New Findings r What is the central question of this study?Peripheral hypoglossal nerve stimulation is a novel therapeutic approach aimed at recruiting lingual muscles electrically and thus relieving pharyngeal airflow obstruction during sleep but the effects of corticomotor stimulation of upper airway muscles during sleep are unknown. r What is the main finding and its importance?Using transcranial magnetic stimulation, we show that corticobulbar excitability of the submental muscles is decreased during sleep in apnoeic patients. Furthermore, we demonstrate that transcranial magnetic stimulation briefly recruits submental muscles and increases maximal inspiratory flow as well as the inspiratory volume of flow-limited respiratory cycles without arousing patients from sleep. We suggest that this central neurostimulation approach is capable of improving upper airway mechanics in sleep apnoea patients.Transcranial magnetic stimulation (TMS) can activate the corticobulbar system and briefly recruit upper airway dilator muscles, improving the inspiratory airflow dynamics of flow-limited respiratory cycles during sleep. The purpose of this investigation was to quantify the effects of TMS-induced twitches applied during sleep on flow-limited respiratory cycles in 14 obstructive sleep apnoea patients. Submental muscle motor threshold (SUB MT ) and motor-evoked potential (SUB MEP ) were examined during wakefulness and sleep. The TMS-induced twitches were applied during stable non-rapid eye movement (NREM) sleep, during non-consecutive flow-limited respiratory cycles at the beginning of inspiration, with intensities varying from sleep SUB MT up to maximal stimulation without arousal. Maximal inspiratory flow, inspiratory volume, shifts of electroencephalogram frequency and pulse rate variability were assessed. Cortical and/or autonomic arousal after TMS was observed in only 13.8% of all twitches applied. The SUB MT increased during NREM sleep (wakefulness, 24.8 ± 9.3%; and NREM sleep, 28.3 ± 9.5%; P = 0.003). Augmenting stimulator output from SUB MT to maximal stimulation before arousal enhanced SUB MEP peak-to-peak amplitude (from 0.09 ± 0.05 to 0.4 ± 0.3 mV; P = 0.005) with a concomitant rise in maximal inspiratory flow (from 376.2 ± 107.9 to 411.9 ± 109.3 ml s −1 ; P = 0.008) and inspiratory volume (from 594.8 ± 189.2 to 663.7 ± 203.1 ml; P = 0.001) in all but one patient. Corticobulbar excitability of submental muscles decreases during NREM sleep. Brief

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The aim of the present study was to assess the effects of one-week tongue-task training (TTT) on sleep apnea severity in sleep apnea subjects. Ten patients with sleep apnea (seven men, mean [± SD] age 52 ± 8 years; mean apnea-hypopnea [AHI] index 20.9 ± 5.3 events/h) underwent 1 h TTT in the authors' laboratory on seven consecutive days. A complete or limited recording and tongue maximal protruding force were assessed before and after one-week TTT. One-week TTT was associated with a global AHI decrease (pre-TTT: 20.9 ± 5.3 events/h; post-TTT: 16.1 ± 5.1 events/h; P<0.001) and AHI decrease during rapid eye movement sleep (pre-TTT: 32.2 ± 18.4 events/h; post-TTT: 16.7 ± 6.6 events/h; P=0.03), while protruding force remained unchanged. The authors consider these results to be potentially clinically relevant and worthy of further investigation in a large randomized trial.