Multicenter assessment of quantitative sensory testing (QST) for the detection of neuropathic-like pain responses using the topical capsaicin model

Background: The use of quantitative sensory testing (QST) in multicenter studies has been quite limited, due in part to lack of standardized procedures among centers. Aim: The aim of this study was to assess the application of the capsaicin pain model as a surrogate experimental human model of neuropathic pain in different centers and verify the variation in reports of QST measures across centers. Methods: A multicenter study conducted by the Quebec Pain Research Network in six laboratories allowed the evaluation of nine QST parameters in 60 healthy subjects treated with topical capsaicin to model unilateral pain and allodynia. The same measurements (without capsaicin) were taken in 20 patients with chronic neuropathic pain recruited from an independent pain clinic. Results: Results revealed that six parameters detected a significant difference between the capsaicin-treated and the control skin areas: (1) cold detection threshold (CDT) and (2) cold pain threshold (CPT) are lower on the capsaicin-treated side, indicating a decreased in cold sensitivity; (3) heat pain threshold (HPT) was lower on the capsaicin-treated side in healthy subjects, suggesting an increased heat pain sensitivity; (4) dynamic mechanical allodynia (DMA); (5) mechanical pain after two stimulations (MPS2); and (6) mechanical pain summation after ten stimulations (MPS10), are increased on the capsaicin-treated side, suggesting an increased in mechanical pain (P < 0.002). CDT, CPT and HPT showed comparable effects across all six centers, with CPT and HPT demonstrating the best sensitivity. Data from the patients showed significant difference between affected and unaffected body side but only with CDT. Conclusion: These results provide further support for the application of QST in multicenter studies examining normal and pathological pain responses

Complex interaction of sensory and motor signs and symptoms in chronic CRPS.

Spontaneous pain, hyperalgesia as well as sensory abnormalities, autonomic, trophic, and motor disturbances are key features of Complex Regional Pain Syndrome (CRPS). This study was conceived to comprehensively characterize the interaction of these symptoms in 118 patients with chronic upper limb CRPS (duration of disease: 43±23 months). Disease-related stress, depression, and the degree of accompanying motor disability were likewise assessed. Stress and depression were measured by Posttraumatic Stress Symptoms Score and Center for Epidemiological Studies Depression Test. Motor disability of the affected hand was determined by Sequential Occupational Dexterity Assessment and Michigan Hand Questionnaire. Sensory changes were assessed by Quantitative Sensory Testing according to the standards of the German Research Network on Neuropathic Pain. Almost two-thirds of all patients exhibited spontaneous pain at rest. Hand force as well as hand motor function were found to be substantially impaired. Results of Quantitative Sensory Testing revealed a distinct pattern of generalized bilateral sensory loss and hyperalgesia, most prominently to blunt pressure. Patients reported substantial motor complaints confirmed by the objective motor disability testings. Interestingly, patients displayed clinically relevant levels of stress and depression. We conclude that chronic CRPS is characterized by a combination of ongoing pain, pain-related disability, stress and depression, potentially triggered by peripheral nerve/tissue damage and ensuing sensory loss. In order to consolidate the different dimensions of disturbances in chronic CRPS, we developed a model based on interaction analysis suggesting a complex hierarchical interaction of peripheral (injury/sensory loss) and central factors (pain/disability/stress/depression) predicting motor dysfunction and hyperalgesia

The relationship between video display terminals (VDTs) usage and dermatologic manifestations : a cross sectional study

BACKGROUND: Recently, it has been observed that Video Display Terminals (VDTs) usage for long periods can cause some dermatological manifestations on the face. An analytical cross-sectional study was designed in order to determine this relationship. METHODS: In this study, 600 office workers were chosen randomly from an organization in Tehran (Iran). The subjects were then divided into two groups based on their exposure to VDTs. 306 workers were considered exposure negative (non VDT user) who worked less than 7 hours a week with VDTs. The remainders 294 were exposure-positive, who worked 7 hours or more with VDTs. The frequency of dermatologic manifestations was compared in these two groups. RESULTS: In the exposure-positive and exposure-negative groups, the frequency of these dermatologic manifestations were 27 and 5 respectively. After statistical analysis, a P.value of < 0.05 was obtained indicating a statistically significant difference between these two groups for dermatological manifestations. CONCLUSION: According to our study, there is a relationship between dermatologic manifestations on the face and exposure to VDTs

Relating Sick Building Symptoms to Environmental Conditions and Worker Characteristics

40 pages, 1 article*Relating Sick Building Symptoms to Environmental Conditions and Worker Characteristics* (Ohman, Pamela A.; Eberly, L. E.) 40 page

Review of the scientific evidence on the individual sensitivity to electromagnetic fields (EHS)

Publisher Copyright: © 2021 Dariusz Leszczynski, published by De Gruyter, Berlin/Boston 2021.Part of the population considers themselves as sensitive to the man-made electromagnetic radiation (EMF) emitted by powerlines, electric wiring, electric home appliance and the wireless communication devices and networks. Sensitivity is characterized by a broad variety of non-specific symptoms that the sensitive people claim to experience when exposed to EMF. While the experienced symptoms are currently considered as a real life impairment, the factor causing these symptoms remains unclear. So far, scientists were unable to find causality link between symptoms experienced by sensitive persons and the exposures to EMF. However, as presented in this review, the executed to-date scientific studies, examining sensitivity to EMF, are of poor quality to find the link between EMF exposures and sensitivity symptoms of some people. It is logical to consider that the sensitivity to EMF exists but the scientific methodology used to find it is of insufficient quality. It is time to drop out psychology driven provocation studies that ask about feelings-based non-specific symptoms experienced by volunteers under EMF exposure. Such research approach produces only subjective and therefore highly unreliable data that is insufficient to prove, or to disprove, causality link between EHS and EMF. There is a need for a new direction in studying sensitivity to EMF. The basis for it is the notion of a commonly known phenomenon of individual sensitivity, where individuals' responses to EMF depend on the genetic and epigenetic properties of the individual. It is proposed here that new studies, combining provocation approach, where volunteers are exposed to EMF, and high-throughput technologies of transcriptomics and proteomics are used to generate objective data, detecting molecular level biochemical responses of human body to EMF.Peer reviewe

Deoxy-sphingolipids, oxidative stress, and vitamin C correlate with qualitative and quantitative patterns of small fiber dysfunction and degeneration

Defined by dysfunction or degeneration of Aδ and C fibers, small fiber neuropathies (SFNs) entail a relevant health burden. In 50% of cases, the underlying cause cannot be identified or treated. In 100 individuals (70% female individuals; mean age: 44.8 years) with an idiopathic, skin biopsy-confirmed SFN, we characterized the symptomatic spectrum and measured markers of oxidative stress (vitamin C, selenium, and glutathione) and inflammation (transforming growth factor beta, tumor necrosis factor alpha), as well as neurotoxic 1-deoxy-sphingolipids. Neuropathic pain was the most abundant symptom (95%) and cause of daily life impairment (72%). Despite the common use of pain killers (64%), the painDETECT questionnaire revealed scores above 13 points in 80% of patients. In the quantitative sensory testing (QST), a dysfunction of Aδ fibers was observed in 70% and of C fibers in 44%, affecting the face, hands, or feet. Despite normal nerve conduction studies, QST revealed Aβ fiber involvement in 46% of patients' test areas. Despite absence of diabetes mellitus or mutations in SPTLC1 or SPTLC2 , plasma 1-deoxy-sphingolipids were significantly higher in the sensory loss patient cluster when compared with those in patients with thermal hyperalgesia ( P 25 kg/m 2 ), or hyperlipidemia showed significantly lower L-serine (arterial hypertension: P < 0.01) and higher 1-deoxy-sphingolipid levels (arterial hypertension: P < 0.001, overweight: P < 0.001, hyperlipidemia: P < 0.01). Lower vitamin C levels correlated with functional Aβ involvement ( P < 0.05). Reduced glutathione was lower in patients with Aδ dysfunction ( P < 0.05). Idiopathic SFNs are heterogeneous. As a new pathomechanism, plasma 1-deoxy-sphingolipids might link the metabolic syndrome with small fiber degeneration

Vitamin D toxicity – causes, symptoms and diagnosis

Abstract:&nbsp; Introduction and purpose: This review aims to analyze causes, symptoms and diagnosis of overdosing vitamin D resulting in vitamin D toxicity (VDT).&nbsp; Material and method: This paper was based on medical articles collected in Pubmed from&nbsp;2008 to 2021 year. The research has been done by looking through keywords such as “vitamin D” “toxicity”.&nbsp; Results: The review of studies showed that manifestation of VDT is mainly associated with hypercalcemia and its course can range from asymptomatic to life-threatening, including death. We also draw attention to inappropriate use and widespread of vitamin D products.&nbsp; Conclusion: There is a high demand for medical health workers to advise patients on possible effects of inappropriate use of vitamin D products and its toxicity. Medical practitioners should be attentive to quickly identify VDT.&nbsp

The Psychology of the Sick Building Syndrome

42 pages, 1 article*The Psychology of the Sick Building Syndrome* (Hedge, Alan; Erickson, William A.; Rubin, Gail) 42 page

Modeling of VDT Workstation System Risk Factors.

The objectives of this research were to determine the most important risk factors in VDT workstations associated with physical symptoms and to investigate the interrelationship among these risk factors. A conceptual model was first developed to describe the interrelationship among the basic components in a VDT workstation system and their possible health effects. A research model was then proposed to describe the hypothesized relationships among the following categories of variables: demographic, task, workstation design, work environment, psychosocial factors, work posture, psychological stress, musculoskeletal symptoms, visual symptoms, and general physical symptoms. A method which consisted of a questionnaire, measurement and posture analysis was then developed. A field study was conducted among daily computer users in a local industry. Ninety three VDT operators participated in the study. Factor analysis was applied to the physical symptoms to help identify the underlying factors. Multiple regression was used to determine the most important factors related to the physical symptoms and the effect of interactions among the risk factors. The four factors identified among physical symptoms are: ocular discomfort, general musculoskeletal symptoms, upper extremity symptoms, and other physical symptoms. Ocular discomfort is significantly related to screen glare; both general musculoskeletal symptoms and other physical symptoms are related to fatigue; and upper extremity symptoms are related to awkward upper body posture. Many interactions between the risk factors and their effects are identified, such as, psychosocial factors and demographic, and workstation factors and working posture. Psychosocial factors are found to interact with other variables and contribute to psychological stress. The implication of this research is that both physical and social environment need to be evaluated and the interactions among the components of a VDT workstation system need to be understood in order to determine physical symptom risk factors

Video display operator complaints: A 10-year follow-up of visual fatigue and refractive disorders

Visual fatigue and discomfort are very common complaints for video display operators (VDTs). The aim of our study was to study work-related visual symptoms in relation to refractive disorders and psychosocial factors in 3054 public employees by way of follow-ups for 10 years with periodic medical examinations with eye evaluation in the period 2000-2009. Factors related to visual fatigue were evaluated in the follow-up using generalized equation estimation. Visual fatigue was very common in VDT operators (64.03%). During the follow-up, no relationship between visual fatigue and age, sex, seniority of work, visual acuity and refractory disorders was found. Visual fatigue was significantly associated with anxiety perception in a dose-related matter (odds ratio (OR) 7.40, confidence interval (CI) 95% 1.77-31.3), psychosocial factors (OR 1.03, CI 95% 1.01-1.07), use of lenses (OR 1.34, CI 95% 1.09-1.64) and time of VDT usage (OR 1.27, CI 95% 1.04-1.53). This study confirmed that visual fatigue is common in VDT users and is related to anxiety perception, time of VDT usage, use of lenses and stress. No relationship was found between visual fatigue and refractory disorders or visual acuit