Biomedical subjects
Jes Olesen
Publications and source records attributed to Jes Olesen.
Muscle palpation with controlled finger pressure: new equipment for the study of tender myofascial tissues.
While manual palpation is the most important method for evaluation of tender myofascial tissues, it lacks reliability. Therefore, we have developed an instrument, called a 'palpometer', which allows the measurement of pressure exerted during palpation. The palpometer consists of a thin pressure-sensitive plastic device attached to the palpating finger, and of a scale recording the pressure applied to the device. Known forces were applied to the pressure sensitive device under various experimental conditions and the corresponding values were read on the palpometer scale. Then 14 observers, blinded to the palpometer scale, palpated the temporal muscle on the same subject twice, with an interval of 1 week. A highly significant correlation was found between palpometer recordings and forces applied to the pressure-sensitive device (P < 0.0001). Exerted force at a given palpometer value varied 3.1% within and 7.2% between 2 observers. During palpation of the temporal muscle pressure intensities within the 14 observers did not differ significantly from week to week (P = 0.68). Between the 14 observers pressure intensities varied considerably with a range of 73.5-196 arbitrary units. Thus, a reliable instrument for measuring pressure intensities during palpation of myofascial tissue has been developed. The large variation in palpation pressures between observers indicates that palpation of tender myofascial tissue may be considerably improved by use of the palpometer. This instrument will be indispensable in research studies employing palpation and in the training of physicians to diagnose myofascial pain disorders.
Muscle tenderness and pressure pain thresholds in headache. A population study.
Tenderness and pain thresholds in pericranial muscles were studied in a random sample of 735 adults aged 25-64 years. This study was a part of a multifaceted, epidemiological study of different headache disorders. Manual palpation and pressure pain threshold were performed by observers blinded to the persons' history of headache. The aim of the study was to evaluate the possible role of pericranial myofascial nociception in headache pathogenesis. Tenderness in migraineurs did not differ from non-migraineurs. Subjects with episodic tension-type headache and females with chronic tension-type headache were more tender than the rest of the population, and males without any experience of headache were less tender than the rest of the male population. A strong positive correlation between tenderness and frequency of tension-type headache was found (males: P < 10(-4); females: P < 10(-5)), while no relation between tenderness and migraine frequency was seen (P = 0.43). In subjects having actual headache at the day of examination tenderness was 32% increased compared to a matched group with identical usual frequency of headache, but without headache during the examination. A significant relation of tenderness to the recency of last episode of headache was detected in both sexes after control for usual frequency and actual headache (males: P < 10(-3); females: P < 10(-4)). Pressure pain thresholds were largely normal indicating normal pain processing and contradicting the idea that tension-type headache mainly is due to generally increased pain sensitivity. This study supports the pathogenetic importance of muscular factors in tension-type headache, while muscular factors are of no primary importance in migraine.
Cephalic muscle tenderness and pressure pain threshold in a general population.
Tenderness and pain thresholds in pericranial muscles were studied in a general population. A random sample of 1000 adults aged 25-64 years was drawn as part of the Glostrup Population Studies, and 740 adults were examined. This study was part of a multifacetted, epidemiological study of different headache disorders according to the new headache classification. Manual palpation and pressure pain threshold with an electronic pressure algometer were performed by observers blinded to other information such as the person's history of headache, previous illness and mental state. The muscles most commonly tender to manual palpation were the lateral pterygoid (55%), the trapezius (52%), and the sternocleido-mastoid muscles (51%). Females were more tender than men in all the muscles examined by manual palpation. In total, the young age group was more tender than the old age group (P = 0.03). Pressure pain thresholds on temporal muscles showed lower thresholds in women than in men (P less than 10(-3)), and in the total population thresholds increased with age (P less than 0.05). No side-to-side difference in tenderness by manual palpation was found, while the right side showed increased pain thresholds in right-handed individuals (P less than 10(-4)). No side-to-side difference was found in left-handed persons. This study provides data about the normal population and forms the necessary basis for evaluating the importance of muscle tenderness in headache subjects and other selected groups.
Plasma and cerebrospinal fluid beta-endorphin in chronic tension-type headache.
Previous studies have provided evidence of an increased sensitivity to pain, a decreased hypothalamic opioid tone, and decreased cerebrospinal fluid (CSF) beta-endorphin (beta-EP) concentration in patients with primary chronic headache. We applied separate specific radioimmunoassays for beta-EP in CSF and plasma on samples from age-matched controls and a group of 50 patients with chronic tension-type headache (CTH) fulfilling the diagnostic criteria set by the International Headache Society. Median CSF beta-EP concentrations (95% confidence limits) were 12.8 pmol/l (11.0-14.5) in CTH patients and 11.9 pmol/l (10.9-14.2) in the control group, which is not significantly different (P = 0.28). Plasma beta-EP concentrations did not differ either, being 3.1 pmol/l (2.4-3.7) and 3.3 pmol/l (1.8-4.0) in the patients with CTH and in controls, respectively (P = 0.88). Plasma and CSF beta-EP concentrations did not correlate. Reversed-phase high performance liquid chromatography (HPLC) of CSF pools from the headache patients and controls revealed similar profiles of beta-EP-immunoreactivity both when C-terminally and N-terminally directed antisera were used, suggesting a normal post-translational processing of the pro-opiomelanocortin gene in patients with CTH. beta-EP is not involved in the pathogenesis of CTH, or such a role is not reflected in CSF or plasma concentrations of the neuropeptide.
Getting away from simple muscle contraction as a mechanism of tension-type headache.
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Clinical and pathophysiological observations in migraine and tension-type headache explained by integration of vascular, supraspinal and myofascial inputs.
A vascular-supraspinal-myogenic (VSM) model for pain in migraine based on our previous clinical and pathophysiological observations is proposed. According to the model, perceived pain (headache) intensity is determined by the sum of nociception from cephalic arteries and pericranial myofascial tissues converging upon the same neurons and integrated with supraspinal effects (usually facilitating). Vascular input predominates over myofascial input in migraine, whereas significance of supraspinal facilitation is difficult to estimate. The importance of these 3 effects may vary between patients and in the same individual with time. The model is in accordance with recent experimental studies showing convergence of somatovisceral afferents upon n. caudalis neurons. Also, long term potentiation due to nociceptive activation and sensitization of neurons to input from wider areas and non-nociceptive stimuli are relevant to our model. In tension-type headache, nociception is primarily myofascial, but vascular input cannot be disregarded. Supraspinal facilitation probably plays a large, sometimes dominant role (the MSV model). The model explains much of the complexity of the clinical picture of these disorders as well as their tendency to overlap and to change into one another. Also, a number of pathophysiological observations such as why muscles are tender during migraine, why trigger-point injection may cure migraine attacks and why chronic tension-type headache is often associated with episodes of pulsating pain, can be explained. The model gives a rational explanation of empirically developed, internationally accepted, multimodal treatment strategies for migraine and tension-type headache. It may thus serve a useful purpose in explaining the disorder to patients. Finally, the model points to several avenues of future research in animals and man.
Intravenous nitroglycerin as an experimental model of vascular headache. Basic characteristics.
To develop a reliable experimental model of vascular headache, we studied the dose-response relationship between headache and i.v. nitroglycerin (NTG) in 10 healthy subjects. NTG was infused intravenously over periods of 10 min separated by wash-out periods. Doses of 0.25, 0.50, 1.00 and 2.00 micrograms/kg/min were applied successively with one placebo infusion and wash-out period inserted randomly and double blindly. The subjects scored their headache intensity on a scale 0-10. After 1-8 weeks a retest was performed. Nine subjects developed headache already at 0.25 microgram/kg/min, whereas one had no headache at any dose. Headache severity did not increase with doses above 0.5 microgram/kg/min. This ceiling effect was reproducible. The headache was moderate, usually throbbing, bifrontal and not associated with other migrainous features. It reached maximum within 2.5-5.5 min (medians) at various doses and declined rapidly after NTG discontinuation. Wash-out periods of 10-20 min were sufficient. The reproducibility of headache intensity and character was satisfactory in the retest experiment. There were no unpleasant side effects and no visible flushing. Thus blindness was maintained. I.v. NTG is suitable as an experimental headache model. A constant infusion of 0.5 microgram/kg/min will be suitable for studies of arterial diameter, pulsations, blood flow, etc. Comparative studies of sensitivity should use the present infusion schedule but with the two highest doses substituted by 0.06 and 0.125 microgram/kg/min.
Pericranial muscle tenderness and pressure-pain threshold in the temporal region during common migraine.
Twenty-six patients were examined during attacks of common migraine as well as during headache-free interval. Pericranial tenderness was scored blindly by a systematic manual palpation on both occasions by the same observer. Pressure-pain threshold (PPT) in a fixed location over the temporal muscle was determined by the use of a pressure algometer. A 28% increase in total tenderness score was observed during attacks (P less than 0.01). During unilateral attacks, tenderness scores were significantly higher on the ipsilateral side as compared to the contralateral (P less than 0.01). A positive correlation was observed between tenderness on the two sides (P less than 0.05) and the two occasions (P less than 0.01). PPT showed no changes during migraine attacks and there was no difference in PPT between the ipsilateral and contralateral side. A positive correlation was observed between PPT on the two sides and the two occasions (P less than 0.01). PPT was not correlated to the tenderness scores obtained by manual palpation. The absence of a decrease in PPT and the presence of several tender areas in multiple regions, particularly where pain was spontaneously reported to be located, suggest the presence of either a multi-focal peripheral pathological process or referred pain from other structures in the head and neck region.
Peptide-containing nerve fibres in human extracranial tissue: a morphological basis for neuropeptide involvement in extracranial pain?
It has been suggested that a number of peptides may be involved in the transmission of pain. In order to evaluate the possible role of peptides in the development of headache, we have, in the present study, examined the presence of nerve fibres containing neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), substance P (SP) and calcitonin gene-related peptide (CGRP) in human temporal and occipital tissues. In the skin, delicate VIP, SP and CGRP fibres occur beneath the epidermis, sometimes running into the folds of the dermal ridges. In deeper layers of the dermis, small blood vessels are occasionally surrounded by single nerve fibres containing NPY, VIP, SP and CGRP. Large temporal and occipital arteries are surrounded by a meshwork of such fibres. In addition, NPY and VIP fibres are seen around sweat glands and hair follicles. Smooth muscle bundles in the dermis are surrounded by VIP fibres, whereas the temporal muscle per se is devoid of such fibres.
Pressure-pain threshold in human temporal region. Evaluation of a new pressure algometer.
A hand-held pressure algometer with a pressure sensitive strain gauge at the tip was used to measure the pressure-pain threshold (PPT) in the temporal region of healthy volunteers. Various sizes of circular tips and various application rates were tested before selecting an area of 0.5 cm2 and a constant application rate of 0.68 N X sec-1 for future use. A highly significant correlation was found between PPT values obtained from the two sides (of the head) (P less than 0.001) and between PPT values obtained with a 3-week interval (P less than 0.001). In a series of 50 immediate consecutive measurements in the same individual, the mean PPT was 171 kPa (N = 6, 2 S.D. 24%). The mean relative change in PPT after a 3-week interval was 0 +/- 51% (N = 11, 2 S.D.). In the course of 5 repeated determinations at weekly intervals there was a significant increase in PPT (ANOVA, P less than 0.05). Subcutaneous lignocaine significantly elevated PPT compared to placebo. Due to the high inter-individual variation, determinations of PPT for group comparisons should include rather large population samples, whereas in paired studies, the intra-individual variation allows the investigation of much smaller groups (10-20 subjects). It is our experience that the pressure algometer is easy to operate in the hands of a skilled laboratory assistant.
Drug abuse in migraine patients.
Records of all patients discharged with a diagnosis of migraine from 2 Danish neurological departments were examined to determine the incidence of drug abuse. These departments had fixed uptake areas with a population of approximately 500,000 during the 5 year study period (1-1-1976--31-12-1980). Patients were selected for detailed analysis if (1) they used morphinomimetic drugs once a month or more, (2) took 7 or more tablets of weak analgesics a day or (3) consumed more than 60 mg ergotamine a month. A total of 92 patients fulfilled these criteria, 27 only because of ergotamine overuse. Injections of morphinomimetic drugs were given once a week or more frequently to 32 patients. These patients also usually had an escalating consumption and were usually regarded as abusers by their doctors. During admission morphinomimetics were discontinued. None deteriorated, 1/3 remained unchanged whereas 2/3 improved. Thus 32 patients can be regarded as abusers of morphinomimetics which represents an annual incidence of 13 per million inhabitants. We caution against the use of morphinomimetics in migraine.
Action of some pericranial muscles during provoked attacks of common migraine.
In this electromyographic study the activity in the temporal, masseter, sternocleidomastoid and nuchal muscles was recorded bilaterally in 2 males and 2 females during attacks of common migraine precipitated with specific beverages. Muscle activity continuously picked up with bipolar surface electrodes was supplemented by pain ratings at regular intervals, and registrations of similar duration were obtained with the patients free of headache. Recordings were divided into sections of 10 min, and during the last 2 min of each section the average level and the peak of the mean voltage were assessed with intervals of 5 sec. The average of these measurements in per cent of maximal activity was used to characterize the activity in a section. The time course of muscle activity varied between patients and muscles. In general, the migraine attack was characterized by a rise of activity from control level shortly before the patients experienced maximal pain, and location of the hyperactivity corresponded reasonably well with the spatial distribution of pain and tenderness. In two patients activity was sufficiently strong to account for a substantial part of their pain.
Electromyography of pericranial muscles during treatment of spontaneous common migraine attacks.
In 7 patients given a standard treatment during spontaneous attacks of common migraine, activity in the temporal and sternocleidomastoid muscles was studied for 140 min. Pain and nausea ratings were taken with 20 min intervals. Baseline recordings were obtained from all patients during a period without headache and from 8 dental students without a history of migraine. During the attack of migraine, activity in the anterior temporal muscles significantly exceeded the patient's own baseline recordings and all muscles were activated more strongly than in the control sample. The increase in per cent of maximal muscle activity was insufficient to account for ischemic pain. Following treatment the activity of the temporal and sternocleidomastoid muscles decreased in 5 patients at the same time as the pain and nausea to the level of the controls. It is suggested that the moderate increase of activity on admission was a residual from stronger contractions earlier in the attack. In addition to cessation of the attack, placement in supine position and intake of diazepam may have contributed to the decline of muscle activity.
Evaluation of pericranial tenderness and oral function in patients with common migraine, muscle contraction headache and 'combination headache'.
Oral function was evaluated in a group of 13 patients with muscle contraction headache (MCH), 7 patients with common migraine (CM) and 18 patients with 'combination headache' (CM + MCH) and in a control group of 25 normal persons who had never had a headache. Malocclusion and loss of molars were rare in both groups. Impaired denture function and joint disturbances were more frequent in the headache patients but not significantly so. Clenching and grinding teeth and tongue pressure were all significantly more common in headache patients. Tenderness of pericranial muscles was present in all headache patients with severity increasing in the order CM, MCH, CM + MCH; it was absent in all the controls. On the average 9 tender spots were found per patient. Pressure on tender spots evoked pain in other areas (referred pain) in 29 of 38 headache patients. The abnormal tonic hyperactivity in the masticatory muscles and the neck may be the cause of tenderness which again may be an important source of pain in these patients.
Headache provocation by continuous intravenous infusion of histamine. Clinical results and receptor mechanisms.
Histamine, 0.16, 0.33 and 0.66 microgram/kg/min, was infused intravenously to 13 normal non-headache-prone volunteers, 10 patients with chronic muscle contraction headache and 25 patients with common migraine. In the normal group no patients developed pulsating headache. In the migraine group 13 patients developed severe, 9 patients moderate and 2 patients mild pulsating headache, and only 1 patient failed to develop headache at all. The muscle contraction headache patients responded intermediately. At each infusion rate the headache was of constant quality and severity as long as the infusion continued, but disappeared shortly after its termination. Injection of an H1 blocking agent, mepyramine, almost immediately abolished the headache. The H2 blocker cimetidine was much less effective, but still significantly better than placebo. The i.v. histamine infusion test is a useful model for the study of experimental vascular headache.