Autor/a:
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Ràfols de Urquía, Magda; Estévez Piorno, Josep; Estrada Petrocelli, Luis; Garcia Casado, Javier; Prats Boluda, Gema; Sarlabous Uranga, Leonardo; Jané Campos, Raimon; Torres Cebrián, Abel
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Abstract:
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The assessment of respiratory muscle activity by
surface electromyography (sEMG) is a promising noninvasive
technique for the diagnosis and monitoring of chronic
obstructive pulmonary disease. The diaphragm is the most
important muscle in breathing, although in forced inspiration
other muscles, such as sternocleidomastoid, are activated and
contribute to the respiratory process. The measurement of the
sEMG in these muscles (sEMGdi and sEMGscm, respectively)
by means of two electrodes in conventional bipolar configuration
(BEs) is a common practice to evaluate the respiratory muscle
activity and allows to indirectly quantify the level of muscular
activation. However, the resulting signals are usually
contaminated by electrocardiographic (ECG) activity, hindering
the assessment of the activity of these muscles. sEMG signals can
also be recorded using concentric ring electrodes (CREs). CREs
have greater spatial resolution and attenuate distant
bioelectrical interferences. In this scenario, the objective of this
work has been to evaluate the applicability of CREs for the
acquisition of sEMGdi and sEMGscm. For this purpose, both
sEMG signals were recorded simultaneously with BEs and CREs
in healthy subjects while performing an inspiratory load
protocol. To evaluate the effect of the cardiac interference, the
ratio between the mean power in inspiratory segments without
ECG and the mean power in expiratory segments with ECG
(Rcardio) was calculated. Additionally, the ratio between the
mean power in inspiratory segments without ECG and the mean
power in expiratory segments without ECG (Rinex) was also
calculated. The results revealed that the Rcardio and bandwidth
is greater in sEMG signals acquired with the CREs, while the
Rinex is higher in the signals acquired with BEs. These results
suggest that the use of CREs is a recommended alternative for
the acquisition of sEMG in muscles with high cardiac
interference, such as the diaphragm muscle. |