Rousseau Eric, Gakwaya Simon, Melo-Silva César Augusto, Sériès Frédéric
Unité de recherche en pneumologie, Centre de recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada.
Exp Physiol. 2015 Apr 20;100(5):566-76. doi: 10.1113/EP085005. Epub 2015 Mar 21.
What is the central question of this study? Can repetitive transcranial magnetic stimulation (rTMS) of the genioglossus enhance the beneficial effects observed with transcranial magnetic stimulation single twitches on upper airway mechanical properties? What is the main finding and its importance? We found that both inspiratory and expiratory rTMS protocols induce a different activation pattern of upper airway muscles, with evidence for an increase in genioglossus corticomotor excitability in response to rTMS. This is of major importance because it might open the door for rTMS protocols with the goal of increasing corticomotor excitability and, thus, possibly increasing the tonic genioglossus activity, which is known to be diminished during sleep in subjects with sleep apnoea.
Stimulation of upper airway (UA) muscles during sleep by isolated transcranial magnetic stimulation (TMS) twitch can improve airflow dynamics without arousal, but the effect of repetitive TMS (rTMS) on UA dynamics is unknown. Phrenic nerve magnetic stimulation (PNMS) can be used to produce painless experimental twitch-induced flow limitation during wakefulness. The aim of this study was to quantify the effects of rTMS applied during wakefulness on UA mechanical properties using PNMS in subjects with obstructive sleep apnoea (OSA). Phrenic nerve magnetic stimulation was applied to 10 subjects, with and without simultaneous rTMS, during inspiration and expiration. Flow-limitation characteristics and UA obstruction level were determined [maximal (V̇I,max)and minimal inspiratory airflow (V̇I,min),V̇I,max-V̇I,min flow drop (ΔV̇I),oropharyngeal (POro,peak ) and velopharyngeal peak pressures, oropharyngeal k1 /k2 ratios with k1 and k2 determined by the polynomial regression model between instantaneous flow and pharyngeal pressure and UA resistance]. Both genioglossus and diaphragm root mean squares and motor-evoked potential amplitudes (geniolossus, GGAmp ) and latencies were computed. A flow-limitation pattern always occurred after PNMS. A decrease in V̇I,max and an increase in ΔV̇I occurred following rTMS applied during inspiration, and POro,peak values were more negative with both inspiratory and expiratory rTMS. The GGAmp also increased significantly from the second to the last rTMS expiratory train twitch. All other parameters remained unchanged. These results suggest the following conclusions: (i) rTMS does not improve UA mechanical properties in awake subjects with OSA; (ii) the activation pattern of UA muscles differs following isolated twitch and repetitive cortical stimulation of the genioglossus; and (iii) rTMS applied during expiration induces corticomotor facilitation.
本研究的核心问题是什么？对颏舌肌进行重复经颅磁刺激（rTMS）能否增强经颅磁刺激单次抽搐对上气道力学特性的有益效果？主要发现及其重要性是什么？我们发现吸气和呼气rTMS方案均能诱导上气道肌肉产生不同的激活模式，有证据表明颏舌肌皮质运动兴奋性在rTMS作用下增强。这具有重要意义，因为它可能为旨在提高皮质运动兴奋性从而可能增加颏舌肌紧张性活动的rTMS方案打开大门，已知在睡眠呼吸暂停患者睡眠期间颏舌肌紧张性活动会减弱。
在睡眠期间通过孤立的经颅磁刺激（TMS）抽搐刺激上气道（UA）肌肉可改善气流动力学且不会引起觉醒，但重复经颅磁刺激（rTMS）对UA动力学的影响尚不清楚。膈神经磁刺激（PNMS）可用于在清醒状态下产生无痛的实验性抽搐诱导的气流受限。本研究的目的是使用PNMS量化清醒状态下rTMS对阻塞性睡眠呼吸暂停（OSA）患者上气道力学特性的影响。在吸气和呼气期间，对10名受试者施加膈神经磁刺激，同时施加或不施加rTMS。测定气流受限特征和上气道阻塞水平[最大吸气流量（V̇I,max）和最小吸气气流（V̇I,min）、V̇I,max - V̇I,min流量下降（ΔV̇I）、口咽（POro,peak）和腭咽峰值压力、由瞬时流量与咽部压力及上气道阻力之间的多项式回归模型确定的口咽k1/k2比值]。计算颏舌肌和膈肌的均方根以及运动诱发电位幅度（颏舌肌，GGAmp）和潜伏期。PNMS后总会出现气流受限模式。吸气期间施加rTMS后，V̇I,max降低，ΔV̇I增加，吸气和呼气rTMS时POro,peak值均更负。从第二次到最后一次rTMS呼气序列抽搐，GGAmp也显著增加。所有其他参数均保持不变。这些结果提示以下结论：（i）rTMS不能改善清醒OSA患者的上气道力学特性；（ii）孤立抽搐和对颏舌肌进行重复皮质刺激后，上气道肌肉的激活模式不同；（iii）呼气期间施加rTMS可诱导皮质运动易化。
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