Neck pain is a common prevailing musculoskeletal disorder affecting various age groups. Neck pain is listed as one among the most burdensome chronic musculoskeletal problem globally.Though many etiological factors exist for neck pain, but the etiology is often illusive. The presentation of neck pain is usually non-specific or mechanical neck pain. Non-specific neck pain  is defined “as pain in the posterior and lateral aspect of the neck between the superior nuchal line and the spinous process of the first thoracic vertebra with no signs or symptoms of major structural pathology and no or minor to major interference with activities of daily life as well as with the absence of neurological signs and specific pathologies; such as: traumatic sprain and fracture, tumour, infectious or inflammatory cervical spondylolysis, etc”.

Chronic non-specific neck pain is associated with disability, deficits in muscular strength and range of motion, increased pain sensitivity and impaired proprioception. Proprioception is an interoceptive sense that provides informative inputs to central nervous system for motor planning. Cervical spine plays a major role in balance and proprioception as the information from cervical spine has direct access to the center for balance and proprioception. Patients with neck pain  experience  somatosensory deficits due to multiple causes including  sensitivity of receptors , alteration of cortical representation and modulation of cervical afferent inputs.Also, muscles of cervical region mainly suboccipital and deep flexor muscles have high density of muscle spindle that contribute to neck proprioception and impairment in information from these muscles affect postural sway.

Studies have shown that neck pain associated with whiplash injuries and idiopathic neck pain have impact on balance and proprioception. Also, a systematic review on standing balance in patients with idiopathic neck pain and whiplash injuries has stated that they present with poorer balance than the normal population. Whiplash induced trauma damages the key systems of postural control mainly the vestibular and neck receptors for the central nervous system, causing impairments in postural control. On contrary to whiplash injuries there is no inciting trauma in idiopathic neck pain, where the suggested mechanism is likely to be the impaired peripheral mechanoceptors, but a much more precise mechanism to be attributed for this can be proprioceptive dysfunction from spinal and supraspinal causes.Though studies have been done on the assessment of balance and proprioception in patients with neck pain, there is a lack of evidence on the usage of objective assessment to quantify the level of impairment in balance and postural sway.

Biodex Balance SD is an instrument used to quantify the balance and postural sway in individuals with a high reliability of 0.94 for Overall Stability Index.  It is an instrument equipped with circular platform with which measures both static and dynamic balance.  The platform is capable of moving in all 4 directions and adopting 12 static positions and the ability to move in 20 degrees in each direction makes it capable of measuring Antero-Posterior Stability Index and Medio-Lateral Stability Index. Measurement of these indices will quantify the balance and postural sway which will provide a better insight to the dynamic and static balance issues in patients with neck pain.

Existing literature suggests that, there exists a scarcity in the objective assessment of balance and postural sway done in patients with non-specific neck pain. Studies were done on postural and balance impairment with force different objective measures, but a system dedicated to balance assessment has not been used in the previous studies. Hence, this study aims at analyzing the standing balance and postural sway in patients with non-specific neck pain using Biodex Balance SD.