The duty cycle in Functional Electrical Stimulation research. Part II: Duty cycle multiplicity and domain reporting

Abstract

In part I of this review, we introduced the duty cycle as a fundamental parameter in controlling the effect of electrical stimulation pulse trains on muscle structural and functional properties with special emphasis on fatigue. Following on from a survey of the literature, we discuss here the relative ability of intermittent and continuous stimulation to fatigue muscle. In addition, pertinent literature is explored on a more deeper level, highlighting contentions regarding the duty cycle across studies. In response to literature inconsistencies, we propose frameworks upon which the duty cycle parameter may be specified. We present the idea of domain reporting for the duty cycle, and illustrate with practical examples. In addition we dig further into the literature and present a set of notations that have been used by different researchers to report the duty cycle. We also propose the idea of the duty cycle multiple, which together with domain reporting, will help researchers understand more precisely duty cycles of electrical stimulation. As a case study, we also show how the duty cycle has been looked at by researchers in the context of pressure sore attenuation in patients. Together with part I, it is hoped that the frameworks suggested provide a complete picture of how duty cycle has been discussed across the literature, and gives researchers a more trans-theoretical basis upon which they may report the duty cycle in their studies. This may also lead to a more precise specification of electrical stimulation protocols used in patients.

Home-Based Functional Electrical Stimulation of Human Permanent Denervated Muscles: A Narrative Review on Diagnostics, Managements, Results and Byproducts Revisited 2020

“…The outcomes included a significant increase in muscle strength and an increase in the number and size of fast myofibers, that are the first to respond to electrical stimulation and whose content and size are correlated to muscle strength. In muscle biopsies, Pax7- and NCAM-positive muscle satellite cells were also increased in the absence of muscle damage and cellular inflammation [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. Finally, there are many applications of in-home or in-hospital functional electrical stimulation managements of disuse muscle atrophy related to organ diseases, from chronic cardiovascular failures to functional electrostimulation cycling in SCI [ 52 , 53 , 54 , 55 , 56 ].…”

Reporting for Duty: The duty cycle in Functional Electrical Stimulation research. Part I: Critical commentaries of the literature

“…These will be explored extensively in the Part II of this review. 53 We are confident that our suggestions will be followed in the training of those thoracic-level SCI persons after their enrollment in the future studies on intrethecal approach of FES. [55][56][57][58][59][60][61][62][63][64][65][66][67]…”

“…The duty cycle has also been looked at as a parameter of interest in studies of pressure sore attenuation, and select studies from the literature will be presented in table 5 [of Part II of this review]. 53…”

Functional electrical stimulation of permanently denervated muscles, updated 2020

“…In muscle biopsies, a significant increase in the number of Pax7-and NCAM-posi-tive muscle satellite cells was also observed, but there were no signs of muscle damage and/or cellular inflammation. [34][35][36][37][38][39][40][41][42][43][44] Furthermore, there are many more applications of home or in hospital FES to manage disuse muscle atrophy related to several organ diseases, from chronic cardiovascular failures to functional electrical stimulation cycling in spinal cord injury. [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] conclusive remarks In recent years, we have demonstrated the long-term clinical value of co-activation of thigh muscle by home-based Functional Electrical Stimulation training using large surface electrodes.…”