Head & Neck Movements of Whiplash Patients Studied
Study reports normal production of isometric forces but delayed time to peak force
THURSDAY, Dec. 6 (HealthDay News) -- Patients with whiplash-associated disorders demonstrate normal control of head and neck movements, but they take more time to reach peak force during movements compared to controls, researchers report in the November/December issue of the Spine Journal.
Martin Descarreaux, Ph.D., of the Universite du Quebec a Trois-Rivieres in Quebec, Canada, and colleagues compared neck flexion and extension against a fixed head harness in 17 whiplash patients and 14 control subjects. Surface electrodes applied to the sternocleidomastoid and paraspinal muscles allowed the calculation of electromyographic burst duration and amplitude.
Whiplash subjects were able to produce isometric forces with spatial precision similar to healthy controls. However, whiplash subjects required more time to reach peak force, which the authors postulate was a mechanism designed to limit pain and further injury. Compared to controls, the whiplash group also demonstrated increased variability in peak force and increased muscular activity of the paraspinal muscles, though the increase was only statistically significant for the left paraspinal muscle.
When patients present with the complex symptoms and disability patterns related to whiplash, "the nature of the lesion is often unknown to the clinician," the authors write. "The characterization of motor control deficits will eventually help to classify whiplash subjects, design appropriate rehabilitation protocol, and facilitate clinical management of this particular population."