Term
| Differences between EMG and NCS |
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Definition
EMG records electric activity of nerves (done at rest)
NCS assesses the quality of the conduction and speed |
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Term
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Definition
| can localize region of injury and precise location within pathway |
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Term
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Definition
- Radiculopathy
- Peripheral neuropathy
- Entrapment neuropathy
- Carpal tunnel syndrome
-Ulnar neuropathy at the elbow
-Peroneal neuropathy
- Neuromuscular junction disorder
- Botulism
- Myasthenia gravis
- Neuromuscular junction disorder
- Lambert – Eaton myasthenic syndrome
- Myopathy
- Plexopathy (Brachial or Lumbosacral)
- Bell’s palsy
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Term
changes occuring in action potential that lead to dz. |
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Definition
| changes in the onset, duration, amplitude, configuration |
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Term
| a successful dx obtained from EMGs utilizes what other dx methods |
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Definition
| anatomic imaging. Neither test in conclusive on its own. MRIs can find back abnormalities in 50% of individuals who are assymptomatic. abnormal EMG results can occur from benign processes |
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Term
| what is essential to perform prior to facilitating an EMG? |
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Definition
| taking a detailed hx and physical. this will allow you to account for behaviors which could affect the results of the EMG |
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Term
| contraindications for an EMG |
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Definition
cellulitis
pacemaker (if stimulating erb's point) |
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Term
| limitations of EMG results |
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Definition
nThe electromyographer (biggest limitation)
nKnow your anatomy!
nCan not assess CNS (unless doing SSEPs)
nPatient tolerance
nNormal EMG
nTest done too early
nNon-neurogenic abnormality |
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Term
| what does an negative EMG mean? |
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Definition
the test was done too early
not enough nerve damage to show results
incorrect interpretation |
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Term
| what is the appropriate timing for performing an EMG? |
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Definition
4-5 days following traumatic event
1-3 weeks after event if one wishes to view spontaneous potentials |
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Term
| some conditions that would yield normal responses |
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Definition
nDegenerative Joint Disease
nFacet disease
nRheumatoid Arthritis
nOsteoporosis
nFractures
nSprains
nSensory only Radiculopathy
nSpondylolisthesis
nScoliosis
nBursitis
nFibromyalgia
nMyofascial Pain
nPregnancy
nVascular disorders
nPsychogenic disorders
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Term
| what is measured in a nerve conduction study? |
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Definition
latency: the time the impulse took to reach sensor (related to distance traveled)
amplitude increase in millivolts (reflects the number of axons responding to the impluse)
conduction velocity (relates to myelin integrity)
-sensory: has no myoneural jxn so speed is directly related to distance only
-motor: has nymoneural jxn, therefore, must stimulate two nerve segments |
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Term
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Definition
injury causes myelin degradation on axon of a schwann cell and the axon also degenerates because it has been separated from the rest of the cell (Axonotmesis)
degeneration of myelin takes place over ~7 days
effects are seen distal to site of injury |
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Term
| importance of myelination in action potential conduction |
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Definition
the action potential jumps between myelin segments (nodes of ranvier) and therefore never fall too low and is never unable to propogate the signal.
demyelination dismantles the jumping and causes the action potential to plummet |
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Term
| what is the best way to relax a muscle being studied by NCS? |
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Definition
| contract the agonist muscle (the triceps if you're studying the biceps) |
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Term
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Definition
damage to a nerve affecting the myelin sheath but leaves the nerve intact but in a non-conducting state
therefore, wallerian degradation does not take place in this situation |
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Term
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Definition
a complete disruption of the axon, myelin, and epineurium (everything cut in half)
poor prognosis
def. needs surgery |
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Term
| what feature of the anatomy of the PNS may give a false negative electrodiagnostic test result |
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Definition
| the intact nature of the dorsal root sensory ganglion and its existance outside of the spinal cord |
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