Origin of surface motor unit potentials in hypothenar motor unit number estimation. Issue 2 (5th February 2013)

• Record Type: Journal Article
• Authors: Kawamura, Yasuomi; Sonoo, Masahiro; Higashihara, Mana; Chiba, Takashi; Hatanaka, Yuki
• Is Part Of: Muscle & nerve. Volume 48:Issue 2(2013:Aug.)
• Page Start: 185
• Page End: 190
• Publication Date: 2013-02-05
• Subjects: Neuromuscular diseases -- Periodicals; Muscles -- Periodicals; Nerves -- Periodicals; 616.74
• DOI: 10.1002/mus.23746
• Languages: English
• ISSNs: 0148-639X

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p> <italic>Introduction</italic>: Far‐field potentials (FFPs) from muscles other than the abductor digiti minimi (ADM) may interfere with motor unit number estimation (MUNE) from that muscle. <italic>Methods</italic>: We identified the origin of each surface motor unit potential (SMUP) during hypothenar MUNE using the multiple point stimulation method in 20 control subjects by recording from individual ulnar‐innervated muscles with a common proximal reference (pref). <italic>Results</italic>: ADM SMUPs comprised 39.0% of the accepted SMUPs, followed by those from the fourth dorsal interosseous muscle (14.0%), the fourth lumbrical muscle (9.2%), and the second and third palmar interosseous muscles (8.8% each). The percentage of ADM SMUPs varied from 18% to 73% of accepted SMUPs among individual subjects. Accepted non‐ADM SMUPs were usually much smaller than ADM SMUPs, and many more non‐ADM SMUPs were excluded due to their small size. <italic>Conclusions</italic>: A large contribution from non‐ADM or non‐hypothenar SMUPs obscures the meaning of the MUNE value. <italic>Muscle Nerve</italic>, 48: 185–190, 2013</p> </abstract>