Cross-cultural adaptation and psychometric validation of the Arabic version of the Orofacial Awakening Symptoms Questionnaire (OFASQ)

1. Introduction

Orofacial pain represents pain that originates from intraoral structures or the face, head, or neck and includes common conditions such as temporomandibular disorders and neurovascular headaches, including migraine [1]. A large percentage of the general population suffers from chronic orofacial pain (OFP), which often involves interacting mechanisms of peripheral nociception and central sensitization. A diagnostic system, such as the International Classification of Orofacial Pain (ICOP), separates primary from secondary causes and informs clinical decision-making [1, 2]. A multidisciplinary evaluation remains essential due to the complex musculoskeletal, neuropathic, and centralized mechanisms underlying symptom manifestations [2]. Sleep problems, mainly characterized by poor sleep quality and insomnia, commonly co-occur with pain, psychological distress, and disability in OFP [3, 4]. Neck disability is also common among people with OFP, reflecting shared musculoskeletal and psychosocial contributors to pain and functional limitation [5]. Migraine is the most common pain condition associated with OFP and is associated with insomnia and disrupted sleep, which contribute to increased headache frequency, as well as heightened disability [6]. Given the interlinked pathways between OFP, sleep problems, and migraine, there is a need for an appropriate scale that measures orofacial symptoms promptly after waking up to enhance early identification, clinical decision-making, and targeted management.

Several pain assessment instruments have been designed and utilized for the assessment of OFP, but each of them has important limitations in terms of validity and comprehensiveness. Unidimensional measures, such as the Visual Analogue Scale (VAS), Numerical Rating Scale (NRS), and Verbal Rating Scale (VRS), are often applied to quantify pain intensity and have demonstrated high sensitivity and reliability in OFP patients [7]. However, these scales are limited to pain intensity orientation and do not encompass multidimensional qualities, such as pain quality, emotional distress, functional limitation, and temporal variation—factors that are particularly relevant in long-standing OFP disorders [8]. To overcome such limitations, multidimensional instruments like the McGill Pain Questionnaire (MPQ) and the Graded Chronic Pain Scale (GCPS) have been employed to assess the qualitative and psychosocial components of chronic pain [9]. While broader in scope than unidimensional scales, these instruments were not specifically created for OFP populations and have untested psychometric characteristics in this population—such as construct validity, responsiveness, and minimal clinically important difference—which remain insufficiently established. The GCPS, for instance, is useful for grading disability, but has only fair test–retest reliability and limited cross-cultural validation in OFP populations [9]. Condition-specific measurements, such as the Jaw Functional Limitation Scale (JFLS), were then created to quantify mandibular function in Temporomandibular Disorder/Orofacial Pain (TMD/OFP) populations [10, 11]. Although the JFLS offers a focused approach to jaw function, its measurement error properties—such as smallest detectable change and responsiveness—as well as its structural validity remain insufficiently established [10]. In addition, specialized instruments exist for vulnerable groups, including the Orofacial Pain Scale for Non-Verbal Individuals (OPS-NVI) [12], but these tools show low sensitivity in patients with mild cognitive impairment, precluding their use as independent screening instruments in clinical practice [12]. Despite the presence of many pain measurement instruments, those currently used for OFP remain limited by unidimensionality, non-specificity, absence of psychometric validation, and restricted generalizability to heterogeneous groups of patients.

The Orofacial Awakening Symptoms Questionnaire (OFASQ) offers several distinct advantages over to other existing pain scales for orofacial conditions [8, 13]. The scale has demonstrated good psychometric properties, with a Cronbach’s α of 0.82 reflecting coherent measurement of the underlying construct of orofacial awakening symptoms. Construct validity was supported by a unidimensional factor structure, consistent with the theoretical framework underlying the scale [13]. Convergent validity was demonstrated by significant correlations with morning orofacial discomfort, perceived sleep quality, and self-reported sleep bruxism indicators [14, 15]. Test–retest reliability, assessed over a short interval, showed good temporal stability; the Intraclass Correlation Coefficients (ICCs) were within acceptable limits for early-stage instrument development [13]. While many instruments focus on overall pain intensity or disability felt during the day, the OFASQ evaluates orofacial symptoms in the morning, thus bridging a gap in earlier tools that tend to address frequency or presence, but not morning awakening severity of symptoms [13]. This matters because wake-episode symptoms can be prognostic of the severity and prognosis of disorders such as TMD-associated pain [13]. Second, the OFASQ uses a numerical rating scale for each item, rather than dichotomous “yes/no” or categorical response format, allowing consequently for more nuanced quantification of severity of symptoms—an advantage not offered by other instruments, such as the BruxScreen or the Standardized Tool for the Assessment of Bruxism (STAB), which record presence/frequency, but not intensity [13]. Third, its brevity and usefulness in clinical practice enhance its use for daily dental or orofacial pain clinics [13]. Finally, as a symptom-awakening instrument, the OFASQ would provide greater sensitivity for the detection of masticatory system stress or nighttime parafunction earlier than more broad daytime scales [13]. Overall, the OFASQ supplements existing measures by adding a precise, quantifiable measure of morning orofacial symptom severity and, thus, may improve screening, monitoring, and research into orofacial pain and bruxism-related disorders [13].

To date, the OFASQ has been developed and validated in English, and an Italian version has also been developed using a traditional forward-backward translation process. No formal translation, cross-cultural adaptation, or psychometric validation of the OFASQ into other languages has been reported in any peer-reviewed studies [13]. Cross-cultural validation of the OFASQ in Arabic is warranted, as orofacial awakening symptoms are influenced by language, cultural expression of symptoms, and local health-seeking behaviors. Use of a questionnaire that has not been linguistically and culturally adapted may lead to misclassification and biased prevalence estimates in Arabic-speaking populations [13]. The OFASQ was specifically developed to capture the occurrence and functional impact of awakening symptoms, addressing a gap in standard bruxism evaluation tools [13, 16]. Validation and translation of OFASQ into Arabic would, therefore, (1) allow harmonization with other Arabic translations of the TMD and bruxism measures, (2) ensure reliable assessment of symptom interference and severity for research and clinical purposes, and (3) facilitate cross-cultural comparisons and pooled analyses informing regional diagnostic thresholds and treatment planning [17, 18]. Past successful Arabic translations of bruxism and oral health questionnaires demonstrate the feasibility and worth of this endeavor and warrant standard translation, cultural adaptation, and psychometric evaluation [17, 18, 19, 20]. In brief, an Arabic OFASQ would facilitate orofacial symptom detection and observation related to awakening, promote epidemiologic and clinical research in the Middle East and North Africa (MENA) region, and facilitate culturally appropriate treatment of sleep-related orofacial disorders [13, 16]. Accordingly, this study aims to translate and psychometrically validate the Arabic version of the OFASQ. Specifically, we seek to assess its factor structure using confirmatory factor analysis, evaluate internal consistency, examine measurement invariance across sex groups, and assess concurrent validity.

2. Methods

3. Results

Participants’ details are summarized in Table 1.

4. Discussion

The present study aimed to translate, culturally adapt, and psychometrically validate the Arabic version of the OFASQ in a Lebanese adult population. The findings validate the Arabic OFASQ as a psychometrically sound and culturally adapted instrument for assessing orofacial awakening symptoms, most likely related to TMD and bruxism in Arabic-speaking adults. To the best of our knowledge, this is the first validation of the OFASQ in Arabic [13].

CFA supported a unidimensional factor structure, as initially suggested in the scale development [13]. The one-factor model also demonstrated good fit indices (CFI = 0.970, TLI = 0.941, SRMR = 0.033), although the RMSEA was 0.144, indicating some degree of misfit [31]. These results suggest that the Arabic OFASQ assesses a homogeneous construct representing orofacial awakening symptoms, although small item-specific residual correlations may improve subsequent versions of the scale [31]. Moderate RMSEA values are common in short symptom instrument validation studies, particularly when all items heavily load onto a single factor [31, 32, 33]. Although the CFI, TLI, and SRMR values indicated good model fit, the RMSEA value exceeded the commonly accepted threshold (0.08). It is well established that RMSEA can become inflated in models with low degrees of freedom (df) [31, 32, 33]. Our model had a small degree of freedom (df = 17), a condition under which RMSEA tends to overestimate misfit and behave less reliably than other fit indices. Given that the other fit indices (CFI, TLI, and SRMR) met conventional criteria and factor loadings were strong, the overall model was considered acceptable [31, 32, 33].

Furthermore, internal reliability was good, with Cronbach’s α of 0.85 and McDonald’s ω of 0.85, both exceeding the minimum recommended for newly translated scales (0.70). These figures compare favorably to those of the original English validation and indicate the Arabic version maintains equivalent measurement properties across cultures [13].

Tests of measurement invariance identified configural, metric, and scalar invariance between gender groups, supporting measurement equivalence of the OFASQ across men and women [31, 34]. Women had significantly higher OFASQ scores than men, consistent with previous findings reporting higher prevalence and severity of TMD and bruxism symptoms among women [5, 35, 36]. Presumably, these findings reflect a mix of biological and psychosocial factors, such as hormonal influences and greater help-seeking and stress-reactivity [37].

Regarding concurrent validity, OFASQ scores were significantly correlated with poorer quality of sleep, greater insomnia severity, and greater migraine disability. The positive correlation with insomnia severity emphasizes the link between orofacial pain, cervical musculoskeletal tension, and sleep disturbance [38, 39, 40]. Inverse but small correlations with sleep quality suggest that, although sleep influences orofacial symptoms, this relationship may be indirectly mediated by stress and musculoskeletal mechanisms [3, 41]. Overall, these findings—observed in the Lebanese population—are consistent with the biopsychosocial model of orofacial pain, with its emphasis on interdependence among physiological, psychological, and behavioral determinants.

5. Conclusions

This study successfully translated, culturally adapted, and psychometrically validated the Arabic version of the OFASQ [13] among Lebanese adults. The Arabic OFASQ was found to have good reliability and structural validity. The instrument exhibited correlations with sleep quality, insomnia, and migraine disability, reinforcing its concurrent validity and agreement with the biopsychosocial model of orofacial pain, especially in the younger population. The Arabic OFASQ, thus, emerges as a proper, concise, and culturally relevant instrument for the assessment of orofacial awakening bruxism and TMD symptoms in adolescents or young adults of Arabic-speaking populations. Its use within clinical and research settings can facilitate earlier diagnosis and interdisciplinary evaluation, as well as aid cross-cultural uniformity of diagnostic measures in orofacial pain and sleep-related movement disorder research.

Availability of data and materials

All data generated or analyzed during this study are not publicly available. The dataset supporting the conclusions is available upon request to the corresponding author (SH).

Author contributions

SH, SO, FFR, CH and ZA—involved in the study design. CH—wrote the manuscript. ZA, AM, TA and LF—responsible for the data collection. TC and SH—involved in data analysis and interpretation. MF, SO, FFR, CH, ZA, TA, LF and AM—revised the paper for intellectual content. All authors approved its final version.

Ethics approval and consent to participate

The Ethics and Research Committee of the Rayak Hospital approved this study protocol (ECO-R-700). Submitting the form online was considered equivalent to obtaining a written informed consent. All methods were performed in accordance with the relevant guidelines and regulations (Declarations of Helsinki).

Acknowledgment

The authors would like to thank all participants who participated in this study.

Funding

This research received no external funding.

Conflict of interest

The authors declare no conflict of interest.