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

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, multidimensional 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. Gender-related, 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 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 FactorLike 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. THESIS SUMMARY IN SWEDISH Svensk sammanfattning Smarta ar ett omfattande kliniskt problem som orsakar individen stort lidande och samhallet stora kostnader. Bedomning och utvardering av upplevd smarta ar nodvandig for att stalla diagnos, val av behandling och for utvardering av behandlingseffekter. Att bedoma en individs smarta ar en utmaning eftersom smarta ar en multidimensionell erfarenhet baserad pa individens egen rapport. Variation i smartbedomningen kan relateras till individuella faktorer men ocksa till kon och smartetiologi. En generell standard for smartbedomning saknas men skattningsskalor, frageformular och metoder baserade pa psykofysiska koncept anvands. Vid utvardering av smarta och symtom associerade med smarta bor hansyn tas bade till systematiska och individuella variationer. Stressrelaterade symtom i samband med smarta kan mojligtvis detekteras med biokemiska markorer. Icke-farmakologisk smartbehandling anvands ofta inom sjukgymnastisk verksamhet. Dock saknas annu kunskap om optimala behandlingar vid olika tillstand. Konsrelaterade smartlindringseffekter av icke-farmakologiska behandlingsmetoder ar sparsamt dokumenterade liksom effekter av akupunktur hos gravida kvinnor med backensmarta. Syftet med denna avhandling var att utvardera nagra av de vanligaste smartskattningsmetoderna och en nyligen utvecklad metod for att kunna bedoma experimentell och klinisk smarta fran ett sjukgymnastiskt perspektiv. Ytterligare ett syfte var att finna indikatorer, skattade och biokemiska, for associerade symptom till smarta och aven rapporterade terapeutiska effekter. Bedomning av elektrisk sensorisk troskel och elektrisk smarttroskel visade stabila resultat hos friska kvinnliga forsokspersoner och kvinnliga patienter med smarta. I jamforelse med friska forsokspersoner rapporterade smartpatienterna hojd sensorisk troskel och sankt smarttroskel. Utvardering av skattad smartintensitet med visuell analog skala, VAS, och verbal skattningsskala, VRS, hos patienter med smarta av olika etiologi visade att de tva skalorna gav olika resultat och kan darmed ha olika mening. Dessutom kan olika skalor sannolikt tolkas olika och ar darfor inte utbytbara. Hos patienter med fibromyalgi pavisades en relation mellan koncentrationen av corticotropin releasing factor, CRF, i dygnsurin uppmatt med radioimmunologisk teknik och skattade stress-relaterade symptom. Konsrelaterade svar pa transkutan elektrisk hudstimulering, TENS, pavisades vid troskelbedomning hos friska forsokspersoner. Kvinnorna svarade med okning av smarttroskeln medan mannens var opaverkad. Akupunktur lindrade smartintensitet i vila, i samband med dagliga funktioner samt minskade emotionella reaktioner hos gravida kvinnor med backen smarta. Lagre koncentrationer av CRF i dygnsurin och minskning av skattade variabler kunde konstateras efter massage hos patienter med langvarig smarta och stress. Det fanns en pataglig individuell variation i svaret pa de olika sensoriska stimuleringsmetoderna vilket indikerar att behandlingar bor utformas individuellt. Sammanfattning: Utvardering av smarta bor tillvarata de subjektiva variablernas icke metriska egenskaper och beakta bade systematiska och individuella variationer. Troskelbedomningar kan utgora ett vardefullt komplement som utvarderings instrument i klinisk bedomning av smarta forutsatt att kvinnor och man analyseras separat. Biokemiska markorer som CRF-koncentration i dygnsurin, skulle kunna anvandas som matt pa stressrelaterade symtom vid smarta. Terapier som TENS, akupunktur och massage kan provas for att minska smarta och associerade symtom men fler studier kravs. LIST OF PUBLICATIONS I. Lund I, Lundeberg T, Kowalski J, Sandberg L, Norrbrink Budh C, Svensson E. Evaluation of variations in sensory and pain threshold assessments by electrocutaneous stimulation. Physiotherapy Theory and Practice 2005;21:8192. II. Lund I. Lundeberg T, Kowalski J, Svensson E. Gender differences in electrical pain threshold responses to transcutaneous electrical nerve stimulation (TENS). Neuroscience Letters 2005;375:75–80. III. Lund I, Lundeberg T, Lonnberg L, Svensson E. Decrease of pregnant women’s pelvic pain after acupuncture: a randomized controlled single-blind study. Acta Obstetricia et Gynecologica Scandinavica 2006;85:12-19. IV. Lund I, Lundeberg T, Kowalski J, Sandberg L, Norrbrink Budh C, Svensson E. Lack of interchangeability between visual analogue and verbal rating pain scales: a cross sectional description of pain etiology groups. BioMedCentral Medical Research Methodology 2005;5:31. V. Lund I, Lundeberg T, Carleson J, Sonnerfors H, Uhrlin B, Svensson E. Corticotropin releasing factor in urine a possible biochemical marker of fibromyalgia. Responses to massage and guided relaxation. In press for publication in Neuroscience Letters.