Der Schmerz
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The gate-control theory of pain, as originally proposed by Melzack and Wall [8], is nothing but a hypothesis concerning the spinal processing of non-noxious and noxious afferent information. Its basic tenant is that the P cells (projecting neurons) convey noxious information to supraspinal pain systems only after a critical threshold of excitation has been passed, and that access to the P cells is controlled by the SG cells (cells of the substantia gelatinosa Rolandi) or, in other words, the SG cells act as the gate. Since the primary afferent fibres have monosynaptic connections with the P cells the gate can only operate-and this is the critical point of the whole hypothesis-via presynaptic inhibition exerted by axoaxonic contacts on these afferents (Fig. 1). ⋯ As a consequence, Melzack and Wall [9] have now modified their hypothesis considerably. Its present formulation is not much more than a very general statement to the effect that all kinds of afferent input, including noxious input, is under the modulating influence of various mechanisms operating both at the spinal level and from supraspinal (descending) structures. No implications for therapy can be derived directly from such an undefined, in many ways trivial, assumption.
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This study was designed to evaluate the efficacy of different strategies for migraine prophylaxis over a fairly long period. Metoprolol alone was compared with psychotherapy alone and with a combination of metoprolol and psychotherapy. The psychological programme was planned for future use in preventive treatment. In this paper only the results of the psychological therapy are described. ⋯ According to the results, the efficacy of the psychological treatment increases only gradually, as it has also been demonstrated for biofeedback and relaxation training [9]. Subjectively, patients rate the results of psychotherapy higher than those demonstrated by statistics. This may depend on the selection of patients, but also on the fact that subjective criteria of improvement are not contained in statistical evaluation. Responders and non-responders had initial differences regarding vegetative, hormonal and psychological factors. Responders had a more stable circulatory status, suffered more rarely from menstrual migraine and normally took significantly fewer analgesic drugs. On the whole, this psychological programme has proved quite effective.
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This study presents the first-ever account of the prevalence of headache syndromes in Germany and the frequency with which they occur in a large representative sample according to the International Headache Society criteria, as set out in the German translation approved by the Classification Committee. 5000 persons representative of the total population were selected from a panel of 30000 households and requested to answer a questionnaire about headache occurrence during their life to date (lifetime prevalence). Of the 5000 persons who were sent questionnaires, 81.2% (n=4061) completed and returned them: 71.4% (n=2902) said they suffered from headache at least occasionally. Of the base population (all respondents: 100% orn=4061), 27.5% (n=1116) fulfilled the criteria for the IHS classification ofmigraine, 38.3% (n=1557) displayed the criteria oftension headache and 5.6% (n=229) said they suffered from headaches, but did not fulfil the criteria for either migraine or tension headache and were therefore classified in the category other headache. ⋯ The importance of the neurological disorders migraine and tension headache is currently seriously underestimated. They are one of the major health problems of our time. There is an urgent need for much greater attention to them by the health system.
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Several studies of contingent negative variation (CNV) examined whether this method provides a suitable basis for research on pathogenetic processes in chronic headaches-especially migraine. In the present study, the CNV amplitudes and CNV course of 23 migraine patients were compared with those of 22 healthy subjects. CNV was calculated for (a) "total interval", (b) "early CNV component", and (c) "late CNV component". ⋯ The results allow the assumption that the higher level of CNV amplitude in migraine patients is not only due to higher cortical noradrenergic or serotoninergic activation. This study shows that migraine patients cannot decrease their CNV amplutides. This is probably due to defective processing of sensory imput.
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This paper reviews several recently developed animal models that allow a quantitative assessment of the magnitude of nocifensive behavioral responses across a range of noxious stimulus intensities. Models discussed in detail include: (a) the rodent tail flick reflex, and a modification that allows measurement of tail flick magnitude, (b) rat hindlimb flexion withdrawal reflex elicited by noxious thermal stimulation of the paw, and (c) a learned operant response (nose bar press) evoked by noxious thermal stimulation of the rat's tail. These models are discussed in terms of their advantages over previous methods measuring response threshold, their fulfillment of criteria for ideal pain assessment models, and the neuronal circuitry underlying the behavioral response.