Effects of a tongue training program in Parkinson's disease: Analysis of electrical activity and strength of suprahyoid muscles

Objective: To assess the electrical activity of the suprahyoid muscle and the tongue pressure in a two-wing program of tongue strengthening in individuals with Parkinson's disease (PD). Methods: A pre-post-detraining design study included sixty PD patients assigned to two groups randomly. The experimental group (EG) performed tongue isometric pressure exercises using the Iowa Oral Performance Instrument with an increasing scheme of 5% load weekly and traditional tongue therapy for 8 weeks. The control group (CG) performed only traditional therapy. The electrical activity of suprahyoids was measured using surface electromyography (sEMG) during tongue-to-palate pressure. Four selected domains of the Swallowing Quality of Life Questionnaire (SWAL-QOL) mostly related to tongue strength were considered. Results: The experimental group showed increased sEMG values of suprahyoid muscles reaching statistically significant difference at the fourth week of tongue training, while the control did it at the eighth week. Experimental group showed significant improvements in tongue strength (d = 2.128; p = 0.000). Only controls showed detraining effect. Statistically significant difference within groups were found in one and three dimensions of the SWAL-QOL in the CG and EG, respectively. Conclusion: Analysis of electrical activity on suprahyoids muscles provided a better understanding of the changes underlying the outcomes of tongue strength gains obtained through a combined tongue strengthening exercises protocol in PD. Such protocol led not only to increased tongue strength but also to a better perceived swallowing function in PD subjects.

Automated summary

This study assessed the electrical activity of the suprahyoid muscle and tongue pressure in individuals with Parkinson's disease undergoing a tongue strengthening program. The experimental group showed significant increases in suprahyoid muscle activity and tongue strength earlier than the control group. Tongue strength significantly improved in the experimental group, while detraining effect was observed in the control group. Some dimensions of the Swallowing Quality of Life Questionnaire also showed significant differences between the two groups.