Locomotor step training with body weight support improves respiratory motor function in individuals with chronic spinal cord injury

Respir Physiol Neurobiol, 2013 · DOI: 10.1016/j.resp.2013.08.018 · Published: December 1, 2013

Spinal Cord Injury Pulmonology Rehabilitation

Simple Explanation

Spinal cord injury (SCI) alters the control of respiratory muscles innervated below level of injury so as to cause weakness, paralysis and spasticity, leading to, among other problems, respiratory insufficiency which significantly impedes recovery and diminishes quality of life. Exercise programs involving limb muscles are known to increase fitness and improve ventilatory function in individuals with SCI. This study was designed to examine the effects of the LT, specifically the neuroplastic changes that might be induced, as physiologically measured by a surface electromyographic (sEMG) method to evaluate spinal motor output to the muscles of respiration.

Study Duration

Not specified

Participants

8 individuals with chronic C3-T12 SCI

Evidence Level

Prospective case-controlled clinical study

Key Findings

1
FVC, FEV1, PImax, PEmax, amount of overall sEMG activity and rate of motor unit recruitment were significantly increased after LT (p<0.05)
2
The overall amount of sEMG activity represented as Mag values was significantly increased after LT for all tasks
3
The rate of motor unit recruitment, measured as the raising slope of the sEMG envelope during expiratory tasks, was lower and more variable within the SCI group than among NI control subjects

Research Summary

This prospective case-controlled clinical study was undertaken to investigate to what extent the manually assisted treadmill stepping Locomotor Training with body weight support (LT) can change respiratory function in individuals with chronic Spinal Cord Injury (SCI). Pulmonary function outcomes (Forced Vital Capacity /FVC/, Forced Expiratory Volume one second /FEV1/, Maximum Inspiratory Pressure /PImax/, Maximum Expiratory Pressure /PEmax/) and surface electromyographic (sEMG) measures of respiratory muscles activity during respiratory taskswere obtained from eight individuals with chronic C3-T12 SCI before and after 62±10 (Mean ± SD) sessions of the LT. LT significantly improves pulmonary function in individuals with chronic SCI. These improvements are likely the result of neuroplastic changes in spinal neural circuitry responsible for the activation of respiratory muscles preserved after injury.

Practical Implications

Rehabilitation Strategy

Locomotor training can be incorporated as a rehabilitation strategy to improve respiratory function in individuals with chronic SCI.

Neuroplasticity Insights

The study provides insights into neuroplastic changes in spinal neural circuitry related to respiratory muscle activation after locomotor training.

Personalized Training

Further research is needed to determine the degree to which motor control of respiration and respiratory muscle function can be improved through physical training and to elucidate the mechanisms of such improvements.

Study Limitations

1
Small sample size
2
The study does not provide a direct means of separating the effects of alterations in muscular and neural factors in response to the LT.
3
One individual (D20) with considerable post-traumatic dystonia (McKay et al., 2011) of the trunk muscles did not reveal such increased respiratory function.

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