Effect of Oral Muscle–Strengthening Training Using a Smartphone Application on Pronunciation in Older Adults: A Randomized Controlled Trial

OBJECTIVE: To evaluate the effects of smartphone application-based oral muscle-strengthening training on articulation in older adults. METHODS: Eligible participants who scored within the normal range on a speech screening test underwent oral muscle-strengthening training using smartphone application-based content twice weekly for 6 weeks, whereas a control group was instructed to maintain their usual daily routines without receiving any specific intervention. To examine improvements in speech performance, the total percentage of correct consonants (PCC), proportion of whole-word correctness (PWC), phonological mean length of utterance, proportion of whole-word proximity and percentage of correct vowels were assessed. Phonological error patterns were also identified. RESULTS: A total of 47 older adults aged ≥ 65 years, including both men and women, were included. According to the repeated-measures ANOVA, the intervention group demonstrated significantly greater post-intervention improvements than the control group in PCC (from 97.9 at baseline to 99.0 post-intervention, p = 0.031) and PWC (from 0.9 to 1.0, p = 0.004). Although the absolute changes were numerically small, they were associated with moderate effect sizes, indicating clinically meaningful improvements in pronunciation accuracy. The mean number of vowel change errors significantly decreased (from 0.8 to 0.5, p = 0.042). CONCLUSION: Smartphone application-based oral muscle-strengthening training can positively affect pronunciation improvement in older adults. This suggests the potential of non-face-to-face, self-directed interventions to mitigate age-related declines in oral motor function and maintain communication abilities, thereby contributing to enhanced quality of life among older adults. TRIAL REGISTRATION: Clinical Research Information Service of the Korean Government: KCT0011121.