ab1904

Surface EMG of the lumbar part of the erector trunci muscle in patients with fibromyalgia

C. Anders¹, H. Sprott^2,3, H.-C. Scholle¹

¹Motor Research Group, Institute of Pathophysiology and ²Department of Internal Medicine IV, University of Jena, Medical Center, Jena, Germany; ³Department of Rheumatology and Institute of Physical Medicine, University Hospital Zürich, Switzerland.

ABSTRACT
Objective
To determine differences supposed in EMG parameters of the erector trunci region between patients with fibromyalgia and healthy subjects during defined investigation situations.

Methods
During sitting and standing in upright position surface EMG (SEMG) from 15 subjects with fibromyalgia and 10 healthy controls was performed using a 16-channel technique where the electrodes were applied in a well-defined grid pattern (gain 5000, 3 db points at 5 Hz and 700 Hz respectively). SEMG quantification was done by Fourier algorithm using 512 measurement points for calculation.

Results
An increased EMG amplitude could be recorded during rest in fibromyalgia patients compared with controls. Spatial amplitude differences (frequency range 100 - 500 Hz) in the low back region were significantly (p < 0.01) decreased in the patients' group during sitting.

Conclusion
It is the first time that a decreased difference in EMG amplitude of different parts within a certain muscle could be proven in patients with fibromyalgia. As far as is known from the literature this result seems to be a unique finding in fibromyalgia patients.

Key words
Surface electromyography, fibromyalgia, human, pain.

Please address correspondence to: Haiko Sprott, M.D., Center of Experimental Rheumatology, Department Rheumatology and Institute of Physical Medicine, University Hospital Zürich, Gloriastrasse 25, CH-8091 Zürich, Switzerland.
E-mail: haiko.sprott@ruz.usz.ch

Please address reprint requests to: Christoph Anders, MD, Institute of Pathophysiology, Motor Research Group, D-07740 Jena, Germany.
E-mail: cand@moto.uni-jena.de