Change in tongue morphology in response to expiratory resistance loading investigated by magnetic resonance imaging

Effects of Expiratory Muscle Strength Training on Oropharyngeal Swallow Physiology in Persons with Obstructive Sleep Apnea (OSA): A Preliminary Study

Despite the high estimated prevalence of dysphagia in OSA, there is a paucity of evidence supporting behavioral interventions for treatment. The purpose of this study was to assess the impact of expiratory muscle strength training (EMST) on validated, standardized metrics of swallow and airway clearance capacity functions in moderate-to-severe OSA. 10 participants with OSA (mean age = 65.2 years) completed four weeks of EMST training employing a prospective single-arm, double-baseline interventional design. The Modified Barium Swallow Impairment Profile (MBSImP) Component and Composite (Oral Total [OT] and Pharyngeal Total [PT]) scores measured swallow physiology. Airway clearance capacity measures included maximum expiratory pressure (MEP) and peak cough flow (PCF). A historical normative database was used for OSA patient comparison of swallowing metrics. A total of 234 swallows were analyzed. At baseline, impairments in lingual control, oral residue and esophageal clearance were observed. However, no significant differences in the MBSImP Composite (OT/PT) scores were observed between the OSA and healthy referent group. After EMST intervention, there were no significant differences in pre- to post-intervention Composite (OT/PT) scores. However, large effect size was observed for MEP (p < 0.001, d = 3.0), and non-significant, but moderate effect size was observed in PCF (p = 0.19, d = 0.44). Study findings further quantify swallowing in moderate-to-severe OSA and provide preliminary evidence supporting the impact of EMST on airway clearance capacity.

Improvement in Swallowing Function in Patients with Previous Irradiation for Nasopharyngeal Carcinoma by Expiratory Muscle Strength Training

Dysphagia and chronic aspiration are common post-irradiation complications in nasopharyngeal carcinoma (NPC) survivors. Expiratory Muscle Strength Training (EMST) is a simple device-driven exercise therapy for swallowing training. This study investigates the effectiveness of EMST in a group of post-irradiated NPC patients. This prospective cohort, including twelve patients with previous irradiation for NPC and with swallowing disturbance, was performed between 2019 and 2021 in a single institution. Patients were trained with EMST for 8 weeks. Non-parametric analyses examined effects of EMST on primary outcome, maximum expiratory pressure. Secondary outcomes were measured with Penetration-aspiration scale, Yale pharyngeal residue severity rating scale (YPRSRS) by flexible endoscopic evaluation of swallowing, and Eating Assessment Tool (EAT-10) and M.D. Anderson Dysphagia Inventory questionnaire. Twelve patients, with a mean (SD) age of 64.3 (8.2) were recruited. There was no patient dropout with 88.9% overall compliance of training. Maximum expiratory pressure improved by 41% (median 94.5 to 133.5 cmH2O, p = 0.003). There was reduction in Penetration-aspiration scale with thin liquid (median 4 to 3, p = 0.026), and in YPRSRS at pyriform fossa with mildly thick liquid (p = 0.021) and at vallecula with thin liquid (p = 0.034), mildly thick liquid (p = 0.014) and pureed meat congee (p = 0.016). Questionnaire scores did not significantly change statistically. EMST is an easy-to-use and effective exercise therapy to improve airway safety and swallowing function in post-irradiated NPC survivors.

The effect of tongue elevation muscle training in patients with obstructive sleep apnea: A randomised controlled trial

BACKGROUND

Oropharyngeal myofunctional therapy is a multi-component therapy effective to reduce the severity of obstructive sleep apnoea (OSA). However, existing protocols are difficult to replicate in the clinical setting. There is a need to isolate the specific effectiveness of each component of the therapy.

OBJECTIVE

To assess the effects of a 6 weeks tongue elevation training programme in patients with OSA.

METHODS

We conducted a multicentre randomised controlled trial. Eligible participants were adults diagnosed with moderate OSA who presented low adherence to continuous positive airway pressure therapy (mean use <4 h per night). The intervention group completed a 6 weeks tongue elevation training protocol that consisted in anterior tongue elevation strength and endurance tasks with the Iowa Oral Performance Instrument. The control group completed a 6 weeks sham training protocol that involved expiratory muscle training at very low intensity. Polygraphy data, tongue force and endurance, and OSA symptoms were evaluated pre- and post-intervention. The primary outcome was apneoa-hypopnea index (AHI).

RESULTS

Twenty-seven patients (55 ± 11 years) were recruited. According to modified intention-to-treat analysis (n = 25), changes in AHI and c did not significantly differ between groups. Daytime sleepiness (Epworth Sleepiness Scale) and tongue endurance significantly improved in the intervention group compared to the control group (p = .015 and .022, respectively). In the intervention group, 75% of participants had a decrease in daytime sleepiness that exceeded the minimal clinically important difference.

CONCLUSION

Six weeks of tongue elevation muscle training had no effect on OSA severity.

Expiratory muscle strength training evaluated with simultaneous high-resolution manometry and electromyography

OBJECTIVE

To examine feasibility of a simultaneous high-resolution pharyngeal manometry (HRM) and electromyography (EMG) experimental paradigm to detect swallowing-related patterns of palatal, laryngeal, and pharyngeal muscle activity during expiratory training.

STUDY DESIGN

Technical report.

METHODS

Simultaneous HRM, surface submental, and intramuscular EMG were acquired in two healthy participants during five tasks: 10-cc water swallow, maximum expiratory pressure (MEP) testing, and expiratory muscle strength training (EMST) at three pressure levels (sham, 50%, and 75% MEP).

RESULTS

Experimental conditions were feasible. Velopharyngeal closing pressure, palate EMG activity, and pharyngeal EMG activity increased as expiratory load increased. In contrast, thyroarytenoid EMG activity was low during the expiratory task, consistent with glottic opening during exhalation. Submental EMG patterns were more variable during expiratory tasks. Intraluminal air pressures recorded with HRM were correlated with measured expiratory pressures and target valve-opening pressures of the EMST device.

CONCLUSION

Results suggest that a simultaneous HRM/EMG/EMST paradigm may be used to detect previously unquantified swallowing-related muscle activity during EMST, particularly in the palate and pharynx. Our approach and initial findings will be helpful to guide future hypothesis-driven studies and may enable investigators to evaluate other muscle groups active during these tasks. Defining mechanisms of action is a critical next step toward refining therapeutic algorithms using EMST and other targeted treatments for populations with dysphagia and airway disorders.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:797-804, 2017.