New surface electromyogram (SEMG) techniques offer the potential to advance knowledge of healthy and diseased motor units. Conduction velocity (CV) estimates, obtained from indwelling electrodes, may provide diagnostic information, but the standard method of CV estimation from SEMG may be of only limited value. We developed a motor unit (MU) tracking algorithm to extract motor unit conduction v...

For limb muscles, a-motoneurons in the spinal cord are the last elements to integrate and modulate signals from other parts of the central nervous system. Animal research on the dynamic properties of a-motoneurons shows that a-motoneurons behave as differentiators or high pass filters to injected currents. In behaving animals or human subjects, one cannot control the input currents to a-motoneu...

background: to determine whether using mechanical ventilation in neonatal intensive care unit (nicu) influences motor development of low birth weight (lbw) infants and to compare their motor development with normal birth weight (nbw) infants at the age of 8 to 12 months using peabody developmental motor scale 2 (pdms-2). methods: this cross sectional study was conducted on 70 lbw infants in two...

It has long been known that humans have decreased strength and muscle mass with age, but the mechanisms behind this are still not completely understood. In his review, Degens [1] discusses some potential reasons for this loss in strength with age, concluding that the hypertrophy capability of a muscle fiber does not change as one gets older, but rather that there are fewer muscle fibers. The pr...

Medial gastrocnemius surface electromyographic activity and intramuscular electromyographic activity were recorded from six individuals with chronic cervical spinal cord injury to document the recruitment order of motor units during clonus. Four subjects induced clonus that lasted up to 30 s while two subjects induced clonus that they actively stopped after 1 min. Mean clonus frequency in diffe...

Denervated muscle fibers produce spontaneous depolarizations termed fibrillation potentials. These potentials are an indicator of neuromuscular pathology and are detected by inserting a needle electrode into the muscle of interest to detect the time-based signal. A proposed noninvasive method measures the spectral energy corresponding to increased spontaneous muscle activity [1]. This paper exa...

A new technique permitting electromyographic electrode localisation during open muscle biopsy is described. Using this technique recordings were made from biceps brachii from 22 normal subjects and 19 patients with neurogenic atrophy. Motor unit potential duration and onset interspike interval were the best predictors of histochemical evidence for atrophy. Of patients with neurogenic atrophy, p...

SYNOPSIS An on-line computer method is described for the isolation of single motor unit potentials, evoked by stimulation of the anterior tibial nerve at the ankle, from the compound action potential recorded from surface electrodes over the extensor digitorum brevis muscle. The latencies, durations, amplitudes, and areas of the potentials were measured in a group of control subjects and patien...