Multichannel thin-film electrode for intramuscular electromyographic recordings

Abstract

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.

Flexible parylene-based microelectrode arrays for high resolution EMG recordings in freely moving small animals

“…One way to mitigate this problem is to select substrate materials according to a more suitable combination of their electrical and mechanical properties. Several flexible and biocompatible polymers, such as polyimide (Richardson et al, 1993), are being increasingly used (Farina et al, 2008). The flexibility of the resulting devices provides a more conformal coverage of the muscle surface and supplies some degree of strain relief against the forces of micro-motion.…”

Relationship between grasping force and features of single-channel intramuscular EMG signals

“…However, reliable, implantable electrodes have been proposed recently (Weir et al, 2005;Farina et al, 2008b). Thus iEMG interfaces for myoelectric control may be chronically implanted and may provide more stable and more selective recordings than sEMG.…”

Progress in Research of Flexible MEMS Microelectrodes for Neural Interface

“…Complying with these disciplines for biomedical electrodes mentioned above, various kinds of microelectrodes were developed to execute electrical stimulation and electrophysiological signal recording for paralysis recovery after spinal cord injury. Among these manifold electrodes, Michigan neural probes and Utah electrodes array are widely used in central nerve prostheses applications [9,10], while LIFE electrode are usually applied in peripheral nerve and intramuscular researches [7,11].…”