Effect of neck pain on verticality perception: a cohort study.

OBJECTIVE

To use the Rod-and-Frame Test (RFT) as a quantification of the perception of verticality in subjects with and without neck pain.

DESIGN

Cohort study comparing perception of verticality in symptomatic subjects with neck pain versus a control group.

SETTING

Both groups were selected from 2 urban chiropractic offices treating typical neuromusculoskeletal conditions from the general community in Canada.

PATIENTS

Nineteen subjects (11 women, 8 men) with uncomplicated mechanical neck pain and 17 (7 women, 10 men) asymptomatic subjects.

INTERVENTION

The RFT offers a noninvasive method of measuring spatial orientation or the perception of verticality. Studies of the RFT indicate that performance is reliable. The RFT requires subjects to set a luminescent rod to the true vertical in the presence and absence of a luminescent background frame.

MAIN OUTCOME MEASURE

The amount of rotation was measured and recorded by a dial on the back of the device.

RESULTS

Two-way analysis of variance showed statistically significant differences in judging vertical between symptomatic and asymptomatic subjects. Unpaired t tests for each test situation and the Tukey post hoc test showed statistical differences for both groups.

CONCLUSION

There may be a direct connection between the structures that provide internal cues for the body's ability to sense verticality and nociceptive influences affecting the afference of these structures. The overshoot of the symptomatic group could indicate the search for additional proprioceptive information.