Stimulated cervical afferent input increases postural instability in older people with chronic neck pain: a cross-sectional study.

BACKGROUND

Several potential causes can impair balance in older people. The neck torsion maneuver may be useful in demonstrating impaired balance caused by the stimulation of cervical proprioceptive input. Whereas evidence suggests impaired standing balance in older people with chronic neck pain, balance impairment during the neck torsion position and its relationship with clinical characteristics have not yet been investigated in this population. The aims of this study were to investigate whether the neck torsion position could significantly influence balance responses in older people with chronic non-specific neck pain and to determine the relationships between the balance responses and characteristics of neck pain.

METHODS

Sixty-eight older people (34 with chronic non-specific neck pain and 34 controls) participated in the study. Balance was tested using a force plate during comfortable stance with eyes open under four conditions: neutral head on a firm surface, neutral head on a soft surface, neck torsion to left and right on a firm surface and neck torsion to left and right on a soft surface. Balance outcomes were anterior-posterior (AP) and medial-lateral (ML) displacements, sway area and velocity. Characteristics of neck pain were intensity, duration and disability.

RESULTS

Overall, the neck pain group exhibited greater AP and ML displacements, sway area and velocity in the neck torsion position on firm and soft surfaces compared to controls (partial eta squared (η²p) = 0.06-0.15, p < 0.05). The neck pain group also had greater AP displacement, sway area and velocity in the neutral position on a soft surface compared to controls (η²p = 0.09-0.16, p < 0.05). For both groups, the neck torsion position displayed overall greater postural sway compared to the neutral position (η²p = 0.16-0.69, p < 0.05). There were no relationships between the postural sway outcomes and characteristics of neck pain (p > 0.05).

CONCLUSION

The neck torsion maneuver, stimulating the receptors resulted in increased postural sway in older people, with a more pronounced effect in those with neck pain. The study provides evidence supporting the use of neck torsion for assessing impaired balance related to abnormal cervical input in older people with chronic non-specific neck pain.