Design and Medical Safety of Neuromuscular Incapacitation Devices [Emerging Technologies]

Neuromuscular incapacitation (NMI) devices deliver electric shocks that disrupt muscle functions in order to immediately stop a truly pain-resistant, aggressive, focused, or combat-trained attacker. Improvements made to shock waveforms secure temporary incapacitation by capturing motor nerves and causing clonic muscular contractions. Suspects can recover immediately after cessation of current delivery. This article discusses NMI topics with a focus on TASER devices. Current models of TASER devices known as electronic control devices (ECD), utilize compressed nitrogen to propel toward the subject two small probes at a speed of about 48 m/s. A special-waveform electrical signal is transmitted through trailing wires to where the probes make contact with the body or clothing. This signal directly stimulates pre-endplate motor nerve tissue resulting in an immediate loss of the person's neuromuscular control, with the initial reaction being a gravitational dysreflexia (i.e., fall to the ground) and loss of ability to perform coordinated action for the duration of the pulse. This provides the law enforcement officers with an opportunity to subdue the resisting suspect. This section address aspects related to the design of ECDs and medical safety concerns raised by their use in the field.