Stimulation of paralysed quadriceps muscles with sequentially and spatially distributed electrodes during dynamic knee extension

Abstract

BackgroundDuring functional electrical stimulation (FES) tasks with able-bodied (AB) participants, spatially distributed sequential stimulation (SDSS) has demonstrated substantial improvements in power output and fatigue properties compared to conventional single electrode stimulation (SES). The aim of this study was to compare the properties of SDSS and SES in participants with spinal cord injury (SCI) in a dynamic isokinetic knee extension task simulating knee movement during recumbent cycling.MethodUsing a case-series design, m. vastus lateralis and medialis of four participants with motor and sensory complete SCI (AIS A) were stimulated for 6 min on both legs with both electrode setups. With SES, target muscles were stimulated by a pair of electrodes. In SDSS, the distal electrodes were replaced by four small electrodes giving the same overall stimulation frequency and having the same total surface area. Torque was measured during knee extension by a dynamometer at an angular velocity of 110 deg/s. Mean power of the left and right sides (PmeanL,R) was calculated from all stimulated extensions for initial, final and all extensions. Fatigue is presented as an index value with respect to initial power from 1 to 0, whereby 1 means no fatigue.ResultsSDSS showed higher PmeanL,R values for all four participants for all extensions (increases of 132% in participant P1, 100% in P2, 36% in P3 and 18% in P4 compared to SES) and for the initial phase (increases of 84%, 59%, 66%, and 16%, respectively). Fatigue resistance was better with SDSS for P1, P2 and P4 but worse for P3 (0.47 vs 0.35, 0.63 vs 0.49, 0.90 vs 0.82 and 0.59 vs 0.77, respectively).ConclusionConsistently higher PmeanL,R was observed for all four participants for initial and overall contractions using SDSS. This supports findings from previous studies with AB participants. Fatigue properties were better in three of the four participants. The lower fatigue resistance with SDSS in one participant may be explained by a very low muscle activation level in this case. Further investigation in a larger cohort is warranted.

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

“…Cardiovascular and respiratory rehabilitation for patients actually aims to reverse muscle atrophy and weakness [ 12 , 13 ]. Balance between costs and benefits is debated [ 14 , 15 ], but many practitioners recognize the value of electrical stimulation in their daily clinical practice [ 16 , 17 , 18 , 19 ].…”

Standardizing fatigue-resistance testing during electrical stimulation of paralysed human quadriceps muscles, a practical approach

“…Configuration POS2 was adapted from Laubacher et al [ 9 – 11 ]. Four small electrodes (25 × 45 mm) formed a group and were aligned around the desired motor-point.…”

“…A warm-up program was conducted using the CONV electrode configuration. The leg was moved passively (angular velocity 110°/s as used in [ 9 – 11 ]) by the dynamometer between 70° and 130° knee-extension-angle for 180 times. Stimulation was applied at a frequency of 20 Hz during every second knee-extension from 75° to 125° knee-extension-angle.…”

“…Although all studies concluded improvements for the use of distributed stimulation, it is important to note that most results were obtained in able-bodied healthy subjects. Only Laubacher et al reported results for the population with SCI [ 9 ]. They claimed increased fatigue resistance during distributed stimulation in 3 out of 4 subjects, which was mainly supported by higher values of mean power (average power of all contractions) and final power (average of last 20 contractions).…”

Functional electrical stimulation of permanently denervated muscles, updated 2020

“…Indeed, cardiovascular and ventilation rehabilitation protocols for surgical patients are well established and a major component of these is designed to reverse muscle atrophy and weakness [8,9]. Although the balance between cost (time/capital investment/interference with daily living) and long-term benefits is still debated [10,11], many practitioners and institutions recognize the value of electrical stimulation in their daily clinical practice [12][13][14][15].…”