Elsevier

Gait & Posture

Volume 32, Issue 2, June 2010, Pages 199-204
Gait & Posture

Effects of robot-driven gait orthosis treadmill training on the autonomic response in rehabilitation-responsive stroke and cervical spondylotic myelopathy patients

https://doi.org/10.1016/j.gaitpost.2010.04.010Get rights and content

Abstract

Body weight supported treadmill training (BWSTT) assisted with a robotic-driven gait orthosis is utilized in rehabilitation of individuals with lost motor skills. A typical rehabilitation session included: sitting, standing, suspension, robotic-assisted walking at 1.5 and 2.5 km/h, respectively with 50% body weight support and recovery. While the effects of robotic-assisted BWSTT on motor performances were deeply studied, the influences on the cardiovascular control are still unknown.

The aim of the study was to evaluate in stroke (ST) and cervical spondylotic myelopathy (CSM) patients: (1) the autonomic response during a traditional robotic-assisted BWSTT session of motor rehabilitation; (2) the effects of 30 daily sessions of BWSTT on cardiovascular regulation. The autonomic response was assessed through symbolic analysis of short-term heart rate variability in 11 pathologic subjects (5 ST and 6 CSM patients) whose motor skills were improved as a result of the rehabilitation therapy.

Results showed variable individual responses to the rehabilitation session in ST patients at the beginning of the therapy. At the end of the rehabilitation process, the responses of ST patients were less variable and more similar to those previously observed in healthy subjects. CSM patients exhibited an exaggerated vagal response to the fastest walking phase during the first rehabilitative session. This abnormal response was limited after the last rehabilitative session.

We conclude that robotic-assisted BWSTT is helpful in restoring cardiovascular control in rehabilitation-responsive ST patients and limiting vagal responses in rehabilitation-responsive CSM patients.

Introduction

In the last decade, a new therapeutic strategy based on body weight supported (BWS) treadmill training (BWSTT) assisted with a robotic-driven gait orthosis has been proposed as a clinical tool helpful during rehabilitation in gait-impaired individuals [1], [2], [3].

Robotic-assisted locomotion is adjustable in force, BWS and speed so that even patients with severe loss of sensory-motor function can exercise in an environment delivering as much challenge as can be handled. Improvements after robotic-assisted BWSTT include a greater weight-bearing capacity, an increase in walking speed and endurance, an improved gait pattern during BWSTT [4] and, in some cases, an increased ability to walk over ground [5]. While the effect on the motor skills have been deeply assessed, no studies have explored the effects of a rehabilitation protocol based on robotic-assisted BWSTT on the autonomic nervous system (ANS) response in subjects with lost motor skills such as stroke (ST) and cervical spondylotic myelopathy (CSM) patients. In both these populations ANS is impaired. Indeed, it was reported a reduced vagal modulation in ST patients [6], [7] and a decreased sympathetic activity in CSM patients [8]. The assessment of the effects of a rehabilitation protocol not only in terms of an improvement of motor skills but also in terms of recovery of the cardiovascular regulation might permit a more complete evaluation of the rehabilitative process.

In a previous study [9] we showed that a traditional robotic-assisted BWSTT rehabilitation session including standing, walking at different speeds and recovery induces a light but significant cardiovascular response that can be typified using short-term analysis of heart rate variability (HRV). In addition, in [9] we demonstrated that symbolic analysis outperforms spectral analysis in assessing the ANS response to a robotic-assisted BWSTT rehabilitation session.

The aims of this study are: (1) to evaluate the ANS response during robotic-assisted BWSTT protocol in ST and CSM populations; (2) to study the effects of a 6-week daily repetition of a robotic-assisted BWSTT rehabilitation session on the ANS regulation in the same groups of patients. Our study was carried out over ST and CSM patients who exhibited an improvement of their motor skills after robotic-assisted BWSTT rehabilitation therapy (i.e. rehabilitation-responsive subjects) to test the hypothesis of the additional improvement of the cardiovascular regulation. The assessment of the ANS response was carried out by applying symbolic analysis to short-term HRV [9].

Section snippets

Population

The following patients were included in our study: (i) ST patients with hemiparesis as a result of a first cerebral ischemia or hemorrhage according to the definition of the World Health Organization (N = 5, mean age 61 ± 10.5 years, 4 men); (ii) patients suffering from CSM (N = 6, mean age 64.5 ± 5.2 years, 5 men).

Table 1 summarizes the main characteristics of our populations. Only patients with post-injury time interval larger than 12 months were enrolled. Additional inclusion criteria for ST

Results

Fig. 1 shows the result of the motor skills indexes during PRE and POST conditions. A significant increase of FIM (limited to the assessment of walking items) and Barthel indexes (both p  0.05) after the rehabilitation period was found in both groups, while the trunk control test and the JOA index showed a tendency to increase in ST and CSM patients respectively. Motricity index did not vary in ST patients.

Fig. 2 shows an example of RR series during PRE (left panels) and POST (right panels)

Discussion

The major findings of the study are: (1) individual ANS responses to the first BWSTT rehabilitation session were variable and scattered in ST patients; (2) ANS responses of ST patients after 30 daily BWSTT rehabilitation sessions were characterized by a reduction in the inter-subject variability and by the presence of trends more similar to those observed in healthy subjects [9]; (3) individual responses to the first BWSTT rehabilitation session were variable and scattered in CSM patients

Conclusions

Using as a reference the typical response of healthy subjects to a robotic-driven BWSTT rehabilitation session reported in [9], we conclude that our robotic-driven BWSTT rehabilitation therapy is helpful in restoring cardiovascular control in rehabilitation-responsive ST patients and limiting excessive vagal responses in rehabilitation-responsive CSM patients. Since our robotic-driven BWSTT therapy induces mainly passive movements, the improvement observed in the cardiovascular response cannot

Conflict of interest

No conflict of interest.

References (21)

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