BIONic WalkAide for correcting foot drop

The goal of this study was to test the feasibility and efficacy of using microstimulators (BIONs) to correct foot drop, the first human application of BIONs in functional electrical stimulation (FES). A prototype BIONic foot drop stimulator was developed by modifying a WalkAide2 stimulator to control BION stimulation of the ankle dorsiflexor muscles. BION stimulation was compared with surface stimulation of the common peroneal nerve provided by a normal WalkAide2 foot drop stimulator. Compared to surface stimulation, we found that BION stimulation of the deep peroneal nerve produces a more balanced ankle flexion movement without everting the foot. A three-dimensional motion analysis was performed to measure the ankle and foot kinematics with and without stimulation. Without stimulation, the toe on the affected leg drags across the ground. The BIONic WalkAide elevates the foot such that the toe clears the ground by 3 cm, which is equivalent to the toe clearance in the unaffected leg. The physiological cost index (PCI) was used to measure effort during walking. The PCI is high without stimulation (2.29/spl plusmn/0.37;mean/spl plusmn/S.D.) and greatly reduced with surface (1.29/spl plusmn/0.10) and BION stimulation (1.46/spl plusmn/0.24). Also, walking speed is increased from 9.4/spl plusmn/0.4 m/min without stimulation to 19.6/spl plusmn/2.0 m/min with surface and 17.8/spl plusmn/0.7 m/min with BION stimulation. We conclude that functional electrical stimulation with BIONs is a practical alternative to surface stimulation and provides more selective control of muscle activation.

[1]  P. R. Troyk,et al.  Injectable microstimulator for functional electrical stimulation , 1991, Medical and Biological Engineering and Computing.

[2]  R B Stein,et al.  Application of tilt sensors in functional electrical stimulation. , 1996, IEEE transactions on rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society.

[3]  H. Kagaya,et al.  Clinical use of percutaneous intramuscular electrodes for functional electrical stimulation. , 1996, Archives of physical medicine and rehabilitation.

[4]  G. Loeb,et al.  Micromodular implants to provide electrical stimulation of paralyzed muscles and limbs , 1997, IEEE Transactions on Biomedical Engineering.

[5]  G E Loeb,et al.  Functional electrical stimulation using microstimulators to correct foot drop: a case study. , 2004, Canadian journal of physiology and pharmacology.

[6]  Marc Bélanger,et al.  Electrical stimulation for therapy and mobility after spinal cord injury. , 2002, Progress in brain research.

[7]  B. Andrews,et al.  Functional electric stimulation-assisted rowing: Increasing cardiovascular fitness through functional electric stimulation rowing training in persons with spinal cord injury. , 2002, Archives of physical medicine and rehabilitation.

[8]  R. Stein,et al.  Electrical stimulation: can it increase muscle strength and reverse osteopenia in spinal cord injured individuals? , 2000, Archives of physical medicine and rehabilitation.

[9]  E. Marsolais,et al.  Implantation techniques and experience with percutaneous intramuscular electrodes in the lower extremities. , 1986, Journal of rehabilitation research and development.

[10]  G E Loeb,et al.  BION system for distributed neural prosthetic interfaces. , 2001, Medical engineering & physics.

[11]  S C Gupta,et al.  Musculoskeletal responses of spinal cord injured individuals to functional neuromuscular stimulation-induced knee extension exercise training. , 1991, Journal of rehabilitation research and development.

[12]  R Kobetic,et al.  Percutaneous Implantation of Iliopsoas for Functional Neuromuscular Stimulation , 2001, Clinical orthopaedics and related research.

[13]  R. Triolo,et al.  Reliability of percutaneous intramuscular electrodes for upper extremity functional neuromuscular stimulation in adolescents with C5 tetraplegia. , 1994, Archives of physical medicine and rehabilitation.