Electroneurogram ( ENG) - Causes, Symptoms and Treatment .MF .
electroneurogram - a method of research speed of an electric pulse through the nerves.
well known that the central nervous system associated with implementing organs, including muscles and by peripheral nerves.As the nerves are signals in the brain and spinal cord, and vice versa, signals "control" are on the periphery of the brain.
electroneurogram detect peripheral nerve lesion, the level and nature of damage (neuropathic or myopathic), the mechanism of injury (demyelination, axonal damage), the prevalence of lesions, the degree of damage, determine the type of acute or chronic course of pathologic process.
Indications ENG ENG
held for suspected neuropathy and polyneuropathy (diabetic, toxic, alcoholic, traumatic), demyelinating disease, amyotrophic lateral sclerosis, myasthenia gravis, muscular dystrophy, traumatic nerve damage Vertebrogenic roots, Tunnel Syndrome.ENG carried out to monitor the effectiveness of treatment and progression - regression of the disease.
For a qualitative study car
Preparing for ENG
Before the study for 3-5 days should not take drugs that affect the nervous and muscular systems - anticholinesterase drugs, muscle relaxants, tranquilizers.In 3 hours to eliminate smoking, intake of caffeine-containing products - tea, coffee, cola.The presence of a pacemaker, medication affecting blood clotting is necessary to inform your doctor.
electroneurogram to the skin in the area of innervation of the investigated nerve is superimposed metal disc electrode is fixed, electrical signals are applied to it.On the muscles innervated by the nerve, overlaps too electrode.
With the passage of the muscle signal is reduced.Measured transmission speed electrical pulse along the nerve to the muscle.A similar study is conducted on the opposite side, and results are compared.Perform standard research methods and more - F-wave, H-reflex, repeated stimulation.It determines the speed of an electrical pulse along the nerve - a nerve stimulation is performed at different points.Used rhythmic nerve stimulation to determine the functional state, such as detection of myasthenic or myotonic reaction;to study the speed of propagation of excitation along the nerves, their motor and sensory fibers, to assess the neuromuscular transmission and engine parameters and reflex responses to stimulation of the nerves.The normal speed of the motor fibers for the lower than for the sensitive.To interpret the received data has a value of the amplitude, the shape, the magnitude of the oscillations, the duration and speed.
ENG can last from 15 minutes to an hour.Volume of study depends on the preliminary diagnosis.So, in traumatic neuropathy of the radial nerve radial nerve is investigated, and if all the nerves brahiopleksite limbs.
ENG - safe method of investigation.By applying an electrical pulse a little discomfort is possible, although when using needle electrodes sensation can be unpleasant from small to severe pain - the electrodes are located on the site of release of the nerve and irritation of these points is painful in itself, every human individual sensitivity, the pain threshold.Perception electrical stimulus depends on nerve pathology.Needle ENG more accurate methodology.
conductivity rank nerve
Decoding results ENG
With the defeat of the peripheral nerve trunk recorded the sharpest electroneuromyographic-changes: marked reduction of the pulse rate and the sensitive and motor nerves, reducing the amplitude of the action potential of the affected nerve andAnswer muscles innervated by them - they are stretched in time and changed in shape.When speed is reduced axonal damage is insignificant, largely reduced the amplitude of the M-response and action potential of the nerve.When demyelination largely vary the speed of propagation of excitation indicators (rate of motor nerves to the hands - 50-80m \ s leg - 40 - 60 m \ s, sensitive higher by 10 - 15 m \ s).When Tunnel syndromes broken the speed of the nerve distal to the tunnel.
If it affects the anterior spinal cord horn, segmental lesions of the spinal cord is registered dissociated decrease in the amplitude of the maximal muscle response (M-response) until it is not detected (normal M-response in the hands of 10 - 20mV, on the legs 6 - 10 mV) and a sharpreduction in the number of functioning motor units, the value of the pulse rate and amplitude of evoked biopotentials nerve with normal or increased.The absence of M-response speaks of gross degenerative damage to the axons.
electroneurogram now - is a complex computerized device that records the speed of the pulse, the amplitude of the muscular response, an action potential of the nerve, calculates data and provides analysis.From the ratio of these parameters, an experienced doctor of functional diagnostics helps to clarify the diagnosis.
ENG does not diagnose, and describes the changes in the neuromuscular system, characteristic of various pathological processes and helps the doctor - neurologist.The diagnosis is put on the totality of objective clinical data and imaging results.
neurologist Kobzev SV