TWITCHER: a device to stimulate thumb twitch response to ulnar nerve stimulation.

Objective: To design and fabricate a device to simulate evoked thumb adduction in response to ulnar nerve stimulation.

Methods: We implemented a computer-controlled, motorized thumb (TWITCHER) that responds to ulnar nerve stimulation by an unmodified peripheral nerve stimulator. Clinically realistic response patterns are generated for both depolarizing and non-depolarizing muscle relaxants and three modes of stimulation (single twitch, train-of-four, tetanus).

Results: The device has been used in a full-scale patient simulator for the last six years.

Discussion: TWITCHER has been well received by participants in simulation exercises including the use of neuromuscular blocking drugs.