Tibial motor nerve conduction studies: an investigation into the mechanism for amplitude drop of the proximal evoked response. Muscle Nerve 2011 Nov;44(5):776-82
Date
10/19/2011Pubmed ID
22006693DOI
10.1002/mus.22173Scopus ID
2-s2.0-80054848926 (requires institutional sign-in at Scopus site) 24 CitationsAbstract
INTRODUCTION: The amplitude of the compound muscle action potential (CMAP) of abductor hallucis (AH) shows the largest drop with proximal stimulation of any routinely studied motor nerves. The cause has not been established.
METHODS: Four experiments of tibial motor nerve conduction in several healthy control subjects were performed using far-field recordings, collision, H-reflex, and intramuscular recordings of foot muscles.
RESULTS: The proximal CMAP showed a mean peak-peak amplitude of 66% (range 57-79%) compared with the distal response. Collision and H-reflex recordings in AH did not show evidence of a contribution from the tibial-innervated calf muscle. Needle electrode recordings of CMAPs showed consistently different latencies between different foot muscles.
CONCLUSION: Our experiments indicate that temporal dispersion and phase cancellation between the distal tibial-innervated foot muscles recorded by the E2 (i.e., reference) electrode can explain the drop in amplitude between the proximal and distal tibial evoked CMAP.
Author List
Barkhaus PE, Kincaid JC, Nandedkar SDAuthor
Paul E. Barkhaus MD Professor in the Neurology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Action PotentialsElectric Stimulation
Evoked Potentials, Motor
H-Reflex
Humans
Muscle, Skeletal
Neural Conduction
Tibial Nerve
