title: [Control of different electromyogram levels of M. abductor pollicis brevis by means of visual feedback in healthy subjects].
abstract: We studied voluntary control of integrated electromyogram (IEMG) in the range of 20 +/- 5% and 40 +/- 5% of the IEMG of m. abductor pollicis brevis during its maximum voluntary contraction with and without visual feedback. Healthy subjects performed IEMG control with visual feedback in 5 trials; IEMG control with visual feedback in 5 trials for 5 days, and the reproduction of memorized IEMG value without visual feedback after 5 trials of IEMG under the visual control. The accuracy of IEMG control was estimated by the following parameters: time of IEMG being out of the required 10% range (ERROR); IEMG variability (VARIABILITY), and the bias of IEMG mean level (BIAS) during 30-sec trials. The IEMG control in the range of 20 +/- 5% with visual feedback improved in all subjects over the course of 5 trials. Within 5-day training, ERROR and VARIABILITY reduced on the first day only; during the last 4 days there was no accuracy increase. ERROR increased more than twice when the 20% IEMG level was reproduced without vision. The IEMG control in the range of 40 +/- 5% improved neither during 5 trials, nor during 5 days of training with visual feedback. ERROR increased for about 1.5 times when the 40% IEMG level was reproduced without vision. It was concluded that the motor system, particularly the motor cortex, could control the given level of muscle activity using the visual feedback.
authors.forename: V L
authors.initials: VL
authors.lastname: Talis
authors.forename: J M
authors.initials: JM
authors.lastname: Castellote
authors.forename: O V
authors.initials: OV
authors.lastname: Kazennikov
authors.forename: A A
authors.initials: AA
authors.lastname: Grishin
authors.forename: M E
authors.initials: ME
authors.lastname: Ioffe
mesh_terms: D000328:Adult; D004576:Electromyography / Q000379:methods; D056228:Feedback, Sensory / Q000502:physiology*; D005260:Female; D006225:Hand / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D013647:Task Performance and Analysis; D014785:Vision, Ocular / Q000502:physiology*