Premium
Muscle hypertrophy in multifocal motor neuropathy is associated with continuous motor unit activity
Author(s) -
O'Leary Colin P.,
Mann A. Cameron,
Lough Jane,
Willison Hugh J.
Publication year - 1997
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199704)20:4<479::aid-mus11>3.0.co;2-u
Subject(s) - fasciculation , biceps , multifocal motor neuropathy , motor unit , mismatch negativity , medicine , muscle hypertrophy , weakness , electromyography , wasting , physical medicine and rehabilitation , anatomy , cardiology , electroencephalography , psychiatry
Multifocal motor neuropathy (MMN) is typically associated with distal upper limb weakness and wasting. However, proximal muscle bulk, particularly of biceps brachii, may be well preserved even in the presence of severe proximal weakness. Here we report 3 patients with MMN who had true muscle hypertrophy of severely weakened biceps muscles and positive motor symptoms including cramp and fasciculations in these muscles. Electromyographic studies demonstrated markedly impaired recruitment in the affected muscles and continuous motor unit activity comprising multiple fasciculation potentials at a frequency of up to 30 per minute. We propose that this continuous motor unit activity may have contributed to the hypertrophy in these muscles. © 1997 John Wiley & Sons, Inc. Muscle Nerve , 20, 479–485, 1997