Functional diagnostics in diseases of the neuromuscular system

Functional research methods make it possible to evaluate the work of various departments of the neuromuscular system, to establish the level and nature of their damage.

The diagnostic complex includes an assessment of the condition:

• peripheral nerves (sensory and motor fibers);
• Neuromuscular transmission (synapses);
• muscles;
• The functions of the lower motor neurons are indirectly evaluated.

Stimulation electroneuromyography (ENMG, study of nerve conduction function)

What happens during the study:

• Surface electrodes are applied to the skin.
• The nerve is stimulated by a short electrical impulse.

Sensations: short-term electrical impulses of moderate intensity, the muscles of the limb under study contract at the same time.
The study is safe for the patient.

What allows you to identify the method:

• Type of peripheral nerve damage: demyelinating or axonal.
• Local (tunnel) or generalized peripheral nerve damage.

Preparation:

• On the eve and on the day of the study, do not apply creams and oils to the skin.
• The skin in the study area should be free of wounds and damage.
• Inform the doctor about the presence of a pacemaker.
• The study is contraindicated in the presence of a cochlear implant.

Figure 1. An example of applying electrodes

Figure 2. The response of the motor fibers of the ulnar nerve

Figure 3. The response of the sensory fibers of the ulnar nerve

Needle Electromyography (EMG)

What happens during the study:

• A thin sterile disposable electrode is inserted into the muscle.
• The electrical activity of the muscle at rest and during contraction is analyzed.

Sensations: comparable to intramuscular injection. Short-term discomfort is possible.

Diagnostic capabilities:

• Determination of the neurogenic or myogenic nature of the lesion.
• Identification of signs of denervation and reinnervation.

No special training is required.

Figure 4. Spontaneous activity (fibrillation potentials)

Decrement test

This is a method of assessing the state of neuromuscular transmission.

What happens during the study:

• Surface electrodes are applied to the skin
• A series of rhythmic stimulations is performed

Preparation:
On the day of the study, do not take drugs that affect neuromuscular transmission (for example, pyridostigmine bromide/kalimine or neostigmine methylsulfate/proserin) in consultation with the attending physician.

Sensations: short-term electrical impulses of moderate intensity, the muscles of the limb under study are rhythmically contracting.

The study is safe for the patient. It is contraindicated in the presence of a pacemaker and a cochlear implant.

Jitter

This is a highly sensitive study of neuromuscular transmission.
Allows you to identify minimal violations of impulse transmission between nerve and muscle, including in the early stages of the disease.

Preparation is determined individually on the recommendation of a doctor.Figure 5. The study of jitter is normal

Quantitative sensory testing

This is a non-invasive technique for assessing sensitivity (temperature and pain).
It is used to diagnose lesions of thin nerve fibers, including in the early stages of polyneuropathies, when standard stimulation ENMG may not detect changes.

Preparation:

• On the eve and on the day of the study, do not apply creams and oils to the skin.
• The skin in the study area should be free of wounds and damage.

Figure 5. Quantitative sensory testing. An increase in the thresholds of cold and pain sensitivity in a patient with polyneuropathy

You can make an appointment for a consultation and research by calling the unified contact center: +7 (495) 304-30-39 at the Center for Neuromuscular Pathology.