Locomotor pattern in paraplegic patients: training effects and recovery of spinal cord function

Abstract

Recent studies have shown that a locomotor pattern can be induced and utilized by paraplegic patients under conditions of body unloading using a moving treadmill. The present study investigated the behaviour of the locomotor pattern and also the relationship of its development to the spontaneous recovery of spinal cord function assessed by clinical and electrophysiological (tibial nerve somatosensory evoked potentials and motor evoked potentials) examinations. The earliest time that spinal locomotor activity could be induced was when signs of spinal shock had disappeared. This activity was distinct from spinal stretch re¯ex activity. In complete paraplegic patients the locomotor pattern improved spontaneously without training. This was coincident with both an increase of gastrocnemius electromyographic activity during the stance phase of gait and a decrease of body unloading. These eects reached a plateau after about 5 weeks. In complete and incomplete paraplegic patients a near linear increase of gastrocnemius electromyographic activity occurred during the stance phase of a step cycle with daily locomotor training over the whole training period of 12 weeks. This was also coincident with a signi®cant decrease of body unloading. In contrast to this, neither clinical nor electrophysiological examination scores improved after the onset of training in both patient groups. Only in incomplete paraplegic patients was there recovery, albeit statistically insigni®cant, of spinal cord function according to the sensory and motor scores obtained in the neurological examination during the time period before onset of training. An improvement of locomotor function by training was also seen in patients with paraplegia due to a cauda lesion. Such training eects on muscles and tendons could be separated from those on the spinal locomotor centres. The ®ndings of this study may be relevant for the future clinical treatment of paraplegic patients.

Body weight-supported treadmill training in chronic incomplete spinal cord injury: a pilot study evaluating functional health status and quality of life

“…This has prompted further studies of TT during rehabilitation or long thereafter, be it in quasi-or pre-experimental designs. [3][4][5][6][7][8] In most cases, the patient walks/steps on a treadmill while being suspended in a harness that provides a certain amount of body weight support (BWS). Most studies have reported restoration of patient's ability to walk (on the treadmill) and a gradual reduction of the need for BWS.…”

“…Most studies have reported restoration of patient's ability to walk (on the treadmill) and a gradual reduction of the need for BWS. [3][4][5][6][7][8] These encouraging results are generally attributed to the plasticity and adaptive capacity of the spinal cord below the lesion, in which the so-called 'Central Pattern Generator' plays a pivotal role. 9 Up to now, the effectiveness of TT combined with BWS in patients with an ISCI has been almost exclusively evaluated at the level of body functions, 10 mostly by electromyography or measuring speed and BWS on the treadmill.…”

Electrophysiological recordings in patients with spinal cord injury: significance for predicting outcome

“…In studies using SSEP and MEP recordings it could be shown that functional recovery is not in parallel with recovery of spinal impulse transmission. 55 Tibial SSEP in incomplete SCI patients at an acute, post acute (6 months after trauma) and chronic (46 months after trauma) stage showed no improvement of pathological SSEP, although the patients showed a signi®cant functional improvement. The same was true for MEP recordings: the prolonged latencies did not recover, while the amplitudes showed some increment (Figure 2).…”

Parallel facilitatory reflex pathways from the foot and hip to flexors and extensors in the injured human spinal cord

“…Analogously, afferents originating from the foot sole delay the initiation of swing and inhibit long latency flexion reflexes promoting stance (Duysens and Pearson, 1976;Conway et al, 1995). Although specific afferents or neuronal pathways have not been identified in humans, hip-mediated sensory signals affect the walking pattern of spinal injured people by enhancing the swing phase (Dietz et al, 1998(Dietz et al, ,2002, while input from the foot sole acting either in isolation or in combination with input from the hip affect reflexly mediated motor behavior (Knikou and Conway, 2001;Knikou, 2007a;Knikou et al, 2006b).…”

“…Evidence from studies conducted in lower vertebrates (Andersson and Grillner, 1983;Kriellaars et al, 1994;Hiebert et al, 1996;Lam and Pearson, 2001) suggest that this input accesses circuits responsible for walking contributing to phase transition and swing initiation. Blocking of the knee joint during human walking fails to alter the soleus H-reflex modulation pattern (Schneider et al, 2000), while pronounced hip extension enhances the swing phase during assisted walking in human SCI (Dietz et al, 1998(Dietz et al, ,2002. Further, sensory signals mediating static hip angle and sensation from the foot sole interact and induce a hip-dependent graded facilitation of the soleus H-reflex and tibialis anterior (TA) non-nociceptive flexion reflex in people with intact or injured spinal cord at rest (Knikou and Rymer, 2002;Knikou, 2005;Knikou et al, 2006b).…”