40‐Hz Square‐Wave Stimulation Requires Less Energy to Produce Muscle Contraction: Compared with the TASER^®X26 Conducted Energy Weapon

Abstract

Conducted energy weapons (CEWs) (including the Advanced TASER(®) X26 model produced by TASER International, Inc.) incapacitate individuals by causing muscle contractions. In this study using anesthetized swine, the potential incapacitating effect of primarily monophasic, 19-Hz voltage imposed by the commercial CEW was compared with the effect of voltages imposed by a laboratory device that created 40-Hz square waves. Forces of muscle contraction were measured with the use of strain gauges. Stimulation with 40-Hz square waves required less pulse energy than stimulation with the commercial CEW to produce similar muscle contraction. The square-pulse stimulation, at the higher repetition rate, caused a more complete tetanus at a lower energy. Use of such a simple shape of waveform may be used to make future nonlethal weapon devices more efficient.

Prolonged Electro‐muscular Incapacitation in a Porcine Model Causes Spinal Injury

“…For the 19 Hz stimulation, the stimuli are delivered at a slow enough repetition rate that the twitches caused unfused tetanus (i.e., tension is reduced in the muscles between electric pulses as the muscles partially relax between successive twitches) resulting in large oscillations in muscle force, whereas the 40 Hz stimulation has a high enough frequency to cause more sustained tetanic contractions and less oscillation in force. In a previous study (9), anesthetized swine lying in the supine position with electrodes attached to the ventral surface were electrically stimulated at 19 Hz and 40 Hz and the forces generated by the limbs were directly measured with strain gauges. Similarly, the 19 Hz stimuli from a TASER® X26 conducted electrical weapon (Axon Enterprise, Inc., Scottsdale, AZ, USA) caused large oscillations in the force corresponding to unfused tetanus, whereas the 40 Hz stimuli caused fully fused tetanus.…”

“…To extend the duration of incapacitation, researchers have tested waveforms similar to that of commercial EMI devices and new waveforms. New waveforms include trains of squarewave pulses applied with f=40 Hz (although f has varied from 20 to 80 Hz) at varying magnitudes of Q, durations of continuous exposure, and repetition of exposure (8,9). Exposures 30 s and longer in duration have proven effective in causing prolonged incapacitation in both human and animal models at 19 Hz (10)(11)(12)(13).…”

“…Exposures 30 s and longer in duration have proven effective in causing prolonged incapacitation in both human and animal models at 19 Hz (10)(11)(12)(13). In a study by Comeaux et al (2013), a 19 Hz commercial conducted electrical weapon (CEW) and a benchtop 40 Hz waveform were applied in swine for 1 s (9). The forces of muscle contraction for the 40 Hz waveform was similar to that of the 19 Hz waveform (i.e., characteristic of motor incapacitation).…”

“…The forces of muscle contraction for the 40 Hz waveform was similar to that of the 19 Hz waveform (i.e., characteristic of motor incapacitation). Since the 40 Hz waveform produced incapacitation using less pulse energy (9), this waveform could potentially lead to a reduced payload size for untethered delivery.…”

Exposures to Conducted Electrical Weapons (IncludingTASER®Devices): How Many and for How Long are Acceptable?

“…The detailed shape of a CEW waveform may not be important in terms of generating electromuscular incapacitation . Although some in the general public may presume that “electrocution” occurs in any death temporally related to use of a CEW, repeated applications of the device do not result in a “cumulative dose” of electricity per se .…”