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Vascular responses and pain induced by noxious mechanical stimulation of the skin in humans
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THE STRUCTURE OF MEANING OF VERBAL PAIN DESCRIPTORS. W.S. Torgerson*, M_ BenDebba, Depts. of Neurosurgeryand Psychology,The Johns Hopkins University,Baltimore, Md., USA.
Poster 50 GREY Th-Fri Exhibit Hall
In 1971, Melzack and Torgerson proposed a class model augmented with a single Abs No 590 quantitativedimension for specifyingthe relationshipsof meaning between words people use Kl to describe experienced pains. The model characterizeseach word by its value on a common intensitydimension and by its membership in one of 16 mutuallyexclusiveclasses. The classes are grouped into three major domains: sensory, affective, and evaluative. They considered the model tentative; their aim was ‘to present an approach which, hopefully will provide some guidelines for future studies using one or another of the newer, more elaborate multidimensionalscaling or classificationmodels.’ In 1983, we suggested that the class model may not be optimal, and that an ideal-type model augmented with a single quantitativedimension would be more appropriate. Like the originalclass model, the alternativeideal-type model represents words by their value on a common intensityscale. However, the ideal-type model specifies the qualitative meaning of each word by its degree of similarity to each of several types of pain qualities, instead of by it is membership in one and only one type of pain quality. In 1988, we reported on a series experiments, involving similarityjudgments between pairs of descriptors, that demonstrated that the newer ideal-type model is an excellent structural model for representing both the quantitative and the qualitative variations in the subjective meaning of the verbal descriptors. Because each of the experiments involvedonly a subset of the entire set of descriptorsin the original Meback-Torgerson,a single study overallstructure for the entire set of words was not directly available. We have recently developed procedures for combining the results of the experiments, and a complete ideal-type structurefor the entire set of verbal pain descriptors has now been realized. The obtained overall structure specifies each word in terms of its value on a common intensitydimension and its psychologicalproximityto each of 19 ideal pain types. The intensity scale values correspond closely to the intensity values obtained in the original MelzackTorgerson study. The ideal-types revealed by our completely objective procedures make good subjective sense. Fourteen types describe sensory pain qualities, four describe affective qualities. The sensory and affective domains overlap only marginally. Procedures for using the ideal-type representationas a basis for specifyingthe quantitativeand qualitativeaspects of clinical pains have also been developed. Implicationsfor the scoringthe McGillpain questionnairewill be discussed.
VASCULAR RESPONSES AND PAIN INDUCED BY NOXIOUS MECHANICAL STIMULAJION OF THF SKIN IN HUMANS (SPON: D. Bonke) W. Maaerl , G. Geldner , and H.O. Handwerker Institut filr Physiologie und Biokybernetik, Universitiit Erlangen/Nlimberg, Universitlitsstrafie 17, D-8520 Erlangen (FRG)
Poster 51 GREY Th-Fri Exhibit Abs No
Hall 591
AIM OF INVESTIGATION: The study examines the relationship of sympathetic reflexes, local neurogenit inflammation and pain following noxious squeezing of the skin in humans. METHODS: A feedback controlled clamp device was used to squeeze interdigital skin folds of volunteers (n=ZO) with a constant force (8 N, 2 min). Pain was rated on a visual analogue scale. Vasoconstriction was assessed by photoplethysmography of the thumb and index finger. Computerized infrared thermography (AGEMA, GESOTEC) was used to measure the spatial distributlon of this nocifensive sympathetic reflex. RESULTS: The stimulus induced always an immediate drop in temperature of the whole palmar aspect of the hand by l°C on average, which recovered after the end of the stimulus. The magnitude of the vasoconstrictor response assessed by photoplethysmography and by thermography was correlated to the pain ratings. No habituation was seen upon stimulus repetition (1:lO min) in subjective and reflex measures. The thermography revealed that the vasoconstriction was overlaid in the area surrounding the stimulus site by a vasodilatator response. The local vasodilatation developed more slowly than the reflex vasoconstriction. Since it was greatly diminished in patients with nerve damage, it may be at least partially the result of an axon reflex in afferent C-fibers. In contrast to the vasoconstrictor reflex this neurogenic vasodilatation cumulated with stimulus repetition. When 2 N steps were superimposed on the constant squeezing force at various times these changes in nociceptor input were reflected in subjective ratings and in the vasoconstrlctor reflex assessed by photoplethysmography. The latter provided a better discrimination of those steps. CONCLUSIONS: Infrared thermography provides a valid method to assess nocifensive responses in both afferent and efferent C-fibers simultaneously with a high degree of spatial resolution. However, photoplethysmography has a better temporal resolution and thus may better discriminate reflex reactions to stimulus steps. Our method seems to provide a means to assess simultaneously subjective responses, spinal sympathetic reflexes and local inflammatory responses to tonic painful stimuli. Supported by the DFG grant Ha 831/8-S
THE STRUCTURE OF MEANING OF VERBAL PAIN DESCRIPTORS. W.S. Torgerson*, M_ BenDebba, Depts. of Neurosurgeryand Psychology,The Johns Hopkins University,Baltimore, Md., USA.
Poster 50 GREY Th-Fri Exhibit Hall
In 1971, Melzack and Torgerson proposed a class model augmented with a single Abs No 590 quantitativedimension for specifyingthe relationshipsof meaning between words people use Kl to describe experienced pains. The model characterizeseach word by its value on a common intensitydimension and by its membership in one of 16 mutuallyexclusiveclasses. The classes are grouped into three major domains: sensory, affective, and evaluative. They considered the model tentative; their aim was ‘to present an approach which, hopefully will provide some guidelines for future studies using one or another of the newer, more elaborate multidimensionalscaling or classificationmodels.’ In 1983, we suggested that the class model may not be optimal, and that an ideal-type model augmented with a single quantitativedimension would be more appropriate. Like the originalclass model, the alternativeideal-type model represents words by their value on a common intensityscale. However, the ideal-type model specifies the qualitative meaning of each word by its degree of similarity to each of several types of pain qualities, instead of by it is membership in one and only one type of pain quality. In 1988, we reported on a series experiments, involving similarityjudgments between pairs of descriptors, that demonstrated that the newer ideal-type model is an excellent structural model for representing both the quantitative and the qualitative variations in the subjective meaning of the verbal descriptors. Because each of the experiments involvedonly a subset of the entire set of descriptorsin the original Meback-Torgerson,a single study overallstructure for the entire set of words was not directly available. We have recently developed procedures for combining the results of the experiments, and a complete ideal-type structurefor the entire set of verbal pain descriptors has now been realized. The obtained overall structure specifies each word in terms of its value on a common intensitydimension and its psychologicalproximityto each of 19 ideal pain types. The intensity scale values correspond closely to the intensity values obtained in the original MelzackTorgerson study. The ideal-types revealed by our completely objective procedures make good subjective sense. Fourteen types describe sensory pain qualities, four describe affective qualities. The sensory and affective domains overlap only marginally. Procedures for using the ideal-type representationas a basis for specifyingthe quantitativeand qualitativeaspects of clinical pains have also been developed. Implicationsfor the scoringthe McGillpain questionnairewill be discussed.
VASCULAR RESPONSES AND PAIN INDUCED BY NOXIOUS MECHANICAL STIMULAJION OF THF SKIN IN HUMANS (SPON: D. Bonke) W. Maaerl , G. Geldner , and H.O. Handwerker Institut filr Physiologie und Biokybernetik, Universitiit Erlangen/Nlimberg, Universitlitsstrafie 17, D-8520 Erlangen (FRG)
Poster 51 GREY Th-Fri Exhibit Abs No
Hall 591
AIM OF INVESTIGATION: The study examines the relationship of sympathetic reflexes, local neurogenit inflammation and pain following noxious squeezing of the skin in humans. METHODS: A feedback controlled clamp device was used to squeeze interdigital skin folds of volunteers (n=ZO) with a constant force (8 N, 2 min). Pain was rated on a visual analogue scale. Vasoconstriction was assessed by photoplethysmography of the thumb and index finger. Computerized infrared thermography (AGEMA, GESOTEC) was used to measure the spatial distributlon of this nocifensive sympathetic reflex. RESULTS: The stimulus induced always an immediate drop in temperature of the whole palmar aspect of the hand by l°C on average, which recovered after the end of the stimulus. The magnitude of the vasoconstrictor response assessed by photoplethysmography and by thermography was correlated to the pain ratings. No habituation was seen upon stimulus repetition (1:lO min) in subjective and reflex measures. The thermography revealed that the vasoconstriction was overlaid in the area surrounding the stimulus site by a vasodilatator response. The local vasodilatation developed more slowly than the reflex vasoconstriction. Since it was greatly diminished in patients with nerve damage, it may be at least partially the result of an axon reflex in afferent C-fibers. In contrast to the vasoconstrictor reflex this neurogenic vasodilatation cumulated with stimulus repetition. When 2 N steps were superimposed on the constant squeezing force at various times these changes in nociceptor input were reflected in subjective ratings and in the vasoconstrlctor reflex assessed by photoplethysmography. The latter provided a better discrimination of those steps. CONCLUSIONS: Infrared thermography provides a valid method to assess nocifensive responses in both afferent and efferent C-fibers simultaneously with a high degree of spatial resolution. However, photoplethysmography has a better temporal resolution and thus may better discriminate reflex reactions to stimulus steps. Our method seems to provide a means to assess simultaneously subjective responses, spinal sympathetic reflexes and local inflammatory responses to tonic painful stimuli. Supported by the DFG grant Ha 831/8-S