Pressure pain thresholds and thermal nociceptive thresholds in chronic tension-type headache

The nociceptive thresholds to mechanical and thermal stimuli in patients with chronic tension-type headache were compared. Palpation of pericranial tenderness was performed in 50 patients and a total tenderness score (TTS) was calculated. Palpation was repeated, and pressure pain thresholds (PPTs) were determined with a pressure algometer in the temporal and occipital regions. In 32 of the patients, pain thresholds for heat and cold and limens for detection of non-painful temperature changes were determined in the hands and the temporal regions. Twenty-four healthy volunteers served as controls. Scores obtained by manual palpation (TTS) at the first and second visit were positively correlated. A negative correlation between headache severity and PPT was found in the temporal region. A positive correlation between PPT in the temporal and occipital region was found, and PPT and TTS were negatively correlated. Thermal pain thresholds were consistently less extreme in patients compared to controls, and patients reporting severe headache on the examination day were those most sensitive to thermal pain. No difference was found between patients and controls with respect to detection of temperature changes. A correlation was found between PPT and the corresponding cold pain thresholds, but no correlation could be demonstrated between TTS and thermal pain thresholds. In conclusion, headache patients had decreased pain perception thresholds. Chronic tension-type headache might be a result of dysmodulation of nociceptive impulses, but it is likely that sensitized nociceptors also play a role.     

Cephalic and extracephalic pressure pain thresholds in chronic tension-type headache.

Pressure pain thresholds were assessed with an algometer (Somedic Inc.), over the forehead, temple and suboccipital region as well as over the Achilles tendon. A group of 32 patients suffering from chronic tension-type headache was compared to 20 healthy controls and to 10 migraineurs without aura. Although individual values were widely scattered, pressure pain thresholds were on average significantly lower in chronic tension-type headache, not only at pericranial sites but also over the Achilles tendon. Only 50% of these patients had one or more pericranial thresholds 1.5 S.D. below the mean of controls. After muscular biofeedback therapy, all pain thresholds were on average increased. Along with results obtained previously, the present data support the hypothesis that diffuse disruption of central pain-modulating systems, possibly due to a modified limbic input to the brain-stem, is pivotal in the pathophysiology of chronic tension-type headache.     

Stretch reflex and pressure pain thresholds in chronic tension-type headache patients and healthy controls

To compare the jaw-stretch reflex and pressure pain thresholds (PPT) in chronic tension-type headache (CTTH) patients and healthy controls, 30 patients (15 male and 15 female) and 30 age- and sex-matched healthy subjects were investigated. Stretch reflexes were recorded in the temporalis and masseter muscles and PPT was determined in the anterior temporalis, splenius capitis and masseter muscles. The results showed that the amplitude of the stretch reflex in CTTH patients was higher compared with control subjects ( P  < 0.045), and higher in women compared with men in the right and left anterior temporalis muscles ( P  < 0.009). There were no differences in the PPT value between CTTH and control subjects ( P  > 0.509), whereas women showed significantly lower PPT measurements ( P  < 0.046). The results demonstrated a facilitation of the stretch reflex pathways in CTTH patients that is unrelated to measures of pericranial sensitivity.     

Impairment of pain inhibition in chronic tension-type headache

Evidence has been accumulated suggesting that a dysfunction in pain inhibitory systems, i.e. in 'diffuse noxious inhibitory controls' (DNIC)-like mechanisms, might be-amongst other factors-responsible for the development of anatomically generalized chronic pain like fibromyalgia. The aim of the present study was to look for similar impairments in chronic tension-type headache (CTTH) as a regionally specific pain syndrome. Twenty-nine CTTH patients and 25 age- and sex-matched healthy control subjects participated in the study. After baseline assessment of electrical detection and pain thresholds, tonic heat stimuli were concurrently applied by a thermode to the thigh to induce DNIC-like pain inhibition. Tonic heat stimuli were applied either slightly above ('pain' condition) or slightly below ('heat' condition) pain threshold. For determination of electrical detection and pain thresholds, electrocutaneous stimuli were administered either to the forearm (extra-cranial site) or to the temple (cranial site), using a multiple staircase procedure. The increase in the electrical detection and pain thresholds induced by concurrent tonic heat stimulation was significantly smaller in the CTTH patients than in the control subjects. This group difference was present during the 'pain' as well as the 'heat' condition. Furthermore, the electrical detection and pain thresholds were affected in this group-specific manner both at the forearm and at the temple. These findings suggest that patients with CTTH suffer from deficient DNIC-like pain inhibitory mechanisms in a similar manner, as do patients with anatomically generalized chronic pain like fibromyalgia.     

Nociceptive temporalis inhibitory reflexes evoked by CO2-laser stimulation in tension-type headache

The aim of the study was to evaluate the laser-induced suppression periods of the temporalis muscle in patients with tension-type headache, compared with the pattern of temporalis activity suppression induced by electrical stimulation. Fifteen patients with chronic and 10 with episodic tension-type headaches were selected. Suppression periods were recorded simultaneously from both temporalis muscles using both electrical stimuli and CO2-laser stimuli. A significant reduction in the later electrically induced suppression period was found in both tension-type headache groups. Laser stimulation induced a first suppression period (LSP1) with a latency of about 50 ms in all patients. The features of LSP1 were similar across groups. The LSP1 should correspond to the first suppression period induced by electrical stimulus, which is partly a nociceptive response, whereas the second period seemed negligibly linked with the activation of pain-related afferents, though probably their activation may contribute to increase the reflex duration and to emphasize abnormalities in tension-type headache.     

枕颈部压痛点、痛性结节与紧张型头痛的诊治

目的 观察枕颈部压痛点和痛性结节在紧张型头痛(TTH)患者中的分布，探讨枕颈肌障碍在TTH发病中的机理。方法 对380例TTH患者，触诊枕外隆凸下至颈棘突止中线及其旁开，记录每位患者的压痛点、痛性结节总数及部位，实施揉拿、弹拨、点按颈部压痛点及痛性结节的手法治疗。结果 经1—6次治疗，治愈283例、显效58例，总显效率89．7％。结论 枕颈部肌肉障碍在TTH发病机制中起重要作用，针对压痛点和痛性结节实施手法治疗可产生显著疗效。     

Effect of mental stress on cold pain in chronic tension-type headache sufferers

Mental stress is a noted contributing factor in chronic tension-type headache (CTH), however the mechanisms underlying this are not clearly understood. One proposition is that stress aggravates already increased pain sensitivity in CTH sufferers. This hypothesis could be partially tested by examining effects of mental stress on threshold and supra-threshold experimental pain processing in CTH sufferers. Such studies have not been reported to date. The present study measured pain detection and tolerance thresholds and ratings of supra-threshold pain stimulation from cold pressor test in CTH sufferers (CTH-S) and healthy Control (CNT) subjects exposed to a 60-min stressful mental task, and in CTH sufferers exposed to a 60-min neutral condition (CTH-N). Headache sufferers had lower pain tolerance thresholds and increased pain intensity ratings compared to controls. Pain detection and tolerance thresholds decreased and pain intensity ratings increased during the stress task, with a greater reduction in pain detection threshold and increase in pain intensity ratings in the CTH-S compared to CNT group. The results support the hypothesis that mental stress contributes to CTH through aggravating already increased pain sensitivity in CTH sufferers.     

Hypothalamic deep-brain stimulation modulates thermal sensitivity and pain thresholds in cluster headache

Deep-brain stimulation (DBS) of the posterior hypothalamus has been shown to be clinically effective for drug-resistant chronic cluster headache, but the underlying mechanism is still not understood. The hypothalamus as an important centre of homeostasis is connected among others to the trigeminal system via the trigeminohypothalamic tract. We aimed to elucidate whether hypothalamic stimulation affects thermal sensation and pain perception only in the clinically affected region (the first trigeminal branch) or in other regions as well. Thus, we examined three groups: chronic cluster headache patients with unilateral DBS of the posterior hypothalamus (n = 11), chronic cluster headache patients without DBS (n = 15) and healthy controls (n = 29). Perception and pain thresholds for hot and cold stimuli were determined bilaterally in all subjects supraorbitally, at the forearm, and in the lower leg. In DBS patients, thresholds were determined with the stimulator activated and inactivated. Cold pain thresholds at the first trigeminal branch were increased on the stimulated side in the DBS group compared to healthy subjects (p = .015). The DBS group also had higher cold detection thresholds compared to non-implanted cluster headache patients (p < .05). Short-term interruption of stimulation did not induce any changes in DBS patients. Clinically relevant differences were found neither between non-stimulated cluster headache patients and healthy controls nor between the affected and the non-affected sides in the chronic cluster headache patients without DBS. These results support the notion that neurostimulation of the posterior hypothalamus is specific for cluster headache and only affects certain aspects of pain sensation.     

Blink reflex R2 amplitudes in cervicogenic headache, chronic tension-type headache and migraine

Blink reflex R2 amplitude was investigated in seven patients with cervicogenic headache (CEH), 12 patients with chronic tension-type headache, 23 patients with migraine (10 with aura) and 17 headache-free controls. Standard electrical stimulation of the supraorbital nerve was applied and the response was recorded from the ipsilateral and the contralateral orbicularis oculi muscles. Low R2 amplitude was found in CEH patients compared with control subjects. Headache is unilateral in CEH and the ipsilateral and contralateral responses after stimulation on the painful side were most depressed. R2 amplitude was not significantly affected in migraine and tension headache patients. The results suggest that lower brainstem excitability is reduced in CEH. A state of hypoactivity may be present in caudal trigeminal nucleus neurons on the symptomatic side.     

Coping strategies in episodic and chronic tension-type headache

OBJECTIVE: To study the importance of coping with illness strategies in tension-type headache (TTH). BACKGROUND: The pathophysiology of TTH is complex, and coping with illness strategies might contribute to the transformation to a chronic form. METHODS: We examined 89 subjects (mean age, 45.6 +/- 14.8 years; range, 18 to 72 years) with episodic (n = 37) and chronic (n = 52) TTH. Patients were required to fill in a Freiburg Questionnaire of Coping with Illness (FQCI), a von Zerssen Depression Scale, quality-of-life questionnaires, and a headache home diary (over 4 weeks). In addition, pressure pain thresholds (temporal muscles) and total tenderness scores were obtained. RESULTS: Patients with chronic TTH exhibited poorer quality-of-life measures, slightly more depressive symptoms, and significantly stronger avoidance behavior and endurance strategies on FQCI scales F4 and F5 (P< .05). There was no difference between episodic and chronic TTH with respect to measures of muscle tenderness or pain thresholds. CONCLUSIONS: We conclude that disadvantageous coping with illness strategies might contribute to a transformation to chronic TTH.     

Bilateral pressure pain sensitivity mapping of the temporalis muscle in chronic tension-type headache

Purpose.— To analyze pressure pain sensitivity maps in chronic tension-type headache (CTTH) and healthy controls over nine locations covering the temporalis muscle.
Background.— Lower pressure pain thresholds (PPT) have been found in craniofacial muscles in patients with CTTH. Since the temporalis muscle can play a relevant role in the genesis or maintenance of headache, the determination of pressure pain sensitivity maps of this muscle is needed.
Methods.— A pressure algometer was used to measure PPT over 9 points of the temporalis muscle (3 points in the anterior part of the muscle, another 3 in the middle of the muscle, and the remaining 3 in the posterior part) in 15 females suffering from CTTH and 10 healthy women. A pressure pain sensitivity map of both dominant and nondominant sides in patients and controls was calculated.
Results.— Chronic tension-type headache patients showed lower PPT as compared with healthy subjects ( P  < .01). Further, PPT levels of the nondominant side were lower than those on the dominant side for controls ( P  < .01). Within the CTTH group, more bilaterally homogeneous pressure pain sensitivity maps with PPT decreased from the posterior to anterior column were found, whereas among controls, PPT distribution maps were inhomogeneous with side-to-side differences.
Conclusions.— Our data may provide preliminary new key information about muscle sensitivity, since it seems that pressure pain sensitivity maps could be different between CTTH patients and healthy subjects. Further studies with greater sample sizes and other headache populations are now required to confirm our results.     

Genetic factors in migraine and chronic tension-type headache

Pathophysiological studies have dominated migraine research for several years. However, these studies are difficult to interpret because it is difficult to decide whether the observed phenomena are primary or secondary to the migraine attack. For that reason it is important that future migraine research focus on studies that concern migrain etiology. Migraine is a paroxysmal disorder. It is most likely and ion-channel disorder like familial hemiplegic migraine. The present paper focuses on genetic factors in migraine and chronic tension-type headache.     

Increased pericranial tenderness, decreased pressure pain threshold, and headache clinical parameters in chronic tension-type headache patients

OBJECTIVE: The aim was to investigate whether increased pericranial tenderness or decreased pressure pain threshold (PPT) was related to headache intensity, duration, and frequency in chronic tension-type headache (CTTH). METHODS: Twenty-five CTTH patients and 25 matched controls were studied. A headache diary was kept for 4 weeks to substantiate the diagnosis and record the pain history. Three tenderness (total, cephalic, and neck) scores and PPT at both cephalic and neck points were objectively and blinded assessed. Bodily pain perceived by the patients was assessed with the Short Form-36 questionnaire. RESULTS: CTTH patients showed decreased PPT and increased tenderness as compared with controls (P<0.001). Negative correlations were found between PPT on each point and their respective tenderness scores. Within the CTTH group, neither increased tenderness nor decreased PPT seemed to directly influence headache intensity, frequency or duration; or vice versa. DISCUSSION: Increased tenderness may predispose the patients to other perpetuating factors in inducing headache attacks. Further research is needed to clearly define the role of pericranial tender tissues or other factors in the genesis and maintenance of CTTH.     

Steady-state visual-evoked potentials in headache: diagnostic value in migraine and tension-type headache patients

We tested the hypothesis that migraine and tension-type headache are separate disorders based on visual evoked potentials. We recruited 120 migraine without aura patients (MwoA), 64 tension-type headache patients (TTH), and 51 healthy controls. We performed discriminant analysis combined with a stepwise selection of predictors. Mean values of the F1 component were significantly increased over Fp1, C3, P4, O2 and O1 electrodes in MwoA and TTH patients compared with normal subjects. Only the control subjects were correctly distinguished. The increased brain response to visual stimulation detected in both MwoA and TTH may suggest a common neuronal dysfunction in the two headache subtypes.     

Imipramine does not affect argon-laser-induced pin-prick pain thresholds and laser-evoked cerebral potentials

The tricyclic antidepressant imipramine has shown analgesic effect in human clinical and experimental pain studies. The aim of the present study was to test the effect of imipramine on a pure short-term nociceptive stimulus with pin-prick pain quality. In a randomized, placebo-controlled, double-blind, crossover study, the hypoalgesic effect of a single oral dose of 100 mg imipramine was investigated in 10 healthy volunteers. Test procedures performed before and 2, 4, 6, 8, 10, 12 and 14 h after medication included determination of warmth and pin-prick pain thresholds to high-energy argon laser light stimulation on the hand, as well as laser-evoked cerebral potentials to suprathreshold stimulation. Both the warmth and the pin-prick pain thresholds (p=0.49 and 0.85) and the root mean square of the laser-evoked potentials (p=0.89) were unaltered by imipramine. It is concluded that a single oral dose of 100 mg imipramine has no effect on pin-prick pain. This study demonstrates the important fact that a drug may show clear analgesic effect in some experimental pain models while it is without effect in other models; e.g. imipramine is known to affect pain tolerance and summation thresholds. Pre-clinical tests of potentially analgesic drugs should therefore be based on different pain-stimulation modalities.     

Processing capacity in chronic pain patients: a visual event-related potentials study

Chronic pain may impair performance on attentional processing capacity tasks. In the present study, event-related potentials were recorded to examine whether pain patients show performance decrements on attentional processing capacity tasks due to shared resources by pain and attention or, alternatively, due to deficits in allocating attentional resources during pain. Fourteen chronic pain patients and thirty age and education matched healthy controls were investigated. An attentional capacity probe task was used in which the difficulty level was manipulated, resulting in an easy and a difficult condition, while task-irrelevant visual probes were presented. These probe-elicited P3 amplitudes were assumed to provide the most pure estimate of processing capacity since they are relatively free from target-related processes. Event-related potentials were recorded from the midline electrodes Fz, Cz, Pz, and Oz. For the behavioral measures, it was found that pain patients maintained a different speed-accuracy tradeoff. Pain patients showed faster reaction time responses and higher error rates compared to controls. No significant differences were found between pain patients and controls on the primary task. Pain patients differed from controls with respect to amplitudes elicited by task-irrelevant probe stimuli. For healthy controls, the expected decreased amplitude was found for probe stimuli in the difficult compared to the easy task. In contrast, the pain patients did not show decreased probe amplitudes with increasing task load. The data may imply that allocation of attentional resources is deficient in pain patients, instead of attentional capacity.     

The blink reflex in chronic tension-type headache, migraine, and cervicogenic headache

R1 and R2 blink reflex latencies were investigated blind in 10 patients with cervicogenic headache, 11 patients with chronic tension-type headache, 11 patients with migraine, and 9 headache-free controls. There were no R1 or R2 latency differences between the four groups. The latency of R1 increased significantly with headache duration in tension-type headache patients. Shorter R1 latencies were found on the symptomatic side than on the non-symptomatic side in cervicogenic headache patients. The results suggest that a state of hyperactivity may be present in the ipsilateral trigeminal nucleus in cervicogenic headache. Hypoactivity, however, may develop over time in tension-type headache.     

Central pain modulation and scalp tenderness in frequent episodic tension-type headache

Objective.— To determine whether the inhibitory effect of acute limb pain on pain to mechanical stimulation of the forehead is compromised in individuals with frequent episodes of tension‐type headache. Background.— Central pain modulation processes are disrupted in patients with chronic tension‐type headache. This deficit in pain modulation might be a predisposing characteristic that increases vulnerability to tension‐type headache and to symptoms such as scalp tenderness, or could be a feature that develops secondarily during attacks and that persists for a few days afterward. To distinguish between these 2 possibilities in the present study, inhibitory pain control was investigated in participants with episodic rather than chronic tension‐type headache. Methods.— Pressure‐pain thresholds and sensitivity to sharpness in the forehead were measured in 34 individuals with 1‐10 episodes of tension‐type headache per month and in 32 controls before and after immersion of their hand in painfully cold water. Results.— Before the cold pressor test, pressure‐pain thresholds and sensitivity to the sharp stimulus were similar in both groups. Mild headache developed and pressure‐pain thresholds in the forehead decreased from 631 ± 178 g to 579 ± 196 g (mean ± SD) after the cold water immersion in the episodic tension‐type headache group (P < .05). However, sharpness ratings did not change (mean rating 3.2 ± 1.4 on a 0‐10 scale). In contrast, headache did not develop, pressure‐pain thresholds did not change, and sharpness ratings decreased from 3.0 ± 1.3 to 2.3 ± 1.1 after the immersion in controls (P < .01). Conclusions.— These findings suggest that endogenous pain modulation processes are compromised in individuals with frequent episodic tension‐type headache. This deficit could increase vulnerability to scalp tenderness and recurrent episodes of headache.     

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.