Flashcards in L14 Clinical Neurophysiology Deck (14):
what's the utility of nerve conduction studies or electromyography?
characterize underlying nerve pathphysiology
assess severity and prognosis
assess age of nerve lesion
determine underlying basis for weakness
which muscle is the reference electrode placed on for the motor conduction studies?
abductor pollucis brevis
what is the Compound Muscle Action Potential (CMAP)?
summation of all individual muscle fibre action potentials
what's the Sensory Nerve Action Potential (SNAP)?
summation of all individual sensory fibre action potentials
where to stimulate and record for sensory nerve conduction?
stimulate mixed motor/sensory nerve. record area that has no motor fibres.
what does the needle electrode exam help answer?
age of lesion
conduction block vs axonal loss?
axonal loss has loss of CMAP distal and proximal to the lesion, while conduction only shows loss proximal to the lesion
how long does recovery from demyelination take?
1-3 months. usually complete
which type of axons take longer to die distal to an injury?
sensory takes longer than motor to die.
how long does it take to rule out an axonal loss lesion?
what do fibrillations during relaxation of a needle electrode exam indicate?
what type of signals do voluntary contractions produce during needle examination students?
motor unit potentials (MUPs)
reduced recruitment in needle electrode exams indicates what type of lesion?