The Test of Masticating and Swallowing Solids (TOMASS): Reliability, Validity and Normative Data for the Adult Indian Population

Abstract

The Test of Masticating and Swallowing Solids (TOMASS) is a reliable and well-validated tool to assess the effectiveness of solid bolus ingestion. Previous studies have established normative values for 4 to 80+ years across a range of commercially available crackers and countries. The current study aimed to establish normative data for the TOMASS across age and gender groups for a commercially available biscuit (cracker) for the adult Indian population. A total of 300 typical individuals in the age range of 21 to 80 years grouped by age and sex participated in the study. Participants were instructed to eat a commercially (locally) available biscuit ‘as quickly and comfortably as possible,’ and the task was video recorded. The recorded video samples were analyzed to obtain measures of the number of bites, number of masticatory cycles, number of swallows, and total time taken to complete the ingestion of biscuit. Cronbach’s α values revealed a moderate to good (0.71 to 0.82) test–retest reliability; ICC values were suggestive of a high level (> 0.76) of interrater reliability for all the measures of TOMASS. The results of the one-way ANOVA revealed a significant main effect of age (F = 3.12, p < 0.01) and gender (F = 4.37, p < 0.01), but not an interaction between the two. Normative data stratified by age and gender were also generated. The TOMASS assessment procedure was feasible, reliable, and valid. In the current study, we observed that males took fewer bites, took less time, chewed less, and swallowed fewer times than females. A definitive age effect was observed for the number of bites, masticatory cycles, and total time. The normative data generated by the current study can serve as clinical benchmarks to assess the ingestion of solid bouls in the adult Indian population.

Introduction

A clinical swallowing examination provides crucial information related to a patient’s functional abilities that support the diagnosis of feeding and swallowing impairment [1]. This observational assessment estimates a patient’s efficiency of oropharyngeal swallowing and identifies clinical signs of dysphagia through subjective methods that include but not limited to medical history, cognitive and cranial nerve functioning, a structural and functional examination of oropharyngeal structures, and observation of oral intake. However, the subjective nature of these investigations limits its validity, as their results are highly dependent on the experience of the examiner [2].

Observation of oral intake (trial swallows) is an important component of the clinical swallowing examination. Although a variety of bolus textures are used by clinicians, research support is available only for the inclusion of liquids [3]. However, the practice of using thin to thick liquids fails to adequately address the oral phase of swallowing, particularly mastication and bolus preparation. To address this, the “Test of Masticating and Swallowing Solids” (TOMASS) [4] was developed as an assessment method to evaluate oral pharyngeal efficiency for solid bolus intake. Since it was first reported by Athukorala et al. [4], several research reports [5, 6] have reported strong psychometric properties for TOMASS.

While the TOMASS has been established as a reliable and well-validated tool to assess the effectiveness of solid bolus ingestion, significant differences between age, gender, and solid test bolus type (crackers) have been reported [5, 6]. Thus, normative values for the age range 4 to 80 + years, calculated by age and gender, have been established across a range of commercially available crackers (Arnott’s Salada™, Nabisco Saltine™, Carr’s Table Water™, Albert Heijn Basic™, DeBeukelaer Tuc Classic™, Gran Pavesi™, and Osem Golden™) across seven different countries (New Zealand/ Australia, North America, Ireland/United Kingdom, Netherlands, Germany, Italy/Portugal, and Israel) respectively [5, 7].

Study Aim

To establish normative data for the Test of Masticating and Swallowing Solids (TOMASS) across age and gender groups for a commercially available biscuit (cracker) for the adult Indian population.

Method

Study Design

We adopted a cross-sectional design with nonrandomized convenience sampling. The study was carried out at the Department of Audiology and Speech-Language Pathology, Kasturba Medical College, Mangalore, between 2017 and 2019.

Participants

Before the recruitment of participants, ethical approval (IEC KMC MLR 11-18/467) for the study was obtained from the Institutional Ethics Committee of the Kasturba Medical College, Mangalore. A total of 300 typical subjects in the age range of 21 to 80 years were recruited for the study based on the sample size formula 2(Z(1 − α/2) + Z (1 − β) 2) σ2/d2, Z(1 − α/2) = 1.96 and Z(1 − β) = 0.84 at 95% confidence intervals. Group 1 consisted of 96 young adults (49 males and 47 females) in the age range of 21–40 years. Group 2 consisted of 114 middle-aged (60 males and 54 females) adults in the age range of 41–60 years. Group 3 consisted of 89 older adults (34 males and 55 females) in the age range of 61–80 years recruited from the community.

All the participants self-reported no speech, language, and/or neurological problems. Only those participants who obtained a score of < 3 on the Kannada version of Eating Assessment Tool 10 (EAT 10 K) [8] were considered for the study. The exclusion criteria for the participants were poor auditory verbal comprehension and physical impairment (paralysis, quadriplegia, diplegia).

Materials

A commercially available cracker (biscuit), Parle Monaco™, was used for the current study. Each biscuit weighs 6.67gms with a total fat content of 121gms and are identical in size, shape, and appearance. The constituent ingredients of the biscuit are wheat flour, edible vegetable oils, sugar, raising agents, invert sugar syrup, common edible salt, yeast, acidity regulators, emulsifiers, dough conditioner, improver amylase, and other enzymes.

Procedure

Participants were instructed to sit comfortably during the testing procedure. They were instructed to eat the biscuit ‘as quickly and comfortably as possible’ and say their name out loud to indicate the end of the testing procedure. The task was recorded using a hand-held video recorder. Upon completion of the task, a visual inspection of the oral cavity was done to ensure that there was no food residue or pocketing. A stopwatch was used to measure the total time taken by the individual to ingest the complete biscuit, starting when the first bite of biscuit touched the lips and ending with voice onset when the participant stated their name.

Measures

The recorded video samples were analyzed to obtain the following base measures; number of bites, number of masticatory cycles, number of swallows per biscuit (cracker), and total time taken to complete the ingestion of biscuit.

Reliability Measures

To assess the test–retest reliability, TOMASS was performed by 30 participants [10 participants (5 males and 5 females) from each of the three groups] using the same procedure after one week. During the first recording, two raters were present to make independent measures of participant performance as an assessment of interrater reliability. The second rating was used to measure test–retest reliability.

Statistical Analyses

Cronbach’s alpha was used to evaluate the test–retest reliability, and mixed model intraclass correlation was used to determine the inter-rater reliability. A general linear model, one way, fixed-factors ANOVA was carried out to evaluate the effect of age and gender on all variables. The reported p-values represent the application of Bonferonni correction for multiple comparisons when appropriate.

Results

Reliability Measures

Cronbach’s α values revealed a moderate to good (0.71 to 0.82) test–retest reliability for all the measures of TOMASS. ICC values revealed a high level (> 0.76) of interrater reliability for all the measures of TOMASS.

Effect of Age and Gender

Males took fewer bites, took less time, chewed less, and swallowed fewer times compared to females. Across both genders, all measures of TOMASS increased with age, except for the number of swallows (Figs. 1, 2, 3, and 4). However, it was observed that middle-aged adults swallowed fewer times compared to young adults and older adults (Fig. 3).

Fig. 1.

Number of bites taken by males and females represented across age groups as mean (standard deviation). Error bars indicate standard error (SE)

Fig. 2.

Total time taken by males and females represented across age groups as mean (standard deviation). Error bars indicate standard error (SE). *p < 0.05

Fig. 3.

Number of swallows taken by males and females represented across age groups as mean (standard deviation). Error bars indicate standard error (SE)

Fig. 4.

Number of masticatory cycles taken by males and females represented across age groups as mean (standard deviation). Error bars indicate standard error (SE)

One-way ANOVA was performed with age and gender as the between-group factor only for the base (raw) measures. The results of the one-way ANOVA revealed a significant main effect of age (F = 3.12, p < 0.01) and gender (F = 4.37, p < 0.01). However, there was no interaction between age and gender (p = 0.06). Age significantly affected multiple TOMASS parameters (masticatory cycles: F = 14.62, p < 0.05; time: F = 19.33, p < 0.05; and number of swallows: F = 36.57, p < 0.05), except the number of bites (F = 1.83, p > 0.05).

Post-hoc testing for the effect of age on the TOMASS measures have been depicted in Table 1.

Table 1.

Summary of post hoc testing for effect of age on different parameters of TOMASS

Variable	Age groups		Mean difference	Standard error	Significance
Bites	Young adults	Middle aged adults	− .2182	.14281	.383
		Older adults	− .3233	.15170	.102
	Middle aged adults	Young adults	.2182	.14281	.383
		Older adults	− .1051	.14582	1.000
	Older adults	Young adults	.3233	.15170	.102
		Middle aged adults	.1051	.14582	1.000
Total time	Young adults	Middle aged adults	− 3.3893	1.56745	.094
		Older adults	− 11.5133*	1.66505	.000
	Middle aged adults	Young adults	3.3893	1.56745	.094
		Older adults	− 8.1241*	1.60056	.000
	Older adults	Young adults	11.5133*	1.66505	.000
		Middle aged adults	8.1241*	1.60056	.000
Number of swallows	Young adults	Middle aged adults	.0252	.18721	1.000
		Older adults	− .6131*	.19886	.007
	Middle aged adults	Young adults	− .0252	.18721	1.000
		Older adults	− .6383*	.19116	.003
	Older adults	Young adults	.6131*	.19886	.007
		Middle aged adults	.6383*	.19116	.003
Number of mastication	Young adults	Middle aged adults	− 4.9315*	1.64222	.009
		Older adults	− 10.0123*	1.74448	.000
	Middle aged adults	Young adults	4.9315*	1.64222	.009
		Older adults	− 5.0808*	1.67691	.008
	Older adults	Young adults	10.0123*	1.74448	.000
		Middle aged adults	5.0808*	1.67691	.008

*A statistically significant difference

The results of the Table 1 revealed the following trends. For the measure of number of mastication cycles, we found a statistically significant difference between performance of all three age groups. When the measures of total time and number of swallows were compared across age groups, we found a statistically significant difference in performance between young adults and older adults swallowing, middle aged adults and older adults but not for young adults and middle aged adults. For the measure of number of bites, there was no significant difference between any of the groups.

Gender wise comparison revealed that males took fewer bites, took less time, chewed less, and swallowed fewer times than females. We observed a statistically significant effect of gender for number of bites: F = 11.43, p < 0.05; time: F = 25.36, p < 0.05; and masticatory cycles: F = 4.67, p < 0.05)] but not for number of swallows (F = 1.81, p > 0.05).

Normative Data

Normative data stratified by age and gender are represented below as mean and standard deviation for the Parle Monaco biscuit. The benchmark values for raw (base) measures are summarized in Table 2.

Table 2.

Normative data represented as mean and standard deviation by age and gender for different parameters of TOMASS

Gender	Age group	Number of bites		Total time (s)		Number of swallows		Number of masticatory cycles
		Mean	SD	Mean	SD	Mean	SD	Mean	SD
Males	Young adults	1.14	0.35	24.93	10	2.75	0.92	30.2	11.59
	Middle aged adults	1.46	0.92	26.8	10.33	2.73	1.2	32.6	12.46
	Older adults	1.47	0.82	32.61	11.86	3.61	1.75	37.76	14.49
Females	Young adults	1.65	0.84	28.76	11.11	3.12	1.22	30.1	8.53
	Middle aged adults	1.77	1.47	33.9	12.02	3.11	1.23	37.85	12.78
	Older adults	1.87	1.24	41.85	12.46	3.5	1.69	41.65	11.06

Discussion

The Test of Masticating and Swallowing Solids (TOMASS) was developed to provide quantitative measures for the ingestion of a solid bolus. Such measures are of high value as they augment currently available tools by objectively measuring oral intake for textures that are commonly seen in functional diets. Several studies, realizing the importance of a clinically valid and reliable procedure to evaluate the ingestion of solid bolus, have developed reference data to serve as clinical benchmark. This study aimed to extend the application of the TOMASS by generating reference benchmarks for the Indian population using a standardized commercially available biscuit (cracker) and also to report on its psychometric properties.

Feasibility of Testing

The TOMASS assessment procedure was feasible, and on average, each participant approximately took around 5 min to complete the entire test procedure. We noted that a few of the participants, mostly older adults, requested additional and repeated instructions on how many bites to be taken, pausing between the test procedure. However, no such additional information was provided; rather, the participants were asked to eat the biscuit as quickly as and as comfortably as they could. This was done to maintain the homogeneity of testing across participants.

Reliability

In the current study, we found that the TOMASS was a reliable test with moderate to good test–retest reliability for all the measures. However, the original normative study [5] reported a very high test–retest reliability (Cronbach’s α values ranging from 0.94 – 0.99). In the current study, participants returned after one week for the retesting. Whereas in the Huckabee et al. [5] study, the participants were tested after 24 h. These differences in reliability measures between the studies may be due to the time duration between the first and the second testing (retest).

Age and Gender Effects

The present study consisted of three age groups, namely, young adults in the age range of 21–40 years, middle-aged adults in the age range of 41–60 years, and older adults in the age range of 61–80 years. We observed significant changes in the TOMASS measures across the age groups in the present study. As expected, a definitive age effect was observed for the measures of number of bites, masticatory cycles, and total time. However, it was observed that the middle-aged adults swallowed fewer times compared to young adults and older adults, but no statistical significance was found on post hoc analysis. These findings are in agreement with trends reported in the earlier study by Huckabee et al. [5]. When the performance of three age groups was compared, the number of masticatory cycles was the only measure that showed a statistically significant difference. It may be suggestive that the number of masticatory cycles might be more sensitive to provide useful insights into the patient’s swallowing abilities. In the current study, it was observed that males took fewer bites, took less time, chewed less, and swallowed fewer times than females. Studies have reported similar findings across gender for solid bolus ingestion. Huckabee et al. [5] reported that males took fewer bites, chewed and swallowed less, and took a shorter amount of time than their age-matched females in their TOMASS study.

Conclusions

Little is known about the assessment of swallowing using a solid bolus, and there is limited research for the same. The current study aimed to develop benchmark values for the Test of Masticating and Swallowing Solids (TOMASS), a newly established quantitative measure of discrete components of solid bolus ingestion. Normative data reported in the present study are confined only to the adult population. Further studies are required to develop normative data in the pediatric and adolescent population. Furthermore, studies are warranted in individuals with oro-pharyngeal dysphagia to explore the sensitivity and specificity of TOMASS. Future research is directed towards the assessment of the impact of dysphagia rehabilitation on solid bolus ingestion in individuals with dysphagia.

Author’s Contribution

All the authors have equally contributed in every stage in the preparation of this manuscript.

Funding

No funding was received for the study.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Statement of Ethics

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Ethical approval (IEC KMC MLR 11-18/467) for the study was obtained from the Institutional Ethics Committee of the Kasturba Medical College, Mangaluru, Manipal Academy of Higher Education, Manipal, Karnataka, India.

Informed Consent

All the participants signed an informed consent form.

Consent for Publication

All the authors of the study provide their consent for publication.