STUDY DESIGN: Muscle tension with tenderness may be localized or
generalized as in fibromyalgia. Wartenberg's pendulum test
might be appropriate for quantitating muscle damping, at
least in generalized cases.
OBJECTIVE: Damping values provide
aquantitative measure of muscle tension and of the response
to various treatments.
SUMMARY OF THE BACKGROUND DATA:
According to recent anatomic and experimental works,
intrafusal muscle fibers are double-innervated by gamma
motoneurons and sympathetic fibers. With electromyograph
recording, the activity ofextrafusal fibers and gamma
motoneurons (reflexes) can be assessed and separated from the
action of the sympathetic system.
METHODS: An electrogoniometer registers the movements of the freely
swinging leg. On the oscilloscope, the patient's nodular
curve is compared with an ideal calculated dampened curve to
find the damping value. Electromyograph surface electrodes
from the knee extensors and flexors detect the activity of
extrafusal fibers and the occurrence of reflexes.
longstanding severe fibromyalgia, damping values are almost
always elevated,at least in one leg. Half or more of
patients with chronic lumbago and cervical syndrome present
with increased damping. The surface electromyograph remains
silent (in contrast to spastic patients).
findings support the hypothesis that muscle tension in
rheumatic patients results from overactivity ofthe
sympathetic system (or part of it). Even in clinically
localized pain syndromes, muscle damping is often increased in
the legs. The test is valuable for quantitating muscle
tensionand the effectiveness of therapeutic methods.
Wachter KC, Kaeser HE, Guhring H, Ettlin TM, Mennet P, Muller W