Cross Cultural Adaptation, Reliability &Validity of The Arabic Version of 8_Item Jaw Functional Limitation Scale In Temporomandibular Joint Disorders

February 27, 2026 updated by: Wafaa Hashem Ahmed Hasan, Cairo University
The purpose of this study is to test if the translated Arabic version of the (jaw functional limitation scale -8) JFLS_8 , valid (face, content, feasibility) ,reliable (internal consistency, test retest) and culturally adapted enough to quantify the impact of temporomandibular joint (TMJ) disorders on jow function in arabic people or not?

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Temporomandibular disorders (TMD) are relatively prevalent among adults, representing a considerable health concern. These disorders negatively affect psychological well-being and overall quality of life, highlighting the importance of accurate assessment and appropriate management strategies. Consequently, there is a growing need for reliable and efficient tools to assess functional limitations associated with TMD.

The Jaw Functional Limitation Scale with 8 items (JFLS-8) is a concise, valid, and reliable instrument used for the assessment of functional limitations related to the masticatory system. It was developed as a shorter version of the JFLS-20 and has been shown to be more practical for use in busy clinical settings while maintaining strong psychometric properties. The JFLS-8 has demonstrated excellent validity and reliability and has been successfully translated and culturally adapted into several languages, confirming its effectiveness as a clinical assessment tool.

Therefore, there is a clear need to translate the JFLS-8 into an Arabic version, perform cultural adaptation, and evaluate its validity and reliability among patients with temporomandibular disorders in Arabic-speaking populations.

Study Type

Observational

Enrollment (Estimated)

100

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: Dina Sayed Abd Allah, PhD

Study Locations

  • Egypt
      • Giza, Egypt
        • El-Kasr Elainy jaw and dental clinics
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult male and female patients diagnosed with temporomandibular disorders (TMD), aged 18 to 65 years, who are native Arabic speakers. Participants are recruited from El-Kasr Elainy jaw and dental clinics to evaluate the validity, reliability, feasibility, and cultural adaptation of the Arabic version of the 8-item Jaw Functional Limitation Scale (JFLS-8).

Description

Inclusion Criteria:

  • Patients aged 18 to 65 years .
  • Diagnosis of temporomandibular disorders ) jaw pain-popping sounds in the jaw -limited jaw movements - orofacial pain ) for one month at least, not receiving actual treatment for the orofacial region (splinting)
  • Being conscious and oriented.
  • Able to read and write in Arabic.
  • Both Genders were included.

Exclusion Criteria:

  • History of trauma (recent head or neck or TMJ severe trauma)
  • Recent surgery at the neck, head or TMJ
  • Diagnosed systemic and psychiatric diseases; diseases that may affect the TMJ, such as ankylosing spondylitis or rheumatoid arthritis; and pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Face Validity of the Arabic Version of the 8-item Jaw Functional Limitation Scale (JFLS-8)
Time Frame: 30 minutes
It will be assessed using the Clarity Index and Expert Proportion of Clearance, judged by two expert panels (5 experts each) to evaluate whether the scale appears clear and relevant.
30 minutes
Content Validity of the Arabic Version of the 8-item Jaw Functional Limitation Scale (JFLS-8)
Time Frame: 30 minutes
It will be assessed using the Content Validity Index (CVI) and Expert Proportion of Relevance, to confirm that the 8 items adequately cover the construct of jaw functional limitation.
30 minutes
Feasibility of the Arabic Version of the 8-item Jaw Functional Limitation Scale (JFLS-8)
Time Frame: 30 minutes
It will be evaluated by two factors: time needed to complete the questionnaire and the missed item index (ratio of unanswered items).
30 minutes
Internal Consistency Reliability of the Arabic Version of the 8-item Jaw Functional Limitation Scale (JFLS-8)
Time Frame: 30 minutes
It will be measured using Cronbach's alpha to confirm that all 8 items are measuring the same underlying construct.
30 minutes
Test-Retest Reliability of the Arabic Version of the 8-item Jaw Functional Limitation Scale (JFLS-8)
Time Frame: 2 days
It will be assessed using Spearman's rank correlation coefficient, with a subset of patients completing the JFLS-8 again after 2 days under the same conditions.
2 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Visual Analogue Scale (VAS)
Time Frame: 30 minutes
a 10 cm pain intensity scale measuring jaw pain during activity (recorded in cm), used to assess convergent validity with the JFLS-8.
30 minutes
Fonseca Anamnestic Index (FAI)
Time Frame: 30 minutes
a 10-item questionnaire classifying TMD severity (scores: 0-15 = no TMD; 20-40 = mild; 45-65 = moderate; 70-100 = severe), also used for convergent/construct validity testing.
30 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Cairo University

Investigators

  • Study Chair: Salwa Fadl Abdel Mageed, PhD, Professor, Cairo university
  • Study Director: Dina Sayed Abd Allah, PhD, Lecturer, Cairo university
  • Study Director: Eman Sayed Ahmed Shalaby, PhD, Lecturer, Cairo university

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

March 7, 2026

Primary Completion (Estimated)

May 7, 2026

Study Completion (Estimated)

May 15, 2026

Study Registration Dates

First Submitted

February 27, 2026

First Submitted That Met QC Criteria

February 27, 2026

First Posted (Actual)

March 4, 2026

Study Record Updates

Last Update Posted (Actual)

March 4, 2026

Last Update Submitted That Met QC Criteria

February 27, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • P.T.REC/012/006224

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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