RCT: tongue retaining devices vs CPAP for OSA
Reviewed by Vik Veer

This study compared the effect of a tongue retaining device versus the use of CPAP in 27 patients within a crossover RCT design. Tongue retaining devices (also known as tongue stabilising devices), are similar in appearance to a plastic tongue-sized thimble which is placed in front of the incisors during sleep. The tongue is forced into the plastic cup and, through suction, it is retained in a protruding position. These devices are typically very cheap, and a quick search on Amazon suggests that the average price is about £3-£5 each. The study shows that CPAP is more effective by a significant margin, but the tongue retaining devices (TRD) also have a reasonable effect on the apnoea hypopnoea index (AHI). The baseline mean AHI dropped from 38 to 2.5 in the CPAP crossover, which is an effective cure (AHI <5 = normal / 5-15 = mild OSA / 15-30 = moderate AHI / 30+ severe OSA). Although the TRD was not as effective as CPAP, the reduction achieved was still significant at AHI = 12.7. There were some limitations with this study, including variable sleep study technology and use of subjective adherence outcomes, but the short follow-up (three weeks in each arm) is what I would regard as the most glaring issue. In my experience CPAP and TRD both have adherence issues, and therefore it would have been useful to know what the three-month follow-up rates were, and which therapy the patients preferred. Both have very different side-effect profiles, so data on the adherence would have been interesting to see. This study does show that TRDs have a reasonable effectiveness considering the insignificant cost compared to CPAP. CPAP is still the first line option, but TRDs should be considered as a second line or adjuvant therapy. I am aware of some of my patients using TRDs or mandibular advancement devices for time spent away from home. The inconvenience of travelling with CPAP makes these oral devices more appealing. 

Randomized crossover study of tongue-retaining device and positive airway pressure for obstructive sleep apnea.
Banhiran W, Durongphan A, Keskool P, et al.
SLEEP & BREATHING
2020;24(3):1011-8.