Multimodal Vulvar and Peripheral Sensitivity Among Women With Vulvodynia: A Case-Control Study.

OBJECTIVE: To assess differences in vulvar and peripheral sensitivity between women with and without vulvodynia. METHODS: Women with vulvodynia (n = 41) and age-matched controls (n = 43) seen in the outpatient setting were evaluated via surveys, clinical examination, and multimodal sensory testing (pressure, heat, cold, vibration, and electrical stimulation). The relationships between sensitivity to various sensory modalities and case/control status, as well as by vulvodynia subgroups, were assessed using logistic regression. RESULTS: Women with vulvodynia were more sensitive to pressure and to electrical stimuli than were control women at the vulva (median, 22 vs 230 g and 0.495 vs 0.769 mA, respectively; P < 0.001 for each) and at the thumb (median, 2500 vs 4250 g and 0.578 vs 0.764 mA, respectively; P = 0.006 for pressure, P < 0.001 for electrical stimulation). Heat, cold, and vibration detection thresholds did not differ significantly between these groups (P > 0.025). Those reporting spontaneous pain versus provoked pain had greater pressure sensitivity to the thumb (median, 1850 vs 2690 g; P = 0.020) and greater electrical sensitivity at the introitus (0.450 vs 0.608 mA; P = 0.011), and those with primary versus secondary vulvodynia had substantially greater pressure sensitivity to the thumb (median, 2438 vs 3125 g, P = 0.004). However, having localized versus generalized vulvodynia was not associated with differences in pressure or electrical sensitivity. CONCLUSIONS: Sensitivities to pressure and electrical stimuli are greater among vulvodynia cases than among controls and support 2 previously defined subgroups-those reporting spontaneous pain versus those whose pain only occurred when provoked, and those with primary versus secondary vulvodynia.

Multidimensional Dyspnea Profile: an instrument for clinical and laboratory research.

There is growing awareness that dyspnoea, like pain, is a multidimensional experience, but measurement instruments have not kept pace. The Multidimensional Dyspnea Profile (MDP) assesses overall breathing discomfort, sensory qualities, and emotional responses in laboratory and clinical settings. Here we provide the MDP, review published evidence regarding its measurement properties and discuss its use and interpretation. The MDP assesses dyspnoea during a specific time or a particular activity (focus period) and is designed to examine individual items that are theoretically aligned with separate mechanisms. In contrast, other multidimensional dyspnoea scales assess recalled recent dyspnoea over a period of days using aggregate scores. Previous psychophysical and psychometric studies using the MDP show that: 1) subjects exposed to different laboratory stimuli could discriminate between air hunger and work/effort sensation, and found air hunger more unpleasant; 2) the MDP immediate unpleasantness scale (A1) was convergent with common dyspnoea scales; 3) in emergency department patients, two domains were distinguished (immediate perception, emotional response); 4) test-retest reliability over hours was high; 5) the instrument responded to opioid treatment of experimental dyspnoea and to clinical improvement; 6) convergent validity with common instruments was good; and 7) items responded differently from one another as predicted for multiple dimensions.

Effects of sleep restriction and exercise deprivation on somatic symptoms and mood in healthy adults.

OBJECTIVES: Exposure to acute 'stressors' (e.g. infections, pain, trauma) often results in altered sleep habits and reductions in routine activity. In some individuals, these behavioural responses to acute stressors may contribute to the development of chronic somatic symptoms such as widespread pain, fatigue, memory difficulties and mood disturbances, much like those associated with 'functional somatic syndromes' (FSS) such as fibromyalgia or chronic fatigue syndrome. METHODS: Eighty-seven healthy young adults who reported sleeping between 7 and 9 hours nightly and exercising regularly were randomised to one of four groups: exercise cessation, sleep restriction (6 hours nightly), both, or neither. Symptoms of pain, fatigue, cognitive dysfunction and negative mood were measured before and after the 10-day restriction period. RESULTS: Sleep restriction was a potent contributor to the development of somatic symptoms. Exercise cessation was less influential leading only to fatigue. There were no significant interactions between exercise cessation and sleep restriction, except that males were much more likely to develop somatic symptoms when deprived of both sleep and exercise than one or the other. Women were generally much more likely to develop somatic symptoms than men. CONCLUSIONS: This study supports previous research suggesting that both sleep and exercise are critical in 'preventing' somatic symptoms among some individuals. Furthermore, to our knowledge, this is the first time there is data to suggest that women are much more sensitive to decrements in routine sleep and exercise than are men.

Large candidate gene association study reveals genetic risk factors and therapeutic targets for fibromyalgia.

OBJECTIVE: Fibromyalgia (FM) represents a complex disorder that is characterized by widespread pain and tenderness and is frequently accompanied by additional somatic and cognitive/affective symptoms. Genetic risk factors are known to contribute to the etiology of the syndrome. The aim of this study was to examine >350 genes for association with FM, using a large-scale candidate gene approach. METHODS: The study group comprised 496 patients with FM (cases) and 348 individuals with no chronic pain (controls). Genotyping was performed using a dedicated gene array chip, the Pain Research Panel, which assays variants characterizing >350 genes known to be involved in the biologic pathways relevant to nociception, inflammation, and mood. Association testing was performed using logistic regression. RESULTS: Significant differences in allele frequencies between cases and controls were observed for 3 genes: GABRB3 (rs4906902; P = 3.65 × 10(-6)), TAAR1 (rs8192619; P = 1.11 × 10(-5)), and GBP1 (rs7911; P = 1.06 × 10(-4)). These 3 genes and 7 other genes with suggestive evidence for association were examined in a second, independent cohort of patients with FM and control subjects who were genotyped using the Perlegen 600K platform. Evidence of association in the replication cohort was observed for TAAR1, RGS4, CNR1, and GRIA4. CONCLUSION: Variation in these 4 replicated genes may serve as a basis for development of new diagnostic approaches, and the products of these genes may contribute to the pathophysiology of FM and represent potential targets for therapeutic action.

Development of a computerized 2D rating scale for continuous and simultaneous evaluation of two dimensions of a sensory stimulus.

Introduction: One-dimensional rating scales are widely used in research and in the clinic to assess individuals' perceptions of sensory stimuli. Although these scales provide essential knowledge of stimulus perception, their limitation to one dimension hinders our understanding of complex stimuli. Methods: To allow improved investigation of complex stimuli, a two-dimensional scale based on the one-dimensional Gracely Box Scale was developed and tested in healthy participants on a visual and an auditory task (rating changes in brightness and size of circles and rating changes in frequency and sound pressure of sounds, which was compared to ratings on one-dimensional scales). Before performing these tasks, participants were familiarized with the intensity descriptors of the two-dimensional scale by completing two tasks. First, participants sorted the descriptors based on their judgment of the intensity of the descriptors. Second, participants evaluated the intensity of the descriptors by pressing a button for the duration they considered matching the intensity of the descriptors or squeezing a hand grip dynamometer as strong as they considered matching the intensity of the descriptors. Results: Results from these tasks confirmed the order of the descriptors as displayed on the original rating scale. Results from the visual and auditory tasks showed that participants were able to rate changes in the physical attributes of visual or auditory stimuli on the two-dimensional scale as accurately as on one-dimensional scales. Discussion: These results support the use of a two-dimensional scale to simultaneously report multiple dimensions of complex stimuli.

Patients with fibromyalgia display less functional connectivity in the brain's pain inhibitory network.

BACKGROUND: There is evidence for augmented processing of pain and impaired endogenous pain inhibition in Fibromyalgia syndrome (FM). In order to fully understand the mechanisms involved in FM pathology, there is a need for closer investigation of endogenous pain modulation. In the present study, we compared the functional connectivity of the descending pain inhibitory network in age-matched FM patients and healthy controls (HC).We performed functional magnetic resonance imaging (fMRI) in 42 subjects; 14 healthy and 28 age-matched FM patients (2 patients per HC), during randomly presented, subjectively calibrated pressure pain stimuli. A seed-based functional connectivity analysis of brain activity was performed. The seed coordinates were based on the findings from our previous study, comparing the fMRI signal during calibrated pressure pain in FM and HC: the rostral anterior cingulate cortex (rACC) and thalamus. RESULTS: FM patients required significantly less pressure (kPa) to reach calibrated pain at 50 mm on a 0-100 visual analogue scale (p < .001, two-tailed). During fMRI scanning, the rACC displayed significantly higher connectivity to the amygdala, hippocampus, and brainstem in healthy controls, compared to FM patients. There were no regions where FM patients showed higher rACC connectivity. Thalamus showed significantly higher connectivity to the orbitofrontal cortex in healthy controls but no regions showed higher thalamic connectivity in FM patients. CONCLUSION: Patients with FM displayed less connectivity within the brain's pain inhibitory network during calibrated pressure pain, compared to healthy controls. The present study provides brain-imaging evidence on how brain regions involved in homeostatic control of pain are less connected in FM patients. It is possible that the dysfunction of the descending pain modulatory network plays an important role in maintenance of FM pain and our results may translate into clinical implications by using the functional connectivity of the pain modulatory network as an objective measure of pain dysregulation.

Treatment-related changes in brain activation in patients with fibromyalgia syndrome.

Little is known about the effects of successful treatment on brain function in chronic pain. This study examined changes in pain-evoked brain activation following behavioral extinction training in fibromyalgia patients. Using functional magnetic resonance imaging, brain activation to painful mechanical stimuli applied to the 2nd phalanx of the left 2nd digit (m. flexor digitorum) was assessed in 10 patients with fibromyalgia syndrome (FM) before and after behavioral extinction training. The behavioral treatment significantly reduced interference from pain in the FM patients. Mechanical pain threshold and pain tolerance increased significantly after treatment. Activation in the insula shifted bilaterally from a more anterior site before treatment to a more posterior location after treatment. The pre- to post-treatment reduction in both interference related to pain and pain severity were significantly associated with bilateral activation in pain-evoked activity in the posterior insula, the ipsilateral caudate nucleus/striatum, the contralateral lenticular nucleus, the left thalamus and the primary somatosensory cortex contralateral to the stimulated side. These data show a relation between successful behavioral treatment and higher activation bilaterally in the posterior insula and in the contralateral primary somatosensory cortex. Future studies should compare responders and non-responders for differential treatment effects and examine in more detail the mechanisms underlying these changes.

Cardiac-Gated Neuromodulation Increased Baroreflex Sensitivity and Reduced Pain Sensitivity in Female Fibromyalgia Patients.

The study presents a novel approach of programing pain inhibition in chronic pain patients based on the hypothesis that pain perception is modulated by dysfunctional dorsal medial nucleus tractus solitarii (dmNTS) reflex arcs that produce diminished baroreflex sensitivity (BRS) resulting from a conditioned response. This study tested whether administration of noxious and non-noxious electrical stimuli synchronized with the cardiac cycle resets BRS, reestablishing pain inhibition. A total of 30 pain-free normotensives controls (NC) and 32 normotensives fibromyalgia (FM) patients received two, ≈8 min-epochs of cardiac-gated, peripheral electrical stimuli. Non-painful and painful electrical stimuli were synchronized to the cardiac cycle as the neuromodulation experimental protocol (EP) with two control conditions (CC1, CC2). BRS, heart-rate-variability (HRV), pain threshold and tolerance, and clinical pain intensity were assessed. Reduced BRS in FM at baseline increased by 41% during two, ≈8 min-epochs of stimulation. Thresholds in FM increased significantly during the experimental protocol (all Ps < 0.001) as did HRV. FM levels of clinical pain significantly decreased by 35.52% during the experimental protocol but not during control stimulations (p < 0.001). Baroreceptor training may reduce FM pain by BRS-mediated effects on intrinsic pain regulatory systems and autonomic responses.

Predictors of Lumbar Spine Degeneration and Low Back Pain in the Community: The Johnston County Osteoarthritis Project.

OBJECTIVE: To determine the incidence and worsening of lumbar spine structure and low back pain (LBP) and whether they are predicted by demographic characteristics or clinical characteristics or appendicular joint osteoarthritis (OA). METHODS: Paired baseline (2003-2004) and follow-up (2006-2010) lumbar spine radiographs from the Johnston County Osteoarthritis Project were graded for osteophytes (OST), disc space narrowing (DSN), spondylolisthesis, and presence of facet joint OA (FOA). Spine OA was defined as at least mild OST and mild DSN at the same level for any level of the lumbar spine. LBP, comorbidities, and back injury were self-reported. Weibull models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) of spine phenotypes accounting for potential predictors including demographic characteristics, clinical characteristics, comorbidities, obesity, and appendicular OA. RESULTS: Obesity was a consistent and strong predictor of incidence of DSN (HR 1.80 [95% CI 1.09-2.98]), spine OA (HR 1.56 [95% CI 1.01-2.41]), FOA (HR 4.99 [95% CI 1.46-17.10]), spondylolisthesis (HR 1.87 [95% CI 1.02-3.43]), and LBP (HR 1.75 [95% CI 1.19-2.56]), and worsening of DSN (HR 1.51 [95% CI 1.09-2.09]) and LBP (HR 1.51 [95% CI 1.12-2.06]). Knee OA was a predictor of incident FOA (HR 4.18 [95% CI 1.44-12.2]). Spine OA (HR 1.80 [95% CI 1.24-2.63]) and OST (HR 1.85 [95% CI 1.02-3.36]) were predictors of incidence of LBP. Hip OA (HR 1.39 [95% CI 1.04-1.85]) and OST (HR 1.58 [95% CI 1.00-2.49]) were predictors of LBP worsening. CONCLUSION: Among the multiple predictors of spine phenotypes, obesity was a common predictor for both incidence and worsening of lumbar spine degeneration and LBP.

Different Phenotypes of Osteoarthritis in the Lumbar Spine Reflected by Demographic and Clinical Characteristics: The Johnston County Osteoarthritis Project.

OBJECTIVE: To determine if associations between demographic and clinical characteristics and appendicular joint osteoarthritis (OA) reflect different phenotypes of OA in the lumbar spine. METHODS: Participants were from the Johnston County OA Project. Demographic information consisted of age, sex, and race (white and African American), and clinical characteristics consisted of body mass index (BMI), low back pain and injury, and knee, hip, and hand OA. Participants were categorized as having spine OA, facet joint OA, both spine OA and facet joint OA, or neither spine OA nor facet joint OA (referent group). Multinomial regression models were used to determine odds ratios (ORs) and 95% confidence intervals (95% CIs). RESULTS: Of 1,793 participants, the mean ± SD age was 66.2 ± 10.1 years, and the mean ± SD BMI was 30.7 ± 6.2. The majority of the participants were women (n = 1,144 [63.8%]), and 31.8% of the participants (n = 570) were African American. Eighteen percent of participants had neither spine OA nor facet joint OA, 22.8% had facet joint OA, 13.2% had spine OA, and 46.0% had both spine OA and facet joint OA. In adjusted analyses, African Americans were less likely to have facet joint OA (OR 0.68 [95% CI 0.49-0.95]) or both spine OA and facet joint OA (OR 0.51 [95% CI 0.37-0.70]). Women were more likely to have facet joint OA (OR 1.71 [95% CI 1.24-2.36]). Having a BMI of ≥30 was associated with having facet joint OA (OR 1.76 [95% CI 1.28-2.42]) and both spine OA and facet joint OA (OR 1.85 [95% CI 1.37-2.51]). Knee OA was associated with all 3 OA groups, while lower back injury was associated only with those with spine OA. Participants with hip OA were less likely to have facet joint OA. CONCLUSION: Race, sex, BMI, hip OA, and lower back injury may help identify different OA phenotypes in the lumbar spine.

Traditional Chinese acupuncture and placebo (sham) acupuncture are differentiated by their effects on mu-opioid receptors (MORs).

Controversy remains regarding the mechanisms of acupuncture analgesia. A prevailing theory, largely unproven in humans, is that it involves the activation of endogenous opioid antinociceptive systems and mu-opioid receptors (MORs). This is also a neurotransmitter system that mediates the effects of placebo-induced analgesia. This overlap in potential mechanisms may explain the lack of differentiation between traditional acupuncture and either non-traditional or sham acupuncture in multiple controlled clinical trials. We compared both short- and long-term effects of traditional Chinese acupuncture (TA) versus sham acupuncture (SA) treatment on in vivo MOR binding availability in chronic pain patients diagnosed with fibromyalgia (FM). Patients were randomized to receive either TA or SA treatment over the course of 4 weeks. Positron emission tomography (PET) with (11)C-carfentanil was performed once during the first treatment session and then repeated a month later following the eighth treatment. Acupuncture therapy evoked short-term increases in MOR binding potential, in multiple pain and sensory processing regions including the cingulate (dorsal and subgenual), insula, caudate, thalamus, and amygdala. Acupuncture therapy also evoked long-term increases in MOR binding potential in some of the same structures including the cingulate (dorsal and perigenual), caudate, and amygdala. These short- and long-term effects were absent in the sham group where small reductions were observed, an effect more consistent with previous placebo PET studies. Long-term increases in MOR BP following TA were also associated with greater reductions in clinical pain. These findings suggest that divergent MOR processes may mediate clinically relevant analgesic effects for acupuncture and sham acupuncture.

Are psychological treatments effective for fibromyalgia pain?

This article considers four broad classes of psychological techniques and their effects on fibromyalgia (FM) pain. A literature search identified 14 randomized controlled trials (RCTs) of cognitive-behavioral therapy (CBT) and operant-behavioral therapy (OBT), five relaxation RCTs, five biofeedback RCTs, five hypnotherapy RCTs, and two writing intervention RCTs. For psychoanalytic therapy in FM, no RCTs have been published. The highest effect sizes (r = 0.53-2.14) for pain reduction are found after CBT and OBT group treatments. Relaxation as a single treatment has not been proven useful. Hypnotherapy and writing intervention have demonstrated mild treatment effects, whereas psychological treatment is effective in FM pain. Considering the heterogeneity of FM, the promising effects of matched interventions such as CBT and OBT with pharmacotherapy, exercise, and other treatment domains require further research.

Genome-wide association reveals contribution of MRAS to painful temporomandibular disorder in males.

Painful temporomandibular disorders (TMDs) are the leading cause of chronic orofacial pain, but its underlying molecular mechanisms remain obscure. Although many environmental factors have been associated with higher risk of developing painful TMD, family and twin studies support a heritable genetic component as well. We performed a genome-wide association study assuming an additive genetic model of TMD in a discovery cohort of 999 cases and 2031 TMD-free controls from the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) study. Using logistic models adjusted for sex, age, enrollment site, and race, we identified 3 distinct loci that were significant in combined or sex-segregated analyses. A single-nucleotide polymorphism on chromosome 3 (rs13078961) was significantly associated with TMD in males only (odds ratio = 2.9, 95% confidence interval: 2.02-4.27, P = 2.2 × 10). This association was nominally replicated in a meta-analysis of 7 independent orofacial pain cohorts including 160,194 participants (odds ratio = 1.16, 95% confidence interval: 1.0-1.35, P = 2.3 × 10). Functional analysis in human dorsal root ganglia and blood indicated this variant is an expression quantitative trait locus, with the minor allele associated with decreased expression of the nearby muscle RAS oncogene homolog (MRAS) gene (beta = -0.51, P = 2.43 × 10). Male mice, but not female mice, with a null mutation of Mras displayed persistent mechanical allodynia in a model of inflammatory pain. Genetic and behavioral evidence support a novel mechanism by which genetically determined MRAS expression moderates the resiliency to chronic pain. This effect is male-specific and may contribute to the lower rates of painful TMD in men.

Decreased central mu-opioid receptor availability in fibromyalgia.

The underlying neurophysiology of acute pain is fairly well characterized, whereas the central mechanisms operative in chronic pain states are less well understood. Fibromyalgia (FM), a common chronic pain condition characterized by widespread pain, is thought to originate largely from altered central neurotransmission. We compare a sample of 17 FM patients and 17 age- and sex-matched healthy controls, using mu-opioid receptor (MOR) positron emission tomography. We demonstrate that FM patients display reduced MOR binding potential (BP) within several regions known to play a role in pain modulation, including the nucleus accumbens, the amygdala, and the dorsal cingulate. MOR BP in the accumbens of FM patients was negatively correlated with affective pain ratings. Moreover, MOR BP throughout the cingulate and the striatum was also negatively correlated with the relative amount of affective pain (McGill, affective score/sensory score) within these patients. These findings indicate altered endogenous opioid analgesic activity in FM and suggest a possible reason for why exogenous opiates appear to have reduced efficacy in this population.

A psychophysical study of auditory and pressure sensitivity in patients with fibromyalgia and healthy controls.

UNLABELLED: Fibromyalgia (FM) is characterized by widespread tenderness. Studies have also reported that persons with FM are sensitive to other stimuli, such as auditory tones. We hypothesized that subjects with FM would display greater sensitivity to both pressure and auditory tones and report greater sensitivity to sounds encountered in daily activities. FM subjects (n = 30) and healthy control subjects (n = 28) were administered auditory tones and pressure using the same psychophysical methods to deliver the stimuli and a common way of scaling responses. Subjects were also administered a self-report questionnaire regarding sensitivity to everyday sounds. Participants with FM displayed significantly greater sensitivity to all levels of auditory stimulation (Ps < .05). The magnitude of difference between FM patients' lowered auditory sensitivity (relative to control subjects) was similar to that seen with pressure, and pressure and auditory ratings were significantly correlated in both control subjects and subjects with FM. FM patients also were more sensitive to everyday sounds (t = 8.65, P < .001). These findings support that FM is associated with a global central nervous system augmentation in sensory processing. Further research is needed to examine the neural substrates associated with this abnormality and its role in the etiology and maintenance of FM. PERSPECTIVE: Muscle tenderness is the hallmark of FM, but the findings of this study and others suggest that persons with FM display sensitivity to a number of sensory stimuli. These findings suggest that FM is associated with a global central nervous system augmentation of sensory information. These findings may also help to explain why persons with FM display a number of comorbid physical symptoms other than pain.

Intraoral measurement of tactile and filament-prick pain threshold using shortened Semmes-Weinstein monofilaments.

OBJECTIVES: Semmes-Weinstein monofilaments are too long for use in parts of the oral cavity. The present study used shortened Semmes-Weinstein monofilaments to evaluate reliability and spatial differences in the intraoral tactile detection threshold (TDT) and the filament-prick pain detection threshold (FPT) in healthy volunteers. METHODS: For practical purposes, classic Semmes-Weinstein monofilaments with 20 different diameters were cut to half their length (ie, 19 mm) and the bending forces were measured. Eighteen men and 18 women (age range, 20 to 33 y) were recruited to evaluate the reliability and reproducibility of measurements using half-cut monofilaments. The TDT and the FPT were measured on the labial maxillary gingiva, on the palatal maxillary gingiva, and at the anterior tip of the tongue, using a double random staircase method. RESULTS: According to the forces needed to bend the half-cut filaments, they were renumbered from 2.55 to 6.86. There were significant differences of bending force between the half-cut and original monofilaments (P<0.001), Using half-cut filaments, the following differences could be detected; the labial maxillary gingiva had a significantly higher TDT threshold compared with the other test sites (P<0.001). By contrast, the palatal posterior maxillary gingiva had a significantly higher FPT threshold compared with the other test sites (P<0.001). DISCUSSIONS: The present study illustrated that in healthy participants, half-cut Semmes-Weinstein monofilaments reliably and easily assess TDT and FPT intraorally. A combined examination of sensory and pain thresholds using these filaments contributes to the clinical examination for orofacial pain.

The association between experimental and clinical pain measures among persons with fibromyalgia and chronic fatigue syndrome.

Evoked or experimental pain is often used as a model for the study of clinical pain, yet there are little data regarding the relationship between the two. In addition, there are few data regarding the types of stimuli and stimulus intensities that are most closely related to clinical pain. In this study, 36 subjects with fibromyalgia (FM), chronic fatigue syndrome (CFS), or both syndromes were administered measures of clinical pain and underwent a dolorimetry evaluation. Subjects also underwent experimental pain testing utilizing heat and pressure stimulation. Stimulation levels evoking low, moderate and high sensory intensity, and comparable levels of unpleasantness, were determined for both types of stimuli using random staircase methods. Clinical pain was assessed using visual analogue ratings and the short form of the McGill Pain Questionnaire (MPQ). Ratings of heat pain sensation were not significantly associated with clinical pain ratings, with the exception of unpleasantness ratings at high stimulus intensities. Pain threshold and tolerance as assessed by dolorimetry were significantly associated with average measures of clinical pain. Both intensity and unpleasantness ratings of pressure delivered using random staircase methods were significantly associated with clinical pain at low, moderate and high levels, and the strength of the association was greater at increasingly noxious stimulus intensities. These findings suggest that random pressure stimulation as an experimental pain model in these populations more closely reflects the clinical pain for these conditions. These findings merit consideration when designing experimental studies of clinical pain associated with FM and CFS.

Effect of test order on sensitivity in vulvodynia.

OBJECTIVE: To assess the effect of order of sensitivity testing at the vulva and thumb on the sensitivity determined at the second site tested among women with and without vulvodynia. STUDY DESIGN: We evaluated the stability of sensitivity measurements to pressure at the vulva and thumb when the order of testing was randomized to vulva first vs. thumb first; we repeated testing 1 week later in the opposite order. RESULTS: Stability of results over time and the influence of the order of testing were determined among 13 women with vulvodynia and 20 asymptomatic control women. We found a strong correlation between results compared between the first and second visits as well as no order effect. CONCLUSION: The order of testing at vulvar and peripheral sites has little impact on the results of pressure-responsive sensitivity testing among women with and without vulvodynia.