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.     

Patterns of experimentally induced pain in pericranial muscles

Nociceptive mechanisms in the craniofacial muscle tissue are poorly understood. The pain pattern in individual pericranial muscles has not been described before. Experimental muscle pain was induced by standardized infusions of 0.2 ml 1 m hypertonic saline into six craniofacial muscles (masseter, anterior temporalis, posterior temporalis, trapezius, splenius capitis and sternocleidomastoid) in 20 healthy subjects. The pressure pain thresholds (PPTs) were determined before and after infusions. The subjects continuously reported intensity of saline-induced pain on an electronic visual analogue scale (VAS) and the perceived area of pain was drawn on anatomical maps. The pain areas were measured and the localization determined by a new centre-of-gravity method. The PPTs were lowest on the sternocleidomastoid muscle (anova: P<0.001), but the saline-evoked VAS pain scored highest following injection into the masseter muscle (anova: P<0.05). The centre-of-gravity measures demonstrated significantly different localization of the pain areas (anova: P<0.001). The trigeminally vs. the cervically innervated muscles had significantly different patterns of spread and referral of pain according to trigeminally vs. cervically innervated dermatomes (P<0.005). In conclusion, there appear to be characteristic pain patterns and pain sensitivity in different craniofacial muscles in healthy volunteers, which may be of importance for further research on different craniofacial pain conditions.     

The local and referred pain from myofascial trigger points in the temporalis muscle contributes to pain profile in chronic tension-type headache

OBJECTIVE: To assess the local and referred pain areas and pain characteristics evoked from temporalis muscle trigger points (TrPs) in chronic tension-type headache (CTTH). METHODS: Thirty CTTH patients and 30 age and sex-matched controls were studied. A headache diary was kept for 4 weeks to substantiate the diagnosis and record the pain history. Both temporalis muscles were examined for the presence of myofascial TrPs in a blinded fashion. The local and referred pain intensities, referred pain pattern, and pressure pain threshold were recorded. RESULTS: Referred pain was evoked in 87% and 54% on the dominant and nondominant sides in CTTH patients, which was significantly higher (P<0.001) than in controls (10% vs. 17%, respectively). Referred pain spread to the temple ipsilateral to the stimulated muscle in both patients and controls, with additional referral behind the eyes in most patients, but none in controls. CTTH patients reported a higher local [visual analog scale (VAS): 5.6+/-1.2 right side, 5.3+/-1.4 left side] and referred pain (VAS: 4.7+/-2 right side, 3.5+/-2.8 left side) intensity than healthy controls (VAS: 0.8+/-0.7 right side, 0.7+/-0.7 left side for local pain; and 0.3+/-0.2 right side, 0.4+/-0.3 left side for referred pain) in both temporalis muscles (both, P<0.001). The local and referred pain areas were larger in patients than in controls (P<0.001). Twenty-three out of 30 CTTH patients (77%) had active TrPs in the temporalis muscle leading to their usual headache (17 patients on the right side; 12 on the left side, whereas 6 with bilateral active TrPs). CTTH patients with active TrPs in either right or left temporalis muscle showed longer headache duration than those with latent TrPs (P=0.004). CTTH patients showed significantly (P<0.001) lower pressure pain threshold (1.1+/-0.2 right side, 1.2+/-0.3 left side) as compared with controls (2.5+/-0.5 right side, 2.6+/-0.4 left side). CONCLUSIONS: In CTTH patients, the evoked local and referred pain from active TrPs in the temporalis muscle and its sensory characteristics shared similar patterns as their habitual headache pain. Local and referred pain from active TrPs in the temporalis muscles may constitute one of the sources contributing to the pain profile of CTTH.     

Referred pain from trapezius muscle trigger points shares similar characteristics with chronic tension type headache.

Referred pain and pain characteristics evoked from the upper trapezius muscle was investigated in 20 patients with chronic tension-type headache (CTTH) and 20 age- and gender-matched controls. A headache diary was kept for 4 weeks in order to confirm the diagnosis and record the pain history. Both upper trapezius muscles were examined for the presence of myofascial trigger points (TrPs) in a blinded fashion. The local and referred pain intensities, referred pain pattern, and pressure pain threshold (PPT) were recorded. The results show that referred pain was evoked in 85% and 50% on the dominant and non-dominant sides in CTTH patients, much higher than 55% and 25% in controls (P<0.01). Referred pain spread to the posterior-lateral aspect of the neck ipsi-lateral to the stimulated muscle in both patients and controls, with additional referral to the temple in most patients, but none in controls. Nearly half of the CTTH patients (45%) recognized the referred pain as their usual headache sensation, i.e. active TrPs. CTTH patients with active TrPs in the right upper trapezius muscle showed greater headache intensity and frequency, and longer headache duration than those with latent TrPs. CTTH patients with bilateral TrPs reported significantly decreased PPT than those with unilateral TrP (P<0.01). Our results showed that manual exploration of TrPs in the upper trapezius muscle elicited referred pain patterns in both CTTH patients and healthy subjects. In CTTH patients, the evoked referred pain and its sensory characteristics shared similar patterns as their habitual headache pain, consistent with active TrPs. Our results suggest that spatial summation of perceived pain and mechanical pain sensitivity exists in CTTH patients.     

Magnetic resonance imaging study of the morphometry of cervical extensor muscles in chronic tension-type headache

This study analyses the differences in the relative cross-sectional area (rCSA) of several cervical extensor muscles, assessed by magnetic resonance imaging (MRI), between patients with chronic tension-type headache (CTTH) and healthy controls. MRI of the cervical spine was performed on 15 CTTH females and 15 matched controls. The rCSA values for the rectus capitis posterior minor (RCPmin), rectus capitis posterior major (RCPmaj), semispinalis capitis and splenius capitis muscles were measured from axial T1-weighted images using axial MR slices aligned parallel to the C2/3 intervertebral disc. A headache diary was kept for 4 weeks in order to substantiate the diagnosis and record the pain history. CTTH patients showed reduced rCSA for both RCPmin and RCPmaj muscles (P < 0.01), but not for semispinalis and splenius capitis muscles, compared with controls. Headache intensity, duration or frequency and rCSA in both RCPmin and RCPmaj muscles were negatively correlated (P < 0.05): the greater the headache intensity, duration or frequency, the smaller the rCSA in the RCPmin and RCPmaj muscles. CTTH patients demonstrate muscle atrophy of the rectus capitis posterior muscles. Whether this selective muscle atrophy is a primary or secondary phenomenon remains unclear. In any case, muscle atrophy could possibly account for a reduction of proprioceptive output from these muscles, and thus contribute to the perpetuation of pain.     

Possible mechanisms of glyceryl-trinitrate-induced immediate headache in patients with chronic tension-type headache

Nitric oxide (NO) plays an important role in the pathophysiology of primary headaches including chronic tension-type headache (CTTH). Thus, a NO synthase inhibitor reduces headache and muscle hardness while the NO donor glyceryl trinitrate (GTN) causes more headache in patients than in healthy controls. Sensitization of myofascial pain pathways is important in CTTH, and the aim of the present study was to investigate if such mechanisms may also explain GTN-induced immediate headache in patients with CTTH. In a randomized, double-blind, crossover study 16 patients with CTTH and 16 healthy subjects received intravenous infusion of GTN (0.5 microg/kg per min for 20 min) or placebo on two headache-free days separated by at least 1 week. Muscle hardness, myofascial tenderness, mechanical and heat pain thresholds were measured at baseline and at 60 min and 120 min after start of infusion. In patients, GTN infusion resulted in a biphasic response with immediate headache and more pronounced delayed headache. A similar but less pronounced response was seen in controls. There was no difference between GTN and placebo regarding muscle hardness, myofascial tenderness or pressure and heat pain thresholds in either patients or controls (P>0.05). The unchanged sensitivity of pericranial myofascial pain pathways indicates that peripheral and central sensitization is not involved in the mechanisms of GTN-induced immediate headache.     

Patients with chronic tension-type headache demonstrate increased mechano-sensitivity of the supra-orbital nerve

OBJECTIVE: This study aimed to establish whether increased sensitivity to mechanical stimuli is present in neural tissues in chronic tension-type headache (CTTH). BACKGROUND: Muscle hyperalgesia is a common finding in CTTH. No previous studies have investigated the sensitivity of peripheral nerves in patients with CTTH. DESIGN: A blinded controlled study. METHODS: Pressure pain thresholds (PPT) and pain intensity following palpation of the supra-orbital nerve (V1) were compared between 20 patients with CTTH and 20 healthy matched subjects. A pressure algometer and numerical pain rate scale were used to quantify PPT and pain to palpation. A headache diary was kept for 4 weeks to substantiate the diagnosis and record the pain history. RESULTS: The analysis of variance demonstrated significantly lower PPT for patients (0.86+/-0.13 kg/cm2) than controls (1.50+/-0.19 kg/cm2) (P<.001). Pain to palpation was also higher for patients (2.73+/-1.58) than controls (0.15+/-0.28) (P<.001).Within the CTTH group, intensity, frequency, and duration of the headaches were negatively correlated with PPT (rsor=0.72; P<.001). CONCLUSIONS: These findings reveal that mechanical hypersensitivity is not limited to muscles but also occurs in cranial nerves, and that the level of sensitization, either due to peripheral or central processes, is related to the severity of the primary 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.     

The effect of sodium valproate on chronic daily headache and its subgroups

The objective of the study was to assess the efficacy and tolerability of sodium valproate (VPA) on chronic daily headache (CDH) in a prospective, double-blind, randomized, placebo-controlled trial. Seventy patients were included in the study. Twenty-nine had chronic migraine (CM) and 41 had chronic tension-type headache (CTTH). VPA and placebo were applied for 3 months to 40 and 30 patients, respectively. Visual analog scale (VAS) and pain frequency (PF) were used for evaluation. VPA decreased the maximum pain VAS levels (MaxVAS) and PF at the end of the study (P = 0.028 and P = 0.000, respectively), but did not change general pain VAS (GnVAS) levels (P = 0.198). In CM patients, the decreases in MaxVAS, GnVAS and PF parameters were more in VPA treated patients (P = 0.006, P = 0.03, and P = 0.000, respectively). VPA treatment caused more reduction in PF than placebo in the CTTH subgroup (P = 0.000). VPA is effective in the prophylactic treatment of CDH by reducing MaxVAS levels and PF. It was more effective in CM than in CTTH. This study was presented as a poster at “8th Headache Congress Of The European Headache Federation” in Valencia, Spain, between 26–29 April, 2006 and published as an abstract in The Journal of Headache and Pain, Vol 7, Suppl 1 S39 April 2006. An editorial commentary on this article can be found at .     

Myofascial trigger points and their relationship to headache clinical parameters in chronic tension-type headache

OBJECTIVE: To assess the presence of trigger points (TrPs) in several head and neck muscles in subjects with chronic tension-type headache (CTTH) and in healthy subjects; and to evaluate the relationship of these TrPs with forward head posture (FHP), headache intensity, duration, and frequency. BACKGROUND: Tension-type headache (TTH) is a headache in which myofascial TrPs in head and neck muscles might play an important etiologic role. DESIGN: A blinded, controlled, pilot study. METHODS: Twenty-five CTTH subjects and 25 matched controls without headache were studied. TrPs in bilateral upper trapezius, sternocleidomastoids, and temporalis muscles were identified according to Simons et al's diagnostic criteria: tenderness in a hyperirritable spot within a palpable taut band, local twitch response elicited by snapping palpation, and elicited referred pain with palpation. A TrP was considered active if the subject recognized the evoked referred pain as familiar headache. If the evoked referred pain was not recognized as familiar headache, the TrP was considered as latent. Side-view pictures of each subject were taken in both sitting and standing positions in order to assess FHP by measuring the cranio-vertebral angle. Both measurements were made by a blinded assessor. A headache diary was kept for 4 weeks in order to assess headache intensity, frequency, and duration. RESULTS: The mean number of TrPs on each CTTH subject was 3.9 (SD: 1.2), of which 1.9 (SD: 1.2) were active TrPs and 1.9 (SD: 0.8) were latent TrPs. Control subjects only exhibited latent TrPs (mean: 1.4; SD: 0.8). There was a significant difference between the CTTH group and the controls for active TrPs (P < .001), but not for latent TrPs (P > .05). Differences in the distribution of active and latent TrPs within each muscle were also significant for all the analyzed muscles (P < .01). CTTH subjects with active TrPs in the right upper trapezius muscle or left sternocleidomastoid muscle showed a greater headache intensity and duration, but not headache frequency, compared to those with latent TrPs (P < .05). Active TrPs in the right temporalis muscle were associated with longer headache duration (P < .01), whereas active TrPs in the left temporalis muscle were associated with greater headache intensity (P < .05). CTTH subjects with active TrPs in the analyzed muscles had a greater FHP than those with latent TrPs in both sitting and standing positions. Differences were only significant for TrPs in the left sternocleidomastoid and FHP in the sitting position (P < .01). CONCLUSIONS: Active TrPs in upper trapezius, sternocleidomastoid, and temporalis muscles were associated with CTTH. CTTH subjects with active TrPs usually reported a greater headache intensity and longer headache duration than those with latent TrPs. CTTH subjects with active TrPs tended to have a greater FHP than CTTH subjects with latent TrPs.     

Myofascial trigger points and sensitization: an updated pain model for tension-type headache

Present pain models for tension-type headache suggest that nociceptive inputs from peripheral tender muscles can lead to central sensitization and chronic tension-type headache (CTTH) conditions. Such models support that possible peripheral mechanisms leading to pericranial tenderness include activation or sensitization of nociceptive nerve endings by liberation of chemical mediators (bradikinin, serotonin, substance P). However, a study has found that non-specific tender points in CTTH subjects were not responsible for liberation of algogenic substances in the periphery. Assuming that liberation of algogenic substances is important, the question arising is: if tender muscle points are not the primary sites of on-going neurogenic inflammation, which structure can be responsible for liberation of chemical mediators in the periphery? A recent study has found higher levels of algogenic substances, and lower pH levels, in active myofascial trigger point (TrPs) compared with control tender points. Clinical studies have demonstrated that referred pain elicited by head and neck muscles contribute to head pain patterns in CTTH. Based on available data, an updated pain model for CTTH is proposed in which headache can at least partly be explained by referred pain from TrPs in the posterior cervical, head and shoulder muscles. In this updated pain model, TrPs would be the primary hyperalgesic zones responsible for the development of central sensitization in CTTH.     

The use of electromyography and muscle palpation in the diagnosis of tension-type headache with and without pericranial muscle involvement.

The Headache Classification Committee of the International Headache Society recently issued revised diagnostic criteria for headache disorders. According to these criteria, tension-type headache may be subclassified depending upon whether pericranial muscle disorder is found. The presence or absence of pericranial muscle disorder was to be determined by palpating the muscles for tenderness or by measuring electromyographic (EMG) activity. In this study, pericranial muscles were palpated, and EMG activity was measured in 27 episodic tension-type headache patients and 32 headache-free controls. All testing was done while the subjects were in a headache-free state. Muscle tenderness was positively associated with the diagnosis of tension-type headache. Headache subjects exhibited significantly higher levels of temporal EMG activity compared to controls, but EMG data were of little use in assigning individual subjects to diagnostic groups. Measures of muscle tenderness and hyperactivity were only weakly associated. Pericranial muscle tenderness and elevated EMG activity may index different aspects of abnormal muscle function.     

Pain sensitivity and pain reactivity of pericranial muscles in migraine and tension-type headache

We investigated whether experimentally determined, suprathreshold pain sensitivity of pericranial musculature in patients with tension-type headache differs from that of migraine patients or from that of healthy subjects. Furthermore, we looked to see whether differences could be found in the effects of experimental pain induction on EMG activity of pericranial musculature and whether subgroups could be discovered with higher and lower pericranial pain sensitivity within the three diagnostic groups in terms of neurophysiological, psychological and clinical variables. In 20 patients with tension-type headache, 23 patients with migraine without aura, and 29 healthy individuals experimental pain was induced in the temporal muscle by mechanical pressure; pain sensitivity in the entire metrically subdivided suprathreshold pain sensitivity range was measured. Surface EMG activity of pericranial muscles was determined before, during and after experimental pain induction. In addition, headache characteristics as well as personality and mood states were determined and recorded in a standardized fashion. There were no significant differences in pain sensitivity of pericranial musculature between the three groups. Patients with tension-type headache showed significantly higher EMG scores during suprathreshold pain stimulation than did migraine patients. EMG scores of healthy subjects fell between these two groups. With respect to pericranial tenderness significant differences in clinical, neurophysiological and psychological variables were found only between subgroups within the group of patients with tension-type headache. The results indicate that significant differences in the examined groups are found not in pain perception but in the processing or reaction to experimental headache stimuli. In patients with tension-type headache subgroups evolve based on pericranial pain sensitivity with quantitatively and/or qualitatively impaired reactions; for this reason diagnostic grouping according to the IHS classification seems to be pathophysiologically relevant. The intraindividual phasic comparison of pain reactions appears to be more important than the absolute interindividual tonic comparison.     

Generalized hyperalgesia in patients with chronic tension-type headache

Increased pain sensitivity in the central nervous system may play an important role in the pathophysiology of chronic tension-type headache (CTTH). Previous studies using pain thresholds as a measure of central pain sensitivity have yielded inconsistent results and only a few studies have examined perception of muscle pain without involvement of adjacent tissues. It has been suggested that suprathreshold testing might be more sensitive than threshold measurements in evaluation of central hyperexcitability in CTTH. The aim of the study was to compare pain ratings to suprathreshold single and repetitive (2 Hz) electrical stimulation of muscle and skin in cephalic (temporal and trapezius) and extracephalic (anterior tibial) regions between patients with CTTH and healthy subjects. In addition, we aimed to examine gender differences in pain ratings to suprathreshold stimulation and degree of temporal summation of pain between patients and controls. Pain ratings to both single and repetitive suprathreshold stimulation were higher in patients than in controls in both skin and muscle in all examined cephalic and extracephalic regions (P < 0.04). Pain ratings to both single and repetitive suprathreshold electrical stimulation were significantly higher in female compared with male patients (P < 0.001) and in female compared with male controls (P < or = 0.001). The degree of temporal summation of muscular and cutaneous pain tended to be higher in patients than in controls but the differences were not statistically different. This study provides evidence for generalized increased pain sensitivity in CTTH and strongly suggests that pain processing in the central nervous system is abnormal in this disorder. Furthermore, it indicates that suprathreshold stimulation is more sensitive than recording of pain thresholds for evaluation of generalized pain perception.     

Decreased sensitivity of 5-HT1D receptors in chronic tension-type headache

OBJECTIVE: To assess the sensitivity of 5-HT1D receptors in chronic tension-type headache using sumatriptan as a pharmacological probe. BACKGROUND: Previous studies have suggested involvement of serotonergic systems in chronic tension-type headache (CTTH), but relevant experimental data are limited. Sumatriptan, a 5-HT1B/1D receptor agonist, stimulates the release of growth hormone (GH) and inhibits the release of ACTH, cortisol, and prolactin. These effects may be used to explore the function of serotonergic systems in vivo. METHODS: We measured GH, ACTH, cortisol and prolactin (PRL) plasma concentrations in 15 patients with chronic tension-type headache and in 18 healthy controls after subcutaneous administration of sumatriptan (6 mg) or placebo. RESULTS: Placebo administration had no effect on hormone concentrations. GH and PRL secretion after sumatriptan administration was significantly (P<0.01 and <0.05) altered in CTTH patients in comparison with controls. CONCLUSION: Our results suggest that cerebral serotonergic functions mediated by 5-HT1D receptors are altered in CTTH.     

Exteroceptive suppression periods and pericranial muscle tenderness in chronic tension-type headache: effects of psychopathology, chronicity and disability

We examined pericranial muscle tenderness and abnormalities in the second exteroceptive suppression period (ES2) of the temporalis muscle in chronic tension-type headache (CTTH; n = 245) utilizing a blind design and methods to standardize the elicitation and scoring of these variables. No ES2 variable differed significantly between CTTH sufferers and controls (all tests, P>0.05). We found no evidence that CTTH sufferers with daily or near daily headaches, a mood or an anxiety disorder, or high levels of disability exhibit abnormal ES2 responses (all tests, P>0.05). CTTH sufferers were significantly more likely than controls to exhibit pervasive tenderness in pericranial muscles examined with standardized (500 g force) manual palpation (P<0.005). Female CTTH sufferers exhibited higher levels of pericranial muscle tenderness than male CTTH sufferers at the same level of headache activity (P<0.0001). Elevated pericranial muscle tenderness was associated with a comorbid anxiety disorder. These findings provide further evidence of pericranial hyperalgesia in CTTH and suggest this phenomenon deserves further study. Basic research that better elucidates the biological significance of the ES2 response and the factors that influence ES2 assessments appears necessary before this measure can be of use in clinical research.     

Myofascial trigger points in the suboccipital muscles in episodic tension-type headache

Referred pain evoked by suboccipital muscle trigger points (TrPs) spreads to the side of the head over the occipital and temporal bones and is usually perceived as bilateral headache. This paper describes the presence of referred pain from suboccipital muscle TrPs in subjects with episodic tension-type headache (ETTH) and in healthy controls. Ten patients presenting with ETTH and 10 matched controls without headache were examined by a blinded assessor for the presence of suboccipital muscle TrPs. Diagnostic criteria described by Simons and Gerwin were adapted to diagnose TrPs, i.e. presence of tenderness in the suboccipital region, referred pain evoked by maintained pressure for 10 s, and increased referred pain on muscle contraction. Six ETTH patients (60%) had active TrPs and 4 had latent TrPs (40%). On the other hand, 2 control subjects also had latent TrPs. Differences in the presence of suboccipital muscle TrPs between both groups were significant for active TrPs (P<0.001), but not for latent TrPs. Active TrPs were only present in ETTH patients, although TrP activity was not related to any clinical variable concerning the intensity and the temporal profile of headache. Myofascial TrPs in the suboccipital muscles might contribute to the origin and/or maintenance of headache, but a comprehensive knowledge of the role of these muscles in tension-type headache awaits further research.     

Abnormal modulatory influence of diffuse noxious inhibitory controls in migraine and chronic tension-type headache patients

The aim of this study was to evaluate the function of pain modulating systems subserving diffuse noxious inhibitory controls (DNICs) in primary headaches. DNICs were examined in 24 migraineurs, 17 patients with chronic tension-type headache (CTTH) and 20 healthy subjects by means of nociceptive flexion RIII reflex and the cold pressor test (CPT) as heterotopic noxious conditioning stimulation (HNCS). The subjective pain thresholds (Tp) and the RIII reflex threshold (Tr) were significantly lower in CTTH vs. controls. In controls a significant inhibition of the RIII reflex was observed during the CPT (-30%, P < 0.05). Conversely, migraine and CTTH patients showed facilitation (+31%, P < 0.05 and +40%, P < 0.01, respectively) of the RIII reflex during the HNCS. This study demonstrates a dysfunction in systems subserving DNICs in both migraine and CTTH. Impairment of endogenous supraspinal pain modulation systems may contribute to the development and/or maintenance of central sensitization in primary headaches.     

Cervical muscle co-activation in isometric contractions is enhanced in chronic tension-type headache patients

The purpose of the study was to compare the co-activation of cervical agonist and antagonist muscles between people with chronic tension-type headache (CTTH) and healthy controls during brief isometric cervical flexion and extension contractions. Nine women with CTTH and 10 matched controls participated. Surface electromyographic (EMG) signals were detected from the sternocleidomastoid and splenius capitis muscles bilaterally during cervical flexion and extension contractions of linearly increasing force from 0% to 60% of the maximum voluntary contraction (MVC) in 3 s. Sternocleidomastoid and splenius capitis EMG average rectified values (ARV) were estimated at 10% MVC force increments. During cervical extension contraction, sternocleidomastoid (i.e. antagonist muscle) ARV was greater for patients than for controls in the force range 20–60% MVC ( P  = 0.029). During cervical flexion, the left splenius capitis (i.e. antagonist muscle) ARV was greater for CTTH patients regardless of the force level ( P  = 0.02). Maximum cervical flexion and extension force was lower for the CTTH patients compared with controls ( P  = 0.001). In conclusion, women with CTTH demonstrated greater co-activation of antagonist musculature during cervical extension and flexion contractions compared with healthy women. Increased co-activation of antagonist musculature may reflect reorganization of the motor control strategy in CTTH patients, potentially leading to muscle overload and increased nociception.     

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.