Nerve Conduction Study

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Contents 1 Indications 2 Procedure 3 Interpretation 4 More General Terms 5 Additional Terms 6 References

Indications

• peripheral neuropathy

• documenting the existence of a neuropathy
• quantitating its severity
• demonstrating the distribution of a neuropathy
• identifying conduction modality involved (i.e. sensory vs motor)
• provides clues as to underlying pathology ( axonal vs. demyelinating)

• cranial palsy ( Bell's palsy)

Procedure

• tests of peripheral nerves
• performed by stimulating a nerve at one point & measuring the action potential either at another point along the nerve ( sensory conduction) or of the muscle innervated by the nerve ( motor conduction)

Interpretation

• normal conduction velocity (adults)

• arms: 50-70 m/s
• legs: 40-60 m/s

• patterns

• demyelinating neuropathies

• slow conduction velocity
• prolonged distal latency

• axonal neuropathies

• reduced amplitude of motor or sensory nerve action potential

More General Terms

• electrophysiologic measurement

Additional Terms

• nerve conduction

References

1. nlmpubs.nlm.nih.gov/hstat/ahcpr/
2. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 5-6
3. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998

nerve conduction study (NCS); electroneuronography