Exploratory study on the effect of orofacial myofunctional therapy on habitual tongue resting position in people with obstructive sleep apnea.

There was no control group and no randomisation, so any change over the twelve weeks could be the therapy, the sleep hygiene and behavioural advice given with it, or simply the passage of time. Only ten of the eighteen people recruited were analysed. Seven dropped out and one died of unrelated causes, and the people who stayed may not resemble the ones who left. Nobody assessing the ultrasound images knew whether they came from before or after treatment, so the assessor's expectations could have influenced which frame was chosen and how the outline was drawn. No one checked whether two different examiners would measure the same tongue distances the same way, and the person holding the probe may have positioned it differently on the two occasions, which could move the measured distances on its own. The tongue distances involved are fractions of a millimetre, measured on a single hand-drawn frame per person. The time between the first and second sleep study varied between participants and was more than four months in some cases. The participants were not a uniform group: some were already using CPAP and some were not, and the home exercise record sheets were not all returned, so how much exercise was actually done at home is unknown.

The only support declared is a grant from FACEPE (Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco), a state research funding agency in Brazil. No commercial sponsor is named, so there is no company with a product to sell behind this work.

Do not read the fall in the apnea-hypopnea index from 24.4 to 11.2 events per hour, or the smaller number of oxygen desaturation events, as proof that orofacial myofunctional therapy works. There was no control group, only ten people were measured, and the apnea-hypopnea change missed significance (p = 0.051), so these numbers cannot separate the exercises from the sleep hygiene and behavioural advice given alongside them, or from the passage of time.