Pain, its assessment and treatment using sensory stimulation techniques : Methodological considerations

Sammanfattning: Pain is a worldwide clinical problem that causes great suffering for the individual and costs for society. The assessment and evaluation of perceived pain is necessary for diagnosis, choice of treatment, and for the evaluation of treatment efficacy. The assessment of an individual's pain is a challenge since pain is a subjective, multi-dimensional experience based on the person's own self-report. The results are often varied possibly due to individual variation, but also in relation to gender and etiology. A gold standard for pain assessment is still lacking but rating scales, questionnaires, and methods derived from psychophysical concepts, such as threshold assessments are used. In the evaluation of pain and associated variables, both systematic and individual variation should be taken into account, as should pain-associated symptoms. The stress-related symptoms that can be associated with pain may possibly be measured by using a biochemical marker. Non-pharmacological pain treatments are often used in physiotherapeutic practice, but knowledge about the optimal treatments for different pain conditions is still lacking. Genderrelated, pain-alleviating effects of non-pharmacological methods are sparsely documented as are non-pharmacological interventions like acupuncture in pelvic pain in late pregnancy. The aim of this thesis was to evaluate some of the commonly used pain rating methods and to evaluate a newly developed method in order to determine experimental and clinical pain from a physiotherapeutic perspective. Also, the aim was to find indicators, rated and biochemical, of pain-associated symptoms and reported therapeutic effects. Assessments of electrical sensory and electrical pain thresholds were shown to be stable and reliable in healthy female subjects and female pain patients. The sensory threshold was found to be increased and the pain threshold found to have decreased for the pain patients compared with healthy subjects. Evaluation of pain intensity ratings in patients with different pain etiologies using a Visual Analogue Scale and a Verbal Rating Scale showed that the used scales may have different meanings in the different pain groups, probably can be differently interpreted and are, therefore, not interchangeable. Gender-related responses to high frequency transcutaneous electrical nerve stimulation (TENS) were found in assessed thresholds - the women's electrical pain thresholds were found to have increased while those of the men were unaffected, indicating that variability in responses to sensory stimulation may be gender-related. Acupuncture relieves pelvic pain intensity and emotional distress in pregnant women. A relationship between the 24-hour urinary Corticotropin Releasing Factor-Like Immunoreactivity, CRF-LI, concentration and rated stress-related symptoms were found in female patients with fibromyalgia. Lowered concentrations of CRF-LI and decreased rated symptoms were seen after massage. There was great individual variation in response to the different sensory stimulation techniques, suggesting that treatments should be individually based. Conclusion: Analysis of pain assessment should consider the non-metric properties and take the systematical as well as the individual responses into account. Threshold assessment may be an additional valuable tool for clinical evaluation given analyses separated for gender. Biochemical markers such as urinary CRF-LI concentrations may be used for measurement of stress-related symptoms in pain conditions. Therapies like TENS, acupuncture and massage may be tried for the amelioration of pain and stress but further studies are required.