Simple Electromyography (EMG)

What is

Electromyography is an examination that is used to diagnose diseases of the peripheral nervous system and the muscular system; it allows examination of nerve, motor, and sensory conduction and evaluation of muscle activity during voluntary activation and at rest.

How it takes place

Electromyography is performed in two steps: first through electroneurography, the conduction velocity of an electrical stimulus along the nerve is measured, the amplitude of the evoked electrical potential and the distal latency are assessed by electrically stimulating the nerve with a surface stimulator placed on the nerve and recording the evoked electrical potential through surface electrodes placed on the muscle.

Then a needle electrode (fine needle) is inserted into the muscle(s) first at rest, then during minimal contraction of the muscle, and finally at maximal contraction.

At this second stage, the presence of spontaneous electrical activity (sign of denervation), the amplitude and duration of muscle electrical potentials, and the number of motor units activated during maximal exertion are identified; if the number of activated motor units is small, it is nerve suffering, while an early number of motor units indicates muscle suffering.

Electromyography or EMG highlights and localizes the suffering of one or more nerve roots and nerves, the injury of one or more nerve trunks, or the entrapment of a nerve trunk, such as Carpal Tunnel Syndrome, so it is a key examination in its diagnosis. It is indeed useful to perform electromyography in the presence of reduced strength, pain, altered sensation, and tingling.

In cases of suspected radiculopathies from herniated discs, nerve trunk lesions, radiculitis and polyradiculonevritis, polyneuritis, myopathies, myositis and polyinositis, and myasthenia, electromyography is indicated.

No, this is not a dangerous examination and the equipment used complies with the regulations of the Law; sterile disposable needles are used to perform an electromyography, which are discarded after the examination is completed.

Before undergoing the examination, however, it is important to tell your doctor if you are taking antiplatelets and anticoagulants and if you have electrical pacemakers or pacemakers.

Exam Preparation

Neither special preparation nor fasting is required; there is no need to be accompanied, and it is possible to both drive and resume work immediately after the electromyography is performed.
It is recommended not to apply creams or oils to the body, as they prevent the proper passage of electrical currents, and to wear comfortable clothes that are easy to remove.

The cell phone must be turned off.

On the day of the examination, it is necessary to bring documentation of the disorder, such as reports from past specialist visits or any daily discharge letters.