OBJECTIVES: The present study aims to collect data on the pain and sensory perception of both male and female healthy individuals. Although the overarching project has been testing female controls for longer, males have been added to the protocol with the goal of expanding our understanding pain norms. This study compares pain and sensation perception between genders and looks at psychosocial factors that may cause differences between the two populations. METHODS: The protocol for this study is divided into quantitative sensory testing (QST) and questionnaires. QST is a non-invasive procedure that is used to study somatosensory functioning in individuals. This study specifically utilizes a QST battery to understand sensation and pain caused by mechanical and thermal stimuli. The deltoid and hand are used as control regions and the abdomen is the experimental area. Additionally, the Health Screening Form, Pain Rating Questionnaire, Pain Sensitivity Questionnaire, Pain Catastrophizing Scale questionnaire, and 36-item Short Form Survey Instrument are all used to gather information on participants’ medical history, mental status, and other psychosocial factors that may affect pain and sensory processing. Data collected from this protocol is then analyzed on SPSS through descriptive statistics and one-way analyses of variance. RESULTS: Throughout the protocol, there are only three values that are significantly different between the male and female control populations: the thermal sensory threshold of cold on the hand, thermal sensory threshold for heat on the hand, and pressure pain threshold on the hand. The p-values for these are 0.001, 0.013, and 0.044 respectively. Additionally, the abdomen is slightly more sensitive than the control site for certain QST measures like the pain threshold for cold temperatures. CONCLUSIONS: The lack of significant variance between genders for the majority of data points shows that both male and female healthy control perceive pain and sensation similarly. Although there may be some differences in anatomy and development, there are no distinct differences in the overall experience of these phenomena. Although these results suggest that gender does not play a significant role in pain and sensory perception, it is important to continue expanding the database in order to find more conclusive results. / 2021-06-14T00:00:00Z

This thesis presents the design and validation of a wireless interface for a vulvar quantitative sensory testing device (v-QueST). The wireless interface works in tandem with an Android application which allows a patient to indicate when their pressure pain threshold has been reached via an on-screen button. Using the fully assembled prototype, the sampling frequency and response time of the wireless interface was validated. The results indicated that the sampling frequency was sufficient to meet the desired specifications, and the time delay between the tap of the on-screen button and the reading of the force measurement was negligible. However, inspection of the force time-series acquired from the v-QueST device through Bluetooth transmission revealed systematic error. Implementation of a new signal conditioner is recommended before using the v-QueST device for research or clinical applications to objectively measure vulvar pain sensitivity.

No description available.

Stress can have influence on pain sensitivity, but the direction of its effects remains unclear. Previous research has reported both increased and decreased pain sensitivities under stress with different sensory tasks. The aim of the current study was to investigate the effect of stress on pain sensitivity using multiple psychological stressors in a relatively large sample of young men and women. Sixty-two participants were included, and pain thresholds, tolerance, and temporal summation were tested using thermal, mechanical, and dynamic tasks before and after stress. A condition of stress was induced by the Stroop task and a mental arithmetic task. On average, there were no significant differences between stress and no stress conditions. Although not significant, pressure thresholds and tolerance had a tendency to decrease under stress conditions, and thermal thresholds and tolerance had a tendency to increase under stress conditions. Temporal summation did not change regardless of condition. These findings suggest that individual differences in response to stress and type of task being completed may play a role in how stress affects pain sensitivity. / 2021-06-17T00:00:00Z

Provoked Vestibulodynia (PVD) is the most common form of chronic vulvar pain, affecting 12% of women in the general population. PVD is characterized by a severe burning pain in response to pressure localized to the vaginal entrance. Research examining the pain component of PVD indicates that it has much in common with other chronic pain conditions. Increased pain sensitivity has been demonstrated in other chronic pain conditions to be due in part to impairment in centrally acting endogenous pain modulation systems, such as Diffuse Noxious Inhibitory Control (DNIC). DNIC is triggered by the simultaneous application of two painful stimuli, with pain at one body site inhibiting pain at another body site. Because DNIC consists of a feedback loop that involves the spinal cord and the brain, it is thought to be dependent upon both sensory and affective pain components. In the current study, 20 women with PVD and 24 controls underwent sensory testing to determine the integrity of DNIC function. Unexpectedly, women with PVD displayed a DNIC response of greater magnitude than controls. Participants also completed measures to assess the interplay between group, DNIC, and psychosocial functioning. Women with PVD experienced decreases in psychosocial functioning; however, this reduction was not found to mediate the relationship between group and DNIC function. Findings of intact DNIC function in women with PVD do not imply that PVD is not a chronic pain condition. DNIC is a complex and dynamic process and warrants further study using different stimuli and paradigms. This study supports previous literature, while adding to the development of a greater understanding of the interaction between psychophysical and psychosocial components of chronic pain, which will allow for the creation of better assessment and treatment strategies. / Thesis (Master, Psychology) -- Queen's University, 2007-09-14 00:14:17.698

Neuropathic pain (NP) after spinal cord injury (SCI) can significantly and negatively affect a person’s quality of life and is often refractory to currently available treatments. In order to advance the field and find effective therapeutic avenues; signs, symptoms, and biomarkers in humans should be identified and related to specific pain-generating mechanisms. The present work utilizes quantitative sensory testing (QST) and magnetic resonance spectroscopy (MRS) to evaluate the relationship between the functional integrity of the dorsal column-medial lemniscus pathway (DCML), the spinothalamic tract (STT), and metabolic markers of neuronal loss and glial activation in the thalamus of persons with/without NP after SCI. This work was based on the hypothesis that the presence/severity of NP after SCI is dependent both on function of ascending somatosensory pathways and changes in neuronal and glial markers in the thalamus. The results indicate that NP is associated with a decreased afferent DCML input to the thalamus resulting in a loss of inhibitory neurons and that residual function from STT afferents may contribute to thalamic glial activation and NP. Based on this work, in combination with previous studies in animals and humans, it can be proposed that NP after SCI partly results from the combination of residual STT function and loss of neuronal inhibition leading to neuronal hyperexcitability in the spinal cord and the thalamus. Thus, the presence of NP in chronic SCI is dependent on several underlying mechanisms which may be measured in human subjects with methods such as QST and MRS. Clinical implications and recommendations for further research are enclosed.

Background: Knee pain is a common musculoskeletal complaint with an estimated annual population prevalence of 25% in people aged over 55 years. There are many causes of knee pain though osteoarthritis (OA) is one of the most frequent. Not all people with OA, however, have knee pain. There is discordance between pain intensity and disease severity, the reason for which is unknown. Variation in pain sensitivity may be one possible explanation. Quantitative sensory testing (QST) is a non-invasive technique using non-painful and painful stimuli to assess altered sensitivities in the skin and muscle. Little is known, however, about pain sensitivity in people with knee pain and the role of psychosocial factors in relation to pain sensitivity and pain intensity. Intra-articular steroids are a widely used and effective therapy for knee OA though response to treatment varies in both magnitude and duration of response. Pain sensitivity and/or psychosocial factors may explain some of the variation observed in response to treatment. Aims: To determine whether (i) greater sensitivity to stimuli is associated with higher levels of pain intensity in a population-based sample with knee pain, and whether those associations are mediated by psychosocial factors, (ii) there are changes in QST following intra-articular steroid injections in patients with symptomatic knee OA, and (iii) whether psychosocial factors and sensitivity to stimuli at baseline predict change in pain following intervention. Methods: 72 men and women with knee pain were recruited from a population-based cohort. All had QST assessments and completed a range of questionnaire instruments addressing pain intensity and psychosocial factors. QST assessments (including thermal, mechanical, vibration and pressure) were made at the most affected knee and contralateral forearm. Assessments of tender point count, wind-up ratio and diffuse noxious inhibitory control were also performed. Structural equation modelling was used to determine whether associations between QST measures and pain intensity were mediated by a latent psychosocial factor. In a separate open label trial of intra-articular steroid injections, 32 men and women with symptomatic knee OA underwent QST assessments and also completed questionnaires. The assessments were performed at both knees at the baseline visit (prior to injection) and at a post-injection visit 5-15 days later. Changes in QST were assessed using Wilcoxon matched pairs signed-rank with linear regression used to determine baseline QST predictors of change in pain. Results: In the observational study, mechanical hyperalgesia (tender point count, mechanical pain sensitivity, and allodynia), illness perceptions, catastrophizing and disability scores were positively associated with higher levels of pain intensity. Mediation analyses revealed stronger associations for the indirect effect including a latent psychosocial mediator between measures of mechanical hyperalgesia and global pain, and stronger associations for the direct effect between measures of mechanical hyperalgesia and knee pain. In the intervention study no changes in QST were observed between visits. However, lower baseline mechanical pain thresholds at the injected knee and illness perceptions predicted response to treatment. Conclusion: Illness perceptions and mechanical hyperalgesia can be used to identify subjects experiencing higher levels of global and knee pain intensity, and those who were more likely to respond to intra-articular steroid therapy. Changes in knee pain following intervention with steroid injection are not explained by changes in pain sensitivity.

Malnutrition remains a persistent and increasing problem in Sub-Saharan Africa (SSA). Food production has not kept pace with population growth, and many people have poor access to adequate, nutritious diet. In many areas of the developing world, maize is a vital staple and a main source of dietary protein. In Eastern and Southern Africa, maize is the basic food for the subsistence farmers. Per capita consumption of maize in Malawi, Zambia and Zimbabwe is 100 kg per year, while in Tanzania, per capita consumption is estimated at 73 kg per year. Unfortunately, the nutritional value of conventional maize is poor, partly due to the low biological value of its protein. To ensure sufficient protein intake, conventional maize should therefore be consumed with complementary protein sources, such as legumes or animal proteins. The complementary proteins sources however, tend to be expensive, or take a lot of time and fuel to cook, for instance beans. The main aim of this study was to evaluate the sensory characteristics and consumer acceptance of quality protein maize (QPM) in rural Tanzania. QPM is a maize cultivar which has almost double the amount of tryptophan and lysine. QPM has been adopted in several countries of SSA, but very few studies have been undertaken on its acceptance by consumers. In Tanzania, no study has been undertaken to elicit consumers‟ acceptability for this maize variety. The sensory characteristics of food products affect consumers‟ immediate consumption gratification. This study makes a unique contribution to the literature by exploring the roles that sensory evaluation and nutritional information play in shaping consumers‟ QPM flour purchasing behaviour through economic experiments in rural Tanzania. A triangle test was undertaken to find out whether there is a difference between QPM and conventional maize. Additionally, a rural household survey was undertaken which collected consumers‟ demographic, farming and individual characteristics. This was done using structured questionnaires administered by trained enumerators. Moreover, modified home use sensory testing and central location sensory testing were also undertaken to determine sensory characteristics of QPM and conventional maize. Stiff porridge, a major maize product in East and South Africa, was used to undertake this experiment. Finally, acceptability of QPM was tested using experimental auctions with the Becker-DeGroot-Marschak (BDM) procedure, and maize flour was used to undertake this experiment. The sensory evaluation findings of the study indicated that consumer characteristics of QPM stiff porridge were highly appreciated than those of conventional maize stiff porridge. This was observed both in the modified home use testing and central location testing. Likewise, consumers were willing to pay more for QPM than for conventional maize in all evaluation criteria used. Triangle test showed a significant difference between QPM and conventional maize. Sensory evaluation however needs to be repeated with other QPM varieties to ensure that it is not only a specific QPM variety that has favourable consumer characteristics. This study further revealed that providing QPM nutritional information to consumers increases their willingness to pay for QPM. Subjects who were provided with QPM nutritional information had higher WTP for QPM than those who were not. This shows that creating awareness of the nutritional contents, especially of the new varieties, would increase the appreciation by consumers hence help in fighting malnutrition in SSA. Providing QPM nutritional information, on the other hand, decreased consumers‟ WTP for conventional maize. This was unexpected because the information provided only concerned QPM. The study recommends that another study be carried out to find out the cause of decrease in WTP for conventional maize when QPM nutritional information is provided. This study clearly reveals that QPM is acceptable by rural consumers in Tanzania. This information can help policy makers in Africa to better understand consumers' food behaviour and make initiatives to improve diet and health, which can be important in reducing malnutrition in Sub Saharan Africa. / Dissertation (MSc(Agric))--University of Pretoria, 2011. / Agricultural Economics, Extension and Rural Development / unrestricted

Background: Chronic pain is pain which has lasted for more than 3 months and is reported by 40 to 50% of adults in developed countries. The prevalence of chronic pain is consistently higher in women than in men. Chronic pain is more often reported by older adults than younger adults. As well as duration, pain can also be described in terms of its “widespreadness” by counting the number of body areas experiencing pain, or by the source of the pain e.g. musculoskeletal. Many social, psychological, physiological and behavioural factors have been found to be associated with pain. Altered sensitivity to stimuli may indicate aberrant pain processing mechanisms. Quantitative sensory testing (QST) evaluates responses to experimental, painful and non-painful stimuli. Although originally used in neurological conditions, QST data for people with musculoskeletal pain show differences from healthy controls. Aim: The aim of this study was to determine the relationship between sensitivity to stimuli (measured by QST), and both the number of body areas with pain and the prevalence of chronic widespread pain, and how these relationships vary with age and sex. Methods: A postal questionnaire which included questions about pain location and duration of pain, as well as known risk factors for pain, was returned by 2623 participants aged 34-101 years. A sub-group of 290 participants aged 34-97 years were selected on the basis of their responses to the pain questions and undertook a physical assessment which included QST. Regression models were used to quantify the relationships between QST factors and pain. Pain was classified as a continuum of “widespreadness” (0-29) and as “no pain”, “chronic widespread pain (CWP)” and “some pain” (i.e. pain other than CWP). Regression models with interaction terms were used to investigate whether these relationships varied between older (aged over 65 years) and younger (aged 65 years and younger) people, and between men and women. Results: There were very few differences in QST variables (except tender point count) across the two pain classifications, however, differences in several QST variables were found between the age and sex groups (Chapter 6). Three of the QST measures, tender point count, cool detection threshold at the foot and thermal sensory limen at the foot, were statistically significantly related to number of painful areas, and tender point count and cool detection threshold at the foot were also significantly different among participants with “no pain” and those with CWP (Chapter 7). None of these relationships were significantly moderated by age or sex (Chapter 8). Sleep quality and beliefs about pain duration were found to be statistically significantly related to number of pain areas and to the presence of CWP in all the analyses (Chapter 7). Conclusion: The findings from this study indicate that some QST variables are related to pain, but none of the relationships are moderated by age or sex. The importance of sleep quality and pain beliefs as risk factors for pain has been further confirmed. Further research may allow treatments for pain to be tailored to the individual in the light of these facts.

Quantitative sensory testing (QST) is a useful tool in evaluating patients with neuropathic pain. In light of the COVID-19 pandemic and taking into consideration the transportation barriers that many chronic pain patients face, there is an increasing need for a valid QST protocol that can be completed at home. This study sought to establish and validate an at-home QST protocol for the evaluation of patients with neuropathic pain. A sample of 18 patients with neuropathic pain who had previously completed the validated bedside QST protocol completed the at-home QST assessment and a series of questionnaires. Bivariate correlations between in person and at home QST measures were assessed using Pearson correlations, and Spearman's rho was applied when variables showed non-normal distributions. Results found that comparable at home QST protocols included punctate hyperalgesia, cold allodynia, cold hyperalgesia, and the cold pain tolerance-time measure. At home tests that did not show strong correlations with previously established beside QST included static mechanical allodynia, dynamic mechanical allodynia, temporal summation of mechanical pain, and the cold pain tolerance- pain rating. This research will be instrumental in testing less mobile participants or those who cannot come to a laboratory site for traditional QST testing and future sensory phenotyping of patients that will move the field toward a more individualized medicine approach. / 2024-01-28T00:00:00Z