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PubMed1994

[Movement-related cortical potential upon stepping forward].

We investigated movement-related cortical potentials (MRCPs) in 10 healthy subjects when they were stepping the right leg forward volitionally from the standing position, and compared with MRCPs associated with the foot dorsiflexion solely in sitting position. We recorded electroencephalogram (EEG), electrooculogram, surface electromyogram (EMG) on lower limb, and statokinesigram. We examined each EMG onset and several points on the statokinesigram as trigger points. MRCPs triggered by the right tibialis anterior, the left gastrocnemius, and the left soleus muscle had slow negative potentials containing slow phase and steeper phase. The potentials of both phases had the largest gradient at Cz. MRCPs triggered by the EMG onset of these three muscles resembled those associated with the foot dorsiflexion in their wave form, time course, and distribution pattern, but spread widely over the anterior recording sites. On the other hand, MRCPs triggered by the first deviation on the statokinesigram--by that first deviation assumed to take the first and foremost movement in this paradigm, were found to be delayed after the trigger point. The tibialis anterior muscle contributes to elevating a foot, and the contralateral gastrocnemius and soleus muscle to sustaining the weight. We were able to record apparent MRCPs when we adopted these EMG bursts, which play an important role in stepping forward, as trigger points. These records will be useful to analyze the mechanism of gait disturbance.

Action Potentials↗
PubMed2001

The neurophysiology of myofascial pain syndrome.

This article discusses the neurophysiology of myofascial pain syndrome. The local twitch response is a characteristic finding of this condition; it is activated by snapping palpation, pressure, or needle insertion at the trigger point. It is manifested by a burst of activity in the muscle band that contains the activated trigger point. No activity is seen at other muscles bands. Data from experiments with the rabbit indicate that this is a spinal reflex, as it is abolished by transection of the motor nerve innervating the trigger point and infusion of lidocaine. Transection of the spinal cord above the level of the trigger point fails to permanently alter the trigger point response. Needle examination recordings from trigger points show low-voltage spontaneous activity and activity resembling end-plate spikes. This activity is reduced with infusion of phentolamine and local intramuscular infusions of phenoxybenzamine. There are four hypotheses to explain the findings seen at the trigger point. The first is that trigger points are found at the muscle spindle. While this theory may explain the effects of alpha-adrenergic antagonists at the trigger point, it does not fully explain the electromyographic (EMG) findings recorded at the trigger point. The second theory is that trigger points represent hyperactive end-plate regions, as the EMG activity recorded at trigger points resembles that described at the end-plate region. Other theories that either deny the existence of myofascial pain syndrome or believe it represents a focal dystonia are also discussed.

Animals↗
PubMedDate not supplied

Treatment of myofascial pain.

OBJECTIVE: To investigate the effectiveness of ultrasound treatment and trigger point injections in combination with neck-stretching exercises on myofascial trigger points of the upper trapezius muscle. DESIGN: Depression and anxiety associated with chronic pain were assessed using the Beck Depression Inventory (BDI) and the Taylor Manifest Anxiety Scale (TMAS). The study population comprised 102 patients who had myofascial trigger points in one side of the upper trapezius. The patients were randomly assigned to one of three groups: group 1 received ultrasound therapy to trigger points in conjunction with neck-stretching exercises; group 2 received trigger point injections and performed neck-stretching exercises; and group 3, the control group, performed neck-stretching exercises only. Treatment effectiveness was assessed using subjective pain intensity (PI) with a visual analog scale, pressure pain threshold (PT) with algometry, and range of motion (with a goniometer) of the upper trapezius muscle. RESULTS: Compared with the control group, patients in groups 1 and 2 had a statistically significant reduction in PI, an increase in PT, and an increase in range of motion. There were no statistically significant differences between treatment groups 1 and 2. Although not statistically significant, patients in the control group had better results at the 3-mo follow-up. The BDI scores indicated depression in 22.9% of the patient, with 4.8% of the patients having severe depression. High anxiety scores on the TMAS were present in 89.3% of the patients. When BDI and TMAS scores were compared with PI or PT levels, no significant correlations were found, but when compared with pain duration before treatment, correlations were significant. CONCLUSIONS: Patients with myofascial pain syndrome had higher scores for anxiety than for depression. When combined with neck stretching exercises, ultrasound treatment and trigger point injections were found to be equally effective.

Adult↗
PubMed1989

Are "cervicogenic" headaches due to myofascial pain and cervical spine dysfunction?

The purpose of this investigation was to evaluate whether the pain of cervicogenic headache could be due to referred symptoms from myofascial trigger points. The presence or absence of cervical spine dysfunction was also of interest. Eleven patients with cervicogenic headaches were systematically examined for myofascial trigger points and cervical spine dysfunction. All patients had at least three myofascial trigger points on the symptomatic side. In eight of these patients, trigger point palpation clearly reproduced their headache. There were 70 myofascial trigger points (35 "very tender", 35 "tender") and 17 non-myofascial tender points on the symptomatic side, compared to 22 myofascial trigger points (one "very tender", 21 "tender") and 19 non-myofascial tender points on the asymptomatic side. These differences were statistically significant [chi-square (2df) = 22.04, p less than 0.0001]. All patients had some evidence of cervical dysfunction. Ten patients (91%) had specific segmental dysfunction of occiput on atlas and/or atlas on axis. Five patients were entered into a non-invasive, interdisciplinary pain management program designed to treat cervical spine dysfunction and myofascial pain. Treated patients reported a significant decrease in the frequency and intensity of their headaches during a median two-year follow-up. It is concluded that myofascial trigger points may be an important pain producing mechanism in cervicogenic headache and that segmental cervical dysfunction is a common feature in such patients. Conservative, non-surgical treatment appears to be effective in reducing the frequency and intensity of cervicogenic headache. These data suggest that surgical approaches should be reserved only for those patients who fail conservative therapy.

Adult↗
PubMedDate not supplied

NEUROLAB, a comprehensive program for the analysis of neurophysiological and behavioural data.

A comprehensive and versatile computer software for IBM-compatible microcomputers has been developed. It is designed for quantitative off-line analysis of A/D-sampled intracellular or extracellular recordings and behavioural or stimulus data. The program works with single files or file sets. It supports data to be viewed on the monitor and allows sectioning of interesting data for common analysis. It offers 19 filters/operators for data processing and comprehensive possibilities to set and calculate trigger points. Data of trigger points can be exported as ASCII files. Standard neurophysiological histograms like interval-, PST-, phase histograms or auto- and cross-correlograms can be obtained. Time-dependent and phase-dependent averaging is possible for all original and filtered data. All graphical output on the display can directly be copied to a plotter/laser printer or HP-GL file by keyboard commands.

Animals↗
PubMed1998

Cervicogenic headache: a critical review of the current diagnostic criteria.

Opinions are divided on the use of the term cervicogenic headache (CGH) in cases with no evidence of cervical damage. According to Sjaastad et al. (1990), CGH is diagnosed from three features: (1) unilateral headache triggered by head/neck movements or posture; (2) unilateral headache triggered by pressure on the neck; (3) unilateral headache spreading to the neck and the homolateral shoulder/arm. Other characteristics are not essential for CGH diagnosis, including pain improvement after greater occipital nerve (GON)/C2 block. However, other authors give different definitions of CGH, and this may explain why reported frequencies for this headache vary so widely. In this paper we critically review the major diagnostic criteria of Sjaastad et al. for CGH in the light of clinical studies conducted at our institute and other literature findings. In a study of 500 headaches we found only two patients with unilateral headache triggered by head/ neck movements or posture, and no cases of neck pressure-induced headache. No clear-cut criteria are given in the literature for differentiating CGH trigger points from myofascial trigger points. In another study of 440 primary headache patients we found that in the unilateral long-lasting headache group (64 migraines and 10 tension-type headaches), a pain involving the occiput/neck was present in 30 migraine and seven tension headache patients; thus, according to the CGH major criteria, 10% (30/307) of 'migraines' and 7% (7/96) of 'tension headaches' could be diagnosed as CGH. However, one cannot exclude that the association of unilateral pain with posterior irradiation is due to the high prevalence of migraine, tension-type headache and chronic neck pain. The relation between CGH and whip-lash injury has been put in doubt by a recent study which found no difference in headache frequency between trauma and control groups and reported no specific headache pattern in the trauma group. Other reports suggest that, when it occurs, CGH usually disappears within a year of whip-lash, throwing doubt on the appropriateness of surgery for post-traumatic CGH. The lack of specificity of GON/C2 block as a treatment for CGH adds further difficulties to the diagnosis of this headache. We conclude that, although neck structures play a role in the pathophysiology of some headaches, clinical patterns indicating a neck-headache relationship have still not been adequately defined. We believe that further rigorous studies are needed to definitively confirm the validity of CGH as a nosological entity.

Head↗
PubMedDate not supplied

Myofascial disorders in the trochlear region in unilateral migraine: a possible initiating or perpetuating factor.

OBJECTIVE: Some patients with trochlear disorders have been found to suffer from concurrent migraine. However, a trochlear examination is not systematically done in patients with migraine. Moreover, a search for myofascial trigger points in the superior oblique muscle has never been reported in these patients. METHODS: The trochlear region was examined in 20 participants with strictly unilateral migraine without side-shift and in 20 controls. Referred pain elicited by different maneuvers during manual palpation (ie, maintained pressure, active muscle contraction, and stretching of the superior oblique muscle) was assessed with a visual analog scale. All participants were headache free on the day of evaluation. RESULTS: Sixteen participants with migraine (80%) perceived referred pain on examination of the trochlear area. It was described as a tightening sensation in the retro-orbital region, sometimes extending to the supraorbital region and the homolateral forehead. In 15 participants with migraine, both the active contraction and the stretching of the muscle increased the referred pain, which was consistent with definite myofascial trigger points. All the definite trigger points were ipsilateral to the side of the headache. Conversely, only 5 controls (20%) had referred pain. None of them had definite myofascial trigger points because muscle stretching did not increase the intensity of pain. The intensity of referred pain at each stage of the trochlear examination was greater in subjects with migraine than in controls (P<0.001). CONCLUSION: Patients with unilateral migraine commonly perceive referred pain from the trochlear area that probably comes from the myofascial trigger points. Myofascial disorders in the trochlear region might contribute to the perpetuation of concomitant migraine.

Adult↗
PubMed1988

Primary fibromyalgia syndrome and myofascial pain syndrome: clinical features and muscle pathology.

Primary fibromyalgia syndrome (PFS) is a common form of nonarticular rheumatism with diffuse musculoskeletal aching and stiffness at multiple sites and tender points at characteristic locations. Nonmusculoskeletal "systemic" symptoms, eg, fatigue, poor sleep, irritable bowel symptoms, and chronic headaches, are also common. Although PFS is similar to myofascial pain syndrome (MPS) in that both conditions cause muscle pain and tenderness, important differences exist. Unlike PFS, muscle pain in MPS is usually local or regional, accompanied by trigger points. Unlike tender points, trigger points produce a referral pain pattern specific to each muscle. Moreover, "systemic" features of PFS are usually absent in MPS. Common and important pathologic changes in muscle in PFS are moth-eaten appearance of Type I fiber by histochemistry, and myofibrillar lysis with glycogen and mitochondria deposition by electron microscopy; inflammatory changes are absent by light microscopy. Recent investigations have shown that PFS is a characteristic clinical entity. Further controlled studies are, however, essential to establish the pathologic changes in tender muscles in PFS.

Adult↗
PubMed2001

Regional myofascial pain syndrome and headache: principles of diagnosis and management.

Myofascial pain is frequently overlooked in dealing with headache pain. Myofascial pain is defined as pain and/or autonomic phenomena referred from active trigger points, with associated dysfunction. The trigger point is a focus of hyperirritability in the muscle, that when compressed, is locally tender, and if sensitized, gives rise to referred pain and tenderness. The therapy for myofascial pain requires enhancing central inhibition through pharmacology or behavioral techniques and simultaneously reducing peripheral inputs through physical therapies including exercises and trigger point-specific therapy.

Combined Modality Therapy↗
PubMed2004

Myofascial pain: diagnosis and management.

Clinical understanding and management of myofascial pain is overlooked frequently when dealing with pain. Myofascial pain is defined as pain or autonomic phenomena referred from active trigger points, with associated dysfunction. The trigger point is a focus of hyperirritability in the muscle that, when compressed, is locally tender and, if sensitized, gives rise to referred pain and tenderness. The pain quality is dull or achy and associated with autonomic changes. Myofascial pain is poorly understood, which results too often in underdiagnosis and poor management. The pathogenesis likely has a central mechanism with peripheral clinical manifestations. The therapy for myofascial pain requires enhancing central inhibition through pharmacology or behavioral techniques and simultaneously reducing peripheral inputs through physical therapies including exercises and trigger point-specific therapy.

Analgesics↗
PubMed2004

Urologic myofascial pain syndromes.

Treatment of pain of urogenital origin, chronic pelvic pain syndrome, can be frustrating for patients and physicians. The usual approaches do not always produce the desired results. Visceral pain from pelvic organs and myofascial pain from muscle trigger points share common characteristics. Referred pain from myofascial trigger points can mimic visceral pain syndromes and visceral pain syndromes can induce trigger point development and myofascial pain and dysfunction. The referred pain syndrome can long outlast the initial event, making diagnosis difficult.

Cystitis↗
PubMed1999

Dopamine fluctuations in the nucleus accumbens during maintenance, extinction, and reinstatement of intravenous D-amphetamine self-administration.

Moment-to-moment fluctuations of nucleus accumbens dopamine (DA) were determined in rats self-administering or passively receiving "yoked" intravenous infusions of D-amphetamine. The initial lever presses of each session caused elevations in DA concentration, usually to an initial peak that was not maintained throughout the rest of the session. As the initial ("loading") injections were metabolized, DA levels dropped toward baseline but were sustained at elevated plateaus by subsequent lever pressing that was spaced throughout the remainder of the 3 hr sessions. During this period, DA levels fluctuated phasically, time-locked to the cycle of periodic lever pressing. Consistent with the known pharmacological actions and dynamics of amphetamine, peak DA elevations were seen approximately 10-15 min after each injection, and the mean DA level was at a low point in the phasic cycle at the time of each new lever press. During extinction periods when saline was substituted for amphetamine, DA levels dropped steadily toward baseline levels despite a dramatic increase in (now-unrewarded) lever pressing. Noncontingent injections during extinction reinstated lever-pressing behavior and increased nucleus accumbens DA concentrations. These data are consistent with the hypothesis that under the conditions of this experiment-during periods of amphetamine intoxication in well-trained animals-the timing of amphetamine self-administration comes primarily under the control of extracellular DA concentrations. The probability of lever pressing during the maintenance phase is highest when DA concentrations fall near a characteristic trigger point, a trigger point that is significantly elevated above baseline, and falls as DA concentrations fall below or increase above that trigger point.

Animals↗
PubMed2003

[Non-medical therapy of myofascial pain].

METHODS: In a prospective study, the efficacy of manual therapy and dry needling was examined in 84 patients with chronic low back pain (mean duration of pain 4.4 years). RESULTS: The initial value of pain on the visual analogue scale was about 6.6, the follow up value was reduced to 3.67 (p=0.0033). CONCLUSIONS: Manual trigger point therapy of myofascial trigger points in the low back is effective.

Back Pain↗
PubMed1999

Association between paroxysmal trigeminal neuralgia and atypical facial pain.

Paroxysmal trigeminal neuralgia and atypical facial pain are both fairly common conditions that produce pain in the face of different character. Trigeminal neuralgia is sharp and shooting, brought on by facial movement, change of temperature and by touching the face at a specific point (the trigger point). Atypical facial pain is dull and unrelenting and its site is ill-defined. Trigeminal neuralgia is generally more common in older people, and affects women slightly more than men, and atypical facial pain generally affects younger people, with women predominating. The pains should never be confused. We have noticed that many patients with trigeminal neuralgia have additional symptoms of atypical facial pain and so we reviewed the records of the Pain Relief Unit retrospectively. Of the 83 patients identified with trigeminal neuralgia where records were adequate, 35 (42%) also had atypical facial pain. Five of these had developed it before the onset of trigeminal neuralgia and could be examples of pretrigeminal neuralgia. There were eight patients in the series with multiple sclerosis, of whom two also had atypical facial pain. There seemed to be no relationship between the development of atypical facial pain and the interventions used to treat trigeminal neuralgia. It is important that both conditions are identified and treated individually.

Acute Disease↗
PubMed2006

How do acupuncture and moxibustion act? - Focusing on the progress in Japanese acupuncture research -.

The mechanisms of action of acupuncture and moxibustion as reported by Japanese researchers are reviewed. The endogenous opioid-mediated mechanisms of electroacupuncture (EA) as used in China are well understood, but these are only one component of all mechanisms of acupuncture. These studies emphasize the similarity of the analgesic action of EA to various sensory inputs to the pain inhibition mechanisms. In Japanese acupuncture therapy, careful detection of the acupuncture points and fine needling technique with comfortable subjective sensation are considered important. The role of polymodal receptors (PMR) has been stressed based on the facts that PMRs are responsive to both acupuncture and moxibustion stimuli, thermal sensitivity is essential in moxibustion therapy, and the characteristics of acupuncture points and trigger points are similar to those of sensitized PMRs. Acupuncture and moxibustion are also known to affect neurons in the brain reward systems and blood flow in skin, muscle, and nerve. Axon reflexes mediated by PMRs might be a possible mechanism for the immediate action of acupuncture and moxibustion. Reports on the curative effects of acupuncture on various digestive and urological disorders are also reviewed briefly.

Acupuncture↗
PubMed1976

Piriform syndrome.

Among a variety of deep muscle trigger points, the piriform muscle trigger point is selected for individual scrutiny. This seems fully justified by the great potential for confusing this entity with discogenic disease and consequently having unnecessary surgical procedures carried out.The diagnosis can be made from findings on simple physical diagnostic tests and an appropriate history. Low back and hip pain with pain radiating down the back of the leg should suggest piriform syndrome as part of the differential diagnosis. This is especially true if a female patient has complaint of dyspareunia. Pain and weakness on resisted abduction-external rotation of the thigh is a sign of piriform syndrome. This is confirmed by tenderness and reproduction of the patient's complaints by digital pressure over the belly of the piriform muscle, completing the diagnostic criteria. Local injection of the muscle belly is curative. There are no laboratory or x-ray findings leading to a diagnosis.

Back Pain↗
PubMed2006

[Equipment for low reactive level laser therapy including that for light therapy].

Equipments used for light therapy include machinery used for irradiation by low reactive level laser, xenon light and linear polarized infra-red ray. Low reactive level laser is divided into two types of laser according to the medium by which laser is obtained ; semiconductor laser and helium-neon laser. Low reactive level laser has only one wave length and produces analgesia by action of light itself. On the other hands, Xenon light and linear polarized infra-red ray produce analgesia by warming effect induced by light in addition to the action of light itself. There are four methods of irradiation by these light sources; irradiation of acupuncture points, of trigger points, along nerves causing pain and of stellate ganglion area. Indication for light therapy includes various kinds of diseases such as herpes zoster, post herpetic neuralgia, cervical pain, lumbago due to muscle contracture, complex regional pain syndrome, arthralgia etc. However, we have to know that light therapy does not exert analgesic effects equally to all patients. But light therapy does not accompany pain and rarely shows any side effects. Therefore it is thought to be an alternative for patients who reject injection or patients who are not indicated for nerve block because of patients' conditions such as bleeding tendency.

Helium↗
PubMed1998

Myofascial pain syndrome: characteristics, diagnosis, and treatment.

Myofascial Pain Syndrome (MPS) is defined as a chronic muscle pain disorder associated with focal areas of exquisite tenderness called trigger points. It is a common cause of chronic orofacial pain and is commonly seen in patients with temporomandibular disorders. When stimulated, trigger points refer pain to surrounding areas, and the pain may resemble other conditions. Diagnosis of MPS is made by identifying trigger points and their associated pain referral pattern. Physical therapy maneuvers and injection are the most common and successful treatments. Eradication of trigger points can diminish or eliminate the pain associated with this syndrome.

Adult↗