It is crucial to understand the complex processes of chewing and swallowing, especially in patients diagnosed with oral cavity cancer, as these basic functions are often severely impacted. As the first oral phase of swallowing is critical for the entire process, any impairment at this stage can make the subsequent phases even more challenging. There is a need for a more integrated approach in skill training programs that focus on both chewing and swallowing simultaneously. Using biofeedback during training increases patient control of their swallowing motions, helping restore normal function.

Including chewy tubes within a rehabilitation plan assists these patients by strengthening the chewing muscles, thus providing targeted sensory input to improve overall muscular endurance for mastication. The research also uses thermo-tactile stimulation (TTS) to test the enhancement of the swallowing function in these patients. These approaches combined will be studied to create a comprehensive oral cancer rehabilitation plan.

Inclusion and exclusion criteria

Participants must be 18 years or older,native speakers of Kannada and both men and women are eligible for the study. The lesion should be located on the tongue or buccal mucosa. Participants who have undergone cancer treatment, which may include surgery, radiotherapy (RT), or chemoradiotherapy (CRT), will be eligible for inclusion. They must be at least 6 weeks post-surgery, with or without radiation. The participant should have relatively good dentition (teeth), at least on one side of the mouth.  Participants may have a Nasogastric tube or not, but they must have a Functional Oral Intake Scale (FOIS) score of 3 or higher to be included in the study.

Patients will be excluded if there is a recurrence of cancer during the study. Those with dysphagia caused by neurological conditions will also be excluded. Furthermore, patients who experience flap failure or require repeated reconstructions will not be eligible for participation.

Statistical methods

Statistical analysis will be performed using Jamovi (v2.3). Descriptive statistics will summarize participant demographics. Normality will be tested using the Shapiro-Wilk test. Mean ± SD will be reported for normally distributed data; median and IQR for non-normal data. Categorical variables will be shown as frequency (%). Pre- and post-intervention differences will be analyzed using paired t-tests or Wilcoxon signed-rank tests (p < 0.05). If missing data exceeds 10%, imputation will be applied.

Tools

The Tongue ROM Severity Rating Scale (Lazarus et al., 2014) assesses protrusion, lateralization, and elevation to identify oral motor deficits. The MiK Jaw Pitch is an instrument that provides reliable jaw opening measurements. The Functional Oral Intake Scale (FOIS) (Cary et al., 2005) is a validated 7-point scale for tracking oral intake levels. The Residue in the Oral Cavity Scale (Nakagawa et al., 2014) evaluates post-swallow residue to assess oral clearance. The Water Swallow Test (Hey et al., 2013) screens for aspiration risk using graded volumes. The KSWAL-QOL captures dysphagia-related exertion via patient-reported outcomes. Participants considered in this study are native speakers of Kannada, and assistance will be provided if reading issues are reported. All the tools are standardized, published, and freely available. For intervention, Chewy Tubes enhance oral strength and sensation, while sEMG (Myotrac Infiniti) provides real-time feedback on submental muscle activity to improve coordination.consi

Detailed description of procedure/processes

Approval from the Institutional Research Committee (IRC), Institutional Ethics Committee (IEC), and Clinical Trials Registry of India (CTRI) registration will be completed and then the study will be conducted. 

Patients visiting the Swallowing clinic, Department of Speech and Hearing, Kasturba Medical College, will undergo a preliminary screening to determine eligibility. Eligible participants will be briefed on the study and provided with informed consent before assessments or interventions. Pre- and post- intervention assessments will be conducted by a qualified swallowing therapist or supervised student clinician using standardized outcome measures. A single-blinded design will be used to reduce bias, with therapists randomly assigned to pre- or post-assessments.

All participants will complete a 50 mL water swallow test. Those who fail will be referred for FEES to rule out silent aspiration. Participants at risk will not be excluded but will receive individualized compensatory strategies. Assessments will also include tongue range of motion, mouth opening, KSWAL-QOL, and oral residue evaluation. Participants will then begin a structured four-week intervention. In the first week, they will attend a 45-minute in-person session to learn the skill training regimen and receive a personalized chart outlining frequency, repetitions, intensity, and duration. Adherence will be tracked using response sheets, and weekly follow-up calls will support compliance.

Exercise dosage follows the Loewen et al. (2021) model: six exercises × 10 repetitions × 3 times/day = 180 repetitions/day. The regimen targets tongue movement, jaw strength, and mouth opening. Each participant will receive a chewy tube, with usage and sanitization instructions provided. TTS will be administered by caregivers trained during in-person sessions.

Chewy Tubes are safe and effective oral motor devices suitable for both children and adults. They are made from high-grade silicone and have dimensions of 14 cm × 10 cm × 1 cm, with a weight of 0.1 kg. The Chewy Tubes manufactured and sold by B-Arm are approved for use in India, having been registered under the CDSCO Medical Device category (License no: TN/M/MD/019319).

These devices feature a sturdy, chewable surface designed for practicing biting and chewing skills without the use of food. They provide oral sensory input and help strengthen the muscles involved in biting.

In this study, participants will be instructed to chew and clench on the Chewy Tube for 3–5 seconds on each side of the mouth. 

Budget and proposed funding source

Review of literature

Existing literature on dysphagia highlights various assessment tools and interventions for individuals with neurological, cancer-related, and age-associated swallowing issues. Tool validation studies like Chandrashekaraiah et al. (2024) and Lazarus et al. (2014) show promising results but are limited by subjective diagnoses and small samples. Intervention studies report benefits from rehabilitation programs (Tang et al., 2011), chewy tube exercises (He et al., 2013), and skill training (Athukorala et al., 2014; Perry et al., 2018), though often constrained by methodological flaws and lack of follow-up.

Schwarz et al. (2018) suggest thermo-tactile stimulation may reduce aspiration, but inconsistent methods limit conclusions. Dosage reporting varies across studies, as noted by Krekeler et al. (2021) and Loewen et al. (2021), with no standard protocols. Hajdú et al. (2021) found combined resistance and swallowing exercises beneficial in cancer patients, though care variations may have influenced results. Nakagawa et al. (2014) found both chew-swallow food and puree safe in the elderly, but clinical relevance was limited.

Epidemiological data from Khare et al. (2022) and Sathiya et al. (2023) contextualize dysphagia in cancer populations, though affected by sampling bias. Overall, while findings support positive outcomes, small samples, subjective measures, and lack of standardization highlight the need for more rigorous research.