What kind of nerve stimulator is in common clinical use?
The peripheral nerve stimulator, which is used to sub-jectively observe or palpate the response, is most com-monly used in practice. Although these stimulators provide subjective and potentially inaccurate results, they are compact, user-friendly, and inexpensive. In combination with sound clinical tests and judgment, they are usually adequate to evaluate the degree of neuromuscular respon-siveness. Direct muscle stimulation may mimic a neuro-muscular response. Care must be taken to evaluate a true neuromuscular response rather than direct muscle stimu-lation by the current. For example, the response to ulnar nerve stimulation should be observed or palpated in the adductor pollicis brevis of the thumb. This site, remote from the stimulating electrodes, eliminates the possibility of direct muscle stimulation. Other possible stimulation sites include facial, posterior tibial, and common peroneal nerves. Regardless of the site selected, quantitative evaluation of result is highly variable from one observer to another.