A tongue resistance training program improves strength, endurance, and swallowing in frail older adults with mild cognitive impairment: a double-blind randomized controlled trial

BACKGROUND: Age-associated decline in swallowing and tongue function is associated with mild cognitive impairment (MCI) and frailty. However, evidence regarding effectiveness of tongue resistance exercises in frail older adults with MCI is limited with methodological variations and lack of follow-up. OBJECTIVE: To determine the effectiveness of a tongue resistance training program (TRTP) in improving tongue strength (anterior tongue strength [ATS] and posterior tongue strength [PTS]), tongue endurance (anterior tongue endurance [ATE] and posterior tongue endurance [PTE]), and swallowing pressure (saliva swallowing pressure [SSP] and effortful swallowing pressure [ESP]) in frail older adults with MCI. METHODS: A prospective, double-blind, randomized controlled trial design. Participants were randomly assigned to TRTP (n = 23) or cheek-bulging exercises (n = 23). Generalized estimating equation model involving intention-to-treat approach was used for data analysis. RESULTS: A total of 46 frail older adults with MCI were recruited (women: 80.0%; mean age: 75.7 ± 6.7 years). TRTP significantly improved ATS (β = 6.4; p = 0.016, 95%CI = 1.2-11.5), SSP (β = 12.5; p < 0.001, 95%CI = 9.2-15.9), and ESP (β = 14.2; p < 0.001, 95%CI = 9.3-19.0) at immediate posttest. However, no significant improvements were observed for PTS (β = 4.0; p = 0.231, 95%CI = - 2.6-10.6), ATE (β = - 4.5; p = 0.173, 95%CI = - 10.9-2.0), and PTE (β = 2.4; p = 0.489, 95%CI = - 4.5-9.4). At 12-week follow-up, sustained improvements were observed for SSP (β = 6.1; p < 0.001, 95%CI = 2.6-9.7) and ESP (β = 7.9; p < 0.001, 95%CI = 3.9-11.9). No significant short-term effects on ATS, PTS, ATE, and PTE (p > 0.05). CONCLUSION: TRTP effectively improved ATS, SSP, and ESP in frail older adults with MCI. Future research should integrate progressive resistance exercises sustained isometric and isokinetic exercises, and task-specific training. Trial Registration Clincialtrials.gov: NCT06766487(2024.12.02).