TY - JOUR
T1 - Neural control properties of the external anal sphincter in young and elderly women
AU - Dias, Nicholas
AU - Zhang, Chuan
AU - Li, Xuhong
AU - Neshatian, Leila
AU - Orejuela, Francisco J.
AU - Zhang, Yingchun
N1 - Funding Information:
This study was supported by NIH DK082644, DK113525, and AG053778, and the University of Houston.
Publisher Copyright:
© 2019 Wiley Periodicals, Inc.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2019/9
Y1 - 2019/9
N2 - Aims: The prevalence of fecal incontinence (FI) increases with age and affects more than 15% of the elderly population. Sarcopenia, skeletal muscle structural, and functional decline with aging, is known to be caused by neuromuscular dysfunction. However, age-related alterations of the neuromuscular function of the external anal sphincter (EAS) have not been studied. This study aims to quantitatively characterize the effect of aging on the EAS by assessing the firing patterns and size of motor unit action potential (MUAP) using high-density surface electromyography (HD-sEMG) recording and analysis techniques. Methods: Thirteen young (31.0 ± 3.6 years) and 14 elderly (64.3 ± 6.2 years) healthy women were recruited for this study. EMG activity of the EAS during maximal voluntary contraction was recorded by a 64-Channel, HD-sEMG intra-rectal probe. HD-sEMG signals were decomposed into MUAP spike trains to extract the firing rate and amplitudes thereof. Results: HD-sEMG decomposition was successfully performed. For the young and elderly groups, mean motor unit (MU) firing rates of 11.4 ± 2.1 pulses per second (PPS) and 9.6 ± 2.3 PPS, and mean MUAP amplitudes of 45.2 ± 14.3 µV and 61.9 ± 21.2 µV were respectively obtained. Both the MU firing rate and MUAP amplitude were significantly different between two groups (P <.05). Moreover, the MUAP firing rate and amplitude correlated with age with a linear regression model (P <.05). Conclusions: This study represents the first effort to examine the effect of aging on the neuromuscular function of EAS. Results suggest an age-related impairment of lower motor neuron descending excitation to the EAS with a compensatory increase in mean MU size.
AB - Aims: The prevalence of fecal incontinence (FI) increases with age and affects more than 15% of the elderly population. Sarcopenia, skeletal muscle structural, and functional decline with aging, is known to be caused by neuromuscular dysfunction. However, age-related alterations of the neuromuscular function of the external anal sphincter (EAS) have not been studied. This study aims to quantitatively characterize the effect of aging on the EAS by assessing the firing patterns and size of motor unit action potential (MUAP) using high-density surface electromyography (HD-sEMG) recording and analysis techniques. Methods: Thirteen young (31.0 ± 3.6 years) and 14 elderly (64.3 ± 6.2 years) healthy women were recruited for this study. EMG activity of the EAS during maximal voluntary contraction was recorded by a 64-Channel, HD-sEMG intra-rectal probe. HD-sEMG signals were decomposed into MUAP spike trains to extract the firing rate and amplitudes thereof. Results: HD-sEMG decomposition was successfully performed. For the young and elderly groups, mean motor unit (MU) firing rates of 11.4 ± 2.1 pulses per second (PPS) and 9.6 ± 2.3 PPS, and mean MUAP amplitudes of 45.2 ± 14.3 µV and 61.9 ± 21.2 µV were respectively obtained. Both the MU firing rate and MUAP amplitude were significantly different between two groups (P <.05). Moreover, the MUAP firing rate and amplitude correlated with age with a linear regression model (P <.05). Conclusions: This study represents the first effort to examine the effect of aging on the neuromuscular function of EAS. Results suggest an age-related impairment of lower motor neuron descending excitation to the EAS with a compensatory increase in mean MU size.
KW - external anal sphincter
KW - motor unit action potential
KW - motor unit control
KW - multichannel electromyography
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U2 - 10.1002/nau.24108
DO - 10.1002/nau.24108
M3 - Article
C2 - 31321803
AN - SCOPUS:85071089003
VL - 38
SP - 1828
EP - 1833
JO - Neurourology and Urodynamics
JF - Neurourology and Urodynamics
SN - 0733-2467
IS - 7
ER -