The effect of voice training interventions on patients with oropharyngeal dysphagia: a systematic review

Background Voice training has been proposed as an intervention to improve swallowing function in patients with dysphagia. However, little is known about the effects of voice training on swallowing physiology. Objectives This systematic review investigates the effect of voice training on the swallowing function of patients with oropharyngeal dysphagia and provides the theoretical basis for improving the swallowing function and life quality of patients with oropharyngeal dysphagia. Data sources A systematic review using a narrative synthesis approach of all published studies was sought with no date restrictions. Five electronic databases (EMBASE, PubMed, CINAHL, Web of Science, and The Cochrane Library) were searched from inception to April 2022. Study selection Eight studies were included. Two researchers screened the literature according to inclusion and exclusion criteria, extracted data, and carried out quality control according to the Cochrane handbook5.1.0. Data were analyzed narratively and descriptively. Conclusions In general, statistically significant positive therapy effects were found. Voice training improves the oral and pharyngeal stages of swallowing in patients with neurological causes of dysphagia, such as stroke, and in patients with non-neurological causes of dysphagia, such as head and neck cancer. However, the current literature is limited and further primary research is required to provide more evidence to support voice training intervention in dysphagia. Future studies could further refine the content of voice training interventions, increase the number of patients enrolled, assess the long-term effects of voice training interventions and add associated assessments of the quality of life after treatment.