Degenerative cervical myelopathy (DCM) is the most common cause of non-traumatic spinal cord dysfunction in adults and may lead to progressive motor, sensory, and autonomic impairment. Accurate and standardized assessment of neurological function is essential for clinical decision-making, prognostic evaluation, and comparison of treatment outcomes. The Modified Japanese Orthopaedic Association (mJOA) score is one of the most widely used clinician-based outcome measures for evaluating neurological status in patients with DCM. Although the mJOA has been translated and validated in several languages, no validated Turkish version currently exists.

This prospective, cross-sectional validation study aims to culturally adapt the mJOA score into Turkish and evaluate its validity, reliability, and clinical correlation in Turkish-speaking patients diagnosed with DCM. Adult patients (≥18 years) with clinically and radiologically confirmed DCM presenting to the outpatient clinics of Physical Medicine and Rehabilitation and Neurosurgery will be included. Previously obtained cervical magnetic resonance imaging will be reviewed retrospectively to determine myelomalacia levels, while clinical scales will be administered prospectively.

Construct validity will be assessed by examining correlations between the Turkish mJOA scores and the Neck Disability Index, as well as the Nurick grading system. Inter-rater reliability will be evaluated using the Intraclass Correlation Coefficient (ICC [2,1]) between two independent evaluators, and test-retest reliability will be assessed in clinically stable patients after 7-14 days. Feasibility will be evaluated by recording the administration time and potential difficulties during application.

This study is expected to provide a valid and reliable Turkish version of the mJOA score, facilitating standardized assessment of DCM in Turkish clinical practice and enabling comparability with international research.

Degenerative cervical myelopathy (DCM) represents the leading cause of non-traumatic spinal cord dysfunction in adults and is characterized by progressive neurological impairment involving upper and lower extremity motor function, sensory deficits, and sphincter dysfunction. Standardized and reliable clinical assessment tools are essential for determining disease severity, guiding treatment decisions, and ensuring comparability across clinical studies.

The Modified Japanese Orthopaedic Association (mJOA) score is a clinician-based functional assessment tool widely used to evaluate neurological status in patients with DCM. It assesses four domains: upper extremity motor function (0-5 points), lower extremity motor function (0-7 points), sensory function (0-3 points), and sphincter function (0-3 points), yielding a total score ranging from 0 to 18. Lower scores indicate more severe neurological impairment. Although the mJOA score has undergone cross-cultural adaptation and validation in several languages, a culturally adapted and psychometrically validated Turkish version is currently unavailable.

This study is designed as a prospective, cross-sectional validation study aiming to perform the cultural adaptation and psychometric evaluation of the Turkish version of the mJOA score in patients with DCM. The translation process was conducted using a standardized forward-backward translation methodology in accordance with internationally accepted cross-cultural adaptation guidelines.

Participants will include adult patients (≥18 years) with clinically and radiologically confirmed DCM who present to the outpatient clinics of Physical Medicine and Rehabilitation and Neurosurgery. Previously obtained cervical magnetic resonance imaging (MRI) scans will be reviewed retrospectively to determine the level of cervical myelomalacia. Demographic and clinical variables, including age, sex, body mass index, symptom duration, treatment status, and affected side, will be recorded.

Construct validity will be evaluated by analyzing correlations between Turkish mJOA total and subdomain scores and the Neck Disability Index (NDI), a validated Turkish instrument measuring cervical disability. Given that higher mJOA scores reflect better neurological function and higher NDI scores indicate greater disability, a significant negative correlation is hypothesized. Additionally, correlations between mJOA scores and the Nurick grading system will be assessed using Spearman's rank correlation analysis. Differences in mJOA scores across categorized Nurick severity groups will be analyzed using non-parametric statistical tests.

Inter-rater reliability will be assessed in at least 50 patients by two independent evaluators (an experienced clinician and a trained clinician) using the Intraclass Correlation Coefficient (ICC [2,1]). Test-retest reliability will be evaluated in clinically stable patients after a 7-14-day interval using ICC analysis. Floor and ceiling effects will be examined and considered present if more than 15% of participants achieve the lowest or highest possible scores.

Feasibility will be assessed by recording the time required to administer the Turkish mJOA and documenting any comprehension or implementation difficulties. No interventional procedures are involved in this study, and no adverse events are anticipated.

The results of this study are expected to establish a valid, reliable, and feasible Turkish version of the mJOA score, enabling standardized assessment of DCM severity in Turkish clinical practice and facilitating international research collaboration and outcome comparison.

Inclusion Criteria:

• Adults aged 18 years and older
• Patients diagnosed with degenerative cervical myelopathy using clinical or magnetic resonance imaging
• Able to provide written informed consent to participate in the study
• Cognitive competence to understand Turkish forms and scales

Exclusion Criteria:

• Spinal cord injury due to trauma, tumor, infection, inflammatory diseases, etc., pathologies
• Previous cervical surgery
• Severe cognitive impairment or communication problems that would prevent participation in the study
• Subjects who were informed about the study but refused to participate

This study will include patients aged 18 years and older who have been diagnosed with degenerative cervical myelopathy based on clinical and radiological evaluation and who have applied to the Physical Medicine and Rehabilitation Outpatient Clinic and Neurosurgery Outpatient Clinic at İzmir Democracy University Buca Seyfi Demirsoy Education and Research Hospital.

Individual participant data (IPD) will not be shared because the data contain potentially identifiable sensitive clinical information, and sharing was not covered in the original informed consent provided to participants. Additionally, institutional and national data protection regulations limit the transfer of raw, de-identified individual-level data outside the research team.