Degradation of neuronal function following a spinal cord injury: mechanisms and countermeasures.

The aim of this study was to evaluate the course of spinal neuronal activity following spinal cord injury (SCI). In patients with a complete SCI, the leg muscle EMG activity early and up to 33 years after an SCI was analysed during locomotor movements induced and assisted by a driven gait orthosis (DGO). Only in chronic SCI patients did a premature exhaustion of neuronal activity occur. This was reflected in a reduced density and fading of leg muscle EMG activity. The early exhaustion of EMG activity was more pronounced in the leg flexor (e.g. biceps femoris) than extensor (e.g. gastrocnemius) muscles. The timing of the leg muscle pattern remained unchanged in the chronic patients. A preserved amplitude of motor action potentials following repetitive peripheral nerve stimulation and during spasms indicated an interneuronal site of impairment. In patients who participated in a locomotor training programme lasting up to 13 weeks, no positive effect on the slope of exhaustion was seen. It is concluded that a degradation of spinal neuronal activity takes place following an SCI. If in the future regeneration of spinal tract fibres becomes feasible in patients with complete SCI, such an approach can only become functionally successful if neuronal activity below the level of the lesion is maintained. This might be achieved by a continuous training approach starting early after injury.

[1]  M. Dimitrijevic,et al.  Studies of spasticity in man. 4. Changes in flexion reflex with repetitive cutaneous stimulation in spinal man. , 1970, Brain : a journal of neurology.

[2]  A. Lundberg,et al.  Interneurones in the spinal cord , 1981, Trends in Neurosciences.

[3]  R. J. Gregor,et al.  Effects of training on the recovery of full-weight-bearing stepping in the adult spinal cat , 1986, Experimental Neurology.

[4]  A Roby-Brami,et al.  Long-latency spinal reflex in man after flexor reflex afferent stimulation. , 1987, Brain : a journal of neurology.

[5]  R. J. Gregor,et al.  Weight-bearing hindlimb stepping in treadmill-exercised adult spinal cats , 1990, Brain Research.

[6]  R. Harris-Warrick,et al.  Modulation of neural networks for behavior. , 1991, Annual review of neuroscience.

[7]  V R Edgerton,et al.  Potential of adult mammalian lumbosacral spinal cord to execute and acquire improved locomotion in the absence of supraspinal input. , 1992, Journal of neurotrauma.

[8]  A. Wernig,et al.  Laufband locomotion with body weight support improved walking in persons with severe spinal cord injuries , 1992, Paraplegia.

[9]  S. Rossignol,et al.  Enhancement of locomotor recovery following spinal cord injury. , 1994, Current opinion in neurology.

[10]  V. Dietz,et al.  Locomotor activity in spinal man , 1994, The Lancet.

[11]  P. Katz.  Intrinsic and extrinsic neuromodulation of motor circuits , 1995, Current Opinion in Neurobiology.

[12]  A. Wernig,et al.  Laufband Therapy Based on‘Rules of Spinal Locomotion’is Effective in Spinal Cord Injured Persons , 1995, The European journal of neuroscience.

[13]  P. S. Dickinson,et al.  Interactions among neural networks for behavior , 1995, Current Opinion in Neurobiology.

[14]  V. Dietz,et al.  Locomotor capacity of spinal cord in paraplegic patients , 1995, Annals of neurology.

[15]  E. Garcia-Rill,et al.  Effects of exercise and fetal spinal cord implants on the H-reflex in chronically spinalized adult rats , 1996, Brain Research.

[16]  M. Schwab,et al.  Degeneration and regeneration of axons in the lesioned spinal cord. , 1996, Physiological reviews.

[17]  V. Dietz,et al.  Locomotion in patients with spinal cord injuries. , 1997, Physical therapy.

[18]  R. Waters,et al.  International Standards for Neurological and Functional Classification of Spinal Cord Injury , 1997, Spinal Cord.

[19]  Carlo J. De Luca,et al.  The Use of Surface Electromyography in Biomechanics , 1997 .

[20]  F Mauguière,et al.  Clinical use of polysynaptic flexion reflexes in the management of spasticity with intrathecal baclofen. , 1997, Electroencephalography and clinical neurophysiology.

[21]  Graham H. Creasey,et al.  International Standards for Neurological and Functional Classification of Spinal Cord Injury. American Spinal Injury Association. , 1997 .

[22]  B. Dobkin,et al.  Human lumbosacral spinal cord interprets loading during stepping. , 1997, Journal of neurophysiology.

[23]  E. Bizzi,et al.  Motor systems , 1997, Current Opinion in Neurobiology.

[24]  V R Edgerton,et al.  Use-dependent plasticity in spinal stepping and standing. , 1997, Advances in neurology.

[25]  V R Edgerton,et al.  Full weight-bearing hindlimb standing following stand training in the adult spinal cat. , 1998, Journal of neurophysiology.

[26]  V R Edgerton,et al.  Locomotor capacity attributable to step training versus spontaneous recovery after spinalization in adult cats. , 1998, Journal of neurophysiology.

[27]  H. Ogata,et al.  EFFECT OF ACTIVITIES OF DAILY LIVING ON FIBER TYPE ATROPHY OF THE VASTUS LATERALIS MUSCLE IN PATIENTS WITH JOINT DISORDERS , 1998, American journal of physical medicine & rehabilitation.

[28]  E. Ling,et al.  Transsynaptic changes of neurons and associated microglial reaction in the spinal cord of rats following middle cerebral artery occlusion , 1998, Neuroscience Letters.

[29]  Kimitaka Nakazawa,et al.  Phase-dependent electromyographic activity of the lower-limb muscles of a patient with clinically complete spinal cord injury during orthotic gait , 1998, Experimental Brain Research.

[30]  Chein-wei Chang,et al.  EVIDENT TRANSSYNAPTIC DEGENERATION OF MOTOR NEURONS AFTER SPINAL CORD INJURY: A Study of Neuromuscular Jitter by Axonal Microstimulation , 1998, American journal of physical medicine & rehabilitation.

[31]  V. Dietz,et al.  Treadmill training of paraplegic patients using a robotic orthosis. , 2000, Journal of rehabilitation research and development.

[32]  N. Chino,et al.  Physiologic decrease of single thenar motor units in the F-response in stroke patients. , 2000, Archives of physical medicine and rehabilitation.

[33]  Locomotion in Patients with Spinal Cord Injury , 2000 .

[34]  A Curt,et al.  From spinal shock to spasticity , 2000, Neurology.

[35]  K G Pearson,et al.  Neural adaptation in the generation of rhythmic behavior. , 2000, Annual review of physiology.

[36]  V. Dietz,et al.  Long term effects of locomotor training in spinal humans , 2001, Journal of neurology, neurosurgery, and psychiatry.

[37]  Ariel Miller,et al.  From spinal shock to spasticity , 2001 .

[38]  V. Dietz,et al.  Driven gait orthosis for improvement of locomotor training in paraplegic patients , 2001, Spinal Cord.

[39]  Martin E. Schwab,et al.  Plasticity of motor systems after incomplete spinal cord injury , 2001, Nature Reviews Neuroscience.

[40]  V. Dietz.  Proprioception and locomotor disorders , 2002, Nature Reviews Neuroscience.

[41]  L. Martin,et al.  Axonal transection in adult rat brain induces transsynaptic apoptosis and persistent atrophy of target neurons. , 2002, Journal of neurotrauma.

[42]  V. Dietz,et al.  Locomotor activity in spinal man: significance of afferent input from joint and load receptors. , 2002, Brain : a journal of neurology.

[43]  G. Raisman.  A promising therapeutic approach to spinal cord repair. , 2003, Journal of the Royal Society of Medicine.

[44]  V. Dietz,et al.  Effectiveness of automated locomotor training in patients with chronic incomplete spinal cord injury: a multicenter trial. , 2005, Archives of physical medicine and rehabilitation.