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 uniquefinding in fibromyalgia patients.