Effectiveness of Tongue Resistance Exercises on Tongue and Swallowing Function in Frail Older Adults With MCI

Primary outcomes

1. Tongue strength (anterior tongue strength [ATS] and posterior tongue strength [PTS])

   Time frame: Assessments were performed at baseline (T0), 4-week mid-intervention (T1), 12-week immediate post-intervention (T2), and 12-week follow-up (T3).

   Tongue strength was measured using IOPI (Model 3.1) device, which was set to record peak pressure and repeated strength to evaluate the maximum pressure exerted during each repetition . The bulb was placed on the palate inside the upper front teeth and at the junction of the hard palate and soft palate to measure ATS and PTS. Maximum isometric pressure (MIP) was defined as the pressure generated when the participant pushed the tongue forcefully against the palate and maintained it for 3 seconds for both the anterior and posterior tongue. Each exercise was performed thrice, with 1-minute intervals between trials. The highest value from the three trials was recorded. MIP is reported in terms of kilopascals. The average pressure values for the anterior and posterior parts of the tongue were 55.95 ± 14.13 kPa and 53.23 ± 12.24 kPa, respectively.

2. Tongue Endurance (anterior tongue endurance [ATE] and posterior tongue endurance [PTE])

   Time frame: Assessments were performed at baseline (T0), 4-week mid-intervention (T1), 12-week immediate post-intervention (T2), and 12-week follow-up (T3).

   Tongue endurance was measured using IOPI (Model 3.1) device using the target mode with the target value set at 50% of the individual's MIP. The bulb was placed on either the anterior tongue or the posterior tongue to measure ATE and PTE. The participant pushed the tongue against the palate for 3 seconds. If the pressure exceeded the target value, the instrument displayed a green light indicating the goal had been achieved. Tongue endurance was assessed only once. For the assessment of tongue endurance, interrater reliability was .97, and interrater reliability was .95. Tongue weakness, defined as a tongue pressure of <30 kPa, is associated with a risk of malnutrition.At the indicated cutoff values, the assessment sensitivity was 92% (95% CI: 75% to 98%), specificity was 96% (95% CI: 87% to 99%), positive predictive value was 92% (95% CI: 75% to 98%), negative predictive value was 96% (95% CI: 87% to 99%), and accuracy was 94.7% (95% CI: 87% to 98%).

3. Swallowing pressure (saliva swallowing pressure [SSP] and effortful swallow pressure [ESP]).

   Time frame: Assessments were performed at baseline (T0), 4-week mid-intervention (T1), 12-week immediate post-intervention (T2), and 12-week follow-up (T3).

   Saliva swallowing pressure (SSP) was measured using IOPI (Model 3.1). The IOPI device was set to record peak pressure and repeated strength to evaluate the maximum pressure exerted during each repetition. The bulb was placed on the palate inside the upper front teeth. The participant gently closed the mouth and then swallowed saliva normally (without pressing the bulb with the tongue). An SSP of <10.3 kPa among older adults is associated with an increased risk of aspiration pneumonia.Effortful Swallowing Pressure (ESP) was measured using IOPI (Model 3.1). The IOPI device was set to record peak pressure and repeated strength to evaluate the maximum pressure exerted during each repetition. The bulb was placed on the palate inside the upper front teeth. The participant gently closed the mouth performed an effortful saliva swallow (eg, an egg), but did not press the bulb with the tongue.

4. Aspiration assessment

   Time frame: Assessments were performed at baseline (T0), 4-week mid-intervention (T1), 12-week immediate post-intervention (T2), and 12-week follow-up (T3).

   The references were developed using a structured evaluation form. Information for each option was obtained by interviewing the case or caregiver or by reviewing the institution's records. The evaluation included determining whether there had been a physician-diagnosed case of pneumonia, a fever ≥ 38℃, or respiratory symptoms such as coughing or difficulty breathing, as well as recording the dates of occurrence.