Premium
The estimated numbers and relative sizes of thenar motor units as selected by multiple point stimulation in young and older adults
Author(s) -
Doherty Timothy J.,
Brown William F.
Publication year - 1993
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/mus.880160404
Subject(s) - motor unit , stimulation , medicine , physical medicine and rehabilitation , electromyography , compound muscle action potential , audiology , physical therapy , electrophysiology , anatomy
Multiple point stimulation (MPS) is described as a method of estimating the numbers of motor units in the median innervated thenar muscles of young and older control subjects. Stimulation at multiple sites along the course of the median nerve was employed to collect a sample of the lowest threshold, all‐or‐nothing surface‐recorded motor unit action potentials (S‐MUAPs). The average, negative peak area, and peak‐to‐peak amplitude of the sample of S‐MUAPs was determined and divided into the corresponding value for the maximal compound muscle action potential to derive the motor unit estimate (MUE). In 37 trials from 17 younger subjects (20—40 years), the mean MUE was 288 ± 95 SD based on negative peak area and, in 33 trials from 20 older subjects, mean values were 139 ± 68. In 23 young and older subjects, MPS was performed on at least two occasions and the MUEs were found to be highly correlated ( r = 0.88). © 1993 John Wiley & Sons, Inc.