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Sonographic and electrodiagnostic features of hereditary neuropathy with liability to pressure palsies
Author(s) -
Ginanneschi Federica,
Filippou Georgios,
Giannini Fabio,
Carluccio Maria A.,
Adinolfi Antonella,
Frediani Bruno,
Dotti Maria T.,
Rossi Alessandro
Publication year - 2012
Publication title -
journal of the peripheral nervous system
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 67
eISSN - 1529-8027
pISSN - 1085-9489
DOI - 10.1111/j.1529-8027.2012.00437.x
Subject(s) - medicine , elbow , entrapment neuropathy , entrapment , anatomy , carpal tunnel syndrome , electrophysiology , axon , surgery
Abstract In hereditary neuropathy with liability to pressure palsies ( HNPP ), the increase in distal motor latencies ( DMLs ) is often out of proportion to the slowing of conduction velocities, but the pathophysiological mechanism is still unclear. We used a combined electrophysiological and ultrasonographic ( US ) approach to provide insight into this issue. Twelve HNPP subjects underwent extensive electrophysiological studies and US measurements of the cross‐sectional area ( CSA ) of several peripheral nerves. US nerve enlargement was only observed in the carpal tunnel, Guyon's canal, the elbow and the fibular head. We did not observe US abnormalities at sites where nerve entrapment is uncommon. An increase in DMLs was observed regardless of US nerve enlargement. The increased nerve CSA only in common sites of entrapment likely reflected the well‐documented nerve vulnerability to mechanical stress in HNPP . No morphometric changes were seen in the distal nerve segments where compression/entrapment is unlikely, despite the fact that the DMLs were increased. These data suggest that factors other than mechanical stress are responsible for the distal slowing of action potential propagation. We speculate that a mixture of mechanical insults and an axon‐initiated process in the distal nerves underlies the distal slowing and/or conduction failure in HNPP .