Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 18 (10), 1101-14

Characteristics of Motor Unit Discharge in Subjects With Hemiparesis

Affiliations

Characteristics of Motor Unit Discharge in Subjects With Hemiparesis

J J Gemperline et al. Muscle Nerve.

Abstract

We studied the discharge rates and recruitment characteristics of single motor units in paretic and contralateral arm muscles of 6 hemiparetic subjects. Motor unit activity in biceps brachii was recorded at different elbow torques, and the activity related both to the mean level of surface electromyographic activity, and to the degree of weakness. In 3 of the 6 subjects, there were significant reductions in mean discharge rate of motor units in the paretic muscle. All 6 subjects showed compression of the range of motoneuron recruitment forces, and a failure to increase motor unit discharge rate during voluntary force increases in paretic muscles. These rate reductions could potentially alter the precise match of motoneuron properties to the mechanical properties of the innervated muscle fibers, and reduce the efficiency of muscle contraction. This reduction could lead, in turn to increased effort, to fatigue, and ultimately to a sense of weakness for voluntary force generation.

Similar articles

See all similar articles

Cited by 68 PubMed Central articles

See all "Cited by" articles

Publication types

LinkOut - more resources

Feedback