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By S. Khosrawi MD Physiatrist Introduction to Electrodiagnostic Medicine By S. Khosrawi MD Physiatrist 27/11/2018

History In the late 1700’s scientists realized that bodily tissue could generate an electrical signal. Not too long after this (1791), Galvani discovered that the muscles used electricity. Muscular electrodes were developed in as early as 1841. In the 1930’s EMG began to be used for clinical purposes. 27/11/2018

neuromuscular examination EDX consultation evaluates nerve and muscle function and is a direct extension of the clinical history and neuromuscular examination 27/11/2018

EDX studies are a supplement to, not a replacement for, a careful history and physical examination by the referring physician and by the EDX physician as part of the EDX consultation 27/11/2018

EDX consultation provides helpful information to evaluate the integrity and function of motor, sensory and autonomic neurons, nerve roots, brachial and lumbar plexi, peripheral nerves, neuromuscular junction, and muscles And sometimes CNS 27/11/2018

lower motor neuron lesions , Main purposes: Is there any lower motor neuron lesions , or not ? If yes , Where ? 27/11/2018

numbness, paresthesia dysautonomia fatigability weakness atrophy pain 27/11/2018

Instrumentation 27/11/2018

Neuropathic Process NCS Axonal Demyelinating Latency NCV Amplitude 27/11/2018

Radiculopathy or Plexopathy H-reflex Late responces F-wave 27/11/2018

EMG 27/11/2018

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Nerve trauma 27/11/2018

NCV in nerve trauma 27/11/2018

Axon loss(Wallerian degeneration) EDx abnormalities appear: Distal CMAP: 5-6 days Distal SNAP: 10-11 days Fibrillation and PSWs: 14-21 days 27/11/2018

Regeneration In complete transection "nascent" potentials within 2 months Within 4-6 months the motor units become of longer duration, of higher amplitude, and are less polyphasic. At about 8-12 months they reach normal size for the muscle being examined. 27/11/2018

Reinnervation In partial nerve injury reinnervation is accomplished by collateral sprouting ,begins in the first two months after nerve injury and results in a prolongation in the duration of the reinnervating motor unit duration and an increase in the number of its phases 27/11/2018

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Root Lesion Normal S-NCV Low motor amplitudes and slowed conduction velocity if the axonal loss is severe The H-reflex and F-wave may be delayed or absent in the areas of involvement 27/11/2018

Plexus Lesions Impaired motor & sensory NCS Erb's point stimulation H-reflex and F-wave studies can be helpful in plexus dysfunction in that responses may be delayed, diminished, or absent 27/11/2018

Routine Upper Extremity(NCV) Median sensory and motor studies with F-waves Ulnar sensory and motor studies with F-waves Radial sensory study 27/11/2018

Routine Lower Extremity)NCV) A sural sensory study A superficial peroneal sensory study A peroneal motor study with F-waves A posterior tibial motor study with F-waves H- refelx studies in peripheral neuropathies and suspected lumbosacral root lesions 27/11/2018

Generalized Neuropathic Process )NCV) A routine upper extremity A routine lower extremity H-reflex studies 27/11/2018

Routine Upper Extremity (EMG) The first dorsal interosseous (an ulnar C8, T1 muscle) The flexor pollicis longus (an anterior interosseous C7,8 muscle) The flexor carpi radialis (a median C7 muscle) The brachioradialis (a radial C5,6 muscle) The triceps (a radial C7,8 muscle) The deltoid (an axillary C5,6 muscle). paraspinal 27/11/2018

Routine Lower Extremity (EMG) The extensor digitorum brevis or extensor hallucis longus (peroneal L5-S1 muscles) The flexor digitorum longus (a posterior tibial L5-S1,2 muscle) The tibialis anterior (a peroneal L4,5 muscle) The medial gastrocnemius (a posterior tibial S1,2 muscle) The vastus lateralis (a femoral L3,4 muscle) The gluteus medius (a superior gluteal L4,5 and S1 muscle) paraspinal 27/11/2018

Peripheral Neuropathy (EMG) A routine upper extremity examination with an extra distal muscle included, the abductor digiti minimi A routine lower extremity examination with the abductor hallucis included 27/11/2018

Anterior Horn Cell (EMG) A routine upper extremity A routine lower extremity A third upper or lower extremity depending on the areas of clinical involvement The tongue 27/11/2018

Inconclusive diagnosis Rapidly evolving disease Course of the disease Clinical situations where appropriate medical management requires repeat testing Second diagnosis Inconclusive diagnosis Rapidly evolving disease Course of the disease Unexpected course Change in course Recovery from injury 27/11/2018

Acceptable tests per 12-month period: Clinical situations where appropriate medical management requires repeat testing Second diagnosis Inconclusive diagnosis Rapidly evolving disease Course of the disease Unexpected course Change in course Recovery from injury Acceptable tests per 12-month period: Two for CTS,radiculopathy,PNP,myopathy,& NMJ disorders Three for motor neuronopathy , plexopathy & trauma But repeat EDX testing is NOT necessary in 80% of all cases 27/11/2018

THE END 27/11/2018