Combined Effect of Virtual Reality Training (VRT) and Conventional Therapy on Sitting Balance in Patients with Spinal Cord Injury (SCI): Randomized Control Trial
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.360934
Source of Support: None, Conflict of Interest: None
Keywords: Paraplegia, trunk control, xbox kinect
SCI is a condition that leads to high rates of morbidity as well as mortality with a global incidence of SCI ranging from 9.2 to 56.1 per million. In SCI, there is an impairment in the motor and sensory system, as well as in the transmission of impulses across the site of lesion leading to a variety of impairments, including the ability to maintain balance in sitting. Most of the functional activities performed by SCI survivors are carried out in the seated position. Postural stability in sitting depends on the potential to maintain the center of mass within the base of support while making appropriate adjustments to changes in position. Based on the level of injury, the nerve supply to certain muscles may be disrupted leading to difficulty in maintaining balance during dynamic activities in the sitting posture leading to decreased independence in activities of daily living. Hence new patterns of postural control need to develop using non-postural muscles.,,
Previous studies have shown that adherence to rehabilitation has proven to be challenging in patients with SCI despite improvements in physical, psychological domains and an overall improvement in the quality of life. This may be attributed to its long and exhausting nature as well as individual variability in prognosis. VRT is an emerging field of rehabilitation, which can be used in addition to conventional therapy in patients with SCI and has been hypothesized to provide an interactive environment, which may encourage active exploration, enhance engagement, and may motivate the individual to exercise. Virtual reality systems using motion detection can incite patients to generate repetitive movements which are of high intensity, while providing multimodal feedback.,,,
Previously, studies have been performed which have shown positive results of VRT on stroke patients, cerebral palsy and traumatic brain injuries., However, there is a paucity of literature available on its effect on sitting balance in SCI; therefore, this study is aimed at assessing the effect of a combination of VRT and conventional therapy on sitting balance in individuals with SCI.
This parallel-group single-blinded randomized control trial was conducted in an Outpatient Neurological Department of a tertiary health care setup. The protocol was approved by the Institutional Ethical Committee. All SCI survivors attending the outpatient department were screened. Those who fulfilled the inclusion criteria and provided their written consent to participate were included in the study. Patients who had a neurological level of injury of D10 and below, and were classified as type A or B on the Asia Impairment Scale were included in the study. The other inclusion criteria were the ability to sit unsupported for 30 s and the ability to raise their hands to the head without losing balance, as this is the minimum requirement to participate in VRT. Patients with musculoskeletal deformities, recent fractures of upper limb or lower limb, visual deficits and significant cognitive impairment were excluded from the study. The subjects were then randomly allocated into two groups; those receiving conventional therapy alone (Group A) and those receiving a combination of VRT and conventional therapy (Group B).
The outcome measures included the Modified Functional Reach Test (MFRT) and the T-shirt test. Both the tests were conducted by a blinded assessor prior to and post the intervention period of four weeks.
Modified Functional Reach Test (MFRT)
The participant was seated on a chair without arm rests, with hips and knees in 90 degrees of flexion, feet supported, and two inch clearance between the popliteal fossa and the seat of the chair. A tape measure was attached at level of the acromion process of subject's shoulder. The shoulder was flexed to 90 degrees, horizontal to the floor and maximum reach distance was measured. The participants were not allowed to use the non-reaching upper extremity for weight-bearing. The maximum reach distance to the right, left, and forward was measured.
The participant was placed in the long sitting position with one or both hands supporting the body. A t-shirt slightly larger than the participants' size was placed on the knees and time to put on t-shirt was measured after a signal 'start'. Similarly, the time to take off the T-shirt was measured. This test was repeated thrice and the mean total time was calculated.,
Both the groups (A and B) received their routine therapy on six days of the week for 45 min. The exercise program received by both the groups is mentioned in [Figure 1]a. In addition, Group B was given 30 min of VRT in the seated position using Xbox Kinect [Figure 1b-d] and Group A received 30 min of conventional therapy focused on training sitting balance so as to equalize the duration of intervention received by both the groups. The additional intervention was provided on three days of the week for four weeks.
The data were analyzed using SPSS statistical software version 16. The distribution of the variables was assessed using the Shapiro–Wilk test. Normal distribution was observed only for the forward reach distance on the MFRT. The matched pair sample t test was used to compare the pre and post differences within the groups and the independent sample t test was used to compare the differences between the two groups for forward reach distance. The Wilcoxon signed rank test was used to compare within-group differences and the Mann–Whitney U test was used to compare between-group differences for right and left reach distances and t-shirt test time as it was not normally distributed. The statistical level of significance was set at α = 0.05.
Flow of participants
24 subjects were recruited for the study. Outcomes were attained for all variables of all the participants, except for three subjects who discontinued the intervention. The flow of the participants is mentioned below in [Figure 2]. The demographic data of the subjects are available in [Table 1].
Results for MFRT
The within-group analysis showed that both the groups showed significant difference post the intervention (P < 0.05) in all the reach distances. On comparison between the two groups, it was seen that Group B showed significant improvement in all the reach distances [Table 2].
Results for T-shirt test:
The within-group analysis showed that both the groups showed significant differences post the intervention (P < 0.05) in the T-shirt test. On comparison of the two groups, it was seen there was no significant difference between the two groups [Table 3].
Rehabilitation to improve sitting balance in patients of SCI has been proved to be very important as it is closely associated with improvement in functional independence as well as ability to use upper extremity for purposeful activities of daily living.,,
The results of this study showed that a combination of VRT and conventional therapy showed significant improvement in the MFRT distances in all directions as compared to conventional therapy alone [Table 2]. However, a combination of VRT and conventional therapy proved to be as effective as conventional therapy alone in improving the time taken to perform the T-shirt test, as no significant difference was obtained between the two groups [Table 3].
The improvement in the MFRT in the VRT group may be attributed to the fact that the postures and movements required during the performance of the games replicated the motion that was required to be performed during the MFRT. The game of tennis demanded the person to lean forward during a power shot, shifting the weight in the medial and lateral directions along with trunk rotation, while using the upper extremity to hit the ball with a racket. Skiing required sustained forward flexion of the trunk through the hips to increase the speed with medial lateral weight shifts in accordance with virtual slope which was visible on the screen, while simultaneously performing controlled skiing movements of the upper extremity. The improvement in the forward reach distance could be attributed to the fact that during forward reaching activities patients with SCI relied on non-postural muscles for trunk stability. In a study performed to assess the postural muscle responses during forward reaching in subjects with SCI, the authors suggested that the subjects relied on the latissmus dorsi and ascending fibers of trapezius in a tonic manner, with the pectoralis major working to stabilize the shoulder girdle against the activity of the aforementioned muscles., The forward displacement of the upper extremities was counteracted by extending the head and upper spine, keeping the line of gravity within the base of support., Similarly, the games included in the present study required to maintain sustained of forward flexion of the trunk in a tonic manner, while engaging the upper extremity in purposeful activity, thereby allowing training for the use of these non-postural muscles to maintain trunk stability.
The improvement in the in right and left reach distances could be due to the fact that the subjects included in the study had a neurological level of injury of D10 and below, which allowed preservation of a part of abdominal muscle function, namely the internal and external obliques which are responsible for postural control in the horizontal plane due to their diagonal and transverse orientation along the trunk. The subjects in the VRT group performed repetitive weight shifts in the horizontal plane along with intra-axial trunk rotation. Trunk rotation is a multi-planar movement with coupling between the torque of trunk rotation and lateral flexion. It is brought about by the compound action of the internal and external obliques, latissmuss dorsi and to a lesser extent the illiocostalis lumborum., Repetitive performance of multi-planar movements during VRT allowed strengthening of the above muscles leading to significant improvement in the right and left reach distances.
In contrast to this, the exercises performed in the conventional therapy group consisted of a variety of task-specific exercises; however, they were majorly in a single plane and did not include much multi-planar movements. The activities performed in the conventional group were more dynamic and did not require the subject to maintain sustained holding of the forward flexed, requiring activation of the muscles only in short bursts in a phasic manner.
Maintenance of balance is an integrated action of inputs from the vestibular, auditory, visual and somatosensory system. In SCI, there is impairment in the somatosensory system. The virtual reality system provided multi-modal feedback, which may have compensated for the somatosensory loss to a certain degree, allowing the person to identify incorrect patterns of ongoing postural control and provided an opportunity to correct them which was not possible in the conventional therapy group. These findings were also consistent with previous studies where Nintendo Wii and Nintendo Wii fit was used in addition to conventional physical therapy to improve balance in patients with complete and incomplete spinal cord injury respectively. Both these studies showed significant improvement in reach distances.,
Another outcome measure used in the present study was the T-shirt. The test was selected as it has been found to correlate significantly with the ability to maintain static sitting balance. The absence of additional effect of VRT may be because the games included did not further challenge postural stability through vertical displacement of center of mass as is required during upper body dressing and undressing, with the games facilitating weight shifts namely in the frontal and sagittal plane. Furthermore, most of the subjects included in the study had a more chronic duration since injury and had probably learned and practiced the postural adjustments required to perform upper body dressing and undressing. This is in accordance with the results of a study performed to determine the validity and reliability of assessment tools used to measure unsupported sitting in subjects with SCI which stated that performance times of functional tasks improved with chronicity of injury. This was evident in the fact that the subjects in the present study already had a mean value of ≤12 s at the beginning of trial, leaving little room for improvement and thus, this may have masked the treatment effect. In addition, the test was performed in the long sitting position, in which stability is provided by performing a posterior pelvic tilt, with an increase in the intrathoracic and intra-abdominal pressure and the locking effects of the bones and various ligaments allowing them to hang on these structures. Most of the balance in this position can be maintained by passive mechanisms, with less active contribution of the muscular forces and hence, both the interventions were equally sufficient in improving the minimally required muscular contribution in this position.
These findings are in contrast to a previous study where VRT using Nintendo Wii showed a significant difference in the T-shirt test. This may be because the duration of intervention provided in the aforementioned study was for 6 weeks, whereas the present study provided an intervention for 4 weeks. The aforementioned study also did not provide the equal duration of intervention to both the groups, providing an additional 30 min of VRT for 6 weeks to the experimental group, which was not accounted for in the conventional therapy group, leading to greater improvements in the T-shirt test in the VRT group.
VRT has previously been used as an effective tool in improving balance in various other neurological conditions such as stroke,,, Parkinson disease, and cerebral palsy., The results of this study suggest that a combination of VRT and conventional therapy can be used as a part of a comprehensive rehabilitation program for the training of individuals with SCI to improve their balance in sitting.
The few limitations of the study were the limited generalizability of the results as the subjects included in the study were only low paraplegics and they had a more chronic duration of SCI and its effect in more acute settings couldn't be commented upon. Future research may also focus on the development of virtual reality games specific to the level and type of injury, with parameters for appropriate intensity and task selection.
The addition of VRT to conventional therapy is effective in improving the sitting balance in individuals with SCI by improving their reaching abilities in the forward, right and left direction and can be used as a part of a comprehensive rehabilitation program.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]