Baseline Cervical Joint Position Error and Headache Intensity

Cervicogenic headache is a type of headache associated with problems or dysfunction in the neck. People with cervicogenic headache may experience headache pain along with neck pain, reduced neck movement, and difficulties with normal neck function. Cervical joint position error (JPE) is a measure of how accurately a person can return their head to its starting position after moving the neck. A greater JPE may indicate reduced accuracy of neck position sense. The purpose of this retrospective study is to determine whether the amount of cervical JPE measured before physiotherapy is associated with headache intensity at the completion of physiotherapy in adults clinically classified with cervicogenic headache. The study will also examine whether baseline cervical JPE is associated with achieving a meaningful reduction in headache intensity. The study will use existing clinical records of adults aged 18 to 65 years who were clinically classified with cervicogenic headache and received routine physiotherapy at a university teaching hospital. Records from January 2023 to December 2025 will be reviewed. Participants must have had cervical JPE and headache intensity recorded before physiotherapy and must have completed at least four physiotherapy sessions with a treatment-completion assessment. Cervical JPE will be assessed from the recorded baseline measurements obtained using a CROM (Cervical Range of Motion) device. Headache intensity will be assessed using the Numeric Pain Rating Scale (NPRS), where 0 represents no pain and 10 represents the worst imaginable pain. The primary outcome will be headache intensity recorded at the treatment-completion assessment. The study will compare baseline cervical JPE with treatment-completion headache intensity while taking into account other relevant factors, including baseline headache intensity, neck disability, age, and sex. The study will also examine whether participants achieved a reduction of at least 2 points on the NPRS during the observed treatment period. As this is a retrospective observational study, the researchers will not assign or change participants' treatment. The study will use information already available in clinical records and will not require participants to receive additional treatment or undergo additional assessments. The study is intended to determine whether baseline cervical JPE may be associated with subsequent headache outcomes and whether it may be useful as a potential prognostic factor. It will not determine whether cervical JPE causes headache or whether JPE should be used to select a particular physiotherapy treatment. The findings may help guide future research on factors that are associated with treatment outcomes in people with cervicogenic headache. Further prospective studies may be needed to determine whether cervical JPE has useful prognostic value at the individual patient level.

Inclusion Criteria: * Adults aged 18-65 years. * Clinically classified with cervicogenic headache (CGH) based on the retrospective classification rule derived from the Cervicogenic Headache * International Study Group criteria. * At least 3 of the 5 documented CGH features were present. * Baseline cervical joint position error (JPE) was measured before physiotherapy. * Baseline headache intensity (NPRS) was documented. * Completed at least 4 physiotherapy sessions. * Had at least one treatment-completion outcome assessment. * Clinical records contained sufficiently complete baseline and outcome information. Exclusion Criteria: * History of cervical spine surgery. * Cervical trauma or whiplash within the previous 6 months. * Cervical fracture, instability, or severe structural pathology. * Rheumatoid or other inflammatory cervical disease. * Neurological disorders affecting cervical sensorimotor function. * Vestibular disorders affecting JPE testing. * Migraine or another primary headache disorder as the predominant diagnosis. * Systemic malignancy affecting the cervical region. * Incomplete baseline JPE or treatment-completion outcome data.