A Conducted Energy Device (CED), commonly known as a Taser, is a tool designed to temporarily incapacitate a person by delivering an electrical charge. This device fires two small, barbed darts connected to the unit by insulated wires, which then transmit a pulsed electrical signal across the target’s body. The primary function is to achieve Neuro Muscular Incapacitation (NMI), effectively overriding the body’s voluntary control. While marketed as a “less-lethal” option, the question of whether a Taser can cause permanent damage focuses on the electrical output’s direct effects and the indirect physical trauma that can result.
The Mechanism of Neuro Muscular Incapacitation
The Taser achieves its goal of incapacitation by leveraging the difference between high voltage and low amperage. The device initially delivers a high voltage, often around 50,000 volts, which is necessary to penetrate thick clothing or skin and establish an electrical circuit between the two darts. Once contact is made, the sustained voltage is much lower, but the electrical current, or amperage, is what affects the body. This current is very low, typically only a few milliamperes (around 2.1 to 5 mA), which is generally below the threshold for causing massive tissue damage.
The low-amperage electrical pulses mimic the body’s own nerve signals, effectively hijacking the communication between the brain and the muscles. This interference overrides the voluntary neural commands, causing strong, involuntary, and sustained muscle contractions (Neuro Muscular Incapacitation). The person becomes temporarily paralyzed and unable to control their movement for the duration of the electrical cycle, which is typically five seconds.
Cardiovascular and Respiratory Impact
The most significant risk of direct, life-threatening harm from the electrical discharge involves the cardiovascular system. If the Taser probes land in a way that creates a current pathway across the chest, the electrical signal can interfere with the heart’s natural rhythm. This interference can potentially induce ventricular fibrillation (V-fib), a chaotic, rapid quivering of the heart’s lower chambers that prevents it from pumping blood effectively. V-fib is a form of sudden cardiac arrest and requires immediate defibrillation to restore a normal rhythm.
Research indicates the risk of inducing V-fib is not negligible, particularly when the darts land with a small spread over the anterior chest, creating a transcardiac path. One study, using a computational model, estimated the overall risk of V-fib for a common Taser model to be around one percent. Pre-existing conditions, such as heart disease, drug use, or extreme stress, can significantly heighten this cardiac risk.
If the heart stops or is compromised, the resulting lack of blood flow to the brain can cause cerebral hypoxia. Severe or prolonged hypoxia leads to the death of brain cells and can result in permanent neurological damage, even if the individual is resuscitated. The combination of electrical risk and subsequent oxygen deprivation represents the most serious path to long-term morbidity associated with the device’s direct effects.
Secondary Physical Trauma and Musculoskeletal Injury
Beyond the direct electrical effects, a significant source of permanent damage comes from the body’s reaction to the incapacitation. The uncontrolled loss of muscle function caused by NMI often leads to an immediate, unprotected fall to the ground. This uncontrolled descent greatly increases the risk of severe secondary physical trauma, such as head injuries. Injuries like basilar skull fractures, subarachnoid hemorrhage, or other traumatic brain injuries can occur when the head strikes a hard surface, leading to permanent neurological deficits or death.
The violent, involuntary muscle contractions themselves can generate enough force to cause musculoskeletal injuries without any fall at all. These contractions are comparable in force to those experienced during a grand mal seizure or electrocution. Specific orthopedic injuries reported include shoulder dislocations, which can cause chronic joint instability, and bone fractures. Spinal compression fractures, particularly in the thoracic vertebrae, have been documented, caused by the overwhelming force of the paraspinous muscles contracting simultaneously. Such fractures can lead to chronic pain or long-term disability, even if they are stable and managed without surgery.
Assessing Long-Term Neurological and Nerve Effects
The question of lasting nerve damage focuses on the peripheral nervous system, the network of nerves outside the brain and spinal cord. While the electrical impulse is designed to be transient, some individuals report lingering symptoms after the event, such as paresthesia—a feeling of tingling, numbness, or “pins and needles”. Localized muscle weakness or pain that persists for a long period has also been reported in a small number of cases.
True permanent nerve damage, involving the demyelination or axon loss of peripheral nerves, is considered rare but possible, especially with prolonged or repeated exposures. Such damage could potentially lead to chronic peripheral neuropathy, causing long-term altered sensation or motor function in the affected limb. Studies on the cognitive effects indicate that while a temporary decline in functions like short-term memory and processing ability may occur, these effects typically resolve within an hour in healthy subjects.
Finally, the psychological consequences of the event represent a non-physical form of permanent damage. Being subjected to a Taser discharge is a highly traumatic experience that can lead to significant long-term mental health issues. Post-traumatic stress disorder (PTSD), anxiety, and emotional distress are recognized as serious consequences that can persist long after the physical effects have resolved, profoundly affecting a person’s quality of life.