PubMed · 15406965
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
A LUNDERVOLD. 1949. A technical error in electromyography.. https://pubmed.ncbi.nlm.nih.gov/15406965/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Electromyograms recorded from the lower limbs of humans while running were submitted to a time/frequency analysis using wavelets. The results of the wavelet analysis yielded intensity spectra at every time point during the swing and the stance phase. It was previously shown that more or less high frequency components get activated during different periods of the movement. The purpose of this study was to test to what extent the spectra can be reconstructed by a linear superposition of two generating spectra that were associated to groups of fast and slow muscle fibers. The terms fast and slow do not only refer to the conduction velocity but also to the shape of the motor unit action potential and are used to characterize the groups in a broader sense. The principal component analysis of the spectra confirmed that a two dimensional spectral space was appropriate. A parametric spectral decomposition was used to extract the generating spectra within the two dimensional spectral space. The generating spectra were in turn used to compute the power with which the groups of muscle fibers contribute to the measured spectra and thus to the overall muscular activity. The power that was obtained for the different time points during the movement reflects the biomechanically important interplay between the groups of muscle fibers while running.
A male Caucasian patient is presented with a greater than 10-year history of painless weakness of the right leg, stable over the last 7 years. His examination demonstrated severe wasting and moderate weakness of his right calf muscle. Electrodiagnostic study revealed acute denervation of the right calf and chronic partial denervation of multiple right leg muscles. MRI demonstrated atrophy and fatty infiltration of the right calf muscles. Based on previous clinical, electrophysiologic, and radiologic descriptions of this disorder, a diagnosis was made of benign monomelic amyotrophy of the lower limb. Serologic examination for anti-glycoconjugate antibodies revealed high titers of IgM antibodies with selective binding to the disialoganglioside N-acetylgalactosaminyl GD1a (GalNAcGD1a). Testing for antibodies to GalNAcGD1a should be considered in patients with this phenotype. Their presence could suggest a role for immunomodulatory therapy.
Explore the source record for details and available documents.