Use of electromyographic signals for characterization of voluntary coughing in humans with and without spinal cord injury-A systematic review.

Abstract

Individuals with spinal cord injury (SCI) frequently have an ineffective cough ability due to dysfunctions in expiratory muscles. In such cases, several articles have reported the occurrence of residual muscular activity in muscles that are accessory to coughing. The knowledge about this activity may be useful for building cough assistance devices. The goal of this review is to investigate and to describe the electromyographic signals generated during voluntary coughing in healthy people and in patients with SCI. Two researchers performed, blindly and independently, a systematic review of the following databases: PubMed, PEDro, LILACS, and Science Direct. We conducted the searches using descriptors in English, Portuguese, and Spanish, with no limitations regarding the publication year. The review included articles describing experiments performed in humans and with the use of electromyographic signals in the analysis of voluntary coughing. Among the 156 initially found articles, only nine had results that described the study of electromyographic signals associated with voluntary coughing. The results showed evidence that, during voluntary coughing, electromyographic signals are generated both in expiratory and accessory muscles in healthy subjects. In individuals with SCI below the 5th cervical level (C5), the electromyographic signal appeared only in the clavicular portion of the pectoralis major, especially in the explosive cough phase. Our evaluation of the current literature shows that, according to the analysed studies, the electromyographic signals are more pre-eminent in the expiratory phase of the pectoralis major, during voluntary cough of individuals with SCI (C5-T12).