電刺激踩車已經成為一種替代行走訓練的方法，主要幫助對象通常是伴隨著不對稱的行走模式的中風病人，這是由於半邊偏癱所造成的。為了去評估肌肉活化的對稱性，肌電圖和踩車表現已被用來當成評估工具，然而在踩車過程中，給予肌肉電刺激適當的角度卻沒有一致的結果。同樣地，在電刺激踩車下，肌肉收縮是由自主收縮與外部電刺激兩個不同的來源所產生。因此本研究目的就是使用濾波的方法將自主肌電訊號給分離出來並且利用死點來找到適當的電刺激角度。我們的梳狀濾波器可以將自主肌電訊號從混合肌電訊號中給分離出來，並且利用遮斷電路來減少邊界效應。形狀對稱參數和面積對稱參數可以藉由肌電訊號來取得，並用其來當作評估踩車表現的工具。病人分別被要求在四種情形下進行踩車兩分鐘，並在踩車過程的前後各收下一段踩車的表現，利用踩車表現觀看前後的差異性。這四種情形分別是踩車不配合電刺激，踩車搭配固定角度給予電刺激，以及踩車配合死點找到的電刺激角度給予電刺激，和踩車搭配連續電刺激。其結果顯示病人在經過兩分鐘的訓練後，前後踩車的表現出現了一些改變，尤其是利用死點找到電刺激角度尤為明顯。未來可以利用死點來找到每一位中風病患最適當給予電刺激的角度，並且利用濾波的技術來取得病患的自主肌電訊號，進而為病患量身打造最適當的訓練模式。

Electrical stimulation (ES)-induced cycling has been developed as an alternative method of gait training for stroke patients usually exhibit asymmetrical movement patterns due to hemiparesis. To evaluate the asymmetry of muscle activity, electromyography (EMG) and biomechanical observation of cycling smoothness have been developed as assessment tools. However, there is no consensus agreement on the exact stimulation patterns, ranges of stimulation for each muscle. Also, the EMG signal during ES has been a combination of volitional muscle activation (volitional EMG) and ES-induced muscle activity (stimulus EMG). Thus, the aims of the study are to utilize filtering technique to separate volition and stimulus EMG during FES cycling and to derive the ES patterns from the dead spots, the decreased cycle speed during one cycle of pedaling. Our comb filtering approach by separating the filtering process to raw EMG and stimulus EMG can significantly reduce the edge effect after appropriate blocking circuit. The shape symmetry index (SSI) and area symmetry index (ASI), obtained from EMG underwent comb filter and linear envelops (LE) representation, were used to quantify the level of symmetry and motor performances. We also compared four testing conditions of free cycling, ES at pre-defined stimulation patterns, pattern defined from dead spots, and ES of entire cycle. Our pilot study on stroke patients indicate that there were some evident changes in two-minute of immediate training observed from SSI and ASI indices, especially in the ES-shifted training scheme. It is expected that a simple ES patterns den be derived simply from dead spots which can be combined with filtered EMG for providing sufficient information for designing individual-tailored stimulation pattern and training schemes for stroke patients in the future ES-induced cycling training protocol.

[1] C. W. Peng, S. C. Chen, C. H. Lai, C. J. Chen, C. C. Chen, J. Mizrahi, and Y. Handa, "Review: Clinical Benefits of Functional Electrical Stimulation Cycling Exercise for Subjects with Central Neurological Impairments," J Med Biol Eng, vol. 31, pp. 1-11, 2011.
[2] H. Y. Chen, S. C. Chen, J. J. J. Chen, L. L. Fu, and Y. L. Wang, "Kinesiological and kinematical analysis for stroke subjects with asymmetrical cycling movement patterns," J Electromyogr Kinesiol, vol. 15, pp. 587-595, 2005.
[3] J. J. J. Chen, N. Y. Yu, D. G. Huang, B. T. Ann, and G. C. Chang, "Applying fuzzy logic to control cycling movement induced by functional electrical stimulation," IEEE Trans Rehabil Eng, vol. 5, pp. 158-169, 1997.
[4] J. Szecsi, C. Krewer, F. Muller, and A. Straube, "Functional electrical stimulation assisted cycling of patients with subacute stroke: kinetic and kinematic analysis," Clin Biomech (Bristol, Avon), vol. 23, pp. 1086-94, Oct 2008.
[5] I. S. Hwang, H. M. Lee, R. J. Cherng, and J. J. J. Chen, "Electromyographic analysis of locomotion for healthy and hemiparetic subjects—study of performance variability and rail effect on treadmill," Gait Posture, vol. 18, pp. 1-12, 2003.
[6] B. S. Shenkman, E. V. Lyubaeva, D. V. Popov, A. I. Netreba, Y. R. Bravy, P. P. Tarakin, Y. S. Lemesheva, and O. L. Vinogradova, "Chronic effects of low-frequency low-intensity electrical stimulation of stretched human muscle," Acta Astronautica, vol. 60, pp. 505-511, 2007.
[7] E. Langzam, Y. Nemirovsky, E. Isakov, and J. Mizrahi, "Partition between volitional and induced forces in electrically augmented dynamic isometric muscle contractions," IEEE Trans Neural Syst Rehabil Eng, vol. 14, pp. 322-335, 2006.
[8] Y. Hara, "Neurorehabilitation with new functional electrical stimulation for hemiparetic upper extremity in stroke patients," J Nihon Med Sch, vol. 75, pp. 4-14, Feb 2008.
[9] E. Ambrosini, S. Ferrante, A. Pedrocchi, G. Ferrigno, and F. Molteni, "Cycling induced by electrical stimulation improves motor recovery in postacute hemiparetic patients: a randomized controlled trial," Stroke, vol. 42, pp. 1068-73, Apr 2011.
[10] S. Ferrante, A. Pedrocchi, G. Ferrigno, and F. Molteni, "Cycling induced by functional electrical stimulation improves the muscular strength and the motor control of individuals with post-acute stroke. Europa Medicophysica-SIMFER 2007 Award Winner," Eur J Phys Rehabil Med, vol. 44, p. 159, 2008.
[11] E. Langzam, E. Isakov, and J. Mizrahi, "Evaluation of methods for extraction of the volitional EMG in dynamic hybrid muscle activation," J Neuroeng Rehabil, vol. 3, p. 27, 2006.
[12] E. Langzam, Y. Nemirovsky, E. Isakov, and J. Mizrahi, "Muscle enhancement using closed-loop electrical stimulation: Volitional versus induced torque," J Electromyogr Kinesiol, vol. 17, pp. 275-284, 2007.
[13] H. C. Lo, K. H. Tsai, F. C. Su, G. L. Chang, and C. Y. Yeh, "Effects of a functional electrical stimulation-assisted leg-cycling wheelchair on reducing spasticity of patients after stroke," J Rehabil Med, vol. 41, pp. 242-246, 2009.
[14] L. R. Sheffler and J. Chae, "Neuromuscular electrical stimulation in neurorehabilitation," Muscle Nerve, vol. 35, pp. 562-590, 2007.
[15] C. Frigo, M. Ferrarin, W. Frasson, E. Pavan, and R. Thorsen, "EMG signals detection and processing for on-line control of functional electrical stimulation," J Electromyogr Kinesiol, vol. 10, pp. 351-60, Oct 2000.
[16] A. E. Hines, P. E. Crago, G. J. Chapman, and C. Billian, "Stimulus artifact removal in EMG from muscles adjacent to stimulated muscles," J Neurosci Methods, vol. 64, pp. 55-62, 1996.
[17] H. C. Lo, K. H. Tsai, F. C. Su, and C. Y. Yeh, "Functional Electrical Stimulation Cycling Wheelchair for Stroke Patients: Design and Preliminary Evaluation Results," Journal of Medical and Biological Engineering, vol. 31, pp. 295-300, 2011.
[18] M. Gfohler, T. Angeli, T. Eberharter, P. Lugner, W. Mayr, and C. Hofer, "Test bed with force-measuring crank for static and dynamic investigations on cycling by means of functional electrical stimulation," IEEE Trans Neural Syst Rehabil Eng, vol. 9, pp. 169-80, Jun 2001.
[19] K. Hunt, C. Ferrario, S. Grant, B. Stone, A. McLean, M. Fraser, and D. Allan, "Comparison of stimulation patterns for FES-cycling using measures of oxygen cost and stimulation cost," Medical engineering & physics, vol. 28, pp. 710-718, 2006.
[20] E. Idsø, T. Johansen, and K. Hunt, "Finding the metabolically optimal stimulation pattern for FES-cycling," Power [W], vol. 10, p. 14, 2004.
[21] J. Petrofsky, "New algorithm to control a cycle ergometer using electrical stimulation," Medical and Biological Engineering and Computing, vol. 41, pp. 18-27, 2003.
[22] J. S. Petrofsky, C. A. Phillips, J. Almeyda, R. Briggs, W. Couch, and W. Colby, "Aerobic trainer with physiological monitoring for exercise in paraplegic and quadriplegic patients," Journal of Clinical Engineering, vol. 10, p. 307, 1985.
[23] D. Pons, C. Vaughan, and G. Jaros, "Cycling device powered by the electrically stimulated muscles of paraplegics," Medical and Biological Engineering and Computing, vol. 27, pp. 1-7, 1989.
[24] J. Rasmussen, S. T. Christensen, M. Gföhler, M. Damsgaard, and T. Angeli, "Design optimization of a pedaling mechanism for paraplegics," Structural and Multidisciplinary Optimization, vol. 26, pp. 132-138, 2004.
[25] K. Chen, S. C. Chen, K. H. Tsai, J. J. J. Chen, N. Y. Yu, and M. H. Huang, "An improved design of home cycling system via functional electrical stimulation for paraplegics," International journal of industrial ergonomics, vol. 34, pp. 223-235, 2004.
[26] J. Mizrahi, M. Levy, H. Ring, E. Isakov, and A. Liberson, "EMG as an indicator of fatigue in isometrically FES-activated paralyzed muscles," IEEE Trans Rehabil Eng, vol. 2, pp. 57-65, 1994.
[27] J. J. Chen, N. Y. Yu, D. G. Huang, B. T. Ann, and G. C. Chang, "Applying fuzzy logic to control cycling movement induced by functional electrical stimulation.," IEEE Trans Rehabil Eng., vol. 5, pp. 158-69, 1997.
[28] E. Idsø, B. Saunders, L. Duffell, T. Johansen, and K. Hunt, "Quantitative assessment of force distribution for FES cycling," in 11th Annual Conference of the International FES Society Zao, Japan, September 2006.