The Effect of Adding Virtual Reality Training on Traditional Exercise Program on Balance and Gait in Unilateral,Traumatic Lower Limb Amputee

Abstract

Objective:

Lower limb amputation is common in war combat and armed conflict as well as in traumatic settings and presents a challenge for health care providers. The incorporation of advanced technologies, particularly virtual reality, presents an opportunity to address the main consequences of amputation, principally balance and gait. The aim of this study was to investigate the additional effect of virtual reality with a traditional rehabilitation exercise program on balance and gait in unilateral, traumatic lower limb amputees.

Materials and Methods:

Thirty-two traumatic lower limb amputees, fulfilling a postfitting rehabilitation program at least 6 months ago, were recruited and randomly assigned into two identically sized groups; group C (control group) experiencing the traditional exercise program and group VR (virtual reality group) experiencing an addition of a virtual reality training. The intervention was conducted over 6 weeks at a rate of three sessions per week. Outcome measures assessed before and after 6 weeks were the Berg Balance Scale (BBS), Timed Up and Go (TUG) test, Dynamic Gait Index (DGI), and 6-minute walk test (6 MWT).

Results:

Both interventions induced improvement in all measured parameters (P < 0.05); however, virtual reality demonstrated significant superior effects only on the balance markers, TUG test, DGI, and BBS (P < 0.05), but not on the 6 MWT (P > 0.05).

Conclusion:

Virtual reality is a promising, amusing, and safe intervention for addressing balance and gait in unilateral, traumatic lower limb amputees.

Introduction

War combat and armed conflict as well as traumatic settings are highly correlated with debilitating wounds at different body system levels, particularly the musculoskeletal system.¹ Although medical care has markedly advanced, especially that related to advanced resuscitation, amputation secondary to armed combat and conflict is still increasing, and the injuries largely affect civilians. Such a fact leads to the conclusion that there will be large numbers of amputees and increasing burden on the injured as well as on health services and societies.² Amputation affects both upper and lower limbs. However, lower limbs are more affected than upper limbs and males are more affected than females.³ Lower limb amputation (LLA) leads to many reported disturbances, preventing the amputee to assume a normal and self-accepted quality of life. Falls are commonly encountered with LLA, and an increased fall risk remains throughout the life span after injury.⁴ Reduced level of independence and mobility restriction lead to major consequences for LLA.⁵ Still, many researchers reported that the postfitting rehabilitation program is a potential factor determining the success of many functional outcomes.⁶

Addressing such major consequences of LLA is considered a challenge for patients, families, and health care providers. The focus in lower limb amputee rehabilitation is usually independent walking.⁷ Many rehabilitation strategies have been proposed and implemented, addressing functional outcomes in lower limb amputees.^8–10 Advanced technologies often present an opportunity for health care practitioners, particularly physical therapists, to incorporate them into rehabilitation programs. Virtual reality exercising has recently emerged and proven its effectiveness in improving many functional parameters in various clinical settings, including neurological¹¹ and musculoskeletal disorders,¹² and in different age groups.^13,14 However, its effectiveness in improving functional parameters in lower limb amputees has been poorly investigated, particularly in traumatic amputations. This is why the purpose of this study was to explore the effect of virtual reality on selected balance and gait parameters in unilateral, traumatic lower limb amputees.

Materials and Methods

Study design

This was a prospective, multicenter, single-blinded randomized trial conducted in three facilities in Lebanon, namely the Physical Therapy Outpatient Clinic (PTOC) at Beirut Arab University (BAU), International Committee of the Red Cross (ICRC) Weapon Traumatology Training Centre (WTTC) in Tripoli, and Al Motahidin Orthopedic Center in Bekaa. A detailed study methodology is summarized in the study flow chart (Fig. 1).

FIG. 1.

Study flow chart. 6 MWT, 6-minute walk test; BBS, Berg Balance Scale; C, control; DGI, Dynamic Gait Index; ICRC, International Committee of the Red Cross; TUG, Timed Up and Go test; VR, virtual reality.

Participants

The researchers went through the databases of the Physical Rehabilitation Program of the ICRC in addition to the PTOC databases. Traumatic lower limb amputees were identified and were contacted for their willingness to participate in the study. Sixty subjects gave their preliminary acceptance to participate and only 32 completed the full timeline of the study. The study started in March 2017 and was terminated in March 2019. Ethical approval was obtained from the Institutional Review Board at BAU before study commencement [No: 2017H-0032-HS-R-0239]. The study abided by the Guidelines of the Declaration of Helsinki on the conduct of human research.

Criteria for selection of subjects were as follows: aged between 18 and 40 years; only traumatic or war-wounded, unilateral lower limb amputees; and subjects who terminated their routine postfitting rehabilitation and are currently using their prostheses for gait and locomotion at least 6 months before participation in the study.

Upon their first encounter, participants were allowed to undergo an orientation session about the study details and agreed to participate by signing an informed consent validated and approved by the BAU Institutional Review Board. They were also informed that they are free to withdraw at any time.

Grouping

Anonymity was guaranteed by coding of participant's information. The 32 participants were randomly assigned into two equal groups by a blinded and an independent research assistant who opened sealed envelopes containing a computer-generated randomization card. The two groups were as follows: group C (control group), where 16 participants underwent 6 weeks of the traditional rehabilitation program according to the reference manual developed by the ICRC¹⁵ at a rate of three sessions per week for 6 weeks; and the VR (virtual reality) group,¹⁶ where participants underwent the same rehabilitation program implemented in group C in addition to a virtual reality training three times per week for 6 weeks.

Participant's evaluation

All participants were screened for balance and gait using the 6-minute walk test (6 MWT),¹⁷ Arabic validated version of Berg Balance Scale (BBS),¹⁸ Timed Up and Go (TUG) test,¹⁹ and Arabic validated version of Dynamic Gait Index (DGI).²⁰ Two physical therapists, research assistants, not intervening with the treatment regimen applied, blindly performed the examination of all participants. Evaluations were performed before and after 6 weeks of intervention. The two research assistants were trained on the proper use of the scales before starting the study.

Treatment intervention

Traditional rehabilitation program¹⁶: Groups C and VR went through the traditional rehabilitation program progressively as follows:

Weeks 1 and 2: Stool stepping exercise, gait exercise, walking laterally, and balance exercise on one foot.

Weeks 3 and 4: Walking over obstacles, walking on a line, walking backward, and balance exercises while exercising for the sound leg.

Weeks 5 and 6: Walking on a line with speed and closed eyes, balance exercises while exercising for the sound leg, balancing on an unstable surface with both legs, and walking up and down stairs.

Each exercise was performed for 5 minutes with a total of 20 minutes each session.

Virtual reality program

Preparation

To perform the virtual reality training intervention, Kinapsys™ rehabilitation gaming equipment was used. Kinapsys is a rehabilitation gaming tool providing functional rehabilitation.²¹ Built-in games are designed to foster balance and gait. The system uses Kinect™ sensors developed by Microsoft to identify body movement through a camera and an infrared sensor to capture joints and body segments. Additionally, all games could be controlled in terms of timing and level of difficulty, and the participant can collect scores and consequently obtain direct feedback. Characteristics of the videogames used are summarized in Table 1.

Table 1.

Characteristics of the Kinapsys Gaming Used in This Study

Health topic(s)	Musculoskeletal gait and balance rehabilitation
Targeted age group(s)	Adult, unilateral, traumatic lower limb amputees (6 months postfitting with prosthesis)
Other targeted group characteristics	NA
Short description of game idea	Football, going over obstacles, multidirectional movements, avoidance of exercise with movement, and tennis
Target player(s):	Individual
Guiding knowledge or behavior change theory(ies), models, or conceptual framework(s):	Balance and gait
Intended health behavior changes:	Improving balance and gait
Knowledge element(s) to be learned:	• Using increased unilateral stance alternatively on both lower limbs
	• Trying to maintain balance while moving the trunk and upper limbs
	• Trying to move in all directions (forward, backward, sideways, and diagonal)
Behavior change procedure(s) (taken from Michie inventory) or therapeutic procedure(s) employed:	The participant is given the opportunity to be motivated, through purposeful movement therapy, to be capable of improving his/her balance and gait outcome measures
Data shared with parent or clinician:	No
Type of game: (check all that apply)	Active – Role-playing – Simulation – Sports
Game components
Player's game goal/objective(s):	Scoring of each game
Rules:	Keep the same designed game space and score the highest number in 5 minutes set for each game
Game mechanic(s):	Each of the five games has its own virtual setup on the screen
Procedures to generalize or transfer what is learned in the game to outside the game:	Improvement in balance and gait outcome measures (Dynamic Gait Index, Berg Balance Scale, 6-minute walk test, and Timed Up and Go test)
Virtual environment
Setting (describe):	TV screen
Avatar
Characteristics:	The participant's own picture is taken by the camera and converted to a cartoon human
Abilities:	NA
Game platform(s) needed to play the game (check all that apply):	Kinect Xbox^®, computer, and screen
Sensors used:	Infrared camera that captures joints and body segments (calibrated before every game)
Estimated play time:	25 minutes per session (5 minutes/five games)

NA, not applicable.

To select suitable exercises, five amputees (not included in the study) were allowed to experience 18 different programs built in the system addressing balance and gait stability. They were allowed to rate the selected games according to their own experience. After this session, five games were selected according to the participants' rating. These games were as follows: football, going over obstacles, multidirectional movements, avoidance exercise with movement, and tennis.

Virtual reality session

All participants in the VR group experienced the progressive, traditional rehabilitation program similar to that applied in group C, in addition to 25 minutes of virtual reality training (five games, each game for 5 minutes). Sessions were conducted three times per week for 6 weeks. The level of difficulty was determined at the first session and raised every 2 weeks.

Data analysis

Results are expressed as mean ± standard deviation (SD). First of all, the distribution of data was checked using the Shapiro–Wilk test (sample size below 2000), where the result was not significant (P > 0.05), therefore our sample data were found to be normally distributed. Additionally, a power analysis was performed and it demonstrated a convenient sample number, which is comparable with another study.²² An intention-to-treat analysis was performed to avoid risk of bias that may be introduced when comparing groups, especially those associated with dropouts. Comparison of different variables within and between groups was performed using paired and unpaired t tests for normally distributed data. The Statistical Package for the Social Sciences (SPSS) (version 23 for Windows) was used for data analysis. The alpha level was set at 0.05.

Results

Of 60 identified traumatic lower limb amputees, 32 participants did terminate all requirements of the study. The dropout rate was estimated as 46.6%; however, when contacted, 22 of those who dropped out expressed difficulty in accessing the rehabilitation venues (most of them were living in Syrian camps) and public transportation is not available to and from camps (usually camps are located far from Lebanon central cities). The remaining six participants did leave Lebanon during the period of the study. However, the intention-to-treat analysis was performed to ensure accuracy of results. The personal characteristics of participants who fulfilled all requirements of the study are expressed as mean and SD in Table 2. It can be also shown that the majority of the sample in both groups was males and the most frequent type of amputation was the transtibial type.

Table 2.

Personal Characteristics of Patients in Both Groups

Items	Group C	Group VR
Items	Mean ± SD	Mean ± SD
Age (years)	27.625 ± 4	27.625 ± 7.6
Body mass (kg)	28 ± 2.1	27.8 ± 2.2
Height (m)	1.72 ± 0.07	1.68 ± 0.06
Male (n)	14	15
Female (n)	2	1
Transfemoral amputation (n)	3	3
Transtibial amputation (n)	13	13

C, control; n, number; SD, standard deviation; VR, virtual reality.

Table 3 represents the mean and SD of groups C and VR before and after 6 weeks of intervention. It highlights four variables measured, including the DGI, TUG test, BBS, and 6 MWT. The baseline values of all outcome measures recorded, at the beginning of the study, were almost similar (P < 0.05). The participants received their prostheses at least 6 months ago. The interpretation of results showed that for group C, DGI scores increased from 17.56 ± 1.55 to 20 ± 1.21, TUG time reduced from 11.45 ± 2.69 to 10.02 ± 1.68, BBS score increased from 43.44 ± 4.15 to 49.19 ± 3.45, and the 6 MWT distance increased from 156.13 ± 117.5 to 211.56 ± 124.01. For the VR group, scores showed similar variations as follows: DGI scores increased from 17.81 ± 1.72 to 22.75 ± 0.93, TUG time reduced from 11.11 ± 2.08 to 8.05 ± 1.4, BBS score increased from 43.19 ± 3.67 to 51.38 ± 3.10, and the 6 MWT distance increased from 166.19 ± 108.24 to 262.63 ± 110.92. The within-group inferential analysis revealed highly significant positive effects of both treatment regimens. Such observations confirm that both the traditional physical therapy program implemented and the addition of virtual reality gave results in favor of improving balance and gait in the lower limb traumatic amputee; and this improvement was significant for different outcome measures recorded, including the DGI, BBS, TUG test, and 6 MWT.

Table 3.

Means and Standard Deviations of Dynamic Gait Index, Timed Up and Go Test, Berg Balance Scale, and Six-Minute Walk Test for Both Groups, C and VR, in Addition to the Within- and Between-Group P Values

	Group C			Group VR			Group C vs. VR
	Pre	Post	Within-group P value	Pre	Post	Within-group P value	Between-group P value
DGI	17.56 ± 1.55	20 ± 1.21	0.0002^a	17.81 ± 1.72	22.75 ± 0.93	0.0004^a	0.0001^a
TUG	11.45 ± 2.69	10.02 ± 1.68	0.0001^a	11.11 ± 2.08	8.05 ± 1.4	0.0004^a	0.001^a
BBS	43.44 ± 4.15	49.19 ± 3.45	0.0005^a	43.19 ± 3.67	51.38 ± 3.10	0.0002^a	0.035^a
6 MWT	156.13 ± 117.5	211.56 ± 124.01	0.0004^a	166.19 ± 108.24	262.63 ± 110.92	0.0003^a	0.091

Significance considered at P < 0.05.

6 MWT, 6-minute walk test; BBS, Berg Balance Scale; DGI, Dynamic Gait Index; SD, standard deviation; TUG, Timed Up and Go test.

The between-group inferential analysis (Table 3) revealed that addition of virtual reality to the traditional physical therapy program implemented provoked significant positive changes in the DGI scores, BBS, and TUG time only (P < 0.05), while scores of the 6 MWT improved, but such improvement was not significant (P > 0.05). This means that addition of virtual reality along with 6 weeks of the traditional physical therapy program did give significant results for DGI, TUG test scores, and BBS, but not significantly for the 6 MWT.

Discussion

This study was performed to evaluate the effect of adding a virtual reality program to a traditional physical therapy program for unilateral traumatic and war-wounded lower limb amputees on various gait and balance outcome measures, particularly the DGI, BBS, TUG test, and 6 MWT. Subjects recruited for this study were traumatic and war-wounded, unilateral lower limb amputees. From 60 identified subjects, only 32 fulfilled the study requirements and continued the study program. The main challenge in this study was the difficulty reported by participants in accessing the treatment centers and not all were able to commit to the whole period due to other unexpected obligations. Participants were divided randomly into two identically sized groups. The first group C experienced 6 weeks of traditional physical therapy and the second VR group underwent the same program as group C in addition to virtual reality training. The program was set for 6 weeks at a rate of three sessions per week.

Regarding demographics, males were more affected with LLA and the transtibial type was the most encountered type. In another research in Pakistan, similar reporting was published,²³ they also reported a similar age range. The mean age in this study was 27.625 years and relatively comparable with other published data reporting a mean of 30 ± 9 years.²⁴ The possible explanation regarding the age group might be that injuries affect the active civilian's age group in war and armed conflicts in addition to traumatic incidence. However, the similar mean observed in both groups with a slight difference at the level of SD cannot be explained but being a coincidence. Additionally, the transtibial predominance might be due to the cause of injury in war conflicts, including land mines or gunshot injuries.

From results presented in Table 3, it was evident that the traditional physical therapy program, with or without the addition of virtual reality training, did induce a positive effect on all outcome measures taken, targeting evaluation of balance and gait. However, all participants had terminated their postfitting rehabilitation program, which was discontinued at least 12 months before enrolling in the study. This can be explained by the fact that amputees, even after they finish their postfitting rehabilitation program, present with long-lasting gait and balance deficiencies that must not be underestimated. The results of the current study match with others stating that resisted exercise programs and functional training are more effective than supervised gait training alone.²⁵ On the other hand, it has been claimed that lower limb amputees present a higher fall risk from the time of amputation to many years later and that relevant safety and fall prevention strategies are warranted after discharge from the rehabilitation program.⁴ A recent systematic review concluded that LLA rehabilitation presents a challenge and approaches to rehabilitation of specific amputee groups are needed.⁶

It has been reported that lower limb amputees present a level of asymmetry in load distribution, such disturbance leads to neuromuscular adaptations after amputation. These adaptations are the consequence of the defect in afferent information secondary to limb loss.²⁶ The same authors highlighted the importance of increasing the feedback on lower limb prostheses to regain and foster postural control and functional balance. It seems that the implemented rehabilitation exercises have potentially induced such reintegration of sensory feedback either in the exercising group or in association with virtual reality training. Both interventions aimed to reestablish sensory motor integration and consequently foster motor control. A systematic review and meta-analysis concluded that virtual reality training has a promising effect.¹¹ It has been deduced that virtual reality has the potential to induce neuronal plasticity in patients presenting neglect.²⁷ Thus, it can be concluded that the observed improvement might be reported and explained by possible associated neuronal changes and motor learning.

Another recent systematic review concluded that even though there is no agreement on details regarding which exercise regimens should be used in rehabilitation of amputees, it appears that most rehabilitation programs implemented and published in the literature gave acceptable results in terms of balance and gait. The authors also considered the promising, but not documented, role of technological advances in rehabilitation. They claimed that the main defect in the literature is the vagueness of rehabilitation exercises implemented.⁶ In this study, the exercises implemented were precisely described to identify a road map for future investigators.

When comparing both groups, it was found that addition of virtual reality training to the traditional exercise program induced significant additional positive effects assessed solely with the DGI, BBS, and TUG test. On the contrary, it did not add any remarkable effect on the 6 MWT possibly because the latter reflects the aerobic capacity and fitness level rather than a balance marker, especially since the program implemented was limited to 6 weeks, and maybe if it was extended to more than this period, we might have observed significant changes.

In another population studied, it has been claimed that there was a lack of perfect correlation between the DGI and BBS. The researcher concluded that these two tests might measure different aspects of balance. They also concluded that the DGI appeared more sensitive in rating the balance status.²⁸ In the present study, scores of both DGI and BBS did demonstrate significant improvement altogether, meaning that interventions implemented for targeting balance demonstrated sufficient improvement. Both the DGI and BBS have been claimed to be valid and reliable in clinically assessing balance in lower limb amputees.²⁹

On the other hand, VR did significantly improve TUG test scores when compared with exercise alone. The TUG test has been found to be a sensitive marker of mobility in lower limb amputees.³⁰ From what has been stated, it seems that VR did induce a significant improvement in static and dynamic balance in lower limb amputees. This is congruent with others reporting similar results using VR on lower limb amputees, with a smaller sample size and similar age group.³¹

VR has been considered as an addition to usual therapeutic strategies and credited for improving balance and walking. In addition, it is considered a stimulating method to motivate and promote adherence to the rehabilitation program built to address prosthetic rehabilitation.³² It has also been reported that it enhances the learning environment through assuring visual and auditory feedback and consequently promoting motor learning.³³ More in-depth studies reported that VR induced an increase in postural control in cerebral palsy children.³⁴ It seems that VR might be the reason behind improvement in motor control, and consequently this might explain the improvement in balance associated with such an intervention. Finally, VR has the advantage of reduced cost in addressing gait and balance, as previously reported by others.³⁵ It has the advantage of achieving desired improvements in balance and gait parameters with minimal need for the presence of a specialist, which was desirable especially in situations where there is lack of a complete setup for traditional rehabilitation service or in situations where security issues are considered.³⁵

Conclusion

Both traditional rehabilitation exercises and virtual reality training are effective, as assessed by the BBS, TUG test, DGI, and 6 MWT. However, virtual reality shows superior effects with the DGI and TUG test in war-wounded, unilateral lower limb amputees.

Limitations of the study

Even though this study was a randomized controlled trial, it has some limitations. The program of rehabilitation and VR were implemented through a trial phase before designing suitable games; however, it might be possible that the games did not suit all participants. Additionally, participants were asked not to be involved in any training regimen throughout the study period; however, such issues cannot be guaranteed. Finally, outcome measure scoring might be affected by the psychological status of the participant, which cannot be overlooked.

Potential of the study

This is one of the rare studies investigating virtual reality training on traumatic lower limb amputees especially when considering the balance perspective. Additionally, the sessions were fully supervised by previously trained physical therapists (research assistants) blinded to participant allocation and not involved in the study. Finally, the assiduous follow-up of participants by the researchers and the individualized exercise training implemented can reinforce this study.

Footnotes

Acknowledgments

The authors thank Drs. Mouhamad Idam Saab and Aya Bibi who did the assessment of participants before and after the intervention. They also thank all colleagues who participated in implementation of exercises in different locations of the study.

Author Disclosure Statement

No competing financial interests exist. All authors read and approved the final manuscript.

Funding Information

This study was part of a project funded by the International Committee of the Red Cross (ICRC) through a memorandum of understanding between Beirut Arab University and ICRC in April 2017.

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