Effect of orbicularis oris muscle training on muscle strength and lip closure function in patients with stroke and swallowing disorder

[Purpose] We aimed to investigate the effect of resistance training of the orbicularis oris muscles on lip muscle strength and closure function in patients with swallowing disorder with facial palsy after stroke. [Participants and Methods] This study recruited 10 patients with swallowing disorder and facial palsy after stroke. All the participants received orbicularis oris muscle training at an intensity of 70% of 1 repetition maximum by using an Iowa oral performance instrument. Muscle strength and lip closure function were evaluated after orbicularis oris muscle training. [Results] After the intervention, the orbicularis oris muscle strength showed a statistically significant increase from 20.5 ± 5.15 to 25.3 ± 4.2 kilopascal. Lip closure function showed a statistically significant improvement from 2.6 ± 1.5 to 1.2 ± 1.0. [Conclusion] This study recommends to train at an intensity of 70% of 1 repetition maximum for 4 weeks to increase theorbicularis oris muscle strength and improve lip closure function.