EMG Analysis of the Late Exteroceptive Suppression Period of Temporal Muscle Activity in Episodic and Chronic Tension-Type Headaches

Abstract

EMG analysis of the late exteroceptive suppression period of the temporal muscle activity is discussed as comparative methodology in the assessment of patients suffering from chronic tension-type headache and from migraineurs. After electrical perioral trigeminal nerve stimulation during maximum voluntary jaw occlusion, early (ES1) and late (ES2) exteroceptive suppression periods can be registered above the temples using surface EMG recordings. In patients suffering from chronic tension-type headache the duration of the late suppression period is shortened (p less than 0.001) compared to migraineurs or controls. However, patients suffering from episodic tension-type headache display late suppression periods of temporal muscle activity of differing lengths.

Abnormalities of masseter inhibitory reflex in patients with episodic tension-type headache

“…To some extent, our results are in contrast to the findings of Wallasch et al(1991). They reported shortened duration of S2 in patients suffering from chronic TTH compared to migraineurs and controls.…”

Central and peripheral mechanisms in chronic tension-type headache

“…More recently, the second temporalis / masseter exteroceptive suppression period (ES2), or 'silent period' has been found to be significantly shortened or abolished in chronic tension headache, but not in migraine or in most other symptomatic headaches (Schoen en et al 1987;Nakashima and Takahashi 1991;Wallasch et al 1991;Gobel and Weigle 1991;Mathew 1992;Schoenen 1993a,b). Temporalis/masseter ES2 is a transient suppression of voluntary activity of temporalis and masseter muscles produced by stimulation of the trigeminal nerve, and is mediated in the brain stem by multisynaptic neuronal nets (Cruccu and Bowsher 1986).…”

“…This suggests abnormal ES2 responses observed in chronic tension-type headache may reflect an excessive inhibition of these interneurons secondary to a disturbed limbic control of brain stem relays such as the periaqueductal gray and the raphe magnus nucleus (Schoenen et al 1987). The shortened second exteroceptive silent period observed in chronic tension-type headache may thus index a dysfunction of the endogenous central pain control system (Schoenen et al 1987;Wallasch et al 1991), and represent an interface between the psychogenic and myogenic factors putatively involved in the pathogenesis of chronic tension-type headache (Schoenen et al 1987).…”

Central mechanisms in tension-type headaches

“…They are induced by the activation of the same afferent axons, and mediated in the brainstem by separate oligo-(ES1) and multisynaptic (ES2) neural nets, activating brainstem interneurons that inhibit the motorneurons of jaw-closing muscles [31]. Several studies [32][33][34][35][36] have shown that the second temporalis exteroceptive silent period (ES2) can decrease in patients with CTTH; other studies have demonstrated that silent period remains normal [37][38][39][40][41]. For patients with ETTH, ES2 duration is normal [33,35,36].…”

“…Several studies [32][33][34][35][36] have shown that the second temporalis exteroceptive silent period (ES2) can decrease in patients with CTTH; other studies have demonstrated that silent period remains normal [37][38][39][40][41]. For patients with ETTH, ES2 duration is normal [33,35,36]. On the basis of reduced ES2 duration, it was suggested that there is a deficient activation or excessive inhibition of brainstem inhibitory interneurons [32], which are under the control of limbic structures (periaqueductal grey, amygdala, hypothalamus, and orbitofrontal cortex) (Fig.…”