Study Design

A randomized, controlled, assessor-blinded clinical trial was conducted at a tertiary care hospital in Thailand from January 2021 to December 2023. The study was approved by the institutional review board (COA 870/2020) and registered in the Thai Clinical Trial Registry (TCTR20201207003).

Selection Criteria

Stroke patients with dysphagia were enrolled based on the following inclusion criteria: failure of the 90 mL water swallowing test, which has been recommended as a screening tool for aspiration in stroke patients [16]; stroke onset within six months; age over 18 years; medical stability; ability to perform swallowing exercises, determined by cognitive and visual capacity to understand and follow instructions; and access to a mobile electronic device such as a smartphone or tablet. Participants who failed the water swallowing test subsequently underwent a clinical swallowing assessment by a rehabilitation physician not involved in the study to confirm the presence of swallowing dysfunction. However, due to financial constraints, instrumental evaluations such as videofluoroscopic or endoscopic swallowing studies were not performed. Patients were excluded if they had visual impairments, dysphagia unrelated to stroke, or required transfer to another healthcare facility. Participants unable to continue the program for medical reasons or those who requested withdrawal were discontinued from the study.

Sample Size

Based on the study by Emmerson et al.[15], a sample size of 44 participants was determined to achieve 80% power with a 95% confidence interval, accounting for a 10% dropout rate.

Procedure

Stroke patients with dysphagia who met the inclusion criteria were invited to participate in the study. All participants received a detailed explanation of the procedures and provided informed consent prior to enrollment. They were then randomly assigned to either the intervention or control group using a computer-generated randomization process, and baseline characteristics were recorded. Although lesion location and size are recognized as important factors influencing the severity and recovery of post-stroke dysphagia [17,18,19, 20], imaging data were not collected as part of the study due to resource constraints commonly encountered in clinical settings in Thailand.

Control Group

Participants in the control group received a printed handbook illustrating five standard swallowing exercises: lip exercises, tongue range of motion and strengthening, chin tuck against resistance (CTAR), and the Masako maneuver.

Lip and tongue exercises were prescribed to improve oral musculature strength and mobility, essential for bolus control and transit during the oral phase of swallowing. Lip exercises included six targeted movements: wide mouth opening, broad smiling to expose the teeth, lip pursing (as if whistling), firm lip closure, sucking the cheeks inward, and puffing out the cheeks. Tongue range of motion tasks involved protrusion, circular movement around the lips, and elevation toward the palate followed by sweeping toward the uvula. Strengthening tasks consisted of pressing the tongue forcefully against the inner cheeks bilaterally; resistance was increased by applying external finger pressure as participants progressed. Each exercise was performed for ten repetitions per session, with one full set comprising all prescribed movements. These exercises are commonly used in dysphagia rehabilitation to enhance lip seal, intraoral pressure, and bolus manipulation, and have demonstrated efficacy in improving oral-phase swallowing function, particularly in post-stroke populations [21].

The CTAR exercise was performed using resistance from an inflatable ball, following established protocols. When unavailable, alternatives such as a rolled towel or the participant’s fist were used. The exercise included both isometric (chin pressed against resistance and held for 30 s) and isokinetic (chin pressed and released for 30 repetitions) components, which together comprised one set. For participants unable to complete 30 repetitions, a modified set of 10 was permitted. This exercise targets the suprahyoid muscles responsible for hyolaryngeal elevation and has shown comparable or superior muscle activation to the Shaker exercise [22].

The Masako maneuver, or tongue-hold swallow, was prescribed to enhance pharyngeal strength and coordination. Participants were instructed to gently protrude the tongue and hold it in place with their teeth or lips while performing a dry swallow. For those unable to maintain tongue position using lip strength alone, manual support with the hand was recommended. This exercise was performed for ten repetitions per set. Repetitive practice of this maneuver has been shown to improve swallowing function in stroke patients with dysphagia [23].

All exercises, except for CTAR, were prescribed at ten repetitions per set, three sets per day, for one month. This dosage aligns with commonly reported clinical practice. A systematic review of dysphagia rehabilitation protocols indicated that oromotor and tongue exercises are frequently prescribed in sets of 10 repetitions. In contrast, CTAR is typically administered as three isometric holds and 30 isokinetic repetitions per session, performed three to seven times per week [24], supporting the use of a similar dosing framework.

Intervention Group

Participants in the intervention group accessed the same set of exercises through a video-based program delivered via mobile electronic devices. The video featured a simulated patient performing each exercise in real time, allowing participants to follow along. A voiceover narration guided them throughout the session—providing instructions, signaling when to start and rest, counting repetitions, and reminding them to complete the exercises three times daily. Countdown intervals were included to mark 30-second rest periods between movements within the same category, promoting structured and consistent practice. Exercises in different categories were delivered in separate videos, allowing participants to choose when to perform each one throughout the day.

Exercise Monitoring and Follow-up

Prior to discharge, all participants were assessed to ensure accurate performance of the prescribed exercises. They were instructed to refrain from using additional training media or seeking dysphagia-related treatment at other healthcare facilities during the study period. Each participant received a self-reported logbook to document their adherence to the home exercise regimen. To support compliance, weekly reminder phone calls were made to participants in both groups, encouraging them to maintain their logbooks and continue the prescribed exercises as instructed.

At the one-month follow-up, a blinded assessor evaluated each participant to assess exercise adherence (based on logbook entries), swallowing function, and satisfaction with the assigned instructional media.

Outcome MeasurementsSwallowing Exercise Adherence

Given the absence of a standardized metric for measuring adherence to swallowing exercises [25, 26], a self-reported logbook was employed to monitor adherence throughout the study. This method has been shown to provide greater accuracy than retrospective surveys or interviews [27] by allowing real-time or near-real-time documentation.

Participants in both groups were instructed to record their performance for each prescribed exercise during every session. For each exercise category, adherence was categorized into three levels: no repetitions performed; less than 50% of the prescribed repetitions completed; or at least 50% of the prescribed repetitions completed.

Exercise adherence was then quantified as the percentage of days in which participants met the exercise target—defined as completing ≥ 50% of the recommended repetitions for all prescribed exercises across three sets—relative to the total number of assigned days.

$$\begin & Swallowing\;exercise\;adherence\;(percentage\;of\;days\;meeting\;the\;exercise\;target) \\ & }\frac}\;}\;}\;}\;}\;}\;}}}}\;}\;}}} \times } \\ \end$$

(1)

Swallowing Function

Swallowing function was assessed using the Functional Oral Intake Scale (FOIS) by a blinded occupational therapist to minimize bias. FOIS is a reliable and clinically meaningful tool for evaluating swallowing function in individuals with neurological impairments, particularly those recovering from stroke. It has demonstrated excellent interrater reliability and sensitivity to changes in oral intake over time. FOIS has also been validated against other established assessments, such as the Mann Assessment of Swallowing Ability (MASA), showing strong criterion validity and supporting its use as a functional outcome measure [28]. A systematic review has further identified FOIS as one of the most commonly used tools for monitoring dysphagia recovery in stroke populations [17]. The scale consists of seven levels, ranging from level 1 (nothing by mouth) to level 7 (total oral diet with no restrictions), and can be dichotomized to distinguish between tube-dependent patients (FOIS ≤ 3) and those with full oral intake (FOIS >3).

Media Satisfaction

Media satisfaction was evaluated using a 0–10 Numeric Rating Scale, where 0 indicated no satisfaction and 10 represented the highest level of satisfaction.

Statistical Analysis

Data were analyzed using PASW Statistics for Windows, version 18.0 (SPSS Inc, Chicago, IL, USA). Quantitative data were summarized as mean ± standard deviation or median with interquartile range, depending on distribution, while categorical data were reported as frequencies and percentages. Continuous variables were analyzed using independent t-tests or Mann–Whitney U tests, as appropriate. FOIS scores and other discrete numeric data were assessed using the Mann–Whitney U or Wilcoxon signed-rank test. Categorical variables were compared using Fisher’s exact test, Pearson’s chi-square test, or McNemar’s test, as applicable. No corrections for multiple comparisons (e.g., Bonferroni) were applied, as the analyses did not involve comparisons across multiple groups or time points. Statistical significance was set at p < 0.05.