Effect of an Oral Neuromuscular Training Device on Dysphagia: an Assessor-blinded Randomized Controlled Trial

Dysphagia is a frequent complication following stroke, with an estimated prevalence of 42%. One training modality which have been implemented in both hospitals and municipalities for alleviating dysphagia are oral neuromuscular training devices. These devices are hand-held acrylic devices which are inserted between the lips and teeth by the patient or an assistant and pulled forward against lip pressure. According to the developers of one of these devices coined IQoro, the training strengthens the orofacial and pharyngeal muscles. One of recent studies by the developer of IQoro, have demonstrated a positive effect of IQoro in improving swallowing function and reducing clinical signs of aspiration among older people in intermediate care. However, aspiration risk was based on unblinded subjective water swallowing tests, and findings may therefore be biased. Additionally, it should be considered that the study was a cluster-randomized study, in which the intervention was performed in some care units, and the usual care was performed in other care units. Since usual care is not described in detail, results in favor of IQoro may also be due to differences in the usual care practice between care units. Focusing on individuals with stroke, only observational studies have been carried out. These studies have shown functional improvements in all four quadrants of the mouth, improved lip strength, and improved swallowing capacity. However, observational studies suffer from the inherent limitation that it is not possible to establish whether training with IQoro is actually the cause of these improvements.

The present research group recently published a small Randomized Controlled Trial (RCT), investigating the effectiveness of IQoro on swallowing function and decannulation in a very selective population of patients with cuffed tracheostomies due to severe acquired brain injury . Here, 22 subjects were randomized to either usual care, or usual care plus IQoro training as an add-on. In the study, there was no effect of IQoro in either time until decannulation, or swallowing function (as the implicit mechanism of action), compared with usual care. Patients with cuffed tracheostomy tubes are a very selective patient group, and results may not be generalized to a broader group of patients with post-stroke dysphagia.

Based on this, more high-quality clinical trials with IQoro, on a broader population of patients with dysphagia admitted for neurorehabilitation is warranted, in order to clarify whether training with IQoro have an effect on swallowing.

Aim and hypothesis The aim of this study is to investigate the effectiveness of oral neuromuscular training with IQoro on swallowing function in patients with dysphagia due to stroke. The hypothesis is that patients will have improved swallowing function because of training with IQoro as an add-on to usual care, compared with patients who only receive usual care.

Study design An assessor-blinded randomized controlled trial. Study participants will be randomly assigned to either the IQoro (intervention group) or usual care (control group). The trial will be conducted in accordance with the ethical principles outlined in the Declaration of Helsinki and approved by the Danish National Medical Research Ethics Committee