What is it?
Electromyography or Electromyogram (EMG) is the electromyographic study of the upper limbs and/or lower limbs.
Electromyography is literally writing down (recording) muscle electrical activity.
When we use the word “electromyography” in a broad sense, we mean the study of the electrical activity of muscles and nerves.
When muscles are active, they produce a significant electrical current.
This current is generally proportional to the level of muscle activity.
Tests carried out:
- Electromyographic study of the upper limbs
- Electromyographic study of the lower limbs
- Electromyographic study of upper and lower limbs
How is it done?
The process of performing an electromyography involves inserting a needle electrode (electrode) into the muscle to be studied in order to measure the electrical activity.
This activity is visualized on an oscilloscope and is also evaluated audibly through a microphone.
Since skeletal muscles are usually extensive, it may be necessary in some cases to insert the needle in more than one place in order to obtain a more effective and informative EMG.
After insertion of the needle and the study at rest, the patient is asked to contract the muscle (for example, bend their leg or arm).
Tests performed during Electromyography
The study of nerve conduction velocities is a procedure normally carried out using electromyography.
In this test, the nerve is electrically stimulated and the response is recorded via recording electrodes on a target structure (e.g. a muscle in the case of determining motor conduction velocity – MCV, or peripheral sensory nerve endings in the case of sensory conduction velocity – SCV).
The time elapsed between the stimulus and the response is called latency.
The difference in latency between responses corresponding to stimuli at different locations on the nerve trunk allows the distance between the two points to be used as a dividing line, calculating the nerve’s conduction velocity in that segment (expressed in m/s).
A decrease in this speed may correspond to nerve pathology.
Conduction velocities can be used to detect peripheral nerve lesions (such as polyneuropathy, or localized peripheral nerve trunk compromises).
Body temperature must be kept constant and at an appropriate level, as low temperatures can slow down nerve conduction.
What does it detect?
Electromyography can be useful in detecting abnormal muscle electrical activity, which can occur in many pathologies and conditions, whether they are primarily based in the muscle or secondary to lesions of the respective tributary nerves.
For which cases is it indicated?
An EMG is usually requested for complaints of reduced strength, or for sensory complaints (pain, reduction or perversion of sensitivity in a given area).
It can also be used to detect actual muscle weakness as opposed to weakness due to pain or motivational problems, or secondary to a lesion in the Central Nervous System.
Agreements and Prices of Electromyography
For electromyography we only have agreements with Multicare, Mimed and IN Casa da Moeda.
Ask us about private prices.
Where to do it?
Electromyography can be done at X-Clinic (Av. Eng. Duarte Pacheco, nº26 – Middle floor, 1070-110 Lisboa) or at NRD (Avenida Columbano Bordalo Pinheiro, nº 11-B, r/c, 1070 – 060 Lisboa – Next to Praça de Espanha)