Fibular motor nerve conduction studies: Investigating the mechanism for compound muscle action potential amplitude drop with proximal stimulation

2015 ◽  
Vol 52 (6) ◽  
pp. 993-996 ◽  
Author(s):  
Jordan T. Kamel ◽  
Rory J. Knight-Sadler ◽  
Leslie J. Roberts
Keyword(s):  
Action Potential ◽  
Nerve Conduction ◽  
Compound Muscle Action Potential ◽  
Motor Nerve ◽  
Nerve Conduction Studies ◽  
Action Potential Amplitude ◽  
Muscle Action ◽  
Motor Nerve Conduction ◽  
Potential Amplitude ◽  
Muscle Action Potential

Motor Nerve Conduction Studies

2016 ◽  
pp. 257-291
Author(s):  
Lyell K. Jones ◽  
James C. Watson
Keyword(s):  
Action Potential ◽  
Nerve Conduction ◽  
Compound Muscle Action Potential ◽  
Motor Nerve ◽  
Conduction Block ◽  
Neuromuscular Diseases ◽  
Muscle Action ◽  
Motor Nerve Conduction ◽  
Muscle Action Potential ◽  
Nerve Disease

A compound muscle action potential (CMAP) is the summated action potential recorded from muscle during a motor nerve conduction study (NCS). Motor NCSs with recording of CMAPs may be used for several purposes in assessing neuromuscular diseases, including providing objective measurements of the extent and localization of the cause of weakness; determining the underlying pathological abnormality, such as conduction block or slowing of conduction at a localized area of neurapractic injury; identifying the changes associated with Wallerian degeneration and regeneration in the motor nerve; and assisting (along with needle EMG) in distinguishing peripheral nerve disease from lower motor neuron disease, neuromuscular junction disease, and myopathies. This chapter will review the concepts and techniques of motor NCS and CMAP recording, will describe the technique and measurements, and will discuss the findings in various neuromuscular diseases.

Late Responses

2016 ◽  
pp. 312-327
Author(s):  
Ruple S. Laughlin
Keyword(s):  
Nerve Conduction ◽  
Compound Muscle Action Potential ◽  
Motor Nerve ◽  
Clinical Applications ◽  
Nerve Conduction Studies ◽  
Sensory Nerves ◽  
Muscle Action ◽  
Physiological Basis ◽  
Motor Nerve Conduction ◽  
Muscle Action Potential

Late responses are a group of responses occurring after the compound muscle action potential (M-wave) in motor nerve conduction studies and include F-waves, H-reflexes, and axon reflexes. These responses can indirectly measure aspects of proximal conduction that are not obtained with routine motor nerve conduction studies and may be useful in assessing diseases that affect proximal nerves, such as polyradiculopathies. A thorough understanding of the physiological basis, sources of error, and clinical applications and limitations enhances the usefulness of F-waves and H-reflexes as one means to evaluate proximal functioning of the motor and sensory nerves. This chapter will discuss the study methods and applications of F-waves and H-reflexes.

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