Relationship between chronic tension-type headache, cranial hemodynamics, and cerebrospinal pressure: study involving provocation with sumatriptan

OBJECTIVE: To study the relationship between chronic tension-type headache, cranial hemodynamics, and cerebrospinal pressure. BACKGROUND: Cerebrospinal pressure has been found to be above 200 mm in about 50% of patients with chronic tension-type headache. METHODS: Heart rate, blood pressure, common carotid artery diameter and blood flow, and craniovascular resistance and pain at regular intervals before, during, and after head-down tilt-a procedure which increases cerebrospinal pressure, were recorded. After head-down tilt, subcutaneous injections of either placebo or 6 mg of sumatriptan were administered. Chronic tension-type headache intensity before and after withdrawal of 20 mL of cerebrospinal fluid was documented. Cerebrospinal pressure and chronic tension-type headache intensity were measured after subcutaneous injection of 6 mg of sumatriptan. RESULTS: Head-down tilt provoked an increase of headache compared with baseline. Common carotid artery blood flow decreased and craniovascular resistance increased after sumatriptan injection, but not after placebo injection. The pain decreased after head-down tilt and placebo injection, but not after sumatriptan injection. Chronic tension-type headache intensity decreased in all 4 patients studied after withdrawal of 20 mL of cerebrospinal fluid. Cerebrospinal pressure increased in 5 patients with chronic tension-type headache after subcutaneous injection of 6 mg of sumatriptan with slight or no increase of pain. CONCLUSION: The results indicated that cerebrospinal pressure or intracranial venous pressure (or both) are related to chronic tension-type headache.     

Is chronic tension-type headache a vascular headache? The relation between chronic tension-type headache and cranial hemodynamics

Twenty-seven patients with chronic tension-type headache were studied as to end-tidal PCO2, heart rate, mean blood pressure, diameter and blood flow of the common carotid arteries, cranial vascular resistance, and headache intensity at supine rest, after administration of nitroglycerin, and at head down tilt. The results were compared to the results of nitroglycerin and head down tilt provocations in age- and sex-matched controls. During supine rest, no change in chronic tension-type headache occurred. Nitroglycerin and tilting induced significant increase of the headache intensity compared to baseline in patients with chronic tension-type headache (P=0.01 and P<0.05, respectively) in contradistinction to controls who did not develop significant headache. Common carotid artery blood flow changes were similar during nitroglycerin provocations in the two groups, but greater (P<0.05) during head down tilt in patients than in controls. Lumbar cerebrospinal fluid pressure was found to be greater than 20 but less than 26 cm H2O in 45% of the 22 patients studied with chronic tension-type headache. The results indicate that the pain in chronic tension-type headache is related to cranial hemodynamics, presumably to distention of intracranial veins.     

Effects of increasing the intracranial blood volume in cluster headache patients and controls

Eleven patients with episodic cluster headache in period, five patients out of period and six controls were studied concerning the effects of an increase of the intracranial blood volume by tilting. Common carotid artery (CCA) blood flow was similar in all three groups at baseline and during tilting. CCA diameters were similar at baseline and increased during tilting in all three groups, indicating that tilting caused an increase in the extra- and intracranial blood volume. Unilateral pain or sympathetic dysfunction did not appear during tilting in the patients out of period or in the controls. In four of eight studied patients with cluster headache in period, unilateral miosis and ptosis appeared during tilting. Two of these four patients developed intense unilateral pain, while the other two did not report any pain. Four other patients developed slight unilateral pain but no sympathetic dysfunction during tilting.     

Muscular Factors are of Importance in Tension-Type Headache

Recent studies have indicated that muscular disorders may be of importance for the development of increased pain sensitivity in patients with chronic tension-type headache. The objective of the present study was to investigate this hypothesis by examining the pain perception in tension-type headache with and without muscular disorders defined as increased tenderness. We examined 28 patients with episodic tension-type headache, 28 patients with chronic tension-type headache, and 30 healthy controls. Pericranial myofascial tenderness was recorded with manual palpation, and pressure pain detection and tolerances in cephalic and extracephalic locations with an electronic pressure algometer. In addition, thermal pain sensitivity and electromyographic activity were recorded. The main result was significantly lower pressure pain detection thresholds and tolerances in all the examined locations in patients with chronic tension-type headache with a muscular disorder compared to those without a muscular disorder. There were no such differences in any of the examined locations when the two subgroups of patients with episodic tension-type headache were compared. Thermal pain sensitivity did not differ between patients with and without a muscular disorder, while electromyographic activity levels were significantly higher in patients with chronic tension-type headache with than in those without a muscular disorder. Our results strongly indicate that prolonged nociceptive stimuli from the pericranial myofascial tissue sensitize the central nervous system and, thereby, lead to an increased general pain sensitivity. Muscular factors may, therefore, be of major importance for the conversion of episodic into chronic tension-type headache. The present study complements the understanding of the important interactions between peripheral and central factors in tension-type headache and may lead to a better prevention and treatment of the most prevalent type of headache.     

Central sensitization in tension-type headache--possible pathophysiological mechanisms

The aim of the present thesis was to investigate the pathophysiology of chronic tension-type headache with special reference to central mechanisms. Increased tenderness to palpation of pericranial myofascial tissues is the most apparent abnormality in patients with tension-type headache. A new piece of equipment, a so-called palpometer, that makes it possible to control the pressure intensity exerted during palpation, was developed. Thereafter, it was demonstrated that the measurement of tenderness could be compared between two observers if the palpation pressure was controlled, and that the Total Tenderness Scoring system was well suited for the scoring of tenderness during manual palpation. Subsequently, it was found that pressure pain detection and tolerance thresholds were significantly decreased in the finger and tended to be decreased in the temporal region in chronic tension-type headache patients compared with controls. In addition, the electrical pain threshold in the cephalic region was significantly decreased in patients. It was concluded that the central pain sensitivity was increased in the patients probably due to sensitization of supraspinal neurones. The stimulus-response function for palpation pressure vs. pain was found to be qualitatively altered in chronic tension-type headache patients compared with controls. The abnormality was related to the degree of tenderness and not to the diagnosis of tension-type headache. In support of this, the stimulus-response function was found to be qualitatively altered also in patients with fibromyalgia. It was concluded that the qualitatively altered nociception was probably due to central sensitization at the level of the spinal dorsal horn/trigeminal nucleus. Thereafter, the prophylactic effect of amitriptyline, a non-selective serotonin (5-HT) reuptake inhibitor, and of citalopram, a highly selective 5-HT reuptake inhibitor, was examined in patients with chronic tension-type headache. Amitriptyline reduced headache significantly more than placebo, while citalopram had only a slight and insignificant effect. It was concluded that the blockade of 5-HT reuptake could only partly explain the efficacy of amitriptyline in tension-type headache, and that also other actions of amitriptyline, e.g. reduction of central sensitization, were involved. Finally, the plasma 5-HT level, the platelet 5-HT level and the number of platelet 5-HT transporters were found to be normal in chronic tension-type headache. On the basis of the present and previous studies, a pathophysiological model for tension-type headache is presented. According to the model, the main problem in chronic tension-type headache is central sensitization at the level of the spinal dorsal horn/trigeminal nucleus due to prolonged nociceptive inputs from pericranial myofascial tissues. The increased nociceptive input to supraspinal structures may in turn result in supraspinal sensitization. The central neuroplastic changes may affect the regulation of peripheral mechanisms and thereby lead to, for example, increased pericranial muscle activity or release of neurotransmitters in the myofascial tissues. By such mechanisms the central sensitization may be maintained even after the initial eliciting factors have been normalized, resulting in the conversion of episodic into chronic tension-type headache. Future basic and clinical research should aim at identifying the source of peripheral nociception in order to prevent the development of central sensitization and at ways of reducing established sensitization. This may lead to a much needed improvement in the treatment of chronic tension-type headache and other chronic myofascial pain conditions.     

Initiating mechanisms of experimentally induced tension-type headache

To elucidate possible myofascial mechanisms of tension-type headache, the effect of 30 min of sustained tooth clenching (10% of maximal EMG-signal) was studied in 58 patients with tension-type headache and in 30 age- and sex-matched controls. Pericranial tenderness, mechanical and thermal pain detection and tolerance thresholds and FMG levels were recorded before and after the clenching procedure. Within 24 h, 69% of patients and 17% of controls developed a tension-type headache. Shortly after clenching, tenderness was increased in the group who subsequently developed headache, whereas tenderness was stable in the group of patients who remained headache free. Mechanical pain thresholds evaluated by pressure algometry remained unchanged in the group which developed headache, whereas thresholds increased in the group which did not develop headache Thermal pain detection and tolerance thresholds remained unchanged in both groups. These findings indicate that, though there may be several different mechanisms of tension-type headache, one of them is sustained muscle contraction. A peripheral mechanism of tension-type headache is therefore possible, whereas a secondary segmental central sensitization seems to be involved in subjects with frequent, tension-type headache. Finally, the increase in pressure pain thresholds in patients who did not develop headache suggested that clenching activated their antinociceptive system, whereas those developing headache were, unable to do so.     

Comparative study with EMG, pressure algometry and manual palpation in tension-type headache and migraine

According to International Headache Society classification criteria, the presence of pericranial muscle disorder in tension-type headache should be evaluated using one of the following methods: EMG, pressure algometry or manual palpation. The purpose of this study was to compare the results of these three methods in 15 patients with episodic tension-type headache, 29 with chronic tension-type headache and 22 presenting migraine without aura compared to those obtained in healthy individuals. Algometric and EMG recordings at the frontalis muscle during mental arithmetic were more impaired in episodic and chronic tension headache patients than in controls and migraine patients. Chronic tension headache patients were significantly impaired at the trapezius muscle in all three tests compared to controls. Our data indicate that when two or three tests were carried out the diagnostic capacity was significantly improved in comparison to only one test. Moreover, since a different pattern could be seen with pain and without pain, the existence of headache at the time of testing should be taken into consideration.     

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.     

Postlumbar Puncture Headache and its Relation to Chronic Tension-Type Headache

One hundred consecutive patients, the majority suffering from bilateral chronic tension-type headache, investigated with lumbar puncture, were studied as to age, sex, body mass index, diagnosis, lumbar cerebrospinal fluid pressure, and signs of inflammation in the serum in relation to postlumbar puncture headache. Patients younger than 40 years of age were significantly more prone to develop postlumbar puncture headache than patients older than 40 years of age ( P =0.01). Sex, body mass index, cerebrospinal fluid pressure, and signs of inflammation in the serum were not related to the frequency of postlumbar puncture headache in the present study. Postlumbar puncture headache occurred significantly more often in patients with bilateral chronic tension-type headache than in patients with unilateral headache ( P =0.02) and in patients without headache ( P <0.01). In a regression analysis with age, sex, and chronic tension-type headaches, only bilateral headache contributed significantly to the prediction of postlumbar puncture headache ( P <0.01). Age did not contribute apart from the common variance with chronic tension-type headache/no chronic tension-type headache. The results may indicate that postlumbar puncture headache and chronic tension-type headache have etiologic mechanisms in common, mechanisms presumably localized intracranially rather than extracranially.     

Increased muscle pain sensitivity in patients with tension-type headache

Nociceptive mechanisms in tension-type headache are poorly understood. The aim was to investigate the pain sensitivity of pericranial muscles and a limb muscle in patients with tension-type headache. Experimental muscle pain was induced by standardized infusions of 0.5 ml of 1 M hypertonic saline into two craniofacial muscles (anterior temporalis (TPA) and masseter (MAS)) and a limb muscle (anterior tibial (TA)) in 24 frequent episodic tension-type headache patients (FETTH), 22 chronic tension-type headache patients (CTTH) and 26 age and gender matched healthy subjects. Headache patients were examined twice, both on days with and on days without headache. 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. Headache patients demonstrated significantly lower PPTs, higher saline-evoked VAS pain scores and greater pain areas than healthy subjects at all the tested muscle sites (P<0.05). There was a significant gender difference for the PPTs in all three groups of participants (P<0.05) and for VAS pain scores in the CTTH patients (P<0.05). There was no difference in pain sensitivity between FETTH and CTTH or between patients with or without headache. In conclusion, the present study demonstrates the presence of generalized pain hypersensitivity both in FETTH and CTTH compared to controls which is unrelated to actual headache status and extends to include responses to longer-lasting stimuli which are clinically highly relevant. Gender differences in deep pain sensitivity seem to be a consistent finding both in healthy controls and patients with tension-type headache.     

The auditory event related potentials in episodic and chronic pain sufferers.

To examine the cognitive processing differences in chronic and episodic pain sufferers, auditory event-related potentials (P300 or P3) were recorded in two consecutive trials from 23 chronic lower back pain patients, 22 episodic tension-type headache sufferers, and from 23 age- and sex-matched healthy persons. P3 latency and amplitude showed no difference between groups at first trial. Considering P3 latency habituation, healthy controls and episodic tension-type headache sufferers showed a significant change of P3 latency whereas lower back pain sufferers failed. Comparing the amount of habituation lower back pain sufferers stood clearly apart from healthy controls. Although there was a remarkable increase of P3 latency in episodic tension-type headache sufferers, the amount of habituation was not statistically different than it was in lower back pain sufferers. Significant P3 amplitude habituation was observed only in healthy controls. Actually, episodic tension-type headache sufferers also showed some degree of habituation, which was not statistically remarkable. The amount of amplitude habituation was not different between groups. No correlation was observed between P3 habituation and age, disease duration and symptom severity. These results may point to a disturbed attentional processing in chronic pain sufferers. Our findings suggest that in spite of a similar cortical information processing, the neurocognitive networks related with decision making and memory processing seem to work differently in chronic pain sufferers from those in episodic pain sufferers in repeating tasks. Taking into consideration the reported P3 habituation abnormalities in chronic migraine patients we can say that not the location of pain but rather its temporal pattern may have a role in disturbed attentional processing.     

Autonomic Function Testing in Patients with Tension-Type Headache

SYNOPSIS
Autonomic nervous system function was studied in 51 patients with tension-type headache. The Valsalva manoeuvre, deep breathing test, sustained handgrip test, orthostatic test and spectral analysis of heart rate variability in the supine and standing positions were performed in a group of 51 patients of both sexes aged 21 to 50 years and in an age-matched control group of 45 healthy volunteers.
Diastolic blood pressure increase and particularly heart rate increase during sustained handgrip were significantly reduced in the headache group, when compared to the control group, while the results of the remaining tests did not significantly differ between the control and headache groups. No significant differences were found between the episodic (19 patients) and chronic (32 patients) tension-type headache subgroups.
It is concluded that sympathetic function is impaired in tension-type headache patients.     

Study of Pressure Pain and Cellular Concentration of Neurotransmitters Related to Nociception in Episodic Tension-Type Headache Patients

The pressure pain threshold of 30 patients affected by tension-type headache was assessed and the values compared with those of a group of 30 age-matched control subjects. In the patient group, pressure pain threshold values were related to the blood cell concentration of some neurotransmitters which are considered to be involved in the genesis and modulation of pain (β-endorphin levels in peripheral blood mono-nuclear cells [PBMCs], substance P and serotonin concentrations in platelets). The pressure pain thrashold was significantly lower in tension-type headache patients than in control subjects (P<0.0006). Significantly lower levels of B-endorphins-in PBMCs and substance P in platelets, as well as significantly higher levels of serotonin in platelets were found in tension, type headache patients compared to the control subjects (P<0.0001). A significant positive correlation was found between pressure pain threshold values and b b-endorphin levels in both control and patient groups (P<0.0001). On the contrary, a statistically significant negative correlation was evident between pressure pain threshold values and substance P levels in platelets in both patients and control subjects (P<0.01 and P<0.001, respectively). In both groups, there was a negative correlation between b b-endorphins in PBMCs and substance P in platelets (patientsP<0.02, controls P<0.001 ).
The findings of altered β-endorphin levels in blood mono-nuclear cells and substance P levels in platelets could be the peripheral biochemical reflection of the low pressure paid threshold values in tension-type headache patients, and support the hypothesis of an impairment of the antinociceptive systems in this form of headache.     

Leukocyte subsets and cortisol serum levels in patients with migraine without aura and chronic tension-type headache

Leukocyte subsets, serum cortisol and immunoglobulin production were investigated in a group of 12 migraine without aura patients, 12 chronic tension-type headache patients and compared with findings in 12 healthy controls. Chronic tension-type headache patients had statistically significant increased levels of B-lymphocytes (CD19 + cells) ( p < 0.05), while migraine sufferers had a similarly significant decrease in CD8 + T-lymphocytes ( p < 0.05). Migraine patients also had an increased percentage of B-lymphocytes although this failed to reach statistical significance. Immunoglobulin production and cortisol serum levels did not differ in the two headache groups. We conclude that the observed abnormalities in tension-type headache and migraine are unlikely to be a consequence of pain or of hypothalamic-pituitary-adrenal axis dysfunction.     

Trendelenburg position: a tool to screen for the presence of a low CSF pressure syndrome in daily headache patients

Objective.— To test the hypothesis that the Trendelenburg position is an accurate screening investigation for the presence of a low cerebrospinal fluid (CSF) pressure syndrome in patients with daily headache. Background.— The Trendelenburg position causes a rapid increase in intracranial CSF pressure. In a patient with a known CSF leak who overtime had less improvement in the supine position, being placed in Trendelenburg rapidly alleviated her daily headache. This suggested that the Trendelenburg position might be a good screening tool for low CSF pressure syndromes. Methods.— Case reports. All patients were placed in the Trendelenburg position (10°‐20° head‐down tilt) for 5 minutes. A patient was considered to have a positive Trendelenburg test if they experienced complete pain freedom or substantial improvement in baseline head pain in the Trendelenburg position. Results.— Case patients are presented for 3 clinical scenarios: Scenario 1: Daily headache with or without a positional component with a positive response to the Trendelenburg position and subsequent evidence of an underlying low CSF pressure syndrome. Scenario 2: Daily headache with a strong positional component but no improvement in the Trendelenburg position and a negative evaluation for a low CSF pressure syndrome. Scenario 3: Trendelenburg position proves the existence of a post‐lumbar puncture headache in patients with near‐daily headaches. Conclusion.— The Trendelenburg position appears potentially useful as a clinical tool to screen for the presence of a low CSF pressure syndrome in patients with daily headache.     

Frequency of headache is related to sensitization: a population study

Central sensitization is thought to play an important role in the chronification of tension-type headache and in the maintenance and exacerbation of the migraine attack. It has, however, almost exclusively been studied in highly selected patients from headache clinics. The aim of the present study was to evaluate pain perception in primary headaches in the general population. Stimulus-response functions for pressure versus pain, tenderness and pressure pain thresholds were studied in a random sample of 523 adults from the general population. All results were controlled for the effects of age and gender. The area under the stimulus-response function was increased in chronic- and frequent episodic tension-type headache compared with subjects without headache (p<0.001, p<0.001) and in chronic tension-type headache compared with migraine (p=0.01). Increasing slope (p<0.0001) and displacement towards lower pressures was found in the following order: no headache, migraine, frequent episodic tension-type headache, chronic tension-type headache. The displacement of the stimulus-response function was closely associated with frequency of headache. Finally, the stimulus-response function tended to be qualitatively altered in patients with frequent headache. The findings demonstrate, for the first time in a population-based study, a close relation between altered pain perception and chronification of headache, which most likely can be explained by central sensitization.     

Pathophysiological mechanisms of tension-type headache: a review of epidemiological and experimental studies

In this present thesis I have discussed the epidemiology and possible pathophysiological mechanisms of tension-type headache. A population-based study of 1000 subjects randomly selected from a general population, two clinical studies, and a method study of EMG recordings, were conducted. Tension-type headache was the most prevalent form of headache, with a life-time prevalence of 78% in a general adult population. Thirty percent were affected more than 14 days per year and 3% were chronically affected, i.e. had headache at least every other day. Females were more frequently affected than males, and young subjects more frequently affected than older subjects. Females were more sensitive to mechanical pressure pain and revealed more tenderness from pericranial muscles and tendon insertions than males, and young subjects were more pain-sensitive than older subjects. Significantly higher tenderness in pericranial muscles was found in subjects with tension-type headache compared to migraineurs and to subjects without any experience of headache. Tenderness increased significantly with increasing frequency of tension-type headache in both males and females, whereas no such relation was found for mechanical pain thresholds. The applied EMG methodology was fairly reliable and nonpainful, but due to intersubject variability paired studies should be preferred. Subjects with chronic tension-type headache had slightly increased EMG levels during resting conditions and decreased levels during maximal voluntary contraction compared with headache-free subjects, indicating insufficient relaxation at rest and impaired recruitment at maximal activity. In a subsequent clinical, controlled study, the effect of 30 min of sustained tooth clenching was studied. Within 24 h, 69% of patients and 17% of controls developed a tension-type headache. Shortly after clenching, tenderness was increased in the group who subsequently developed headache, whereas tenderness was stable in the group of patients who remained headache-free, indicating that tenderness might be a causative factor of the headache. Likewise, psychophysical and EMG parameters were studied in 28 patients with tension-type headache, both during and outside of a spontaneous episode of tension-type headache. It was concluded that a peripheral mechanism of tension-type headache is most likely in the episodic subform, whereas a secondary, segmental central sensitization and/or an impaired supraspinal modulation of incoming stimuli seems to be involved in subjects with chronic tension-type headache. Prolonged nociceptive stimuli from myofascial tissue may be of importance for the conversion of episodic into chronic tension-type headache. The author emphasizes that tension-type headache is a multifactorial disorder with several concurrent pathophysiological mechanisms, and that extracranial myofascial nociception may constitute only one of them. The present thesis supplements the understanding of the balance between peripheral and central components in tension-type headache, and thereby, hopefully, leads us to a better prevention and treatment of the most prevalent type of headache.     

The wavelength of light causing photophobia in migraine and tension-type headache between attacks

OBJECTIVE: To ascertain the wavelength of light that patients with migraine and tension-type headache find uncomfortable between attacks. BACKGROUND: Photophobia is an abnormal perceptual sensitivity to light experienced by most patients with headache during and, also, between attacks. METHODS: We examined the discomfort threshold to light of low, medium, and high wavelengths in a group of patients with migraine (n=21), patients with tension-type headache (n=19), and healthy controls (n=21). RESULTS: The results indicate that the migraine group had significantly lower discomfort thresholds at the low (P=.001) and high (P=.031) wavelengths compared with both the tension-type headache and control groups; the latter two groups had similar average discomfort levels at these two wavelengths. With the medium wavelength, the control group had significantly higher discomfort thresholds than the migraine (P=.002) and tension-type headache (P=.031) groups; the latter two groups had similar discomfort levels at this wavelength. With unfiltered (white) light, the migraine group had the lowest discomfort threshold and the control group the highest (P=.026), whereas the tension-type headache group had an intermediate discomfort threshold. CONCLUSIONS: There were significant differences between migraineurs, patients with tension-type headache, and healthy controls in the wavelengths that are uncomfortable between attacks.     

Ocular Blood Flow Changes in Cluster Headache and Chronic Paroxysmal Hemicrania

Intraocular pressure and pulsatile ocular blood flow were recorded during and between attacks in patients suffering from cluster headache (n = 18) or chronic paroxysmal hemicrania (n = 7). Similarities, as well as significant differences, were observed between the two groups of patients, pointing to fundamental differences between the two disorders with regard to pathophysiology. Compared with healthy controls, the cluster headache patients demonstrated low pulsatile ocular blood flow values between attacks, with an increase to normal levels during pain. The chronic paroxysmal hemicrania patients, however, had normal values between attacks with a marked and significant increase to high values during attacks.     

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.