (difference in correlation coefficients between groups; p = 0.004). Furthermore, the initial CPM significantly affected the change in CPM in the pregabalin group but not in the placebo group (pregabalin group: adj R2 = 0.51, p < 0.001, y = −0.54x + 2.98; placebo group: p = 0.56, significant difference in regression slopes; p = 0.015). These results indicate that pregabalin has a higher endogenous analgesic effect in individuals with lower original endogenous analgesia.
Significance
The analgesic effect of pregabalin depends on the original endogenous analgesia status. Its effect on conditioned pain modulation (CPM) was stronger for subjects with lower original endogenous analgesia, suggesting that the mechanism of pregabalin involves the improvement of endogenous analgesia.
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Pain patients' letters: The visit before the visit – A qualitative analysis of letters from patients referred to a tertiary pain center
Abstract
Background
Pain centers manage only selected patients, and have long waiting lists. Some patients spontaneously send letters, before the visit, and these letters represent the first contact between the patients and the pain centers. We report a study of the content and format of these letters, for a patient perspective analysis.
Methods
During a 3 month-period, all newly referred patients to a tertiary pain center were considered. If a patient letter was provided, it was collected for analysis. Qualitative analyses including semantic and content analyses were performed to identify themes and categories.
Results
Among 138 newly referred patients, 44 had sent a letter before consultation. Content analysis of 42 letters disclosed four themes: I) pain experience; II) impact of the pain problem; III) patient history; and IV) expectations. These themes could be distributed along four pain dimensions: (1) physical; (2) psycho-affective; (3) social; and (4) temporal. This first study on patient letters reveals that a bio-psychosocial model. Patients contribute actively to their trajectory, not only as healthcare seekers but also by constructing their narrative identity.
Conclusions
Patient letters constitute narrative material to be integrated into clinical analysis, alongside patient interviews, especially in pain management. Pain specialists should take account of this narrative approach to better understand the unvoiced and sometimes silent experience of pain. This may increase quality of medical care by including patient-centered data in an original method. Further studies may be valuable to analyze the possible contributions of such letters to patient management.
Significance
Patients' letters constitute original narrative material to be integrated into clinical analysis, especially for pain management. Patients' letters analyses may improve the patient physician relationship, by understanding patient's perspectives, beliefs and expectations.
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Monday, February 6, 2017
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