Nerve Conduction Studies
Norm of Nerve Conduction Studies
Maximum conduction velocity = 40–80 msec for those 3 years of age and older. Distal latency <4 msec and amplitude 13.2 mV. Values decreased by half for infants and elderly. Equipment and technique vary; thus laboratories establish their own norms.
Usage of Nerve Conduction Studies
Carpal tunnel syndrome, peripheral entrapment neuropathies, tarsal tunnel syndrome, and thoracic outlet syndrome.
Description of Nerve Conduction Studies
Percutaneous stimulation of peripheral, sensory, or mixed sensory/motor nerve fibers. Recording of muscle and sensory action potentials distinguishes between disease processes that cause both segmental demyelinative lesions and axonal losses.
Professional Considerations of Nerve Conduction Studies
Consent form IS required.
Risks
Pain at needle-electrode sites.
Contraindications
Nicotine-patch drug users.
Preparation
- Shave the area for better conduction if needed.
Procedure
- An electrode is applied to the specific nerve area.
- Electrical current is passed through and read distally to determine nerve conduction time.
Postprocedure Care
- Assess the skin area for irritation.
Client and Family Teaching
- Results are normally available within 48 hours.
Factors That Affect Results
- Poor conduction of electrodes from use of outdated electrodes, improper site preparation, or movement during the procedure.
- Lower amplitudes are demonstrated in obese clients than in thin clients.
Other Data
- Professional interpretation must follow the results of the study.
- Supplements electromyographic studies.
