Electroanalgesia is a form of

analgesia Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professionals ...

, or pain relief, that uses

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

to ease

pain Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...

and belongs to a type of

neurotherapy Neurotherapy is medical treatment that implements systemic targeted delivery of an energy stimulus or chemical agents to a specific neurological zone in the body to alter neuronal activity and stimulate neuroplasticity in a way that develops (or b ...

. Electrical

devices A device is usually a constructed tool. Device may also refer to: Technology Computing, electronics, mechanisms and telecommunication * Appliance, a device for a particular task * Computer, a computing device * Device file, an interface of a pe ...

can be internal or external, at the site of pain (local) or delocalized throughout the whole

body Body may refer to: In science * Physical body, an object in physics that represents a large amount, has mass or takes up space * Body (biology), the physical material of an organism * Body plan, the physical features shared by a group of anim ...

. It works by interfering with the electric currents of pain signals, inhibiting them from reaching the

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

and inducing a response; different from traditional analgesics, such as

opiates An opiate is an alkaloid substance derived from opium (or poppy straw). It differs from the similar term ''opioid'' in that the latter is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain ( ...

which mimic natural endorphins and

NSAID Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of ...

s (non-steroidal anti-inflammatory drugs) that help relieve inflammation and stop pain at the source. Electroanalgesia has a lower addictive potential and poses less health threats to the general public, but can cause serious health problems, even death, in people with other electrical devices such as

pacemakers A pacemaker, also known as an artificial cardiac pacemaker, is an implanted medical device that generates electrical pulses delivered by electrodes to one or more of the chambers of the heart. Each pulse causes the targeted chamber(s) to co ...

or internal hearing aids, or with

heart problems Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina pectoris, angina, myocardial infarction, heart attack), heart failure, ...

History

The first cases of electroanalgesia were documented by Greek scholars,

Plutarch Plutarch (; , ''Ploútarchos'', ; – 120s) was a Greek Middle Platonist philosopher, historian, biographer, essayist, and priest at the Temple of Apollo (Delphi), Temple of Apollo in Delphi. He is known primarily for his ''Parallel Lives'', ...

and

Socrates Socrates (; ; – 399 BC) was a Ancient Greek philosophy, Greek philosopher from Classical Athens, Athens who is credited as the founder of Western philosophy and as among the first moral philosophers of the Ethics, ethical tradition ...

, who noticed numbing effects of standing in pools of water on a beach that contained

electric fish An electric fish is any fish that can Bioelectrogenesis, generate electric fields, whether to sense things around them, for defence, or to stun prey. Most fish able to produce shocks are also electroreceptive, meaning that they can sense electric ...

(icthyoelectroanalgesia).[Jensen, Jack E., Richard R. Conn, Gary Hazelrigg, and John E. Hewett. "The Use of Transcutaneous Neural Stimulation and Isokinetic Testing in Arthroscopic Knee Surgery." The American Journal of Sports Medicine 13 (1985): 27-33]. The Chinese practice of acupuncture, dating back to 3000 BCE, also utilizes the properties of electroanalgesia by stimulating specific nerves to produce electrical signals which produce pleasurable responses in the brain. Another ancient analgesic method, aging back to 5000 BCE in

Sumer Sumer () is the earliest known civilization, located in the historical region of southern Mesopotamia (now south-central Iraq), emerging during the Chalcolithic and Early Bronze Age, early Bronze Ages between the sixth and fifth millennium BC. ...

, is to use natural minerals,

vitamin Vitamins are Organic compound, organic molecules (or a set of closely related molecules called vitamer, vitamers) that are essential to an organism in small quantities for proper metabolism, metabolic function. Nutrient#Essential nutrients, ...

s, and

herbs Herbs are a widely distributed and widespread group of plants, excluding vegetables, with savory or aromatic properties that are used for flavoring and garnish (food), garnishing food, for medicinal purposes, or for fragrances. Culinary use typi ...

, usually in a mixture with other natural products. Technology invented specifically for electroanalgesia emerged at the beginning of the 1900s.

Technology

Advancements in technology within the past fifteen years have created multiple forms of electroanalgesia. Doctors can target specific electrical signals caused by pain and cancel them out using electrical signals, optimally with alternating low and high

frequencies Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

Transcranial electrostimulation

A theoretical explanation for the mechanism of pain reduction by transcranial electrostimulation, or TCES, suggests that the electrical stimulation activates the anti-nociceptive system in the brain, resulting in β-endorphin,

serotonin Serotonin (), also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter with a wide range of functions in both the central nervous system (CNS) and also peripheral tissues. It is involved in mood, cognition, reward, learning, ...

and

noradrenaline Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone, neurotransmitter and neuromodulator. The name "noradrenaline" (from ...

release. abis L, Shklar B, Geva D: Immediate influence of transcranial electrostimulation on pain and β-endorphin blood levels: An active placebo-controlled study. Am J Phys Med Rehabil 2003;82:81-85. TCES can be used on people with cervical pain, chronic lower back syndrome, or migraines. It cannot be used on people with orthopedic or radiological potentially serious spinal conditions,

hydrocephalus Hydrocephalus is a condition in which cerebrospinal fluid (CSF) builds up within the brain, which can cause pressure to increase in the skull. Symptoms may vary according to age. Headaches and double vision are common. Elderly adults with n ...

epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...

glaucoma Glaucoma is a group of eye diseases that can lead to damage of the optic nerve. The optic nerve transmits visual information from the eye to the brain. Glaucoma may cause vision loss if left untreated. It has been called the "silent thief of ...

malignant hypertension A hypertensive emergency is very high blood pressure with potentially life-threatening symptoms and signs of acute damage to one or more organ systems (especially brain, eyes, heart, aorta, or kidneys). It is different from a hypertensive urgenc ...

pacemaker A pacemaker, also known as an artificial cardiac pacemaker, is an implanted medical device that generates electrical pulses delivered by electrodes to one or more of the chambers of the heart. Each pulse causes the targeted chamber(s) to co ...

or other implanted electronic device; recent cerebral trauma,

nervous system In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...

infection, skin

lesions A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no de ...

at sites of electrode placement; oncological disease; patients undergoing any other treatments for pain; any invasive therapy, e.g. surgery, within the last month. The equipment used is Pulse Mazor Instruments' Pulsatilla 1000, which consists of a headset with three

electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can consist of a varie ...

s, two that go behind the ears and one that goes on the forehead, that release set frequencies of electricity at set intervals.

Deep brain stimulation

Deep brain stimulation Deep brain stimulation (DBS) is a type of neurostimulation therapy in which an implantable pulse generator is stereotactic surgery, surgically implanted subcutaneous tissue, below the skin of the chest and connected by Lead (electronics), leads ...

, or DBS, was first evaluated as an electroanalgesic in the late 1950s. It works in some chronic pain patients. The mechanism of DBS is unknown. There is some evidence that it decreases pain transmission along sensory discriminative pathways although more recent studies have shown that it has central effects on other brain regions involved in the pain network (Pereira et al. 2007). This method has mainly been used for chronic pain patients after all other options have failed due to potential of intracranial complications (e.g.,

intracranial hemorrhage Intracranial hemorrhage (ICH) refers to any form of Hemorrhage, bleeding Internal bleeding, within the Human skull, skull. It can result from trauma, vascular abnormalities, hypertension, or other medical conditions. ICH is broadly categorized ...

, infection, and oculomotor abnormalities). An electrode is "stereotactically" guided to the site using

magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...

and once in place, the electrode is activated by subcutaneous leads attached to a pulse generator under the skin. It is effective in treating refractory post-stroke pain, atypical face pain, anaesthesia dolorosa, and deafferentation and somatic pain such as in phantom limb or brachial plexus injury (Boccard et al. 2013).

Peripheral nerve stimulation

The use of peripheral nerve stimulation, or PNS, for the relief of chronic pain states was first reported over 30 years ago. Recent studies have demonstrated that electrical stimulation of

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...

s leads to inhibitory input to the pain pathways at the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

level. PNS is most effective in the treatment of neuropathic pain (e.g., posttraumatic neuropathy, diabetic neuropathy) when the nerve lesion is distal to the site of stimulation. hite, Paul F., Shitong Li, and Jen W. Chiu. "Electroanalgeia: Its Role in Acute and Chronic Pain Management." Anestesia and Analgesia 92 (2001): 505-13.

Percutaneous electrical nerve stimulation

Percutaneous electrical nerve stimulation, or PENS, is used mainly in the treatment of intractable pain associated with chronic low back pain syndrome, cancer, and other disorders. It is a technique involving insertion of an ultra-fine acupuncture needle which probes into the

soft tissue Soft tissue connective tissue, connects and surrounds or supports internal organs and bones, and includes muscle, tendons, ligaments, Adipose tissue, fat, fibrous tissue, Lymphatic vessel, lymph and blood vessels, fasciae, and synovial membranes.� ...

s or

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

s to electrically stimulate nerve fibers in the sclerotomal, myotomal, or dermatomal distribution corresponding to the patient's pain symptoms. PENS is related to both

electroacupuncture Electroacupuncture is a form of acupuncture where a small electric current is passed between pairs of acupuncture needles. The Cochrane Collaboration, a group of evidence-based medicine (EBM) reviewers, reviewed acupuncture and electroacupunctu ...

and

transcutaneous electrical nerve stimulation A transcutaneous electrical nerve stimulation (TENS or TNS) is a device that produces mild electric current to stimulate the nerves for therapeutic purposes. TENS, by definition, covers the complete range of transcutaneously applied currents u ...

Percutaneous neuromodulation therapy

PENS used to be a term to describe a neurosurgical procedure involving implantation of temporary stimulating electrodes before an SCS device. The term has recently been changed to percutaneous

neuromodulation Neuromodulation is the physiological process by which a given neuron uses one or more chemicals to regulate diverse populations of neurons. Neuromodulators typically bind to metabotropic, G-protein coupled receptors (GPCRs) to initiate a sec ...

therapy, or PNT. The term PNT was chosen because it more accurately describes the neurophysiologic basis for PENS-induced analgesia.

Transcutaneous electrical nerve stimulation

Transcutaneous electrical nerve stimulation, or TENS, involves the transmission of electrical energy from an external stimulator to the peripheral nervous system via cutaneously placed conductive gel pads. TENS can be subclassified into two variants: * low-intensity (1–2 mA), high-frequency (50–100 Hz) TENS; and * acupuncture-like high-intensity (15–20 mA), low-frequency (1–5 Hz) or "dense-disperse" TENS. The purported mechanism of action of TENS invokes both spinal supraspinal theories.

Transcutaneous acupoint electrical stimulation

Transcutaneous acupoint electrical stimulation, or TAES, is a variant of TENS therapy that involves applying cutaneous electrodes at classical Chinese

acupoint Acupuncture is a form of alternative medicine and a component of traditional Chinese medicine (TCM) in which thin needles are inserted into the body. Acupuncture is a pseudoscience; the theories and practices of TCM are not based on scientifi ...

s and stimulating with alternating high- and low-frequency electric current (" dense-disperse"). Acupoint stimulation is as effective as dermatomal stimulation in producing an analgesic-sparing effect after lower abdominal surgery

H-wave therapy

H-wave therapy (HWT) is a form of electrical stimulation that produces a direct, localized effect on the conduction of underlying nerves. The electrical stimulation used in HWT differs from other forms of electrical stimulation such as TENS in terms of its

waveform In electronics, acoustics, and related fields, the waveform of a signal is the shape of its Graph of a function, graph as a function of time, independent of its time and Magnitude (mathematics), magnitude Scale (ratio), scales and of any dis ...

; it is intended to emulate the H waveform found in nerve signals, thus permitting the machine to use less power while attaining greater and deeper penetration of its low-frequency current. The waves used in HWT are distinct from the H-waves that are part of

electromyography Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyo ...

. It has been used in the treatment of pain related to

diabetic neuropathy Diabetic neuropathy includes various types of nerve damage associated with diabetes mellitus. The most common form, diabetic peripheral neuropathy, affects 30% of all diabetic patients. Studies suggests that cutaneous nerve branches, such as the s ...

, muscle

sprain A sprain is a soft tissue injury of the ligaments within a joint, often caused by a sudden movement abruptly forcing the joint to exceed its functional range of motion. Ligaments are tough, inelastic fibers made of collagen that connect two or ...

temporomandibular joint disorder Temporomandibular joint dysfunction (TMD, TMJD) is an umbrella term covering pain and dysfunction of the muscles of mastication (the muscles that move the jaw) and the temporomandibular joints (the joints which connect the mandible to the skul ...

s, type I

complex regional pain syndrome Complex regional pain syndrome (CRPS type 1 and type 2), sometimes referred to by the hyponyms reflex sympathetic dystrophy (RSD) or reflex neurovascular dystrophy (RND), is a rare and severe form of neuroinflammatory and dysautonomic disorder ...

as well as the healing of wounds such as diabetic ulcers. This electroanalgesic modality was originally recommended as an alternative to TENS for dental analgesia. In a 1999

randomized controlled trial A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical ...

involving a mechanical pain model, the analgesic effects of HWT were found to be short-lasting and identical to those provided by TENS therapy. HWT has not been shown effective in reducing pain in cases other than diabetic neuropathy, nor has it been shown effective in reducing edema or swelling, and it has specifically not been shown effective in treating

chronic pain Chronic pain is pain that persists or recurs for longer than 3 months.https://icd.who.int/browse/2025-01/mms/en#1581976053 It is also known as gradual burning pain, electrical pain, throbbing pain, and nauseating pain. This type of pain is in cont ...

due to

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...

Interferential current therapy

Interferential current therapy, or ICT, is another variant of TENS that uses the principle of

amplitude modulation Amplitude modulation (AM) is a signal modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the instantaneous amplitude of the wave is varied in proportion t ...

to decrease the discomfort of stimulating deeper tissues (e.g., muscle) when using transcutaneously applied electric current. A combination of different stimulation frequencies are used (i.e., one fixed at 4 kHz and another within a variable range) to generate frequencies between 4 and 250 Hz which are alleged to more effectively penetrate the soft tissues while producing less discomfort at the skin surface. With ICT, its postulated mechanism of analgesic action is through direct stimulation of muscle fibers rather than nerves, allegedly improving muscle blood flow and promoting the healing process. Although ICT is used widely in the

physiotherapy Physical therapy (PT), also known as physiotherapy, is a healthcare profession, as well as the care provided by physical therapists who promote, maintain, or restore health through patient education, physical intervention, disease preventio ...

and rehabilitative medicine settings, there is a dearth of rigorously controlled studies to justify its effectiveness in the management of either acute or chronic pain syndromes.

Piezo-electric current therapy

Piezo-electric current therapy, or PECT, is an analgesic technique based on the principle that mechanical deformation of a motorized

piezoelectric Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied stress (mechanics), mechanical s ...

ceramic A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcela ...

rod produces a burst of 10 electrical pulses (five positive and five negative), each lasting 2–3 ms. Each electrical burst lasts for 50 to 250 ms (depending on the motor speed set) and generates a current of approximately 25 mA. The application of PECT to the skin for 2 min produces a tolerable "pricking" pain sensation associated with a neurogenic inflammatory response lasting 3–4 h. The extent and duration of this inhibitory process is directly related to the intensity of the applied stimulus and is alleged to be associated with the release of endogenous endorphins. iller JC, Le Bars D, De Broucker T. Diffuse noxious inhibitory control in man: involvement of an opioidergic link. Eur J Pharmacol 1990;182:347–55.

Controversies

Electroanalgesia poses serious health problems in those patients who need other electrical equipment in their bodies, such as

s and

hearing aid A hearing aid is a device designed to improve hearing by making sound audible to a person with hearing loss. Hearing aids are classified as medical devices in most countries, and regulated by the respective regulations. Small audio amplifiers ...

s, because the electrical signals of the multiple devices can interfere with each other and fail. People with

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

problems, such as

irregular heartbeat Arrhythmias, also known as cardiac arrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. Essentially, this is anything but normal sinus rhythm. A resting heart rate that is too fast – above 100 beats ...

, are also at risk because the devices can throw off the normal electrical signal of the heart.

References

{{Pain Analgesics Electrotherapy Medical treatments