Co-authors: Gabriele de Ramos Luccas & Giédre Berretin-Félix

Please note this article has been translated into English from Portuguese.

In the late 1990s and early 2000s, Brazilian speech-language pathologists who were experts in orofacial motricity started to study the interface between speech-language pathology (SLP) and sleep breathing disorders. Initial research revealed altered stomatognathic system structures and functions in people who snore and have obstructive sleep apnea (OSA). The alterations involved increased tongue volume, both laterally and longitudinally; increased height of the back of the tongue; tongue edge indentation; elongated, hyperemic, or swollen palate and uvula; and functional changes in chewing and swallowing1. However, it was not until 2009, when Dr. Katia Guimarães and colleagues published their article “Effects of Oropharyngeal Exercises on Patients with Moderate Obstructive Sleep Apnea Syndrome” in the American Journal of Respiratory and Critical Care, that speech-language pathology in sleep disorders reached international repercussions and made it possible for SLP to become a more prominent treatment possibility for patients with OSA2.

The Brazilian study announced the first scientific evidence on the effectiveness of an orofacial myofunctional therapy (OMT) program in reducing signs and symptoms in patients with moderate OSA. Since then, different studies have been published, and it is currently known that OMT can significantly improve apnea and hypopnea rates (up to 50% in adults and 62% in children), snoring frequency and intensity, awakening rates, and nocturnal oxygen peripheral saturation3,4,5. It can also significantly increase adherence to continuous positive airway pressure (CPAP) treatment and enhance orofacial myofunctional aspects.  

Since OSA is multifactorial, some studies and clinical practice have highlighted the importance of combined treatments for better results.  In that context, clinical practice has shown that OMT can increase OSA treatments’ therapeutic success when combined with surgeries and oral appliances, and some studies have even shown that associating OMT and CPAP brings positive results6,7. Treatments must be combined individually according to each person’s OSA contributing factors. 

In addition to orofacial motricity, other speech-language pathology specialty areas have investigated how sleep disorders impact certain functions, including swallowing. In that context, studies have shown that patients with OSA may present swallowing disorders that mainly include premature posterior escape and residue in vallecula and pyriform sinuses, who may also experience delayed onset of the pharyngeal swallow response, laryngeal penetration, laryngotracheal aspiration, and esophageal stasis. Besides, individuals with OSA also have a shorter inspiratory suppression time, inhaling back more quickly after swallowing. Other studies have revealed that patients with OSA have reduced oral, pharyngeal, and laryngeal sensitivity. The literature suggests that decreased aference for neuromuscular injuries caused by snoring is one of the main reasons for signs and symptoms in that population8.

Once we swallow saliva during our sleep, it is worth mentioning that the impairment of swallowing and aspiration events can happen not only when eating but also sleeping. OSA promotes hypercapnia and, consequently, increased respiratory rate, increased tidal volume, and awakening in high ventilatory demand, thus predisposing to uncoordinated swallowing with breathing. Studies have shown that individuals with OSA swallow mostly during respiratory awakening and mostly after or followed by inspiration9,10. These data open room for another research subject: Could aspiration mechanisms cause OSA with no symptoms of laryngotracheal aspiration and recurrent lung infections or even the findings of interstitial focal lesions on CT scans of the elderly during sleep? 

Regarding the presence of OSA in patients with dysphagia, although few studies connect OSA to neurogenic dysphagia, some studies show decreased oropharyngeal space after stroke and the prevalence of OSA in different types of neurological diseases also experienced with dysphagia11,12. 

Since the pathophysiology underlying OSA seems to predispose to several swallowing alterations, and neurogenic dysphagia is caused by neurological damage to the oropharyngeal muscles, and the altered neurological control of such musculature may predispose to collapse during sleep, it makes sense to investigate OSA in patients with neurogenic dysphagia and swallowing in patients with OSA. 

For speech-language pathologists who work with dysphagia, learning about sleep enables them to suspect OSA in patients with signs and symptoms of such disorder and refer them for medical diagnosis if any suspicion is identified. Aging is a risk factor for developing dysphagia13 and OSA14, so it is important that speech-language pathologists who work with presbyphagia be aware of any sleep issues. In our clinical practice, several elderly people with dysphagia were diagnosed with OSA after initial suspicion. Therefore, pay attention to patients with dysphagia, especially those who are never awake during therapy, who have severe cognitive and language impairment and motor and clinical symptoms unresponsive to medication as they may be suffering from the consequences of sleep deprivation caused by OSA. Once these are treated, these patients can experience improvement in their general condition, better alertness for therapy, and even improvement in some swallowing symptoms15. 

First of all, speech-language pathologists are health care professionals. Thus, just as eating effectively and safely promotes cognitive, metabolic, and nutritional improvements, the conditions for them to occur happen during the physiological process of sleep.

Conclusions

  1. Orofacial myofunctional therapy is an option for treating individuals with snoring and OSA.
  2. Treatment can be done by itself or combined with other treatments to increase therapeutic success.
  3. Patients with OSA must be submitted to a swallowing assessment by a speech-language pathologist.
  4. Patients with dysphagia, especially the elderly and those affected by neurological diseases, must be checked for sleep-related aspects.
  5. Speech-language pathologists have an important role in identifying possible cases of OSA in patients with risk factors.
  6. Every speech-language pathology field should investigate sleep as it can negatively impact different areas of SLP and at all stages of life.

Links of Interest

https://www.leticiafreixo.com/pagina-inicial (Site in Portuguese)

Co-Authors

Gabriele Ramos de Luccas is a PhD Student at Bauru School of Dentistry, University of São Paulo (USP) – Department of Speech-Language Pathology and Audiology, Bauru, São Paulo, Brazil.  She is a Sleep Medicine Speech Language Pathologist With Accredited Certification by the Brazilian Sleep Society.

Giédre Berretin – Félix is a graduate in Speech Language Pathology (Bauru School of Dentistry, University of São Paulo – 1996) and holds a Master’s degree in Oral Physiology (Campinas State University – 1999) and a Ph.D. in Physiopathology in Clinical Medicine (Paulista State University Júlio de Mesquita Filho – 2005). She has completed post doctorate work in Swallowing Disorders (University of Florida – 2010). She is a Full Professor, Department of Speech Therapy and Audiology, Bauru School of Dentistry, University of São Paulo, and is Editor-in-Chief of CEFAC – Speech, Language, Hearing Sciences and Educational Journal. She is a productivity researcher fellow by the National Council of Scientific and Technological Development – Brazil.

References

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