Neck Disability and Temporomandibular Disorders

Primary outcomes

• neck disability [Primary outcome (NDI) was measured once at baseline during the cross-sectional assessment.]: Neck disability was evaluated by The Neck Disability Index (NDI) total score The NDI consists of 10 questions in total, and each question evaluates a different area of daily life. Each question is scored between 0 and 5 points: 0 = no problem at all, 5 = maximum limitation. The total score range can be: Minimum: 0 and Maximum: 50.

Secondary outcomes

• Sleep quality [at baseline]: Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). The sleep-related assessment consists of 7 components, each scored between 0 and 3: 0 = no problem and 3 = serious problem. The total score can range from a minimum of 0 to a maximum of 21. As the score increases, sleep quality deteriorates: ≤5 good sleep quality and >5 poor sleep quality.

Other outcomes

• Cervical Proprioception, Deep Neck Flexor Endurance, and Posture [at baseline]: Cervical proprioception was assessed using the joint position error (JPE) test. Participants were seated in an upright position with a laser pointer securely attached to the head. A target point was marked on a wall at eye level to represent the neutral head position. With their eyes closed, participants were instructed to actively move their head into flexion, extension, and right and left rotation, and then return to the initial neutral position. The deviation of the laser point from the target was recorded for each movement direction. Absolute error values were calculated and expressed in degrees (°). The mean of the absolute errors obtained from the four movement directions was used for statistical analysis, with higher values indicating poorer cervical proprioceptive accuracy.
• Deep neck flexor muscle endurance [at baseline]: Deep neck flexor muscle endurance was assessed using the craniocervical flexion test protocol. Participants were positioned supine with knees flexed and instructed to perform a gentle craniocervical flexion (chin tuck) without lifting the head from the surface. The position was maintained isometrically, and the duration for which the participant could sustain the correct posture without compensation was recorded. Test duration was measured in seconds. Higher values indicate greater deep neck flexor muscle endurance. Unit of Measure: Seconds

Sex: All, ages: 18 Years to 55 Years, accepts healthy volunteers

Inclusion Criteria:

* Participants aged between 18 and 55 years
* non-specific neck pain lasting for at least three months
* participants who were able to read and write in Turkish

Exclusion Criteria:

* Individuals with a history of cervical surgery,
* neck trauma within the previous year,
* neurological or rheumatological disorders,
* cervical radiculopathy,
* inability to discontinue analgesic medication within 48 hours prior to assessment,
* pregnancy,
* cognitive impairment