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Updated: Feb 10, 2026

Functional and Morphological Assessment of Diaphragm Innervation by Phrenic Motor Neurons
Published on: May 25, 2015
Is phrenic nerve conduction affected in patients with difficult-to-treat asthma?
Analúcia Abreu Maranhão1, Marcia Maria Jardim Rodrigues1, Sonia Regina da Silva Carvalho1
1Faculdade de Medicina, Universidade Federal do Estado Rio de Janeiro, Rio de Janeiro, RJ, Brasil.
Abstract:
Objective The aim of this study was to obtain data on phrenic neuroconduction and electromyography of the diaphragm muscle in difficult-to-treat asthmatic patients and compare the results to those obtained in controls. Methods The study consisted of 20 difficult-to-treat asthmatic patients compared with 27 controls. Spirometry, maximal inspiratory and expiratory pressure, chest X-ray, phrenic neuroconduction and diaphragm electromyography data were obtained. Results The phrenic compound motor action potential area was reduced, compared with controls, and all the patients had normal diaphragm electromyography. Conclusion It is possible that a reduced phrenic compound motor action potential area, without electromyography abnormalities, could be related to diaphragm muscle fiber abnormalities due to overload activity.
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