Electromyography and clinical neurophysiology
-
Electromyogr Clin Neurophysiol · Oct 1992
Sympathetic skin response in spinal cord injured patients: preliminary report.
Sympathetic skin responses (SSRs) were recorded in six spinal cord injured patients. These SSRs were obtained at hands and feet, after electrical stimulation of the median or the posterior tibial nerves. ⋯ The origin of these somatosympathetic reflexes are discussed. SSRs recordings seem to be a simple and suitable technique for investigation of the autonomic nervous system of the spinal cord injured patients.
-
Electromyogr Clin Neurophysiol · Nov 1990
Double pattern of relationship between skin temperature, thermoregulation and sensory nerve conduction.
Electroneurographic and thermographic investigations were done in 32 persons. Sensory nerve conduction velocity, amplitude of sensory nerve potential, subjective and objective sensory thresholds were determined during stimulation of each finger. The maximal and minimal skin temperatures for each finger were evaluated from thermograms taken from the dorsal and palmar surface of the hand before and after standard cooling test. ⋯ Correlations for the sensory nerve potential amplitude likewise for the objective and subjective thresholds were stronger than for the conduction velocity. Sensory nerve potential amplitude increases and subjective and objective thresholds decrease with finger temperature. The obtained results suggest that sensory nerve conduction is related not only to the actual tissue temperature but also to local thermoregulatory ability.
-
Electromyogr Clin Neurophysiol · Jan 1990
Comparative StudyElectrotonic potentials of myelinated nerve fibers.
The extracellular electrotonic potentials of a single myelinated nerve fiber in a volume conductor of infinite extent were studied. The spatial distribution of the transmembrane electrotonic potential was obtained by integrating the system of differential equations constituting the model of the activation of a myelinated nerve fiber. The stimulus was step-like. ⋯ The spatial distribution of the extracellular potentials at various radial distances in the conducting medium was calculated using the line source model. Up to a certain radial distance the discontinuous structure of the myelinated fiber is reflected in the oscillatory nature of the extracellular potentials, while further in the volume conductor the potentials are smooth. The magnitude of the radial decline of the extracellular potentials were compared for myelinated fibers of various internodal distances.