Article

Chronic whiplash-associated disorders (WAD) have been shown to be
associated with motor dysfunction. Increased electromyographic (EMG) activity in
neck and shoulder girdle muscles has been demonstrated during different tasks in
participants with persistent WAD. Muscle functional magnetic resonance imaging
(mfMRI) is an innovative technique to evaluate muscle activity and differential
recruitment of deep and superficial muscles following exercise.
The purpose of this study was to compare the recruitment pattern of deep and
superficial neck flexors between patients with WAD and controls using mfMRI.
DESIGN: A cross-sectional design was used. METHOD: The study was conducted in a
physical and rehabilitation medicine department. The participants were 19
controls who were healthy (10 men, 9 women; mean [+/-SD] age=22.2+/-0.6 years)
and 16 patients with WAD (5 men, 11 women; mean [+/-SD] age=32.9+/-12.7 years).
The T2 values were calculated for the longus colli (Lco), longus capitis (Lca),
and sternocleidomastoid (SCM) muscles at rest and following cranio-cervical
flexion (CCF). RESULTS: In the overall statistical model for T2 shift, there was
a significant main effect for muscle (F=3.906, P=.033) but not for group
(F=2.855, P=.101). The muscle x group interaction effect was significant
(F=3.618, P=.041). Although not significant, there was a strong trend for lesser
Lco (P=.061) and Lca (P=.060) activity for the WAD group compared with the
control group. Although the SCM showed higher T2 shifts, this difference was not
significant (P=.291). LIMITATIONS: Although mfMRI is an innovative and useful
technique for the evaluation of deep cervical muscles, consideration is required,
as this method encompasses a postexercise evaluation and is limited to resistance
types of exercises. CONCLUSIONS: Muscle functional magnetic resonance imaging
demonstrated a difference in muscle recruitment between the Lco, Lca, and SCM
during CCF in the control group, but failed to demonstrate a changed activity
pattern in the WAD group compared with the control group. The mild symptoms in
the WAD group and the wide variability in T2 values may explain the lack of
significance.

Langue : ANGLAIS