BACKGROUND Many commonly used anesthetic agents produce a dose-dependent amplitude reduction and latency prolongation of evoked responses, which may impair diagnosis of intraoperative spinal cord injury. Dexmedetomidine is increasingly used as an adjunct for general anesthesia. Therefore, the authors tested the hypothesis that dexmedetomidine does not have a clinically important effect on somat...

This study investigated the behavior of motor units in the semispinalis cervicis muscle. Intramuscular EMG recordings were obtained unilaterally at levels C2 and C5 in 15 healthy volunteers (8 men, 7 women) who performed isometric neck extensions at 5%, 10%, and 20% of the maximal force [maximum voluntary contraction (MVC)] for 2 min each and linearly increasing force contractions from 0 to 30%...

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...

TO THE EDITOR: Enoka and Duchateau (2) correctly call for caution when interpreting voluntary surface electromyography (sEMG) in terms of neural drive. If voluntary sEMG signals recorded during nonfatiguing isometric contractions depend on the number of motor units recruited, their firing rate, and their size (5), modeling found no direct association between neural drive and voluntary sEMG ampl...

background: the time and frequency features of motor unit action potentials (muaps) extracted from electromyographic (emg) signal provide discriminative information for diagnosis and treatment of neuromuscular disorders. however, the results of conventional automatic diagnosis methods using muap features is not convincing yet. objective: the main goal in designing a muap characterization system...

X-linked recessive bulbospinal neuronopathy (X-BSN) is an adult-onset spinal and bulbar amyotrophy. Neurophysiologic studies demonstrate subclinical involvement of sensory nerves with diminished or absent sensory nerve action potientials and denervation changes, indicating the involvement of sensory neurons. We report the clinical features, findings of electrophysiologic study, and results of m...

It is currently not possible to record electromyographic (EMG) signals from many locations concurrently inside the muscle in a single wire electrode system. We developed a thin-film wire electrode system for multichannel intramuscular EMG recordings. The system was fabricated using a micromachining process, with a silicon wafer as production platform for polyimide-based electrodes. In the curre...

Glossary Amplitude modulation Refers to a signal in which changes in amplitude carry sensory information. Corollary discharge Refers to a copy of a motor command that is sent from motor areas to sensory areas in the brain. It is often used to predict and eliminate sensory responses to self-generated stimuli. Electrosense Ability to detect electric fields. A passive electrosense is one in which ...

On the basis of a sag test in unfused tetanus we classified fast and slow motor units (MUs) in medial gastrocnemius muscle of the rat. The following parameters of motor units were investigated: single twitch force, duration of the action potentials, maximum-minimum amplitude time (M-MAT), action potentials amplitude and their latencies after stimulus (to the onset of potentials) and the diamete...