The Importance of Gait Analysis in Incomplete Spinal Cord Injury Patients in Field of Neurorehabilitation

8/20/2019 The Importance of Gait Analysis in Incomplete Spinal Cord Injury Patients in Field of Neurorehabilitation

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J.L. Pons et al. (Eds.): Converging Clinical & Engi. Research on NR, BIOSYSROB 1, pp. 673–677.DOI: 10.1007/978-3-642-34546-3_109 © Springer-Verlag Berlin Heidelberg 2013

The Importance of Gait Analysis inIncomplete Spinal Cord Injury Patientsin Field of Neurorehabilitation

*

Soraya Pérez-Nombela1,**, Antonio José del Ama-Espinosa1,Ana de los Reyes-Guzmán1, Ángel Gil-Agudo1,

Francisco Molina-Rueda2, and Diego Torricelli3

1 Biomechanics and Technical Aids Department National Hospital forSpinal Cord Injury, Toledo, [email protected]

2 University Rey Juan Carlos, Alcorcón, Spain3

Bioengineering Group, CSIC, Arganda, Spain

Abstract. The most important aspect in rehabilitation of incomplete spinal cordinjury (SCI) is the possibility to recover walking ability. Lower limbsexoesqueletons are of increasing importance in neurorehabilitation of SCI patients toachieve gait with this type of robotic device. The objective of this study was toanalyze the gait from biomechanical point of view to help in describe theoretical and

experimental biomechanicals models for kinematics compatibility with neurorobots(NR). An experimental protocol was carried out in 9 patients with SCI and 10control subjects (CG). Data were obtained using a three-dimensional motionanalysis system, two force plates and surface electromyography system. The mostrelevant findings involved the knee and ankle, specially in the sagittal plane. Thisinformation is found important for the development of neurorobotic andneuroprosthetic devices, aimed to design better and tailored neurorehabilitationstrategies.

1 Introduction

The consequence a spinal cord injury is a partial or complete loss of motor,sensory and autonomic functions below the level of lesion [1]. Trauma to thespinal cord and interruption of the spinal interneuronal circuits connecting thebrainstem and the supraspinal motor center interfere with several aspects ofnormal gait [2]. The physicians who treat acutely injured spinal cord injurypatients have noted that most ask whether they will walk again. It is important,therefore, to know the probability that an acutely injured patient with incomplete

* This research is part of the HYPER project funded by CONSOLIDER-INGENIO 2010

CSD2009-00067, Spanish Ministry for Science and Innovation.** Corresponding author.



674 S. Pérez-Nombela et al.

tetraplegia will become ambulatory [3]. So, the percentage of subjects who regainsome walking capacity depends strongly on the extent of spinal cord lesion. Onthe other way, a number of new therapeutic interventions, such as body-weightsupported locomotor training and robotic technologies aim to improve walkingfunction and reduce co-morbidities [4].

Gait rehabilitation robots are of increasing importance in neurorehabilitation.Conventional devices are often criticized because they are limited to reproducingpredefined movement patterns of gait. Robots should support patients only asmuch as needed and stimulate them to produce maximal voluntary efforts [5]Main targets of the HYPER proyect (Hybrid Neuroprosthetic and Neuroroboticdevices for Functional Compensation and Rehabilitation of Motor Disorders) are,on one hand to speed up the rehabilitation procedures and on the other to improvethe outcome of the therapy using new paradigm and technology [6].

One of work packages of this complex research in neurorehabilitation is

biomechanics. The hybrid development of Neurorobots (NRs) and Neuroprotheses(NPs) will require biomechanical scientific support to overcome critical issues forefficiency, safety and dependability. This new concept poses new challenges thatcan be answered with Biomechanics assessment. Therefore, the aim of this study isto assess gait, both healthy and pathological, to identify specific deficits andmovement models to be used for designing new rehabilitation strategies withhybrid neurorobots.

2 Material Y Methods

Nine patients with incomplete spinal cord injury (SCI) participated at theexperiment and their data were compared with a control group (CG) of 10 subjectswith similar demographic and anthropometric characteristics. The clinicalcharacteristics are shown in the Table 1.

Table 1 Clinical characteristics of the SCI group

VARIABLE SCI Group (n=9)Sex (men, %) 5 (56.00)Age (years) 39.32 (12.76)Level of injury at cervical (%) 5 (56.00)Level of injury at dorsal (%) 3 (33.00)Level of injury at lumbar (%) 1 (11.00)

We certify that all the participants provided informed consent prior to beincluded in this study and the experimental protocol desing was approved by local

ethics committee. The research was carried out in the Biomechanical andTechnical Aids Department of the National Hospital for Spinal Cord Injury(Toledo, Spain).



The Importance of Gait Analysis in Incomplete SCI Patients 675

Kinematic data were obtained using a three-dimensional motion analysis systemwith two scanner units (CODA System.6, Charnwood Dynamics, Ltd, UK). Elevenactive markers were positioned and attached to anatomic landmarks as describedpreviously [7]. Kinetic data were obtained synchronously using two force platforms(Kistler Instrument AG, Switzerland) with a sampling frequency of 1000 Hz.Finally, the electromyography data (EMG) were recorded using 14 channels ofsurface electromyography system (Noraxon®) with a sampling frequency of 1500Hz; and the electrodes were positioned as described Cram et al. [8].

All patients with SCI walked with their usual footwear along a 10m walkway atself-selected speed, while temporal-spatial, kinematics, kinetis and EMG datawere recorded. The controls were registered walking at three different speeds. Asthe patients´ range of speed varied between 0.51 and 0.88 m/s, medium speedtrials of the CG were used to make the comparison. Five valid trials were obtainedfor each subject to reduce intrasubject variability. Subjects rested for one minutebetween trials to avoid fatigue.

The distribution of samples was analyzed with Kolmogorov-Smirnov test, andthe samples don´t shown normal distribution. So we analyzed the differencesbetween SCI and CG at medium speed using a non-parametric test, U-MannWhitney. The differences were considered significant for P less tan 0.05. SPSS forWindows (v.12.0) were used for the statistical analysis.

3 Results

The kinematics results for the pelvis and hip indicated that statistically significantdifferences were not found. But in the more distal joints, there are somedifferences between groups.

Figure 1 (a) shows that the knee flexion at the initial contact was significantlygreater (p<0.05) in the SCI group (7.72 ± 3.25) than in the CG at medium speed(3.77 ± 5.50). It must be noted that the CG showed higher knee range of motion inthe sagittal plane (61.96 ± 4.44) than in SCI group (53.78 ± 14.30).

The ankle dorsalflexion at the initial contact was smaller (p<0.05) in the SCI

group (2.21 ± 5.69) than in the CG at medium speed (8.96 ± 7.38). However, themaximal plantar-flexion value was greater (p<0.05) in CG (-6.24 ± 9.34 in SCIgroup and -12.10 ± 9.62 in CG) and the plantar-flexion was smaller in SCI groupat the instant of the toe-off (-1.95 ± 12.14 in SCI group and -11.56 ± 7.92 in CG).See Figure 2 (a).

In the same way, the kinetic parameters begin to appear differences in the distal joints of the lower limbs. It was found that the maximal external rotation momentof the knee was lower (p<0.05) in the SCI group (0.10 ± 0.06) than in CG (0.15 ±0.07) at medium speed (Figure 1(b)).

In the ankle joint, it was obtained that all the moments of the sagittal planewere greater in the CG at medium speed. (Figure 2(b)) These findings of the ankle joint could be due to the ankle power generation was also lower in the SCI group(p<0.05) (Figure 2(c)).



676 S. Pérez-Nombela et al.

Fig. 1 (a) Kinematic curve in the sagittal plane for the Knee. Positive values indicatedflexion. Grey line shows CG at medium speed and black line the SCI group. (b) Kineticrotation moment. Positive values indicated external rotation mment.

Fig. 2 (a) Kinematic curve in sagittal plane for the ankle. Positive values indicateddorsiflexion. Grey line represents CG at medium speed and black line the SCI group. (b)Ankle plantarflexor moment. Positive values indicated plantarflexion moment. (c) Sagittalplane of power of the ankle joint. Positive values indicated power generation.

EMG outcomes vary greatly between subjects; probably, due to this variability,only we found statistically significant differences in the zero crossing variable, inthe medial and lateral hamstrings and tibialis anterior muscles was greater in SCIgroup (p<0.05). This parameter is related to muscle strength, so this fact indicatethat SCI group have to do slightly more strength with these muscles.

4 Conclusions

The most remarkable walking differences between patients with incomplete SCI

and CG were found in the knee and ankle joints. Reduced knee flexion duringswing phase combined with a peak of plantarflexion after toe-off can lead to ainsufficient toe-clearance. Furthermore, ankle joint moment and power at toe-off

(a) (b)

(c)

(a) (b



The Importance of Gait Analysis in Incomplete SCI Patients 677

are greatly reduced compared to healthy subjects, which also impairs walkingprogression, affecting step length and walking velocity. Regarding hip actuation,this population does not apparently need intervention.

Therefore neurorehabilitation therapies for this population must be targetedtowards a functional compensation or re-education of the maximal flexion of theknee during swing phase combined with a reduction of ankle plantarflexion afterthe toe-off. Another objective of the neurorehabilitation must be increase userability to generate ankle plantarflexion moment, either by reducing dorsalflexionmuscle spasticity or potentiating plantarflexion muscle force.

In conclusion design of future neurorobotic devices for rehabilitation ofincomplete SCI patients should provide motor control in cuadriceps, triceps suraeand pretibialis muscles in order to provide knee stability during stand phase ofgait, reduce plantarflexion after toe-off, and increase knee flexion during swingphase.

This article has shown how biomechanical gait analysis can be used to assessthe specific functional deficits within a population of SCI patients, directed todesign better and tailored neurorehabilitation strategies with neuroprosthesis andneurorobots.

References

[1] Wirz, M., Zörner, B., Rupp, R., Dietz, V.: Outcome after incomplete spinal cordinjury: central cord versus Brown-Sequard syndrome. Spinal Cord 48(5), 407–414

(2010)[2] Chang, H.A., Chuang, T.Y., Lee, S.J., Liao, S.F., Lee, H.C., Shih, Y.H., Cheng, H.:Temporal differences in relative phasing of gait initiation and first step length inpatients with cervical and lumbosacral spinal cord injuries. Spinal Cord 42(5), 281–289 (2004)

[3] Burns, S.P., Golding, D.G., Rolle, W.A., Graziani, V., Ditunno, J.F.: Recovery ofambulation in motor-incomplete tetraplegia. Arch. Phys. Med. Rehabil. 78(11), 1169–1172 (1997)

[4] Hidler, J.: Robotic-assessment of walking in individuals with gait disorders. In: Conf.Proc. IEEE Eng. Med. Biol. Soc., vol. 7, pp. 4829–4831 (2004)

[5] Duschau-Wicke, A., von Zitzewitz, J., Caprez, A., Lunenburger, L., Riener, R.: Path

control: a method for patient-cooperative robot-aided gait rehabilitation. IEEE Trans.Neural Syst. Rehabil. Eng. 18(1), 38–48 (2010)

[6] De Mauro, A., Carrasco, E., Oyarzun, D., Ardanza, A., Frizera Neto, A., Torricelli, D.,Pons, J.L., Gil, A., Florez, J.: Virtual reality system in conjunction with neuroroboticsand neuroporsthetics for rehabilitation of motor disorders. Stud. Health Technol.Inform. 163, 163–165 (2011)

[7] Kadaba, M.P., Ramarkrishnan, H.K., Wooter, M.E., Gainey, J., Gorton, C., Cochran,G.V.: Repeatability of kinematics, kinetic, and electromyograhic data in normal adultgait. J. Orthop. Res. 7, 849–860 (1989)

[8] Cram, J.R.: Introduction to surface electromyography, 2nd edn. Jones and Barlett

Publishers, Boston (1998)

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The Importance of Gait Analysis in Incomplete Spinal Cord Injury Patients in Field of Neurorehabilitation