Performance Characteristics of Novel Instruments for Mucosal and Pelvic Muscle Pain Sensitivity Assessment

Background: Despite considerable advances in our understanding of mechanisms operative in persistent pain states, little is known about the pathophysiology of chronic pain in gynecology. Advances in the field have been critically impaired by lack of methodology and conceptual models to investigate the joint and independent contribution of pelvic muscle and mucosa to persistent pain. Using provoked vestibulodynia (PVD) as our model, we set to develop novel instruments for assessing mucosal and muscle pain sensitivity. PVD is a clinical diagnosis rendered after excluding other conditions and is diagnosed when genital palpation of vulvar mucosa with a cotton swab is painful. PVD is a heterogeneous diagnosis. Other conditions associated with PVD, such as myofasical dysfunction (i.e., difficulty with muscle relaxation and pain), psychological distress (i.e., anxiety and somatization), and nongenital somatic pain in response to thermal and mechanical stimuli, are thought to be secondary to a persistent pain state. PVD is clinically subdivided into two subgroups (primary and secondary) based on onset of pain. Primary VVS is defined when the onset of pain was with the first act of intercourse or tampon use. Secondary VVS is characterized by a pain free interval prior to the onset of pain. We hypothesized that the experience of pain in the primary subgroup of women with PVD may be driven by pelvic muscle (akin to orofacial pain), with the mucosa acting as a referral site

Tactile motion lacks momentum

The displacement of the final position of a moving object in the direction of the observed motion path, i.e. an overestimation, is known as representational momentum. It has been described both in the visual and the auditory domain, and is suggested to be modality-independent. Here, we tested whether a representational momentum can also be demonstrated in the somatosensory domain. While the cognitive literature on representational momentum suggests that it can, previous work on the psychophysics of tactile motion perception would rather predict an underestimation of the perceived endpoint of a tactile stimulus. Tactile motion stimuli were applied on the left and the right dorsal forearms of 32 healthy participants, who were asked to indicate the subjectively perceived endpoint of the stimulation. Velocity, length and direction of the trajectory were varied. Contrary to the prediction based on the representational momentum literature, participants in our experiment significantly displaced the endpoint against the direction of movement (underestimation). The results are thus compatible with previous psychophysical findings on the perception of tactile motion. Further studies combining paradigms from classical psychophysics and cognitive psychology will be needed to resolve the apparently paradoxical predictions by the two literatures

Temporomandibular Disorder Modifies Cortical Response to Tactile Stimulation

Individuals with temporomandibular disorder (TMD) suffer from persistent facial pain and exhibit abnormal sensitivity to tactile stimulation. To better understand the pathophysiological mechanisms underlying TMD, we investigated cortical correlates of this abnormal sensitivity to touch. Using functional magnetic resonance imaging (fMRI), we recorded cortical responses evoked by low frequency vibration of the index finger in subjects with TMD and in healthy controls (HC). Distinct subregions of contralateral SI, SII, and insular cortex responded maximally for each group. Although the stimulus was inaudible, primary auditory cortex was activated in TMDs. TMDs also showed greater activation bilaterally in anterior cingulate cortex and contralaterally in the amygdala. Differences between TMDs and HCs in responses evoked by innocuous vibrotactile stimulation within SI, SII, and the insula paralleled previously reported differences in responses evoked by noxious and innocuous stimulation, respectively, in healthy individuals. This unexpected result may reflect a disruption of the normal balance between central resources dedicated to processing innocuous and noxious input, manifesting itself as increased readiness of the pain matrix for activation by even innocuous input. Activation of the amygdala in our TMD group could reflect the establishment of aversive associations with tactile stimulation due to the persistence of pain

Reliability and Reproducibility of Novel Methodology for Assessment of Pressure Pain Sensitivity in the Pelvic Region

Introduction: • Vestibulodynia, the most common type of chronic vulvovaginal pain, affects nearly 1 in 10 women at some point in their lifetime1 • Current clinical diagnostic criteria for vestibulodynia dates back to Friedrich’s case series of 86 patients published in 19872 which include 1) entry dyspareunia (painful intercourse), 2) tenderness to pressure within the vestibule, and 3) physical findings limited to erythema without other obvious pathology2 • Fredrich’s criteria is limited to evaluation of the vulvar vestibuleunlike mucosa, the spectrum of normal and abnormal tenderness in the pelvic floor and its constituent muscles (e.g. puborectalis muscle) has not been described • Although the body of literature on vestibulodynia has expanded, no revised criteria including beyond Friedrich’s initial description to include pelvic floor dysfunction have been formulated • Our hypothesis is that vestibulodynia is a heterogeneous disorder and that mucosal and muscle pain sensitivities can be used to identify distinct subgroups of patients • The purpose of this study was three fold: 1) to develop instrumentation and methodology for the objective assessment of vulvar mucosal and pelvic muscle sensitivities, 2) to establish a standardized clinical approach for assessing pain sensitivity in vulvar mucosa and pelvic musculature, and 3) to relate these measures to patients’ clinical pain report

Tactile Perception in Adults with Autism: a Multidimensional Psychophysical Study

Although sensory problems, including unusual tactile sensitivity, are heavily associated with autism, there is a dearth of rigorous psychophysical research. We compared tactile sensation in adults with autism to controls on the palm and forearm, the latter innervated by low-threshold unmyelinated afferents subserving a social/affiliative submodality of somatosensation. At both sites, the groups displayed similar thresholds for detecting light touch and innocuous sensations of warmth and cool, and provided similar hedonic ratings of the pleasantness of textures. In contrast, increased sensitivity to vibration was seen in the autism group on the forearm, along with increased sensitivity to thermal pain at both sites. These findings suggest normal perception along with certain areas of enhanced perception in autism, consistent with previous studies

Perceptual and Neural Response to Affective Tactile Texture Stimulation in Adults with Autism Spectrum Disorders

Autism spectrum disorders (ASD) are associated with differences in sensory sensitivity and affective response to sensory stimuli, the neural basis of which is still largely unknown. We used psychophysics and functional magnetic resonance imaging (fMRI) to investigate responses to somatosensory stimulation with three textured surfaces that spanned a range of roughness and pleasantness in a sample of adults with ASD and a control group. While psychophysical ratings of roughness and pleasantness were largely similar across the two groups, the ASD group gave pleasant and unpleasant textures more extreme average ratings than did controls. In addition, their ratings for a neutral texture were more variable than controls, indicating they are less consistent in evaluating a stimulus that is affectively ambiguous. Changes in brain blood oxygenation level-dependent (BOLD) signal in response to stimulation with these textures differed substantially between the groups, with the ASD group exhibiting diminished responses compared to the control group, particularly for pleasant and neutral textures. For the most unpleasant texture, the ASD group exhibited greater BOLD response than controls in affective somatosensory processing areas such as the posterior cingulate cortex and the insula. The amplitude of response in the insula in response to the unpleasant texture was positively correlated with social impairment as measured by the Autism Diagnostic Interview-Revised (ADI-R). These results suggest that people with ASD tend to show diminished response to pleasant and neutral stimuli, and exaggerated limbic responses to unpleasant stimuli, which may contribute to diminished social reward associated with touch, perpetuating social withdrawal, and aberrant social development

Searching for stochastic gravitational waves using data from the two colocated LIGO Hanford detectors

Searches for a stochastic gravitational-wave background (SGWB) using terrestrial detectors typically involve cross-correlating data from pairs of detectors. The sensitivity of such cross-correlation analyses depends, among other things, on the separation between the two detectors: the smaller the separation, the better the sensitivity. Hence, a colocated detector pair is more sensitive to a gravitational-wave background than a noncolocated detector pair. However, colocated detectors are also expected to suffer from correlated noise from instrumental and environmental effects that could contaminate the measurement of the background. Hence, methods to identify and mitigate the effects of correlated noise are necessary to achieve the potential increase in sensitivity of colocated detectors. Here we report on the first SGWB analysis using the two LIGO Hanford detectors and address the complications arising from correlated environmental noise. We apply correlated noise identification and mitigation techniques to data taken by the two LIGO Hanford detectors, H1 and H2, during LIGO’s fifth science run. At low frequencies, 40–460 Hz, we are unable to sufficiently mitigate the correlated noise to a level where we may confidently measure or bound the stochastic gravitational-wave signal. However, at high frequencies, 460–1000 Hz, these techniques are sufficient to set a 95% confidence level upper limit on the gravitational-wave energy density of Ω(f) < 7.7 × 10[superscript -4](f/900  Hz)[superscript 3], which improves on the previous upper limit by a factor of ~180. In doing so, we demonstrate techniques that will be useful for future searches using advanced detectors, where correlated noise (e.g., from global magnetic fields) may affect even widely separated detectors.National Science Foundation (U.S.)United States. National Aeronautics and Space AdministrationCarnegie TrustDavid & Lucile Packard FoundationAlfred P. Sloan Foundatio

A directed search for gravitational waves from Scorpius X-1 with initial LIGO

19 pages, 8 figuresInternational audienceWe present results of a search for continuously-emitted gravitational radiation, directed at the brightest low-mass X-ray binary, Scorpius X-1. Our semi-coherent analysis covers 10 days of LIGO S5 data ranging from 50-550 Hz, and performs an incoherent sum of coherent $\mathcal{F}$-statistic power distributed amongst frequency-modulated orbital sidebands. All candidates not removed at the veto stage were found to be consistent with noise at a 1% false alarm rate. We present Bayesian 95% confidence upper limits on gravitational-wave strain amplitude using two different prior distributions: a standard one, with no a priori assumptions about the orientation of Scorpius X-1; and an angle-restricted one, using a prior derived from electromagnetic observations. Median strain upper limits of 1.3e-24 and 8e-25 are reported at 150 Hz for the standard and angle-restricted searches respectively. This proof of principle analysis was limited to a short observation time by unknown effects of accretion on the intrinsic spin frequency of the neutron star, but improves upon previous upper limits by factors of ~1.4 for the standard, and 2.3 for the angle-restricted search at the sensitive region of the detector

Tactile motion lacks momentum

The displacement of the final position of a moving object in the direction of the observed motion path, i.e. an overestimation, is known as representational momentum. It has been described both in the visual and the auditory domain, and is suggested to be modality-independent. Here, we tested whether a representational momentum can also be demonstrated in the somatosensory domain. While the cognitive literature on representational momentum suggests that it can, previous work on the psychophysics of tactile motion perception would rather predict an underestimation of the perceived endpoint of a tactile stimulus. Tactile motion stimuli were applied on the left and the right dorsal forearms of 32 healthy participants, who were asked to indicate the subjectively perceived endpoint of the stimulation. Velocity, length and direction of the trajectory were varied. Contrary to the prediction based on the representational momentum literature, participants in our experiment significantly displaced the endpoint against the direction of movement (underestimation). The results are thus compatible with previous psychophysical findings on the perception of tactile motion. Further studies combining paradigms from classical psychophysics and cognitive psychology will be needed to resolve the apparently paradoxical predictions by the two literatures

Emulsion filled polysaccharide gels: Filler particle effects on material properties, oral processing, and sensory texture

Addition of filler particles is a common approach to alter food structure and thereby change sensory properties. The goal of this investigation was to determine how filler particles alter oral processing patterns and sensory texture perception of two model food gels with distinct mechanical properties. Agar gels (brittle) and kappa-carrageenan-locust bean gum gels (ductile) were formulated to have similar strength (fracture stress) but different deformability (fracture strain). Increasing the phase volume of oil droplets decreased fracture stress and stress intensity factor of both filled gels, while the main effect on fracture strain and fracture surface energy was observed for the highly deformable kappa-carrageenan-locust bean. Adding oil had general effects of decreasing sensory hardness and particle size and increasing the rate of breakdown. Furthermore, agar gel texture was more sensitive to adding oil, with changes observed in several textural properties of agar gels with no corresponding change in kappa-carrageenan-locust bean gels. Adding oil did not change the oral processing pattern based on distance and velocity of jaw movement, along with temporal aspects of each chewing cycle. However, jaw velocity and movement were adjusted for differences in gel type. kappa-carrageenan-locust bean gels generally required more muscle activity to prepare for swallowing, and increasing oil content decreased overall muscle activity for both gels. These results imply that gel structure, rather than the amount of oil filler, determined the oral processing pattern