Magnetic coil stimulation of the brachial plexus

This study establishes a protocol and normal values for magnetic stimulation of the brachial plexus at the mid-clavicular point. We evaluated twenty normal subjects bilaterally, and determined normal latencies to the abductor pollicis brevis, abductor digiti minimi, biceps, triceps, deltoid, infraspinatus, latissimus dorsi, and rhomboid major. Our values were comparable to latency values obtained with electrical stimulation at Erb's point and reported in the literature. Patient's compared their comfort between electrical stimulation and magnetic stimulation and magnetic stimulation was found more comfortable. To demonstrate that magnetic stimulation is an easier and less painful method to study brachial plexus injuries, we report two cases where we were unable to record evoked responses with electrical stimulation at Erb's point yet easily obtained magnetic recordings.