Hand construction of quadrifilar wire electrodes for electromyography

Array electrodes have become increasingly popular for making surface and indwelling electromyographic (EMG) recordings. We describe a method for in-house construction of indwelling quadrifilar fine-wire electrodes. Quadrifilar electrodes facilitate the mapping of vector myoelectric signatures of motoneuron firing activities of the motor nucleus, a procedure referred to as EMG decomposition. The finished electrode has four detectors, each 50 mum in diameter, arranged in a rhombus pattern. Motor unit recruitment and firing information are aids to better understanding control deficits and behaviors evidenced in the final common pathway of the central nervous system.