Effects of Tongue Exercise Frequency on Tongue Muscle Biology and Swallowing Physiology in a Rat Model.

Age-related changes in muscle composition and function are often treated using exercise, including muscles of the tongue to treat swallowing impairments (dysphagia). Although tongue exercise is commonly prescribed, optimal tongue exercise doses have not been determined. The purpose of this study was to evaluate effects of varying tongue exercise frequency on tongue force, genioglossus muscle fiber size, composition and metabolism, and swallowing in a rat model. We randomized 41 old and 40 young adult Fischer 344/Brown Norway rats into one of four tongue exercise groups: 5 days/week; 3 days/week; 1 day/week; or sham. Tongue force was higher following all exercise conditions (vs sham); the 5 day/week group had the greatest change in tongue force (p < 0.001). There were no exercise effects on genioglossus (GG) fiber size or MyHC composition (p > 0.05). Significant main effects for age showed a greater proportion of Type I fibers in (p < 0.0001) and increased fiber size of IIa fibers (p = 0.026) in old. There were no significant effects of citrate synthase activity or PGC-1α expression. Significant differences were found in bolus speed and area (size), but findings were potentially influenced by variability. Our findings suggest that tongue force is influenced by exercise frequency; however, these changes were not reflected in characteristics of the GG muscle assayed in this study. Informed by findings of this study, future work in tongue dose optimization will be required to provide better scientific premise for clinical treatments in humans.

Factors Affecting Hearing Aid Adoption by Adults With High-Frequency Hearing Loss: The Beaver Dam Offspring Study.

PURPOSE: Hearing loss (HL) is common among middle-age and older adults, but hearing aid adoption is low. The purpose of this study was to measure the 10-year incidence of hearing aid adoption in a sample of primarily middle-age adults with high-frequency HL and identify factors associated with hearing aid adoption. METHOD: This study included 579 adults (ages 34-80 years) with high-frequency pure-tone average > 25 dB HL (3-8 kHz) enrolled in the Beaver Dam Offspring Study. Hearing aid adoption was measured at 5- and 10-year follow-up examinations. Cox discrete-time proportional hazards models were used to evaluate factors associated with hearing aid adoption (presented as hazards ratios [HRs] and 95% confidence intervals [95% CI]). RESULTS: The 10-year cumulative incidence of hearing aid adoption was 14 per 1,000 person years. Factors significantly associated with adoption in a multivariable model were higher education (vs. 16+ years; 0-12: HR: 0.36, 95% CI [0.19, 0.69]; 13-15: HR: 0.52, 95% CI [0.27, 0.98]), worse high-frequency pure-tone average (per +1 dB; HR: 1.04, 95% CI [1.02, 1.06]), self-reported hearing handicap (screening versions of the Hearing Handicap Inventory score > 8; HR: 1.85, 95% CI [1.02, 3.38]), answering yes to "Do friends and relatives think you have a hearing problem?" (HR: 3.18, 95% CI [1.60, 6.33]) and using closed captions (HR: 2.86, 95% CI [1.08, 7.57]). Effects of age and sex were not significant. CONCLUSIONS: Hearing aid adoption rates were low. Hearing sensitivity, socioeconomic status, and measures of the impact of HL on daily life were associated with adoption. Provider awareness of associated factors can contribute to timely and appropriate intervention.