Electrodiagnosis uses electrical technology to study the nervous system. It can provide information about nerve injuries, muscle injuries, muscle diseases, and prognosis. Electrical signals are generated in the brain and travel through the nervous system to muscles, causing contraction. Electromyography involves placing a needle in muscles to record electrical activity at rest, during minimal and maximal contraction. It can detect nerve injuries and other neurologic conditions. Nerve conduction studies involve electrically stimulating nerves to induce muscle responses like the H-wave, M-wave, and F-wave, which are analyzed to evaluate neurologic function. The H-wave specifically indicates input from muscle spindles to motor neurons and is used to diagnose peripheral neuropathies and other central

1. ELECTRODIAGNOSTIC
Aditya Johan .R, M.Fis

2. INTRODUCTION
 Electrodiagnosis is the field of study that, by employing the science of
electrophysiology, uses electrical technology to study human neurophysiology
 Information needed to answer any questions regarding nerve injury, muscle injury,
muscle disease and prognosis can be obtained through electrodiagnostic testing

3. NEUROPHYSIOLOGIC
 Every practitioner should be well aware of the normal neurophysiologic function of the
nervous system
 Electrical signals are generated in the brain, pass through the spinal cord, and travel
into the peripheral nervous system
 These signals are carried down the nerve to the synaptic cleft, where a chemical release
of acetylcholine crosses the synaptic cleft to create an electrical discharge in the muscle,
This electrical signal causes the muscle to contract

4. NEUROMUSCULAR JUNCTION

5. ELECTROMYOGRAPH
 EMG was the first electrodiagnostic test to be developed
 This procedure involves the placement of a needle into various muscles to record
different stages of muscle activity, including rest, minimal contraction, and maximal
activity
 At rest, normal muscle is electrically silent
 Primary nerve injuries that are severe enough to create neurotmetic or axonotmetic
lesions, which result in Wallerian degeneration of the nerve, demonstrate fibrillation and
positive sharp-wave discharges at rest

6.  When a peripheral nerve is subjected to percutaneous electrical stimulation, action
potentials are induced in the innervated skeletal muscle
 The induced action potential is recorded by evoked EMG, which includes the H-wave, the
M-wave, and the F-wave

8. H WAVES
 The name H-wave was derived from that of Johann Hoffmann, who found the response
for the first time in 1918
 The H-wave or H response is a good indicator of the strength and distribution of the
stimulus input from muscle spindle to the motor neuron (Excitatory postsynaptic
potential/ EPSP)
 The H wave is commonly used, therefore, In the diagnosis of peripheral neuropathy
 The H-wave is also used to examine the state of muscle tone and spasticity, or other
movement disorders of the central nervous system

10.  Normal : Polyphasic 1-4 phase,
duration between 5-15 ms and
amplitude up to 2 mv
 Neuropathy : Polyphasic, high
amplitude and long duration Motor
Unit Action Potential
 Myopathy : Polyphasic, small
amplitude < 300 µv and short
duration of MUAP < 3 ms

15. THE END