Validation of the multimedia version of the RDC/ TMD axis II questionnaire in Portuguese

Objective The aim of the study was to validate the multimedia version of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis II Questionnaire in Portuguese language. Material and methods The sample comprised 30 patients with signs and symptoms of temporomandibular disorders (TMD), evaluated at the Orofacial Pain Control Center of the Dental School of the University of Pernambuco, Brazil, between April and June 2006. Data collection was performed using the following instruments: Simplified Anamnestic Index (SAI) and RDC/TMD Axis II written version and multimedia version. The validation process consisted of analyzing the internal consistency of the scales. Concurrent and convergent validity were evaluated by the Spearman’s rank correlation. In addition, test and analysis of reproducibility by the Kappa weighted statistical test and Spearman´s rank correlation test were performed. Results The multimedia version of the RDC/TMD Axis II questionnaire in Portuguese was considered consistent (Crombrach alpha = 0.94), reproducible (Spearman 0.670 to 0.913, p<0.01) and valid (p<0.01). Conclusion The questionnaire showed valid and reproducible results, and represents an instrument of practical application in epidemiological studies of TMD in the Brazilian population


INTRODUCTION
Temporomandibular disorders (TMD) is a collective term embracing a number of clinical problems that involve the masticatory musculature, the temporomandibular joint or both 11 . Most diagnosed patients suffer from muscle and/or joint pain on palpation and/or mandibular movements 13 . epidemiological studies on TMD have shown conflicting results regarding prevalence and incidence. Such findings could be attributed to different diagnostic criteria. Thus, a standardized methodology is necessary when comparing studies related to these diseases 6,10 .
The contradictory findings may be attributed in part to the lack of standardized diagnostic criteria for defining clinical subtypes of TMD and for psychological assessment. In order to overcome this difficulty, Dworkin and LeResche 2 (1992) developed a set of diagnostic tools for TMD, namely the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), including clinical aspects (Axis I) and psychological/psychosocial factors (Axis II). Axis I permits the reproducibility of the diagnostic criteria for research on TMD in their most common forms of muscle and joint involvement, while Axis II enables the physical diagnosis to be coordinated with an operational assessment of the psychological distress and psychological dysfunction associated with TMD 2,3,12,17 .
The production of the RDC/TMD represented an advance in the study of this subject 2,16 . Although RDC/TMD is a diagnostic system that evaluates only the most common forms of TMD 14,16 , it provides specifications for conducting a standardized clinical physical examination. It has been formally translated/back-translated into 20 languages and is the most common diagnostic method used by the 45-member consortium of RDC/TMD-based international researchers (International Consortium for RDC/TMD-based Research, 2004). Recent studies have demonstrated the validity and reliability of the clinical diagnosis of TMD 8,13 . Furthermore, several studies of the validation of diagnosis in TMD have focused on RDC, comparing its consistency with that of other imaging techniques 13 .
Due to the importance of psychosocial factors in the diagnosis of TMD, the time lag between the examination of the patient and the collection of data has proved to be a problem. With a view to solving this problem, Yap, et al. 18 (2001) developed an on-line computerized version of the RDC/ TMD questionnaire that, despite facilitating the diagnosis, encountered a number of operational problems involving the patient's difficulties in answering the questions and using the computer.
After the initial process, a final procedure of validation was carried out, as a result the RDC/ TMD PORTUGUeSe VeRSION became available to be used in studies conducted in Brazilian population.
The aim of this prospective study was to validate the Brazilian Portuguese-language multimedia version of the RDC/TMD Axis II Questionnaire, a standardized form of research on TMD, enhancing the interaction of clinicians and researchers.

MATERIAL AND METhODS
The present multimedia version of the Questionnaire Axis II of the RDC/TMD followed the written version of the questionnaire in Portuguese validated by Lucena, et al. 9 (2006). It runs on Windows OS 2000 and XP and can exploit multimedia software and data storage bank capabilities.
The questionnaire was designed in such a way that the patient could hear the video presentation and visualize the question, so that at the end of each presentation, the respondent could answer the question, replay it, or go back. The types of questions included yes/no questions and multiplechoice questions. The Graduated Chronic Pain Scale (GCPS) was used for the questions measuring the intensity of pain.
The study population consisted of patients with orofacial pain seeking treatment at the Orofacial Pain Control Center of the Dental School of the University of Pernambuco, Brazil, between April and June 2006. The ages of the subjects ranged from 19 to 55 years (mean = 39.5 years), 93.3% of whom were females and 6.7% males. All patients had TMD. The inclusion criteria were no previous history of TMD treatment and a positive diagnosis of TMD, using the Simplified Anamnestic Index (SAI) 5 . The sociodemographic data of all the subjects with TMD are presented in Table 1.
The research project involving research on humans was submitted to the Research ethics Committee of the University of Pernambuco after granting the permission from the Dental School. Only patients who agreed to participate and signed the informed consent form were enrolled in the study.
The following questionnaires were answered by the participants: 1) SAI 5 questionnaire, which verified the presence of signs and symptoms of TMD, enabling a prompt diagnosis. All patients were classified as having TMD. 2) Portugueselanguage written version of the RDC/TMD Axis II Questionnaire 10 , which consisted of 31 items, divided into sociodemographic, socioeconomic, psychological and psychosocial factors, signs and symptoms, and scale of limitation of mandibular function. 3) Portuguese-language multimedia version of the RDC/TMD Axis II Questionnaire.
The questionnaires were applied to the 30 participants one day after the initial interview as follows: 15 were given the written questionnaire and 15 the multimedia questionnaire for the purpose of testing the validity by means of process test/retest the instrument. None of the patients had received any previous treatment for any associated comorbidity, any pharmacological or psychological therapy for TMD. All of them answered the SAI questionnaire.
The validation process consisted of verifying the internal consistency of the scales of limitation of mandibular function and psychological factors. In order, to have an acceptable internal consistency, a scale should present alpha values of at least 0.7. Convergent validity was simultaneously evaluated by Spearman's rank correlation test 10 . The reproducibility analysis used the weighted Kappa statistical test and Spearman's rank correlation test (m>0.05) 13 . The Statistical Package for the Social Sciences (SPSS) for Windows, Version 10, was used for descriptive and inferential analysis of the data. The level of statistical significance was set at 5%. Internal consistency was estimated by Cronbach's alpha test, values above 0.5 being considered satisfactory 14 .

RESULTS
The time taken by the patients who answered the multimedia questionnaire ranged from 15 to 40 min (mean time of 25 min). By comparing the information obtained from 30 patients submitted to evaluations by two exams with the two versions of the RDC/TMD questionnaire at different times (study test-retest), a consistent and reproducible instrument was identified for obtaining a diagnosis.
The analysis of the internal consistency of the limitation of mandibular function as a RDC/TMD Axis II diagnostic criterion identified 12 items that correlated with each other and with the overall result of the scale, comprising a true scale, with alpha=0.71 and standardized alpha=0.70 ( Table  2).
In addition to the internal consistency of the questions related to psychological factors, comprising 32 items, which also correlated with one another, since the alpha values exceeded 0.90 (alpha=0.94 and standardized alpha=0.94) ( Table  3). Therefore, the alpha values for scale were not increased by the exclusion of any of the items tested.
The multimedia RDC/TMD Questionnaire proved to be reproducible, presenting correlations greater than m>0.05, all of which showed statistical significance when evaluated at different times (Spearman 0.670 to 0.745, p<0.01) ( Table 4).
The reproducibility of the different domains of RDC/TMD Axis II, considering the severity of chronic pain and the three subscales of psychological factors (depression, nonspecific physical symptoms with and without pain items), was analyzed. Considering the information obtained from the 30 patients (testretest study), there was a statistically significant diagnostic agreement in Axis II (m ≥0.7; p<0.01) ( Table 4).

DISCUSSION
Patients younger than 18 years were excluded from the study because many questions are difficult for them to understand or inappropriate and because the RDC/TMD has been calibrated with data only on patients over the age of 18 years 18 .
In this study the assessment of the internal consistency of the scales of limitation of mandibular function and psychological factors presented an overall alpha index of 0.71 and 0.94, respectively. The lowest value used as baseline in clinical studies is 0.7 13 . Thus, the internal consistency of the scales was valid, resulting in a true scale. Spearman's ranks test demonstrated that the proposed version of the instrument generally had a positive correlation, indicating that the validated version is indeed measuring what it was intended to measure 14 .
This study represents an important step for research on TMD in Brazil in several aspects. Firstly, it represents an advance in relation to the method of research previously reported 15 in the study of the TMD; in addition, it will facilitate future population studies involving TMD. As a result, the multimedia version will reduce the cost of printing, making copies of the questionnaire and storing patient data.
The present multimedia questionnaire also permits greater speed in the collection of patient data, storage and statistical analysis, with information being simultaneously entered in a database while the research is being conducted. It also has the advantage of eliminating any bias on the part of the interviewer when dealing with sensitive questions. However, results must be interpreted considering its limitations, as it has been carried out in a specialized pain clinic and with a limited sample of patients. Future investigation in a broad epidemiological survey should confirm the results.

CONCLUSION
The process of validating the Portuguese multimedia version of the RDC/TMD Axis II Questionnaire followed the methodology proposed in the literature and resulted in a reproducible and readily applicable instrument, valid for the Brazilian population, making it possible to introduce an innovative standardized method in epidemiological studies on TMD in Brazil.

AKNOWLEDgEMENTS
This project was supported by PIBIC/CNPq.