Purpose: To determine whether spinal manipulation as an isolated intervention has any effect on proprioception-dependent performance of subjects with chronic neck pain, compared with effects achieved through stretching exercises.
Design: Matched, nonrandomized, controlled trial.
Setting: Private chiropractic clinic.
Participants: Twenty subjects with chronic (daily, > or = 4 months) neck pain. Volunteers were recruited from a pool of patients visiting the clinic or from those referred by informed clinicians.
Intervention: Half of the subjects received six sessions of high-velocity, low-amplitude manipulation to the cervical and upper thoracic regions during a 3-4 wk period. The other half were instructed in stretching exercises for the cervicothoracic muscles, to be performed in two unsupervised sessions daily over the same time period.
Main outcome measures: Pain levels were assessed at baseline and at each of six follow-up sessions using a 100-mm visual analogue scale. The abilities of the blindfolded subjects to reproduce a neutral head position after moving the head and neck through various planes of motion was the method used to estimate proprioceptive acuity. This was done with the use of a laser pointer affixed to the top of an adjustable cap. Points were marked and measured on a target before and after head movement and repositioning.
Results: Subjects receiving manipulation demonstrated a mean reduction in visual analogue scores of 44%, along with a 41% improvement in mean scores for the head repositioning skill. In comparison, a 9% mean reduction in visual analogue scores and a 12% improvement in head repositioning scores was observed for the stretching group. The difference in the outcomes of the head repositioning skill scores was significant (p < or = .05).
Conclusion: The results suggest a possible effect of manipulation on proprioception in subjects with chronic neck pain. The small sample size, lack of true randomization and lack of blinding of the examiner are factors that weaken these findings. Larger, more controlled studies are needed to determine what specific effects manipulation may have on the function of proprioception.