Abstract
Trismus refers to restriction in the ability to open the mouth. Comprehensive evaluation of trismus and its treatment outcomes needs a multidimensional, self-administered, trismus specific tool. In the present scenario, Gothenburg trismus questionnaire is the only reliable instrument to quantify trismus. Translation of this questionnaire helps in providing standardized documentation of trismus related problems and to obtain a patient's perspective on treatment outcomes within various populations. The aim of this study was to translate the Gothenburg trismus questionnaire-2 (GTQ 2) into Telugu (one of the Indian Languages) and validation of the translation for its effective use in regional Telugu speaking patients. The GTQ 2 was translated according to the guidelines framed by the International Society for Pharmacoeconomics and Outcomes Research: (1) forward translation, (2) reconciliation and back translation, (3) cognitive debriefing, and (4) pilot testing. The psychometric properties of the translated version were evaluated by testing its internal consistency, construct validity, known-group validity and floor and ceiling effects. Patients who reported with or without trismus to the Head and Neck Oncology outpatient clinic were enrolled for the study. Comparison of the GTQ scores was done using Mann–Whitney U-test. The Pearson correlation coefficient was used for assessing convergent and divergent validity. Internal Consistency was calculated using Cronbach’s alpha coefficient. The translated version of the GTQ 2 was administered to 60 patients (30 trismus patients and 30 non-trismus patients). GTQ 2 was successfully translated without any significant issues. Construct validity of the translated version was confirmed and it has a good internal consistency (α > 0.7). The translated instrument can differentiate between those with and without trismus (p < 0.0005). A valid and reliable Telugu version of the Gothenburg Trismus Questionnaire-2 is now available for the benefit of Indian patients.
Supplementary Information
The online version contains supplementary material available at 10.1007/s13193-021-01369-7.
Keywords: Trismus, GTQ, Facial pain, Eating limitations, Jaw limited problems, Construct validity
Introduction
Trismus refers to restriction in the ability to open the mouth. It has been reported that a maximal interincisal opening equal or lesser than 35 mm indicates trismus in patients with head and neck cancers [1, 2]. It is a widely recognized complication following treatment for carcinomas of the head and neck [1, 3]. It can be caused by oral submucous fibrosis, invasion of the tumor into the masticatory muscles, their nerves, and the temporomandibular joint or as a complication of radiation therapy or surgery [2, 4]. Trismus leads to impaired eating and chewing, difficulties in speaking and maintaining oral hygiene, pain, altered facial expression, decreased nutrition and consequently creates a negative impact on the overall quality of life [5, 6].
Qualitative improvement of trismus can be achieved with jaw physiotherapy, exercises, using stacked wooden tongue depressors and with mouth opening devices like Hiester’s, TheraBite and Dynasplint [7]. But, there is no standard measure for the assessment of change in quality of life due to trismus.A quantitative measurement of quality of life can be utilized for research purposes and in clinical settings. [8] Focusing on the issues in a standard questionnaire helps in broadening the treatment objectives in terms of trismus.
In the present scenario, Gothenburg trismus questionnaire is the only reliable questionnaire to quantify trismus [6] which was proposed by Johnson et al. [9] at the Department of Otorhinolaryngology and Head and Neck Surgery, Sahlgrenska Academy, University of Gothenburg, Sweden. GTQ is both general and domain specific which helps in assessment of patient reported outcome measures. The GTQ can be used as a screening tool and also as an endpoint in the studies of jaw rehabilitation [9]. The validity of a standard questionnaire like GTQ can be improved by translating and increasing its administration in diverse populations. Also, translated versions will be useful in reaching out to the patients who are unfamiliar with English.
The present study aims to translate the Gothenburg trismus questionnaire-2 into Telugu and validate the translated questionnaire for its effective use in Indian patients for clinical and research purposes.
Materials and Methods
This study followed the guidelines of declaration of Helsinki. Ethical approval for the study was granted by the institutional ethical committee.
The permission and consent to translate the updated questionnaire was obtained from the authors of the original questionnaire and the validation process began in September, 2019. Prior to the translation of the questionnaire, an expert committee was formed to oversee the entire translation and validation procedures.
The Gothenburg Trismus Questionnaire (GTQ)
The Gothenburg Trismus Questionnaire is a self-administered, symptom specific-trismus questionnaire developed for its use as a screening tool and end point in jaw rehabilitation studies [9]. It was the most accepted and comprehensive questionnaire with good psychometric properties. The updated GTQ, GTQ 2 contains 29 items of which 20 items are divided into four domains; Jaw related problems (8 items), Eating limitations (4 items), Muscular tension (3 items) and Facial pain (5 items) [10]. It also includes 3 single items about mouth opening and 6 questions related to any kind of training to improve mouth opening. The new GTQ-2 also includes a picture of a face giving the patient the possibility to locate the pain. The domains are scored by calculating the mean of each domain and transforming it to a scale of range 0 to 100, where a maximum score indicates greater dysfunction due to trismus.
Translation Process
The translation procedure adopted in this study is based on the work done by Wild et al. [11]:
Forward Translation
Initially, the questionnaire was translated from English to Telugu by two independent, bilingual translators who are fluent in both languages. One translator is a registered Oral & Maxillofacial Surgeon whereas the second translator is having a master’s degree in Architecture and also an experienced translator, but totally new to the concept within the questionnaire.
Reconciliation
Dissimilarities between the two translated versions were sorted and reconciliation into a single forward translation was done by an expert panel and the preliminary version was drafted.
Back Translation
After obtaining the reconciled version, it was back translated into the source language i.e. English by a completely new, independent, bilingual translator who was totally blinded to the previous translations. To verify the conceptual equality, the back translated version was sent to the original authors to compare with the original questionnaire.
Review of the Back Translation
The comments from the original authors were reviewed and any dissimilarity between both was modified by the expert panel.
Cognitive Debriefing and Review
To verify the understandability and cultural relevance, Cognitive debriefing was done with the same study population who were considered for the pilot test. The required changes were discussed with the expert panel and modifications were done.
Proofreading
Finally, the translated draft was reviewed and the required grammatical and typographical corrections were made.
Pilot Testing
For cultural adaptation and to verify the idiomatic and semantic equivalence, a pilot test of the preliminary version was performed at a tertiary cancer hospital in South India.
Study Participants
Patients who reported with or without trismus to the Head and Neck Oncology outpatient clinic were enrolled for the study. 60 patients were considered for the pilot test, out of which 30 patients diagnosed with oral cancer and having clinical signs related to trismus (maximal inter-incisal opening less than or equal to 35 mm) were included as study group population and 30 patients diagnosed with other Head and Neck cancers and without having any trismus related clinical signs were included as control group population. Patients who were unable to read and write Telugu were excluded from the study. Voluntary consent to participate in the study was obtained from all the patients and their acceptance to fill the questionnaire was considered as written consent.
All the patients included in the study filled the translated GTQ-2 along with its feedback questionnaire, EORTC QLQ C-30 and HN35 questionnaires. All the participants answered the questionnaire by marking the most apt alternatives and allocating the scores for each question such that, the greater score implies poor QOL in terms of trismus. The maximal interincisal opening was recorded for all the patients and was compared between the trismus and non-trismus patients.
Instruments for Validation
EORTC QLQ-C30 & QLQ HN-35:
EORTC QLQ C30 is a valid and reliable instrument for measuring the quality of life in cancer patients [12]. HN35 is an additional 35 item module for the assessment of quality of life in head and neck cancer patients [13, 14]. Scores of both the modules range from 0 to 100 for all the items. A score of 100 within the symptom scale indicates severe possible symptoms whereas on a functional scale, it indicates maximum functioning.
Psychometric Evaluation
The psychometric properties of the entire study population were evaluated with the exception of the floor and ceiling effect, which was analysed only in the study group patients with trismus.
Construct Validity
The assessment of construct validity evaluates the reliability of the questionnaire in measuring what it is intended to measure [15]. This is assessed by drawing correlations with similar and dissimilar concepts to evaluate convergent and discriminant validity respectively. Confirmation of 75% of an assumed hypothesis indicates a good construct validity of the questionnaire [16]. In this study, the GTQ-2 domains were compared with the domains of EORTC C30 & HN35 questionnaires within the trismus patients. We have formulated a hypothesis, expecting a moderate to strong correlation of the GTQ-2 domains (jaw related problems, eating limitations and facial pain) with the domains ‘pain, swallowing, speech, social eating & opening mouth’ of the EORTC QLQ HN35. The Pearson correlation coefficient was used to evaluate the validity and a score of < 0.3 was considered to be a weak correlation, between 0.3 and 0.6 as moderate and > 0.6 as strong [17].
Known Group Validity
Known-group validity is a different form of divergent validity. It validates the capability of a particular instrument in differentiating two known population groups with different health status. We compared the GTQ-2 domain scores between trismus and non-trismus patients.
Floor and Ceiling Effects
These effects are considered to be present if more than 15% of the study population attains lowest or highest possible scores [18]. Presence of floor and ceiling effects indicates limited content validity of the instrument.
Internal Consistency
The level of interrelatedness within the items of the questionnaire is known as internal consistency [15] and is assessed by the coefficient “Cronbach’s alpha”. A Cronbach’s alpha score of 0.7 to 0.9 indicates a good internal consistency without any item redundancy [19]. We calculated the internal consistency for all the four domains of the questionnaire within the entire study population.
Statistical Analysis
Data analysis was done using StataSE version 15. Descriptive statistics was done using standard methods. Comparison of the GTQ scores between study and control groups was done using Mann–Whitney U-test. The Pearson correlation coefficient was used for assessing convergent and divergent validity. Internal Consistency was calculated using Cronbach’s alpha coefficient. Tests used for comparison between groups of clinical characteristics and socio-demographic data: Mann–Whitney U-test for continuous variables, Mantel–Haenszel Chi Square Exact test for ordered variables and the Fisher’s Exact test for dichotomous variables. Results were considered statistically significant if p < 0.05.
Results
Translation and Adaptation
The translation process did not encounter any major issues. Any dissimilarity between the translated versions was sorted by consensus. Majority of the items within the questionnaire obtained good agreement during the process of forward and back translation.
The process of translation is purely linguistic modification of words but adaptation necessitates alteration of words into more apt and culturally specific words or sentences [20]. So, the following modifications were done.
Within the main question of the domain ‘eating limitation’, 4 patients reported issues in interpreting the true meaning of the word “parimithi”. Therefore, an alternate word “ibbandhi” was added in order to comprehend the question without changing the original meaning. To give more clarity, the same optional word was also included into the first alternative of the domain, changing it from “assalu ledhu” to “assallu ibbandhi ledhu”.
Regarding the diagrammatic question, 3 patients wrongly marked the alternatives as they were confused with the left and right sides of the diagram. So, for more convenience, “left” and “right” sides were marked over the diagram.
Regarding question 29, one patient felt that the word “saadhana” to be referring to “performing generalized body exercises”. Hence, we added an optional word “noru therchukunendhuku” to specify it as “mouth opening exercises”.
All the modified questions were tested back on the same patients and now they could interpret well. The pertinence of the items within the domains of the GTQ was established by individual meetings and discussions with the patients.
Study Population and Pilot Testing
To evaluate its adequacy, the preliminary version of the instrument was administered to the entire study population.
A total of 60 patients agreed to participate in the validation phase of this study and were divided into trismus and non-trismus groups, each having 30 patients.
The mean age of the entire study population is 46 years and it did not differ significantly between the two groups (p = 0.52).Patients having oral cancer with trismus are mostly males (90%) and more often with carcinoma tongue, whereas patients with other Head and Neck cancers without any trismus are mostly females (53%) and more often with Carcinoma Larynx.
The mean MIO of the trismus group (23 mm) was significantly lower than the non-trismus group (43.9 mm), with p < 0.001. The complete clinical and socio-demographic details of the entire study population are shown in Table 1.
Table 1.
Socio-demographic and clinic characteristics of entire study population
| Study group (n = 30) mean (range) | Control group (n = 30) mean (range) | p value | |
|---|---|---|---|
| MIO (mm) | 23 (10–34) | 43.9 (36–53) | < 0.0001 |
| Age (years) | 45 (31–68) | 47 (16–77) | 0.5258 |
| Gender | n (%) | n (%) | 0.0013 |
| Male | 27(90) | 14 (47) | |
| Female | 3 (10) | 16 (53) | |
| Cancer location | |||
| Buccal mucosa | 5 (17) | ||
| Tongue | 20 (68) | ||
| Gingivobuccal sulcus | 1 (3) | ||
| Retromolar trigone | 2 (6) | ||
| Alveolus | 2 (6) | ||
| Control | |||
| Thyroid | 8 (27) | ||
| Post cricoid | 6 (20) | ||
| Larynx | 13 (44) | ||
| Pyriform sinus | 1 (3) | ||
| Nasopharynx | 1 (3) | ||
| Nasal cavity | 1 (3) | ||
None of the study population found the preliminary version hard to comprehend or disturbing and the average filling time was 10–20 min.
Construct Validity
We had formulated a hypothesis on the strength of correlation between the GTQ-2 domains and the items of the EORTC QLQ HN-35. The presumed hypothesis was confirmed as the EORTC QLQ HN35 domains pain, swallowing, speech, social eating and opening mouth were moderately to strongly correlated with the GTQ-2 domains ‘Jaw related problems, eating limitations and facial pain’, with the strongest correlations found in ‘jaw related problems with pain’ (r = 0.828) and ‘eating limitations with pain(r = 0.640) and swallowing’ (r = 0.636). (Table2).
Table 2.
Correlations of GTQ domains with EORTC Q30 & HN35 domains in oral cancer patients having trismus
| GTQ domains | Jaw related problems | Eating limitation | Muscular tension | Facial pain |
|---|---|---|---|---|
| EORTC QLQ C30 (p-value) | ||||
| Physical functioning | -0.2288 (0.2239) | -0.0847 (0.6563) | -0.4391 (0.0152) | -0.1476 (0.4364) |
| Role functioning | -0.2984 (0.1092) | -0.2910 (0.1187) | -0.3831 (0.0366) | -0.3886 (0.0338) |
| Emotional functioning | -0.0706 (0.7110) | -0.0133 (0.9445) | -0.2607 (0.1640) | -0.2510 (0.1810) |
| Cognitive functioning | -0.0344 (0.8569) | -0.1014 (0.5938) | -0.2778 (0.1372) | -0.0673 (0.7238) |
| Social functioning | -0.1668 (0.3783) | -0.0998 (0.5999) | -0.4524 (0.0121) | -0.2187 (0.2456) |
| Global QoL | -0.3463 (0.0609) | -0.0642 (0.7360) | -0.1349 (0.4772) | -0.2856 (0.1260) |
| Fatigue | 0.2610 (0.1635) | 0.2230 (0.2361) | 0.3526 (0.0560) | 0.2151 (0.2536) |
| Nausea & vomiting | 0.1300 (0.4935) | 0.1908 (0.3126) | 0.4110 (0.0241) | 0.2386 (0.2041) |
| Pain | 0.2427 (0.1962) | 0.1892 (0.3166) | 0.2498 (0.1830) | 0.3859 (0.0352) |
| EORTC QLQ H&N 35 | ||||
| Pain | 0.8287 (0.0000) | 0.6405 (0.0001) | 0.4477 (0.0131) | 0.6198 (0.0003) |
| Swallowing | 0.6284 (0.0002) | 0.6364 (0.0002) | 0.2599 (0.1654) | 0.3502 (0.0578) |
| Senses | 0.5312 (0.0025) | 0.5638 (0.0012) | 0.5586 (0.0013) | 0.4425 (0.0143) |
| Speech | 0.5267 (0.0028) | 0.4796 (0.0073) | 0.3847 (0.0358) | 0.5742 (0.0009) |
| Social eating | 0.4506 (0.0125) | 0.5072 (0.0042) | 0.2764 (0.1392) | 0.4055 (0.0262) |
| Social contact | 0.3977 (0.0295) | 0.4543 (0.0117) | 0.4437 (0.0141) | 0.4943 (0.0055) |
| Sexuality | -0.1712 (0.3658) | -0.0200 (0.9166) | 0.1764 (0.3511) | 0.0900 (0.6361) |
| Teeth | 0.5120 (0.0038) | 0.4777 (0.0076) | 0.3084 (0.0972) | 0.3419 (0.0644) |
| Opening mouth | 0.5714 (0.0010) | 0.4495 (0.0127) | 0.2152 (0.2534) | 0.2747 (0.1418) |
| Dry mouth | 0.3107 (0.0947) | 0.0779 (0.6823) | 0.0818 (0.6673) | 0.0691 (0.7168) |
| Sticky saliva | 0.1520 (0.4225) | 0.4101 (0.0244) | 0.4692 (0.0089) | 0.2347 (0.2118) |
| Coughing | 0.3207 (0.0840) | 0.5969 (0.0005) | 0.2583 (0.1681) | 0.2156 (0.2526) |
| Feeling ill | 0.1408 (0.4580) | 0.4814 (0.0071) | 0.1213 (0.5233) | 0.1072 (0.5729) |
Known-Group Validity
To assess the known-group validity, a comparison of the GTQ-2 domain scores was drawn between the study group and control group patients (Table 3). Results showed statistically significant differences among both the groups in all the four domains. Significant lesser scores were seen in the non-trismus patients and this validates the capability of the translated GTQ-2 in differentiating patients with and without trismus.
Table 3.
Mean GTQ scores comparison between patients with and without trismus
| Study group (n = 30) | Control group (n = 30) | p value | |
|---|---|---|---|
| Jaw related problems | 29.06 | 5.94 | < 0.0001 |
| Eating limitations | 42.50 | 8.33 | < 0.0001 |
| Muscular tension | 14.72 | 1.94 | 0.0005 |
| Facial pain | 31.00 | 7.50 | < 0.0001 |
Floor and Ceiling Effects
There were no floor or ceiling effects within the domains ‘jaw related problems, eating limitations and facial pain’. However, the domain muscular tension showed propensity towards a floor effect within the trismus patients (Table 4).
Table 4.
Descriptive statistics grouped by GTQ domains
| Study group | Domains | Items (n) | Range | Floor (%) | Ceiling (%) |
|---|---|---|---|---|---|
| Oral Cancer patients with trismus (n = 30) | Jaw related problems | 8 | 0–91 | 2 (6.6%) | 0 |
| Eating limitation | 4 | 6–94 | 0 | 0 | |
| Muscular tension | 3 | 0–58 | 12 (40%) | 0 | |
| Facial pain | 5 | 0–85 | 3 (10%) | 0 |
Internal Consistency
The domains (jaw related problems, eating limitations and facial pain) with each having 8, 4 and 5 items respectively showed good internal consistency with Cronbach’s alpha > 0.70. The domain muscular tension with 3 items showed a moderate internal consistency (Cronbach’s alpha = 0.54) (Table 5).
Table 5.
Internal Consistency estimates in entire study population (n = 60)
| GTQ | Number of items | Cronbach’s alpha |
|---|---|---|
| Jaw related problems | 8 | 0.95 |
| Eating limitations | 4 | 0.81 |
| Muscular tension | 3 | 0.54 |
| Facial pain | 5 | 0.88 |
Discussion
To our knowledge, this is the first study to translate Gothenburg trismus questionnaire-2 into Indian languages.
The specific aim of the study is to translate the Gothenburg trismus Questionnaire-2 into Telugu (Indian Language) and validate the translation.
Developing tools for estimating the quality of life (QOL) of cancer patients is of the essence, with the increasing acceptance of QOL as an endpoint in cancer clinical trials all around the world. Trismus and its management have a high impact on the quality of life which in turn impacts the quality of care. A novel treatment approach always aims at improving the quality of life by administering specific assessment tools.
Gothenburg trismus questionnaire is a robust instrument developed at the University of Gothenburg, which has been widely accepted across the globe. This instrument was developed with an intention to adequately record and assess trismus and its treatment outcomes.
Translation of this questionnaire helps in providing standardized documentation of trismus related problems and to obtain a patient's perspective on treatment outcomes within various populations.
India, being a land of diversity has many official languages with Telugu being one of the most spoken languages with rich vocabulary. Native Telugu speakers account for 81 million within the entire Indian population [21]. It is very much essential to translate the most comprehensive, self-administered, trismus specific instrument [9] like GTQ into Indian dialects for the benefit of the patients and also in research settings.
Translation of the instrument was done according to the guidelines framed by the International Society for Pharmacoeconomics and Outcomes Research (ISPOR). The back translation of the questionnaire was submitted to the original authors for correlating with the original instrument and the changes suggested by the authors were incorporated into the final instrument and has been approved.
There are minor contradictions between the written and spoken forms of Telugu language and this made the translation challenging. Also, few changes were made for adapting the instrument to the Indian culture and language after thorough panel discussions, to sort the discrepancies in expression between Telugu and English.
A second challenge in translation was due to the existence of different slangs in Telugu, and the translators had taken utmost care in incorporating the apt word for the translation.
Pilot testing was done by administering the translated instrument to both the groups (trismus and non-trismus). Internal consistency within all the domains of the translated instrument was satisfactory, confirming the correlation between the items within the translated questionnaire.
The Convergent and Discriminant validity of the translated instrument was assessed by comparing the domains of the GTQ-2 with the domains of the EORTC QLQ C30 & its supplementary module HN35.The authors of this study hypothesized that a moderate to strong correlation will exist between the GTQ-2 domains and the domains of the EORTC QLQ HN35. The presumed hypothesis was confirmed as the EORTC QLQ HN35 domains pain, swallowing, speech, social eating and opening mouth were moderately to strongly correlated with the GTQ-2 domains ‘Jaw related problems, eating limitations and facial pain’.
Trismus patients reported significantly higher scores on the translated GTQ-2 compared to the non-trismus patients, confirming the capability of the translated version to differentiate between the two.
Lastly, we did not find any floor or ceiling effects for the translated GTQ-2, except for the propensity towards floor effect within the domain muscular tension, as expected from the original validation.
Strengths
The main strength of this study is, it being the first study performed to translate the GTQ-2 into Indian languages within a very relevant population. A second strength is the meticulous methodology followed in translating and validating the instrument to maintain equivalence with the original. Also, receiving continuous support from the original authors throughout the procedure is an additional strength to the study. We were able to evaluate the psychometric properties of the instrument on an ample sample size consisting of 60 subjects.
Limitations
One of the limitations of the study is that, harmonization phase of translation to identify any inter-translation discrepancies could not be done due to lack of any translated versions. Furthermore, the sensitivity and specificity of the translated version could not be assessed due to the sample size in the study design.
Conclusion
Our results showed that the Telugu version of the Gothenburg Trismus Questionnaire-2 is a valid, reliable and culturally sensitive instrument to quantify trismus. Health professionals are encouraged for its use in Indian patients for effectively assessing trismus related problems and treatment outcomes in clinical and research settings.
Supplementary Information
Below is the link to the electronic supplementary material.
Acknowledgements
We would like to acknowledge the developers of the original instrument.
The authors are also grateful to the translation team—Dr. Suhasini Gazula, Mr. Naidu BRS, Dr. Rashmi Avinash and Mr. Pardhasaradhi.
The authors would also like to acknowledge the patients involved in the validation process.
Data Availability
Not applicable.
Code Availability
Not applicable.
Declarations
Ethics Approval and Consent to Participate
Approval was obtained from the institutional ethical committee of Basavatarakam Indo-American Cancer Hospital & Research Institute. Patients gave their informed consent.
Consent for Publication
Consent for translation of the questionnaire obtained from the original authors.
Conflict of Interest
The authors declare no competing interests.
Footnotes
The original version of this article was revised. Affiliation link of Prof Caterina Finizia and Dr T Subramanyeshwar Raos are now corrected.
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Change history
7/12/2021
A Correction to this paper has been published: 10.1007/s13193-021-01384-8
Contributor Information
Bylapudi Bhanu Prakash, Email: prakash.bylapudi@gmail.com.
Sravankumar Chava, Email: gmcsravan@gmail.com.
Jonathan T. Gondi, Email: jona314@gmail.com
L. M. Chandra Sekara Rao S, Email: drlmcsraos@gmail.com.
Caterina Finizia, Email: caterina.finizia@orlss.gu.se.
T. Subramanyeshwar Rao, Email: subramanyesh@gmail.com.
Hemantkumar Onkar Nemade, Email: drhemantnemade@gmail.com.
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