The Effects of a Jaw-Opening Exercise on Submental Muscles and Hyoid Movement During Swallowing in Healthy Adults

Abstract

Objective: Traditionally, swallowing rehabilitation has involved the use of muscle strengthening exercises, such as the head-lift manoeuvre (Shaker et al., 1997), to strengthen the floor of mouth muscles. Clinical reasoning suggests that this particular exercise may be problematic for patients with cervical spine injuries or increased frailty. Recently, Bauer and Huckabee (2010) attempted to determine the efficacy of an alternative exercise for the floor of mouth muscles in healthy adults. The present study aims to expand on this work in a larger population of healthy adults. Study design: Controlled trial; participants matched for age and sex. Participants: 23 healthy adults with no history of neurological or muscular impairment. Method: Participants were assigned into one of two groups: jaw opening exercise (JOE; n = 12) and sham exercise (SE; n = 11). Groups were matched for age and gender. Participants performed their respective exercises three times per day, five days per week, over a six week period. At three times during this period, measures of submental 2-D cross-sectional area and anterior hyoid movement were taken via ultrasound. Additionally, measures of submental muscle myoelectrical activity were taken via surface electromyography. Pre- and post-treatment comparisons, as well as inter-group comparisons, were undertaken. Results: No significant differences were observed between groups on measures of muscle size, anterior hyoid movement, or myoelectrical activity over time. However, this study has contributed to the future development of an alternative exercise to target the submental muscle group.