In the world of physiotherapy, an electrical modality is considered a kind of therapeutic agent that helps physiotherapists in rendering treatment to their patients. Electrical modalities are a series of tools that a physiotherapist commonly uses with other physiotherapy tools like exercises, manual therapy techniques, patient education, and advice for treating an injury, ailment, or deformity. These electrical modalities use the administration of thermal, mechanical, electromagnetic, and light energies for therapeutic purposes. The use of these machines is widely based on the condition being treated. The physiotherapist prefers methods and emerging technologies that can help the patient to lead a quality life. In this blog, we aim to discuss a few of the electrical modalities that are often used for therapeutic purposes.

Electrotherapy or Therapeutic modalities are also known as electrophysical modalities as they create physiological therapeutic effects. Electrotherapy uses electrical signals that interfere with the transmission of neural pain signals into the brain. It slows down or distracts the message from the nerve to the brain, affecting one's Pain Gate. Electrotherapy can also involve the use of this electric current to speed up the healing process where tissue damage has also occurred.  Given below are the benefits of electrotherapy and its different forms.

  • Pain relief.
  • Reduces inflammation.
  • Improves circulation.
  • Increases ROM.
  • Reduces edema.
  • Tissue healing.
  • Enhances muscle activation.
  • Scar tissue remodeling.
  • Skin condition treatment.
  • Decrease unwanted muscular activity.
  • Preservation of strength after trauma or surgery.

ThermotherapyThermotherapy includes superficial heat and deep heat.

Superficial heat:

Superficial heat induces a temperature increase and physiologic changes to the superficial layers of the skin, tissues, fat, muscles, ligaments, tendons, blood vessels, nerves, and joints. Superficial heat penetrates up to usually less than 1 cm. Whereas the deep heat penetrates up to about 3-5 cm. Commonly used superficial heat modalities include hot packs, heating pads, paraffin baths, ultrasound, infrared, and fluid therapy. High temperature provides pain relief, increases local blood flow, metabolism, and elasticity of connective tissues, and subsequently may induce edema and exacerbate acute inflammation.

Deep Heat

Deep heat modalities include therapeutic ultrasound (US), shortwave diathermy (SWD), and microwave diathermy (MWD). Ultrasound is the most commonly used deep heating agent. Heat penetrates up to 3-5 cm or more without overheating underlying subcutaneous tissue or skin.



Cryotherapy or cold therapy includes cold packs, ice massages, cold baths, vapor coolant sprays, and cold compression units. These modalities lower the local tissue temperature. Lo temperature decreases pain, blood flow, edema, inflammation, muscle spasm, and metabolic demand of tissues. Cold therapy is commonly used for acute musculoskeletal pains, swelling, bruising, inflammation, and strains/sprains.


Transcutaneous Nerve Stimulation (TENS)

A TENS unit is a device used to apply low-frequency electrical stimulation through wires and electrodes attached to the patient's skin. There are different types of simulators conventional, acupuncture, hyperstimulation, pulsed, and modulated.  TENS is used for acute/chronic pain, joint effusion/edema, neuromuscular disease, disuse muscle atrophy, and wound/bone healing.


Interferential Therapy (IFT)

IFT delivers low-frequency strong physiological stimulation (<250pps) to nerves. IFT uses two high-frequency currents that are slightly out of phase, and are passed through the skin at the same time where they are set up so that their paths cross and simply interfere with each other. This gives way to a beat frequency which causes low-frequency stimulation deep under the skin. IFT causes pain relief, prevents muscle wastage, maintains a range of motion, increases local blood flow, and reduces edema.


Neuromuscular Electrical Stimulation (NMES)

NMES is a device that can electrically stimulate above the motor threshold to cause a muscle contraction, it is used to cause repetitive stimulation and is thus applied to minimize atrophy and maintain range of motion and also is used in performing a functional task. NMES is used for muscle strengthening, neuromuscular re-education, cardiovascular conditioning, preventing disuse atrophy, osteoporosis, venous thrombosis, spasticity management, shoulder subluxation in hemiplegic limb, phrenic nerve pacing, and urinary incontinence.



Iontophoresis is a gel plate that uses a low electrical current to deliver a substance bearing a charge through the skin. Commonly used medications are anti-inflammatory agents for conditions like palmar-plantar hyperhidrosis, plantar fasciitis, tendonitis, and bursitis.


Spinal Traction

Spinal traction is a technique aiming to reduce pressure on the affected painful segments of the spine and stretch soft tissues.  This is done by pulling the vertebra away from the disc, pressure is released from the disc and associated structures. Spinal traction provides a pulling force to the cervical or lumbar spine by using a special device, manual techniques, or a pulley system. Spinal traction is used for conditions like joint hypomobility, narrowed intervertebral foramen, disc herniation with nerve impingement, spondylolisthesis, and degenerative facet joints.


Ultrasound (US)

Therapeutic ultrasound uses sound waves via the piezoelectric effect to deliver superficial and/or deep heat.  It is used to enhance wound healing, range of motion, pain, inflammation, contractures, and a wide variety of soft tissue disorders. The physiologic effects of therapeutic ultrasound can be divided into thermal i.e heat and non-thermal effects i.e cavitation, acoustic streaming, and standing waves. The non-thermal effects of ultrasound may enhance the process of soft tissue repair, the inflammatory response, protein synthesis, and modulate membrane properties.


Phonophoresis (Sonophoresis)

Phonophoresis uses ultrasound to drive medications into and through the skin by increasing cell permeability for deep heat. Stroking with the probe on affected areas and administering anesthetics or corticosteroids. Phonophoresis is used for osteoarthritis, tendinitis, tenosynovitis, bursitis, epicondylitis, carpal tunnel syndrome, fasciitis, and rapid skin anesthesia.


Shortwave Diathermy (SWD)

Shortwave Diathermy converts high-frequency alternating electromagnetic current to thermal energy to provide deep heat to a large area. It is used for short-term musculoskeletal pain like knee osteoarthritis in pain reduction.


Microwave Diathermy (MWD)

Microwave Diathermy converts electromagnetic microwaves to thermal energy to provide deep heat. It is used for superficial muscles and shallow joints.


Extracorporeal Shock Wave Therapy (ESWT)

Extracorporeal Shock Wave Therapy uses high-intensity pulsed mechanical waves to treat musculoskeletal disorders, it does not produce a thermal effect. It is used for chronic recalcitrant tendinopathies, trigger points, pseudoarthrosis, lateral epicondylitis, and plantar fasciitis.


Low-Level Laser Therapy (LLLT)

Low-Level Laser light is absorbed by enzymes, hemoglobin, fibroblasts, and neurologic tissue. It stimulates cell degranulation causing the release of potent inflammatory mediators, activates phagocytic processes at the site of injury, and activates fibroblast cell function to increase collagen deposition and improves tensile strength, decreases edema produced by inflammation following laser therapy. Also, absorption by hemoglobin releases nitric oxide causing endothelial cell proliferation and increased microcirculation, wound healing, and localized pain control.


Magnetic Therapy

Magnetic therapy exposes the body to a low-frequency magnetic field. This exposure of the body tissues to a weak electrical current enhances cellular permeability and reduces swelling, improves blood circulation through a vasodilating effect, regulates painful stimuli, and reduces pain, promotes muscle relaxation and bone healing.


Ultraviolet (UV) Therapy

UV light is electromagnetic radiation with high energy, used for stimulating collagen metabolism, wound healing, and localized pain control. UV therapy is used for many skin disorders.


Electrotherapy, as a whole, includes a range of treatments that use electricity to reduce pain, improve circulation, repair tissues, and strengthen muscles, resulting in improvements in physical functioning. Though one should take care of its contraindications like skin infection, disturbed skin sensation, open wound, metal in the tissue, patient with a cardiac pacemaker, pregnancy, tumors, over areas of thrombosis or other vascular abnormalities, etc.