Pressure Dolorimeter Research Articles

Development of a Pain Measurement Device Using Electrical Stimulation and Pressure: A Pilot Study

Understanding and precise assessment of pain level are key factors in rehabilitation therapy. Pain is a complex and subjective experience that is affected by an individual’s emotion and health conditions. Various methods have been developed for quantitative evaluation of pain level; however, these methods have several drawbacks. In this work, we developed a pain measurement device for quantitative pain assessment. The system consists of two parts, a component for electrical stimulation and a pressure dolorimeter, for application of two different stresses. Regarding electrical stimulation, the degree of pain is assessed by the applied current. Skin resistance was also analyzed by applying current to remove the effects caused by skin conditions. The electrical stimulation did not induce any histological changes or inflammation in the tissues. Using the pressure dolorimeter, the pain level was assessed according to the degree of inflammation. This system could be used for the quantitative assessment of pain induced by inflammation, wounds, and other factors. Since the described system is the first of its kind, there are many problems that remain to be solved. However, with continuous development, our system could provide more accurate pain assessment by removing skin condition effects and through cross-validation.

Association of cardiorespiratory fitness with pressure pain sensitivity and clinical pain in women with fibromyalgia.

The aim of the present study was to assess the association of cardiorespiratory fitness (CRF) with pressure pain sensitivity and clinical pain in women with fibromyalgia (FM). Thirty-one women with FM were included in the study. Pressure pain sensitivity was assessed with an electronic pressure dolorimeter. The average pressure pain threshold (PPT) from the 18 FM-related tender points and the tender points count (TPC) were recorded. Clinical pain was assessed on a 10-cm visual analog scale (VAS; from the FM impact questionnaire). The patients performed an incremental treadmill test, which consisted in six increasing workloads. Gas exchange was continuously monitored, and peak oxygen uptake (as measure of CRF) was recorded. Pairwise correlation and multiple linear regression were used to examine the association of CRF with PPT and VAS, and binary logistic regression assessed the odds of having <18 positive tender points as a function of CRF. The correlations of CRF with the average PPT and VAS were 0.355, (P < 0.001) and 0.058 (P > 0.05), respectively. Regression analyses revealed that CRF was associated with the PPT (B = 0.093; 95 % CI 0.064-0.122; P < 0.001; R (2) = 0.306) and TPC (OR 1.51; 95 % CI 1.30-1.75; P < 0.001) but not with VAS (B = 0.068; 95 % CI -0.061-0.197; P > 0.05). The findings of this study suggest that CRF is associated with pressure pain sensitivity but not with clinical pain in women with FM. Further longitudinal and intervention studies are needed to determine whether CRF could be involved in some mechanisms of pain processing.

Influence of instrument assisted soft tissue treatment techniques on myofascial trigger points

The purpose of this study was to examine the influence of instrument assisted soft tissue techniques (IASTT) on myofascial trigger points (MTrP). Randomized, controlled study with the researcher assessing the MTrP sensitivity blinded to the treatment rendered. Phase 1 = 27; Phase 2 = 22. MTrPs were identified in the upper back. In phase 1, two MTrPs (right & left) were identified. One was treated with IASTT, the other was a control. In phase 2, one MTrP was identified in a treatment and a control group. In each phase, the treatment groups received six treatments of IASTT. Sensitivity threshold of the MTrP was assessed with a dolorimeter. There was a significant improvement in both groups over time but there was no difference between the treatment and control groups. The use of a pressure dolorimeter may have served as a form of ischemic compression treatment. This assessment tool may have been a mitigating factor in the over-shadowing any potential influence of the IASTT on the MTrP. Thus, another assessment tool needs to be identified for MTrP assessment. Until that technique is identified, the effect of IASTT on MTrPs in inconclusive.

The Relationship of Pressure-Pain Threshold with Alexithymia in Healthy Young Subjects

Objectives: Alexithymia is related to chronic pain with symptomatic patients, but the relationship between alexithymia and pain in healthy young subjects is unclear. Therefore, the aim of this study was to determine the relationship between pressure-pain threshold [PPT] and alexithymia in healthy young subjects.Methods: This study included young volunteers. Pressure-pain threshold was assessed using a pressure dolorimeter over the third fingertip, the biceps brachii muscle, and the pectoral muscle. The Toronto Alexithymia Scale [TAS-20] was used to assess alexithymic traits among the study subjects.Results: Total TAS-20 scores of 104 subjects [30 male, 74 female], aged 18–23, years was 45.3 [SD 7.9]. There was no significant correlation between mean the TAS-20 scores and PPT values. Three facets of TAS-20 [difficulty identifying feelings, difficulty communicating feelings, and externally oriented thinking] were not significantly correlated with PPT. The PPT values of subjects for the biceps brachii muscle, the third finger, and the pectoral muscle were numerically lower on the left side than on the right side, but only PPT of biceps brachii on the left side was significantly lower than the right side.Conclusion: We concluded that there was no correlation between alexithymia and PPT in young healthy subjects. There was no PPT asymmetry in the third finger or the pectoral muscle, whereas biceps brachii muscle revealed PPT asymmetry.

Evoked pain measures in fibromyalgia.

Fibromyalgia is defined by widespread pain and tenderness at a minimum of 11 of 18 defined tender points. Current evidence indicates that tender points are not unique to fibromyalgia and are simply regions in the body where all people are more tender. Tenderness (i.e. sensitivity to pressure) is widespread in fibromyalgia rather than being confined to tender points, and patients are also more sensitive to heat, cold and electrical stimulation. Using the number of painful tender points as a measure of tenderness is clinically expedient but is theoretically vulnerable to bias and is influenced by subjective distress. Other means of assessing tenderness (e.g. pressure dolorimeter devices, or more elaborate psychophysical methods) demonstrate the same increased pain sensitivity in fibromyalgia that is noted with tender point assessments, but these measures are relatively independent of biasing factors or distress. Fibromyalgia is one of only a few syndromes defined by the presence of both spontaneous (i.e. clinical) and evoked (i.e. experimental) pain. While the issues associated with the evaluation of spontaneous pain are shared with all chronic pain syndromes, the issues associated with the evaluation of evoked pain sensitivity are specific to fibromyalgia and related musculoskeletal disorders. This chapter focuses on the evaluation of altered pain sensitivity in fibromyalgia. It describes current measurement methodology, briefly reviews studies of sensitivity to experimentally evoked painful and non-painful sensations, analyses the factors assessed by different measurement methodologies, and concludes with recommendations for future diagnostic criteria and measurement methods.

Pain Perception in Chronic Fatigue Syndrome

AbstractPain complaints (myalgia, arthralgia, headache, sore throat) are commonly associated with chronic fatigue syndrome (CFS), yet to date, these patients' responses to standardized measures of pain perception have not been investigated. Pain perception was measured by pressure dolorimeter and ice water cold prcssor tests, and the McGili Pain Questionnaire among 15 female subjects with CFS, 11 subjects with Major Depression and 11 healthy controls. No differences were found between the groups for pain threshold or intolerance levels on the pressure dolorimeter and cold pressor tests. CFS and depressed subjects endorsed significantly more self-reported pain complaints than did control subjects. Although more pain complaints were predicted by greater somatization and lower health perceptions, pain threshold and intolerance were not associated with psychiatric symptoms or functional status. The study yielded some interesting preliminary observations related to variability in pain tolerance among CFS patie...

Pain Correlates of Depressed Mood

OBJECTIVE: To provide an initial indication of the intensity and quality of pain in young adults reporting depressed mood and to investigate possible underlying mechanisms.DESIGN: Case‐control study.SETTING: University undergraduate subject pool.PARTICIPANTS: Sixty introductory psychology undergraduates classified as either reporting high levels of depressed mood (n=30; age 18.7±0.87 years, mean ± SD) or reporting low levels of depressed mood (n=30; age 18.6±0.81 years).MAIN OUTCOME MEASURES: Beck Depression Inventory, Short‐Form McGill Pain Questionnaire, Pain Catastrophizing Scale, Pittsburgh Sleep Quality Index and pressure dolorimeter pain thresholds.RESULTS: Young adults reporting high levels of depressed mood had significantly higher pain intensity at testing time, as measured by a visual analogue scale (P=0.015) and a present pain index (P=0.002), affective pain intensity for the previous month (P=0.000), pain catastrophizing (P=0.025) and global sleep disturbance (P=0.000) than young adults reporting low levels of depressed mood. Within the group of young adults reporting high levels of depressed mood, significantly higher sleep disturbance scores (P=0.020) were identified in those reporting high levels of overall pain intensity.CONCLUSIONS: The results are discussed in terms of their implications for research as well as for the assessment and treatment of pain in individuals with depression.

The Effect of Ultrasound on the Mechanical Pain Threshold of Healthy Subjects

The purpose of this study was to examine the effect of ultrasound on threshold to pain produced by a pressure dolorimeter. Twenty healthy, pain-free subjects (12 men, 8 women) who were naive to ultrasound received five minutes of continuous 1.1 MHz ultrasound at 1.0 W/cm2 on the dorsal aspect of one forearm. The other arm acted as the control and received sham ultrasound. A pressure dolorimeter was used to measure pain threshold on the treated area and on an untreated area of both arms, before and after the ultrasound. A three-way ANOVA revealed an interaction among arm (control versus experimental), site (treated versus untreated) and time (before versus after treatment). Newman-Keuls post hoc analysis demonstrated a significant (p < 0.05) increase in pain threshold from before (mean = 1.53 kg/cm2, SE = 0.08) to after (1.93 ± 0.12 kg/cm2) treatment only on the dorsal aspect of the experimental arm. There were no changes in pain threshold on the treated site of the control arm (1.49 ± 0.07 − 1.56 ± 0.08 kg/cm2) or on the untreated site on the experimental (1.95 ± 0.12 − 1.96 ± 0.13 kg/cm2) or control (1.95±0.13 − 1.94±0.13 kg/cm2) arm. It is concluded that, in healthy subjects, continuous ultrasound can raise the threshold of pressure-induced pain. The purpose of this study was to examine the effect of ultrasound on threshold to pain produced by a pressure dolorimeter. Twenty healthy, pain-free subjects (12 men, 8 women) who were naive to ultrasound received five minutes of continuous 1.1 MHz ultrasound at 1.0 W/cm2 on the dorsal aspect of one forearm. The other arm acted as the control and received sham ultrasound. A pressure dolorimeter was used to measure pain threshold on the treated area and on an untreated area of both arms, before and after the ultrasound. A three-way ANOVA revealed an interaction among arm (control versus experimental), site (treated versus untreated) and time (before versus after treatment). Newman-Keuls post hoc analysis demonstrated a significant (p < 0.05) increase in pain threshold from before (mean = 1.53 kg/cm2, SE = 0.08) to after (1.93 ± 0.12 kg/cm2) treatment only on the dorsal aspect of the experimental arm. There were no changes in pain threshold on the treated site of the control arm (1.49 ± 0.07 − 1.56 ± 0.08 kg/cm2) or on the untreated site on the experimental (1.95 ± 0.12 − 1.96 ± 0.13 kg/cm2) or control (1.95±0.13 − 1.94±0.13 kg/cm2) arm. It is concluded that, in healthy subjects, continuous ultrasound can raise the threshold of pressure-induced pain.

The reliability and validity of pain threshold measurements in osteoarthritis of the knee.

The purpose of this study was to examine the reliability and validity of measuring pain threshold (PT) of persons with osteoarthritis (OA) of the knee. The PTs of women with and without OA of the knee were measured on 3 occasions at 6 sites at the knee with a pressure dolorimeter. Subjects with OA also recorded their pain on a visual analogue scale (VAS) and on the McGill Pain Questionnaire (MPQ). The reliability coefficients for repeated measures of PT varied from 0.61 to 0.91 in the OA group and from 0.71 to 0.90 in the control group. PT was lower in the OA group at all sites. Only the control group demonstrated significant differences between sites. The correlations between PT and measures of pain intensity were poor. It is concluded that the measurement of PT at the knee distinguishes OA from healthy controls, and that it has moderate reliability. However, it cannot substitute for a measure of pain intensity.