We aimed to determine whether bone-conducted acoustic stimulation could prematurely terminate sleep apnea events, thereby decreasing amplitude and duration of subsequent oxygen desaturation. As oxygen desaturation has been linked to cardiovascular consequences, we postulate this could be a viable therapy in some cases.
Eight patients with severe Obstructive Sleep Apnea (2 women, 45 [20-68] y.o. Apnea-Hypopnea Index: 77.7 ± 22.3/h) underwent polysomnography at the Lausanne University Sleep Center. Short acoustic stimulations were administered by bone conduction every second event of sleep apnea. Sounds were remotely administered using a Dreem® headband worn by patients while undergoing nocturnal polysomnography. Amplitude (%) and duration(s) of oxygen desaturations following terminated apneas were compared to that of non-stimulated previous and subsequent events.
549 stimulations (68.6 ± 38 sounds per patient) in N1 (16.2%), N2 (69.9%), N3 (4.2%), and REM(9.6%) were conducted. Compared to the previous and subsequent non-stimulated apnea, stimulations reduced event duration by 21.4% (-3.4 ± 7.2 s, p < 0.0001) while oxygen desaturation amplitude and duration were reduced by 30.4% (mean absolute difference ± SD: -1.9 ± 2.8%, p < 0.0001), and 39.6% (-5.7 ± 9.2 s, p < 0.0001) respectively. For these variables, each patient showed a significant improvement following acoustic stimulation. Sound-associated discomfort was rated 1.14 ± 1.53 on an 8 points scale (8 = worst) and only 6.8% of emitted sounds were perceived by the patients, suggesting a well-tolerated intervention.
Bone-conducted sound stimuli decreased apnea events duration as well as duration and amplitude of associated oxygen desaturations. Stimulations were well tolerated and rarely perceived by patients. This therapeutic approach deserves further investigation, with monitoring of effects on sleep quality, daytime function/sleepiness and cardiovascular parameters.