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Query: UMLS:C0018681 (headache)
 56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The exteroceptive suppression period (ES) of the temporalis muscle activity is a trigemino-trigeminal brain stem reflex. It will be elicited most when stimulating trigeminal sensory afferents by painful stimuli and typically leads to a biphasic interruption of voluntary muscle activity. The first phase of decreased voluntary activity is called the early exteroceptive suppression period (ES1), the second, the late exteroceptive suppression period (ES2). Between these two suppression periods a phase of increased muscle activity, the so-called facilitation period (FP), can be seen. This phenomenon can be modulated by different stimulating parameters and usually, in healthy subjects, this normal pattern of the exteroceptive suppression can be elicited regularly. The reflex answer may occur at low non-painful stimulus intensities; typically, however, it appears to be most pronounced with high-intensity stimuli. Because of the obvious relationship between stimulus intensity, pain perception and reflex, the reflex is regarded as an antinociceptive reaction. The absence of an inhibition of motor activity can be visualized, for example, in hemimasticatory spasm or dystonic disorders. However, above all the ES nowadays attracts most attention as a tool to analyse different pain syndromes. One main advantage of this method in man is the ability to evaluate certain antinociceptive brain stem mechanisms functionally by means of a simple noninvasive technique. A large number of results have been obtained showing that chronic pain syndromes such as chronic tension-type headache and migraine cause changes within the normal ES recording pattern. Furthermore, some substances used in pain therapy, such as serotonin agonists or antagonists, acetylsalicylic acid or naloxone, may also alter the general appearance of the ES. This review will summarize different parameters that influence the ES reflex answer. Furthermore, the diagnostic value of changes in the ES for pathophysiological processes regarding pain perception and processing in certain pain syndromes will be discussed.
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PMID:[Exteroceptive suppression of activity of the temporal muscle. Principles and applications]. 903 58

We studied the inhibition of voluntary temporalis muscle activity after stimulations of extracephalic cutaneous or mixed nerves in 23 healthy volunteers, 29 patients suffering from migraine without aura, 24 from episodic and 42 from chronic tension-type headache. Two successive EMG suppressions were induced bilaterally after stimulating at 40 mA the index finger or the median nerve, but not after stimulations of the sural or peroneal nerves. They differed from those obtained after labial commissure stimulation at 20 mA, i.e. the classic temporalis silent periods ES1 and ES2. Overall prevalence of index- (3%) and median nerve-induced (16%) early suppression was much lower than that of labial-induced ES1 (100%); prevalence of index-induced late suppression (index-"ES2") was 62% and that of median-"ES2" 48%, compared with 97% for labial-ES2. Latency and duration of index-/median-"ES2" were not significantly different between groups. Index-"ES2" occurred significantly more often in migraineurs (83%) than in controls (48%) suggesting that the spino-bulbar pathways involved in index-/median-"ES2" are hyperexcitable in migraine.
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PMID:Suppression of voluntary temporalis muscle activity by peripheral limb stimulations in healthy volunteers, migraineurs and tension-type headache sufferes. 907 11

Therapeutic mechanisms hypothesized to underlie improvements in tension headache activity achieved with combined relaxation and electromyographic (EMG) biofeedback therapy were examined. These therapeutic mechanisms included (1) changes in EMG activity in frontal and trapezii muscles, (2) changes in central pain modulation as indexed by the duration of the second exteroceptive silent period (ES2), and (3) changes in headache locus of control and self-efficacy. Forty-four young adults with chronic tension-type headaches were assigned either to six sessions of relaxation and EMG biofeedback training (N = 30) or to an assessment only control group (N = 14) that required three assessment sessions. Measures of self-efficacy and locus of control were collected at pre- and posttreatment, and ES2 was evaluated at the beginning and end of the first, third, and last session. EMG was monitored before, during, and following training trials. Relaxation/EMG biofeedback training effectively reduced headache activity: 51.7% of subjects who received relaxation/biofeedback therapy recorded at least a 50% reduction in headache activity following treatment, while controls failed to improve on any measure. Improvements in headache activity in treated subjects were correlated with increases in self-efficacy induced by biofeedback training but not with changes in EMG activity or in ES2 durations. These results provide additional support for the hypothesis that cognitive changes underlie the effectiveness of relaxation and biofeedback therapies, at least in young adult tension-type headache sufferers.
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PMID:Change mechanisms associated with combined relaxation/EMG biofeedback training for chronic tension headache. 928 53

Changes of the second suppressive period (ES2) of the exteroceptive suppression of the temporalis muscle activity are found in patients with chronic tension-type headache (TTH) and are suggested to reflect an abnormal endogenous pain control system. We investigated whether similar changes are found in patients with the fibromyalgia syndrome (FMS) that is also believed to result from disturbed central pain processing. The ES2 values of 27 patients with FMS were compared with those of 18 patients with TTH and 40 healthy volunteers. The duration of ES2 (+/-SD) in FMS patients was 30.6+/-7.5 ms and was not significantly different from the control group (33.1+/-7.8 ms), whereas it was significantly shortened in TTH patients (22.9+/-11.5 ms). Our results indicate that, despite similar concepts on the pathophysiology of the two chronic pain disorders, there are no comparable changes of this brain stem reflex activity in FMS.
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PMID:Exteroceptive suppression of temporalis muscle activity in patients with fibromyalgia, tension-type headache, and normal controls. 980 49

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.
Cephalalgia 2000 Sep
PMID:Exteroceptive suppression periods and pericranial muscle tenderness in chronic tension-type headache: effects of psychopathology, chronicity and disability. 1112 21

Brain stem interneuronal excitability can be assessed by recording the recovery cycle of the blink reflex and exteroceptive suppression of temporalis muscle activity. Abnormal endogenous pain control mechanisms due to disturbed brain stem interneuronal activity have been implicated in the pathogenesis of tension-type headaches. The blink reflex, exteroceptive suppression of temporalis muscle activity, and the recovery curve of both the R2 component of the blink reflex and the ES2 component of the exteroceptive suppression of the temporalis muscle activity were studied in 20 patients with migraine without aura, 32 patients with tension-type headache, and 20 normal controls. In our study, the blink reflex was elicited by stimulation of the supraorbital nerve; the exteroceptive suppression of the temporalis muscle activity was elicited by applying electrical shocks to the labial commissure, both on the lower and upper sides. The recovery cycle was established by delivering paired shocks at different interstimulus intervals. Comparisons were made between normal control subjects, patients with migraine without aura, and patients with tension-type headache. The latency of R1, R2, and R2', the amplitude and size of the R2 and R2' components of the blink reflex, the latency and duration of the ES1 and ES2 components, and the recovery curve of the ES2 component of the temporalis muscle activity did not differ between groups. However, the recovery curve of the R2 component of the blink reflex diminished in patients with tension-type headache compared with the other groups. Our findings indicate reduced excitability of the brain stem interneurons in patients with tension-type headache.
Headache 2001 Feb
PMID:Recovery cycle of the blink reflex and exteroceptive suppression of temporalis muscle activity in migraine and tension-type headache. 1125 98

Brainstem-mediated antinociceptive inhibitory reflexes of the temporalis muscle were investigated in 82 patients (47 F, 35 M, mean age 28.3 years, SD 9.4) with acute posttraumatic headache (PH) following whiplash injury but without neurological deficits, bone injury of the cervical spine or a combined direct head trauma on average 5 days after the acceleration trauma. Latencies and durations of the early and late exteroceptive suppression (ES1 and ES2) and the interposed EMG burst (IE) of the EMG of the voluntarily contracted right temporalis muscle evoked by ipsilateral stimulation of the second and third branches of the trigeminal nerve were analyzed and compared to a cohort of 82 normal subjects (43 F, 39 M, mean age 27.7 years, SD 7.1). Highly significant reflex alterations were found in patients with PH with a shortening of ES2 duration with delayed onset and premature ending as the primary parameter of this study, a moderate prolongation of ES1 and IE duration and a delayed onset of IE. The latency of ES1 was not significantly changed. These findings indicate that acute PH in whiplash injury is accompanied by abnormal antinociceptive brainstem reflexes. We conclude that the abnormality of the trigeminal inhibitory temporalis reflex is based on a transient dysfunction of the brainstem-mediated reflex circuit mainly of the late polysynaptic pathways. The reflex abnormalities are considered as a neurophysiological correlate of the posttraumatic (cervico)-cephalic pain syndrome. They point to an altered central pain control in acute PH due to whiplash injury.
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PMID:Antinociceptive reflex alteration in acute posttraumatic headache following whiplash injury. 1137 4

Stimulating afferent fibers of the trigeminal nerve usually causes two successive suppressions (ES1 and ES2) of the voluntary muscle activity of chewing muscles. The first phase of decreased voluntary activity is called the early exteroceptive suppression period (ES1); the second phase is called the late exteroceptive suppression period (ES2). Between these two suppression periods is a phase of increased muscle activity, the so-called facilitation period (FP). Usually, in healthy subjects this normal pattern of exteroceptive suppression can be elicited regularly. The reflex answer may occur at low non-painful stimulus intensities; however, typically it appears to be most pronounced with high-intensity stimuli. Because of the obvious relationship between stimulus intensity, pain perception and reflex answer, the reflex is regarded as an antinociceptive reaction. Chronic pain syndromes like chronic tension-type headache and migraine without aura cause changes within the normal ES recording pattern. Furthermore, some substances used in pain therapy such as serotoninagonists or antagonists, acetylsalicylic acid or naloxon may also alter the general appearance of the ES. In this review different parameters that influence the ES reflex answer are summarized. Above, the diagnostic value of the changes of the ES for pathophysiological procedures regarding pain perception and pain processing in certain pain diseases is discussed.
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PMID:[Exteroceptive suppression of activity of the temporal muscle in analysis of pain mechanisms]. 1279 57

The second exteroceptive suppression period (ES2) of masseter or temporalis muscle activity may be reduced in adults with chronic tension-type headache. In adults with migraine, ES2 was found normal or tended to be protracted. To date, no studies on exteroceptive suppression in children and adolescents with headaches have been published. We investigated the exteroceptive suppression of masseter muscle activity in 14 migraineurs and 19 controls between 6 and 18 years of age. It was elicited by electrical stimulation at the labial commissure. No differences were found regarding the first suppression period, but ES2 was significantly longer in the migraine group than in controls. The results of the migraine group suggest overactivity of the interneurons of the reflex loop due to impaired inhibitory control from superior antinociceptive systems already at the beginning of this headache disorder.
Cephalalgia 2006 Jun
PMID:Exteroceptive suppression of masseter muscle activity in juvenile migraineurs. 1668 12


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