A pilot study of myoelectrically controlled FES of upper extremity

Abstract

Abstract-Functional electrical stimulation (FES) of upper limbs can be used for the recovery of some hand functions on patients with CNS lesions. This study deals with the control of FES by means of myoelectrical activity detected from voluntarily activated paretic muscles. The specific aim of this paper is to evaluate the accuracy of myoelectrical control in terms of produced force and movement.For this purpose, a specific device called myoelectrical controlled functional electrical stimulator (MeCFES) has been developed and applied to six tetraplegic patients with a spinal cord lesion and one stroke hemiplegic patient.Residual myoelectric signals from the paretic wrist extensor (m. extensor carpi radialis, ECR) have been used to control stimulation of either the wrist extension (i.e., the same muscle) or thumb flexion. A tracking test based on a visual feedback of the produced force or movement compared to a reference target trajectory was used to quantify control accuracy. A comparison was made between the tracking performances of each subject with and without the MeCFES and the learning process for two of the subjects were observed during consecutive sessions.Results showed that the wrist extension was improved in three out of five C5 SCI patients and the thumb flexion was largely increased in one incomplete C3 SCI patient. The hemiplegic patient showed limited thumb control with the MeCFES but indicated the possibility of a carry over effect. It was found that a low residual natural force resulted in a less accurate movement but also with a large increase (up to ten times) of the muscle output. On the contrary, persons with a medium residual force obtained a smaller amplification of muscle force with a higher tracking accuracy.

Clinical evaluation of Functional Electrical Therapy in acute hemiplegic subjects

“…The clinical evaluations of electrical stimulation-based rehabilitation strongly suggest that electrical stimulation promotes functional recovery of reaching and grasping [1][2][3][4]. Many new rehabilitation treatments were designed to enhance the concentrated use of the paretic arm and hand (e.g., intensive exercise [5,6], Constrained Induced Movement Therapy (CIMT) [7][8][9], robot-induced therapy [10], and electrical stimulation [11][12][13][14][15][16][17][18]). …”

Excitability of Spinal Motor Neuron Function after the Transcutaneous Electrical Stimulation (TES) in Healthy Subjects-F-wave Study-

“…This phenomenon is called a "carry-over" effect 14)15) when they are not using the stimulator after TES. The mechanism o f a ' c a r r y -o v er ' e f f e c t m i g h t b e e x p l a i n e d b y reorganization of the central nervous system (CNS) 16) .…”

Functional electrical stimulation reinforced tenodesis effect controlled by myoelectric activity from wrist extensors

“…The myoelectric signal (MES) has a poor information content [15] but has proven useful for controlling commercially available prostheses [16][17]. Furthermore, MES has been demonstrated feasible for FES control in the laboratory [13,[18][19][20][21][22][23]. A few devices are already on the market that use MES to trigger electrical stimulation with a preset duration [24][25][26].…”