“Ambulation by traumatic T4-12 paraplegics using functional neuromuscular stimulation”, Authors : Daniel Graupe, Ross Davies, Hubert Kodylewski, Kate H. Kohn, Critical Review Neurosurgery (1998) 8: 221-231, Springer-Verlag 1998.
1. “The Results of a 35 SCI Subject Experience with the Parastep™ I Walking System”. Authors: K. J. Klose, PhD, B. Needham-Shropshire OTR/L, N. H. Lebwohl MD, B. A. Green, MD. (The Journal of the American Paraplegia Society, April 1994).
Summary: This uncomplicated system is valuable to a significant portion of the paraplegic SCI population. Those individuals who are less successful can utilize the device as a physical conditioning exercise regimen. The cardiovascular and pulmonary demands placed on the individual ambulation are similar to those produced by strenuous exercise. Additionally, the benefits afforded by this activity surpass those attributed to passive standing devices.
2.“Physiologic costs of reciprocal gait in FES assisted walking”. Authors: P. Winchester, PhD, PT, J. J. Carollo, MS, PE, R. Habasevich, MS, PT. (Paraplegia 1994, Vol 32, Pgs 680-686; 1994 International Medical Society of Paraplegia).
Summary: This system was shown to provide comparable performance to the other orthotic options currently available, without the need for the bulky external braces common to hybrid systems. Regular use of the Parastep™ system after initial training can provide upright mobility at a reasonable walking velocity and energy cost. Whether the effort necessary to produce this level of performance is justified depends on the value one places on upright locomotion, and can only be determined on an individual basis.
3.“Functional Neuromuscular Stimulation for Mobility in People with Spinal Cord Injuries. The Parastep™ I System”. Author: Edward Chaplin, MD. (The Journal of Spinal Cord Medicine, 1995).
Summary: Study results indicate that computer-generated FNS to aid standing and reciprocal stepping is a clinically viable mobility orthotic in appropriately selected and trained individuals with spinal cord injury. Changes in self-esteem and disposition toward life were the most noteworthy benefits.
4.“Restoration of gait by functional electrical stimulation for spinal cord injured patients”. Authors: P Gallien, MD, R Brissot, MD, M Eyssette, L Tell, M Barat, L Wiart and H Petit. (Paraplegia 1995, Vol 33, Pgs 660-664; 1995 International Medical Society of Paraplegia).
Summary: This study presents results of 11 male and 2 female neurologically complete SCI patients. The Parastep™ is a reliable FES technology, which patients can easily learn (to use). The results of this study show a quick progression in the acquisition of gait performance, and
noticeable psychological benefits. The method is not indicated for all paraplegic people, and requires the subjects to be highly motivated. The small size (of the system), along with the good tolerance of the device, are related to the long term use by patients (more than 50% in this study). Improvement of the technology ought to permit better efficiency by improving gait speed, which at present is far from normal. Further evaluation is neede3de to know precisely the energy expenditure generated by this method, and to define the selective aspects of the gait cycle, for which this expenditure can be lowered, with, as a result, an increase in the gait.
5.“Metabolic Costs Differences on Paraplegics Walking with the Parastep™ System and the Steeper Advanced Reciprocating Gait Orthosis”. Authors: Cerrel-Bazo H. A., MD, Rizzetto A., PT, Pauletto D., PT, Brown S.W., PhD, JD, Caldana L., MD. (1996 Short Paper Report).
Summary: The present study demonstrates a higher oxygen consumption and a lower metabolic efficiency of the Parastep™ system users during the several testing conditions compared to the ARGO (Steeper Advanced Reciprocating Gait Orthosis) subjects. Compensatory cardio-ventilatory mechanisms are elicited and apparently good enough to support the higher metabolic demand of the Parastep™ users. Metabolic fatigue (RER) (respiratory exchange rate) is lower in the Parastep™ group and below anaerobic threshold. This walking system appears to be a good instrument to condition the cardiovascular and pulmonary system in some well selected and trained paraplegics under standard conditions.
6.“Paraplegics Electrically-induced Walking: Physical Endurance Capacity, Metabolic and Physiological Responses”. Authors: H Cerrel-Bazo, MD, A Rizzetto, PT, D Pauletto, PT, S W Brown, PhD, JD, A Bolner, DSc, M Franceschini, PT, R Bogoni, BSc, L Caldana, MD. (1996 Study Paper Report).
Summary: In both studies presented here, compensatory cardio-ventilatory mechanisms were elicited and this was apparently strong enough to support the higher metabolic demand of walking for the Parastep™ users. Standing with electrically-induced muscle contraction was not fatiguing and did not elicit any autonomic system dysfunction; vital signs were according to the body requirements. This walking system appears to be a good instrument to stress and condition the cardiovascular and pulmonary system in some well selected and trained paraplegics.
7.“Improved Central Cardiovascular Functioning of Paraplegics subsequent to Participation in an FNS Ambulation Programme”. Authors: P L Jacobs, PhD, M Nash, PhD, K J Klose, PhD, B Green, MD. (1997 Short Paper Report).
Summary: Study results indicated that mean VO2 peak increased significantly following training with a significant increase in exercise duration. Post-training sub-maximal HR and RER values were significantly lower at matched workloads with significantly greater SV values. There were no significant differences in cardiac output, VO2, or a-v02 difference throughout sub-maximal workloads. This data indicates that FNS ambulation training improves central cardiovascular functioning in paraplegics. This technology may offer therapeutic benefits to paraplegics with lessened potential for overuse injuries of the shoulders and elbows often associated with excessive upper extremity exercise.
8.“Electrically Induced Muscle Contraction to Assist Paraplegics Individuals on Walking: Patient Compliance”. Authors: Cerrel-Bazo H. A., MD, Rizzetto A., PT, Luca L., MD, Caldana L., MD. (Presentation: 10th European Congress of Physical Medicine and Rehabilitation, Rome, Italy, June 1-4, 1997).
Summary: This study analyzed and presented compliance data on 12 male and 3 female SCI subjects that completed their FES gait (training) program (FGP). Total length of time walking with the EIWS (electrically induced walking system) after the completion of FPG: 10-34 months. No drop-out rate. Conclusion: The Parastep™ system on well selected and trained SCI individuals has an excellent use compliance. The drop-out rate of good walkers so far is none. It can provide locomotion for short distances in a home environment situation, is commonly used as an exercise tool for the good cardio-pulmonary responses (and) improving most probably the self image and well being of these subjects.
9.“Evaluation of a Training Program for Persons with SCI Paraplegia Using the Parastep™ I Ambulation System: Part 1. Ambulation Performance and Anthropometric Measures”. Authors: K. John Klose, PhD, Patrick L. Jacobs, PhD, James G. Broton, PhD, Rosalind S. Guest, BPT, Belinda M. Needham-Shropshire, MS, PT, OTR, Nathan Lebwohl, MD, Mark S. Nash, PhD, Barth A. Green, MD. (Arch Phys Med Rehabil 1997; Vol 78, Pgs 789-793). Note: This is no. 1 of a 5 Part study.
Summary: Statistically significant changes in distance, time standing and walking, and pace were found. Increases in thigh and calf girth, thigh cross-sectional area, and calculated lean tissue, as well as a decrease in thigh skinfold measure, were all statistically significant. The Parastep I system enables persons with thoracic-level spinal cord injuries to stand and ambulate short distances but with a high degree of performance variability across individuals. The factors that influence this variability have not been completely identified.
10.“Evaluation of a Training Program for Persons with SCI Paraplegia Using the Parastep™ I Ambulation System: Part 2. Effects on Physiological Responses to Peak Arm Ergometry”. Authors: Patrick L. Jacobs, PhD, Mark S. Nash, PhD, K. John Klose, PhD, Rosalind S. Guest, BPT, Belinda M. Needham-Shropshire, MS, PT, OTR, Barth A. Green, MD. (Arch Phys Med Rehabil 1997; Vol 78, Pgs 794-798). Note: This is no. 2 of a 5 Part study.
Summary: Statistically significant increases in peak values for time to fatigue, peak power output, and peak VO2 (all, were observed. Heart rate was significantly lower throughout sub-peak levels of arm ergometry after the ambulation training (. Values of upper extremity strength were not significantly altered after training. FNS ambulation by persons with SCI paraplegia results in task-nonspecific training adaptations. Central cardiovascular adaptations were indicated as the primary source of these beneficial alterations in exercise responses.
11.“Evaluation of a Training Program for Persons With SCI Paraplegia Using the Parastep™ I Ambulation System: Part 3. Lack of Effect on Bone Mineral Density”. Authors: Belinda M. Needham-Shropshire, MS, PT, OTR, James G. Broton, PhD, K. John Klose, PhD, Nathan Lebwohl, MD, Rosalind S. Guest, BPT, Patrick L. Jacobs, PhD. (Arch Phys Med Rehabil 1997; Vol 78, Pgs 799-803). Note: This is no. 3 of a 5 Part study.
Summary: No significant change in bone mineral density was found using repeated measures analyses of variance, in 16 patients after 32 sessions of FNS training. Axial loading combined with muscle stimulation and resistive exercise does not result in significant changes in bone mineral density in persons with complete paraplegia.
12.“Evaluation of a Training Program for Persons With SCI Paraplegia Using the Parastep™ I Ambulation System: Part 4. Effect on Physical Self-Concept and Depression”. Authors: Rosalind S. Guest, BPT, K. John Klose, PhD, Belinda M. Needham-Shropshire, MS, PT, OTR, Patrick L. Jacobs, PhD. (Arch Phys Med Rehabil 1997; Vol 78, Pgs 804-807). Note: This is no 4 of a 5 Part study.
Summary: Following repeated measures analyses of variance, subsequent to the ambulation training program, a volunteer sample of 12 men and 3 women with paraplegia indicated desired directional and statistically significant increase in self-concept scores and decreases in depression scores.
13.“Evaluation of a Training Program for Persons with SCI Paraplegia Using the Parastep™ I Ambulation System: Part 5. Lower Extremity Blood Flow and Hyperemic Responses to Occlusion Are Augmented by Ambulation Training”. Authors: Mark S. Nash, PhD, Patrick L. Jacobs, PhD, Berta M. Montalvo, MD, K. John Klose, PhD, Rosalind S. Guest, BPT, Belinda M. Needham-Shropshire, MS, PT, OTR. (Arch Phys Med Rehabil 1997; Vol 78, Pgs 808-814). Note: This is no 4 of a 5 Part study. This is no 5 of a 5 Part study.
Summary: This study addresses the results attained from 11 male and 1 female subjects with complete SCI (Frankel A, ASIA A), aged 21 to 45 years of age, and with injury levels T4-T11. Exercise training using FNS ambulation increases the resting lower extremity AIV in individuals with paraplegia and augments the hyperemic response to vascular occlusion. Improved post-training blood flow is attributable both to vascular structural changes and up-regulation of vascular flow control mechanisms. Limb mass is associated with the volume of arterial blood flow.
14.“Relationships of oxygen uptake, heart rate, and ratings of perceived exertion in persons with paraplegia during FNS assisted ambulation”. Authors: Patrick L. Jacobs, PhD, K. John Klose, PhD, Rosalind Guest, BPT, Belinda Needham-Shropshire, MS, PT, OTR, James G. Broton, PhD, Barth A. Green, MD. (Spinal Cord 1997, Vol 35, Pgs 292-298; 1997 International Medical Society of Paraplegia).
Summary: This study suggests that RPE (ratings of perceived exertion) in not a valid indicator of intensity of effort for persons with paraplegia using an FNS ambulation system. Persons with SCI paraplegia are devoid of direct feedback from musculature below the point of injury and are therefore unable to accurately assess work effort levels during FNS ambulation. HR (heart rate) was confirmed to be an appropriate indicator of exercise intensity in this setting and therefore is an acceptable measure for use in field and experimental settings.
15.“Gait Performance on Paraplegics Deambulation Using an Electrical-Stimulation System Returning to a Usual Life-Environment”. Authors: Cerrel-Bazo H. A., MD, Rizzetto A., PT, Pauletto D., PT, Caldana L., MD. (Presentation: 36th Annual Scientific Meeting of the International Medical Society of Paraplegia, Innsbruck, Austria, May 14-16, 1997).
Summary: The purpose of this study was to evaluate the compliance of electrically induced walking (EIW) on 11 male and 3 female SCI subjects, who had completed a computer controlled exercise (CCE) and gait training program, and had returned to their usual activities of daily living and life situations. Conclusions: The Parastep™ system in well selected and trained SCI subjects can improve locomotion on usual life situations requiring short distances walk(ing), it appears an excellent tool for controlling poor to moderate spasticity, conditioning the cardio-pulmonary system, ameliorating most probably the self image an(d) well being of SCI subjects. All of these (facts) probably being the reason of the high degree (of) user compliance.
16.“Transcutaneous functional neuromuscular stimulation of certain traumatic complete thoracic paraplegics for independent short-distance ambulation”. Authors: Daniel Graupe, PhD, Kate H. Kohn, MD. (Neurological Research, 1997, Vol 19, June, Pgs 323-333).
Summary: Study results indicate that noninvasive FNS can allow certain traumatic complete thoracic-level paraplegics to get out of their wheelchairs and ambulate independently over short distances safely.
17.“Physical Endurance Capacity, Metabolic and Physiological Responses on paraplegics Electrically-Induced Walking”. Authors: H.A. Cerrel-Bazo, MD, A. Rizzetto, PT, D. Pauletto, PT, A. Bolner, DSc, R. Bogoni, BSc, L. Caldana, MD, S. W. Brown, PhD, JD. (Abstract Presentation: The 8th World Congress of the International Rehabilitation Medicine Association [IRMA VIII], Kyoto, Japan, Aug 31-Sep 4, 1997).
Summary: Study 1: The Parastep™ group showed higher statistically significant values for almost all the variables analyzed when compared to the ARGO (Steeper Advanced Reciprocating Gait Orthosis) group. At SPMS (self preferred maximum speed) for 45 minutes the Post-hoc analysis showed a higher metabolic efficiency for the Control group compared to the Parastep™ and ARGO groups. Study 2: During the walking condition, the metabolic and physiological responses were significantly higher for the Parastep™ group. Statistically significant differences were reported for lactic acid, O2-Pulse, ventilation and catecholamines, higher for the Parastep™ group. The Parastep™ group total sweat rate mean was 17.2 mL/h compared to 1.4 mL/h for the Control group. Recovery post walking data showed NO statistically significant differences between the Control and the Parastep™ group. The EIWS (Electrically Induced Walking System) in well selected and trained SCI subjects appears to be a good exercise tool that can allow some SCI paraplegics to perambulate for distances above ½ kilometer at speeds between 15-20 m/min.
18. “Assisting Paraplegic Individuals to Walk by Means of Electrically Induced Muscle Contraction: Gait Performance and Patient Compliance”. Authors: H.A. Cerrel-Bazo, MD, A. Rizzetto, PT, D. Pauletto, PT, L. Lucca, MD, L. Caldana, MD. (Abstract Presentation: The 8th World Congress of the International Rehabilitation Medicine Association [IRMA VIII], Kyoto, Japan, Aug 31-Sep 4, 1997).
Summary: Report is on 30 SCI subjects. 1. Drop-out rate: 4 SCI subjects; 2. Home environment walking: 14 SCI subjects. The average MCWD (maximum continuous walking distance) in meters at SPMS (self preferred maximum speed) prior to home departure was 442.28. The mean SPMS (m/min) was 14.5. The mean daily walking distance at home was 442.85. The mean daily walking time was 90.71 min; 3. FGP (final gait phase): 12 SCI subjects are in the final phase of the gait program; 4. Follow-up evaluation and cardiopulmonary and metabolic expenditure: 5 SCI were able to return to research facility. The treadmill MCWD at SPMS mean, in meters: 842.4. Mean treadmill maximum continuous walking time (min): 49.9. The EIWS (Electrically Induced Walking System) users were able to perform walking under the anaerobic threshold, O2 Pulse (b/min) mean: 10.53. O2 cost (mL/Kg.m) mean: 1.18, O2 rate (mL/Kg.min) mean: 20.38, % maximum heart rate mean: 73.95; 5. Total length of time walking with the EIWS after the completion of FGP: 14-39 months. No drop-out rate. Conclusion: The Parastep™ system on well selected and trained individuals has an excellent user compliance.
19.“SCI Walking by Means of FES Part One: Candidate Selection”. Authors: Cerrel-Bazo H.A., MD, Rizzetto A., PT. (1998 Study Paper Report).
Summary: 436 SCI subjects were medically evaluated between the years 1994 through September 1997. Data presented in this report is from 218 cases analyzed. Electrically induced walking on paraplegics is demanding in the metabolic, physiological and psychological sense, even though an SCI subject may appear a good candidate to participate (in) a FES program during the medical evaluation, is not until the patient is able to stand and produce a few steps of walking that we really (k)now how good of a candidate (they) will be. Stability of a SCI individual held up by means of FES depends not only on the forceful propulsion of the paralyzed muscle, but on the level of injury, the degree of spasticity, the response of the autonomic system, the degree of joint contractures and the weight of the patient. Medical evaluation and patient selection is very helpful to prevent false hope expectations or to understand motivation, to (p)revent not candidates to participate. (End of report received)
20.“SCI Walking by Means of FES Part two: Physiological Responses of Good Walkers”. Authors: Cerrel-Bazo H.A., MD, Rizzetto A., PT. (1998 Study Paper Report).
Summary: Data presented in this 2-study report are, in Study 1, of 2 paralyzed male and 1 paralyzed female individuals and compared with data from 2 male and 1 female non-paralyzed individuals. Levels according to ASIA standards were T5-T8; and in Study 2, 2 male paraplegics (a T8 SCI and a T5-6 SCI-Transverse Myelitis) and two sedentary non-paralyzed male nurses. In both studies, the following variables showed statistically significant differences: VE, VO2, MET, Kcal, between the two groups with the EIWS (Electrically Induced Walking System) values significantly higher (double) than the Control group. RER (respiratory exchange rate) did not approach statistical significance, so no significant differences were found between both groups. The sweating rates (Gr/cm2) measurement was sensitive for values equal or above 0.001 Gr/cm2. During the walking condition, EIWS users’ total sweating rates mean was high (17.2 ml/h) compared to 1.4 ml/h for the control group. In both studies compensatory Cardio-Ventilatory mechanisms were elicited and this was apparently strong enough to support the higher metabolic demand of walking with the EIWS. (End of report received)
21.“SCI Walking by Means of FES Part Three: Reintegration to Home Environment and User Compliance”. Authors: Cerrel-Bazo H.A., MD, Rizzetto A., PT. (1998 Study Paper Report).
Summary: This study analyzed data from interviews conducted with 12 male and 3 female subjects, mean age 34.41 years old, with SCI levels C8-T1 to T8-9. The average maximum continuous walking distance (MCWD) (m) at self selected maximum speed (SPMS) prior to home departure was 444.28 sd: 325.33 meters; the average SPMS (m/min) 14.5 sd: 3.83; the mean daily walking distance at home (m) was 442.85 sd:359; the mean daily walking time (min) was 90.17 sd: 49.91. Two subjects were wheelchair free outside (the) home. 55% uses the EIWS (electrically induced walking system) for short distances locomotion. 90% uses the EIWS as an exercise tool. One subject uses the EIWS 10 minutes per month.
22.“Functional neuromuscular stimulator for short-distance ambulation by certain thoracic-level spinal-cord-injured paraplegics”. Authors: Graupe D., PhD, Kohn K.H., MD. (Surgical Neurology, 1998 Sep, Vol 50(3), Pages 202-207).
Summary: Approximately 400 patients have used the Parastep™ system, essentially all achieving standing and at least 30 feet of ambulation, with a few reaching as much as 1 mile at a time. Recent literature presents data on the medical benefits of using the Parastep™ system, beyond the exercise benefits of short distance ambulation at will, such as increased blood flow to the lower extremities, lower HR at sub-peak work intensities, increased peak work capability, reduced spasticity, and psychological benefits. The authors believe that the Parastep™ FNS system, which is presently commercially available by prescription, is easily usable for independent short-distance ambulation. The authors further believe that its exercise benefits and its other medical and psychological benefits, as discussed, make it an important option for thoracic level traumatic paraplegics.
23.“A 6 Year Clinical Experience of a Transcutaneous Neuroprosthesis for Exercise, Standing and Walking”. Authors: H.A. Cerrel-Bazo, MD, A. Rizzetto, PT, D. Pauletto, PT, C. Parise, E. Cora, R. Bogoni, BSc, A. Bolner, DSc, S. W. Brown, PhD, JD. (Presentation: 39th Annual Scientific Meeting of the International Medical Society of Paraplegia, Sydney, Australia, Nov 2-5, 2000).
Summary: This study analyzed and summarized the metabolic and physiological responses, and determined the energy efficiency and performance in standing and walking by means of a transcutaneous FES system (TFES) of 53 paraplegic and 3 tetraplegic motor complete SCI subjects, following a computer-controlled FES exercise (CCE) program and a gait training program (GTP). Conclusions: Well selected and trained SCI (subjects) can stand and walk by TFES. Treadmill-walking at a constant speed is metabolic demanding. Good TFES walkers adapt their cardio-pulmonary responses to the physical effort. Good standing (and) walking performances appear to be correlated to a higher metabolic efficiency, which may be indirectly proportional to daily changes of the non linear SCI system. TFES standing and walking is a good active physical therapy on well selected SCI subjects.
24.“An overview of the state of the art of noninvasive FES for independent ambulation by thoracic level paraplegics”. Author: Graupe D., PhD. (Neurological Research, 2002 Jul, Vol 24(5), Pgs 431-442).
Summary: A totally noninvasive FES system for independent standing and mobility is presently a viable possibility for complete upper-motor-neuron thoracic-level traumatic paraplegics, which is FDA-approved. Commercially available training programs exist where, upon completion, ambulation distances average 444 m per walk in a four-months daily-training program or 115 m per walk in a 33-session, 11 week program. Medical benefits have been documented, in terms of greatly increased blood flow to the lower extremities, reduced spasticity, reduced incidence of decubiti, and increased thigh circumference. Also, psychological benefits were documented, with significantly improved physical self-concept and significantly reduced depression scores.
25.“The Status of Noninvasive Functional Electrical Stimulation and Ambulation Performance for Thoracic-Level Complete Paraplegics”. Author: Daniel Graupe, PhD. (International Journal of Bioelectromagnetism – IJBEM, 2005 Jun, Vol 7, No 1).
Summary: This paper concludes that a totally non-invasive FES for independent standing and mobility system is presently a reality today for complete upper-motor-neuron thoracic level traumatic paraplegics. Furthermore, one such ambulation system, the Parastep™ FES system, is commercially available, having received FDA approval in 1994. It has also received (2002) approval for reimbursement by the Center for Medicare and Medicaid Services (CMS) that regulates Medicare and Medicaid reimbursements policies in the USA and subsequently by practically all medical insurance companies in the USA. Still, even 10 years after FDA approval and 2 years after reimbursement was approved by Medicare, Medicaid and by most insurers, there is a great ignorance in the paraplegic community about the availability of such a system, and of its performance and benefits. This indicates ignorance regarding the role of FES in paraplegia among physicians involved in the caring of paraplegics and among the physical and occupational therapists, and other related staff. The circulatory benefits and the other medical and psychological benefits should play an important role for patients, for physicians and for insurance companies involved in the care of paraplegics.
26.“Complete T1/T2 Level Traumatic Paraplegia: Evaluation of short-Distance Walking By Transcutaneous FES”. Author: Daniel Graupe, PhD. (Neurological Research, 2007 Jul, Special Section on FES, Vol 30).
27.“Performance and Training for Walking with FES”. Authors: Graupe D, PhD, Cerrel-Bazo H., MD. (Journal of Basic and Applied Myology, Vol 17, Pgs 129-132, 2007).
Summary: This paper summarizes and tabulates the reported results of ambulation performance, interpreted by average walking distances (m/walk) and average speed (m/min), as relate to two different training methods, one, at Vicenza, Italy (14 patients), comprising 4 months of daily training, including considerable muscle-strengthening routines using treadmill exercises, the second, at the Miami School of Medicine, The Miami Project to Cure Paralysis (16 patients), being of 11 weeks of training, 3 one-hour sessions per week.
28.“Walking Performance, medical outcomes and patient training in FES of innervated muscles for ambulation by thoracic-level complete paraplegics”. Authors: Graupe D, PhD, Cerrel-Bazo H., MD, Carraro U., MD. (Neurological Research, 2008 Mar, Vol 30(2), Pgs 123-130).
Summary: Published works in literature reviewed in this paper report average walking distance of 440 m/walk when major muscle reinforcement and preconditioning cardiovascular and respiratory systems precedes gait training, versus average 115 m/walk when undergoing direct gait training. Medical, metabolic and psychologic outcomes, as reported in several works, point to benefits of FES walking, including 60% increase in blood flow to lower extremities. Myofiber tissues of patients with upper motor neuron paralysis compare well with those of normal tissue even many years post-injury, while adipose tissue substitute muscle fibers in patients with lower motor neuron lesions.