Multichannel thin-film electrode for intramuscular electromyographic recordings.
It is currently not possible to record electromyographic (EMG) signals from many locations concurrently inside the muscle in a single wire electrode system. We developed a thin-film wire electrode system for multichannel intramuscular EMG recordings. The system was fabricated using a micromachining process, with a silicon wafer as production platform for polyimide-based electrodes. In the current prototype, the flexible polymer structure is 220 microm wide, 10 microm thick, and 1.5 cm long, and it has eight circular platinum-platinum chloride recording sites of 40-microm diameter distributed along the front and back surfaces with 1,500-microm intersite spacing. The system prototype was tested in six experiments where the electrode was implanted into the medial head of the gastrocnemius muscle of rabbits, perpendicular to the pennation angle of the muscle fibers. Asynchronous motor unit activity was induced by eliciting the withdrawal reflex or sequential crushes of the sciatic nerve using a pair of forceps. Sixty-seven motor units were identified from these recordings. In the bandwidth 200 Hz to 5 kHz, the peak-to-peak amplitude of the action potentials of the detected motor units was 75 +/- 12 muV and the root mean square of the noise was 1.6 +/- 0.4 muV. The noise level and amplitude of the action potentials were similar for measures separated by up to 40 min. The experimental tests demonstrated that thin film is a promising technology for a new type of flexible-wire intramuscular EMG recording system with multiple detection sites.
Farina
Dario
D
Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7 D-3, Aalborg, Denmark. df@hst.aau.dk
Yoshida
Ken
K
Stieglitz
Thomas
T
Koch
Klaus Peter
KP
D000200:Action Potentials; D000818:Animals; D004576:Electromyography / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D008839:Microelectrodes; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D010812:Physical Stimulation; D011817:Rabbits; D012018:Reflex; D015203:Reproducibility of Results; D012584:Sciatic Nerve / Q000502:physiology; D013997:Time Factors