doi: 10.2490/prm.20190011

Progress in Rehabilitation Medicine 2019; Vol. 4, 20190011

CASE REPORT

Virtual Reality-guided, Dual-task, Body Trunk BalanceTraining in the Sitting Position Improved Walking Ability
without Improving Leg Strength
Kyohei Omon, PT a Masahiko Hara, MD, PhD b,c and Hideo Ishikawa, MD d
Background: Virtual reality (VR) technology has been recently introduced in a variety of clinicalsettings, such as physical, occupational, cognitive, and psychological rehabilitation or training.
However, the clinical efficacy of VR rehabilitation compared with traditional training techniques
remains to be elucidated. Case: A 90-year-old man underwent VR-guided, dual-task, body trunkbalance training in the sitting position using a newly developed medical device (mediVR KAGURA, mediVR, Inc., Toyonaka, Japan) after his physical activity level had plateaued. The patient
had difficulty in walking outside the hospital even after having undergone traditional physicaltraining. VR-guided training was performed for 40 min every weekday for 2 weeks. Trunk balance training was performed using reaching tasks, and cognitive stimulation was designed toemulate the cognitive processing involved when walking in a city or town. After the VR-guided
training, the patient’s 6-min walk distance improved from 430 m to 500 m even though there had
been no improvement in muscle strength of the lower extremities. Furthermore, the patient could
successfully walk outside the hospital without falling or colliding with obstacles. Discussion: It
is noteworthy that the patient’s walking ability improved further by the addition of VR-guided,dual-task, trunk balance training carried out in the sitting position. This finding suggests several
possible new approaches to overcoming walking disability. Walking requires lower-extremity
muscle strength, postural balance, and dual-task processing. Currently, no effective quantitative
methods have been identified for postural balance and dual-task training with the patient in thesitting position. Herein, we discuss the possible advantages of VR-guided rehabilitation overtraditional training methods.
Key Words: body trunk balance; dual task; reaching; virtual reality; walking

INTRODUCTION

harmonized physical activity requiring (1) lower-extremity
muscle strength, (2) postural or trunk balancing ability, and(3) dual-task processing.5–8) Whereas lower-extremity
muscle strength can be increased by various methods, noeffective quantitative approach has been identified to train
for balance and dual-task processing skills with the subject
in the sitting position.5–8) VR-guided training can be applied
to rehabilitation of walking disabilities, such as those associated with disuse syndrome after hospitalization in elderly
people. Although this new technology is expected to become

Virtual reality (VR) technology has been recently introduced in a variety of clinical settings, e.g., physical,
occupational, cognitive, and psychological rehabilitation ortraining.1,2) In particular, VR-guided body balance training
to address neurological disorders such as stroke has garnereda lot of attention from physicians and therapists. Balance isessential for walking, and walking ability is a critical basic
function associated with the quality of life.1–5) Walking is a

Received: March 11, 2019, Accepted: May 19, 2019, Published online: May 31, 2019a Department of Rehabilitation, Eishinkai Kishiwada Rehabilitation Hospital, Kishiwada, Japanb Department of Medical Device Development, mediVR, Inc., Toyonaka, Japanc Center for Community-based Healthcare Research and Education, Shimane University, Izumo, Japand Hemoptysis and Pulmonary-Circulation Center, Eishinkai Kishiwada Rehabilitation Hospital, Kishiwada, Japan
Correspondence: Hideo Ishikawa, MD, Hemoptysis and Pulmonary-Circulation Center, Eishinkai Kishiwada Rehabilitation Hospital,
2-8-10 Kanmatsu-cho, Kishiwada, Osaka 596-0827, Japan, Email: h_ishikawa@eishinkaihsp.or.jp
Copyright © 2019 The Japanese Association of Rehabilitation Medicine

12Omon K, et al: VR-guided Dual-task Walking Training

Table 1. Serial changes in physical performance test results
Parameter
Baseline
After VR rehabilitation
Mini-mental state examination
26
26
Six-minute walking test, m
430
500
Timed up and go test, s
9.3
7.8
    dual-task mode, s
14.7
11.5
Ten-meter walk test, s
6.4
6.5
    dual-task mode, s
12.1
9.6
Berg balance scale
5053
Functional independence measure
100
100
Motor
76
76
Cognitive
24
24
Numerical rating scale for enjoyment (0–10)
7
7
Reaching distance in the sitting position, cm*
Left hand 0°
19.3
23.8
Left hand 45°
22.3
33.3
Left hand 90°
34.7
36.7
Right hand 90°
23.5
40.6
Right hand 135°
18.9
36.0
Right hand 180°
18.1
24.2
Hand grip, kg
Left
20.6
20.9
Right
19.2
22.1
Knee extension, kg
Left
21.2
21.4
Right
19.1
18.9
Timed up and go tests and 10-m walk tests were also executed in dual-task mode by asking the patient to count backwardfrom 100 by 2 during the activity.
*0° is to the left side and 180° is to the right side as viewed from above.
an increasingly useful tool to overcome the lack of humanand economic resources associated with rehabilitation medicine, the clinical efficacy of VR rehabilitation compared withtraditional training techniques remains to be elucidated.1–8)
CASE
A 90-year-old man with muscle atrophy and disuse
syndrome resulting from approximately 1-month’s hospitalization following the successful management of an acutehemorrhagic rectal ulcer at another hospital was transferred
to Eishinkai Kishiwada Rehabilitation Hospital for rehabilitation. The patient’s physical activity levels improved
and reached a plateau after 1 month of traditional physicaland occupational training at our hospital. At that time, hisheight was 160 cm, his weight was 47.4 kg, and his cognitive
function corresponded to a mini-mental state examination(MMSE) score of 26. As shown in Table 1, at baseline, thepatient’s 6-min walk distance (6MWD) was 430 m, the timed
up and go (TUG) test result was 9.3 s, the 10-m walk test wascompleted in 6.4 s, and the Berg balance scale (BBS) score
was 50. No motor dysfunctions such as paralysis were noted,
and the functional independence measure (FIM) was 100.
However, the risk of falling or colliding with obstacles suchas telephone poles persisted when the patient walked outside
the hospital, suggesting the presence of impaired dual-task
processing or attention deficits. When the TUG and 10-mwalk tests were evaluated in dual-task mode by asking thepatient to count backward from 100 by 2 during the tests, thetimes required were much longer than the single-task times(Table 1). Baseline values of the Trail Making Test (TMT)
and the Clinical Assessment for Attention (CAT, developedby the Japan Society for Higher Brain Dysfunction) also indicated the presence of generalized attention impairment, suchas the inability to perform TMT part B and the prolonged

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3Prog. Rehabil. Med. 2019; Vol.4, 20190011

Table 2. Trail-making test and clinical assessment for attention
Parameter
Baseline
After VR rehabilitation
Trail-making test
Part A, s
226
NAPart B, s
Could not complete
NA
Clinical assessment for attention
Digit span, forward
7
7
Digit span, backward
3
5
Tapping span, forward
5
5
Tapping span, backward
44
Visual cancellation (triangles)
Time required, s342
148
Correct rate, %100
100
Success rate, %98
100
Visual cancellation (symbols)
Time required, s327
190
Correct rate, %74
81
Success rate, %100
98
Visual cancellation (3)Time required, s416
441
Correct rate, %93
98
Success rate, %100
100
Visual cancellation (Japanese Kana)
Time required, s508
467
Correct rate, %92
96
Success rate, %100
100
Symbol digit modalities test
Accomplishment rate within 90 s, %12
14
Memory updating (three span)
Correct rate, %75
75
Memory updating (four span)
Correct rate, %25
50
Positional Stroop test
Time required, s109
145
Correct rate, %99
100
The success rate was calculated as the number of correct answers/the total number of responses.
NA, not available, i.e., the tests were not performed.
The auditory detection task and paced auditory serial addition test could not be performed because of the patient’s severe
hearing impairment. The continuous performance test could not be performed because of the unavailability of the designatedoperating system for the computer.
time required to complete visual cancellation (Table 2).
To help the patient regain the ability to walk independently, in addition to conventional rehabilitation practices, we
utilized a newly introduced medical device for VR-guided,dual-task, body trunk balance training (mediVR KAGURA,
mediVR, Inc., Toyonaka, Japan, commercially available
from February 4, 2019).5) The mediVR KAGURA system

was developed to help patients regain walking ability by
improving their dual-task processing and trunk balancing.5)
We applied VR-guided training because no additional improvements could be expected in the patient as a result of theaforementioned traditional physical and occupational training; however, the efficacy of VR-guided training remained
unclear. As shown in Fig. 1, the patient was instructed to

Copyright © 2019 The Japanese Association of Rehabilitation Medicine

4Omon K, et al: VR-guided Dual-task Walking Training

Fig. 1. Images of mediVR KAGURA-guided rehabilitation.
(A) A physical therapist demonstrates VR-guided training
tasks. The patient is instructed to catch red or blue falling
objects or to touch red or blue fixed targets with their rightor left hand controllers, respectively, in a three-dimensional
virtual space. These tasks can be provided in the style of avideogame such as (B) a falling carrot thrown by a farmer or(C) a fixed small box bearing a symbol (similar to a police
badge) that is used in a popular Japanese television period
drama.
catch red or blue falling objects or to touch red or blue fixed
targets in a three-dimensional virtual space with his right orleft hand controllers, respectively. To ensure safety, the training was performed with the patient in the sitting position:
training in the standing position is prohibited according to
the device package insert. The mediVR KAGURA system
can provide videogame-like training to enhance motivationand to ensure adherence. By setting seven parameters, i.e.,the distance, angle, height, and size of the object; the size ofthe controller; the inter-task interval; and the falling speed
or time limit for each task, the therapist can provide patientswith reaching training in a dual-task fashion utilizing various levels of physical and cognitive stimulation. Cognitive
stimulation was designed to emulate the way in which cognitive and attention functions are processed during walking.
For example, a red object should be caught using the righthand controller and the blue object should be caught using
the left hand controller. Differentiation of the color of objects

emulates the cognitive processing required to differentiate
traffic signals. The recognition of a new object in threedimensional space and a timely reaching response, withconsideration of the aforementioned seven parameters, emulate the cognitive processing involved in hazard perception
and facilitate hazard avoidance, such as colliding with otherpeople when walking outside the hospital.
The VR system places a radar screen at the center of thehead-mounted display to indicate the direction of the nexttask, and the patient needs to regularly refer to this radar
screen. To evaluate or train the attentional ability of the patient, some gaming characteristics have been added that aredesigned to attract attention away from the radar screen. VRguided training was performed for 40 min every weekday for
2 weeks (5 days per week). First, we tried to provide 20 min
of VR-guided training on a trial basis because Japanese
health insurance guidelines define 20 min of rehabilitation as
1 unit. However, the patient was eager to undergo VR-guided
therapy for 40 min without any interval because he foundit enjoyable (corresponding to a numerical enjoyment rating
scale score of 7).
Serial changes in physical performance and attention testscores 2 weeks after the VR-guided training are shown in
Table 1 and Table 2, respectively. The 6MWD improved
from 430 m to 500 m despite the absence of improvements
in MMSE, FIM, or muscle strength of the lower extremities[which was evaluated by knee extension measured using ahandheld dynamometer (µTas F-1, Anima, Tokyo, Japan)].
TUG test results improved by 1.5 s (from 9.3 to 7.8 s) witha 3.2 s improvement for dual-task TUG. There was no improvement in the 10-m walk test, but the test performance
improved by 2.5 s when carried out in dual-task mode.
Regarding the BBS score, reaching forward, placing alternating feet on a stool, and tandem stance improved by 1
point each. The patient did not get bored of participating inthe VR-based rehabilitation program, as indicated by there
being no changes in the numerical rating score for enjoyment. Several attention test indices, including the digit spanbackward test, the time required to complete visual cancellations of a triangle or symbol, and the correct rate of memory
updating (four span) drastically improved. As a result of 2
weeks of VR-guided training, the patient could successfully
walk outside the hospital without falling or colliding withobstacles. However, after the 2 weeks of VR-guided training,
the patient was unfortunately discharged to a nursing homefor nonmedical reasons. Consequently, potential additional
improvements from further training could not be attempted.
Informed consent for the submission of this case report was

Copyright © 2019 The Japanese Association of Rehabilitation Medicine

5Prog. Rehabil. Med. 2019; Vol.4, 20190011

obtained from the patient by the attending physical therapist in compliance with the standard operating procedures
defined by the institutional ethics committee at Eishinkai
Kishiwada Rehabilitation Hospital.
DISCUSSION
It is noteworthy that, after the lower limb strength had
plateaued, the walking ability of this patient was improvedby the addition of VR-guided, dual-task, body trunk balance training executed with the patient seated. We believethat it would not have been possible to improve the walking
ability without VR-guided training in this case because thepatient’s walking ability had reached a plateau 1 month after
traditional physical and occupational training at our hospital. This result challenges the traditional belief that walking
rehabilitation should be provided in the standing position,
especially by encouraging patients to walk. Consequently,
this finding suggests that there may be several possible new
approaches to improving walking disability.6)
For example, reaching training using hooks or hoops is avery conventional and fundamental approach to improving
postural or trunk balance.7) However, postural balance training cannot be quantitatively performed in a replicable way
using these conventional approaches.5) It is time consuming
to change the intensity of postural balance stimulation because therapists need to repeatedly change the position of
the hook for each task. In contrast, VR facilitates an easy,
prompt, quantitative, and replicable method of training by
accurately setting the distance, angle, height, or other parameters in a three-dimensional virtual space.5) The therapist’s
only responsibility is to adjust these parameters by typing
numbers on the operating panel of a computer. Moreover,the unpredictable nature of VR-training tasks may require
much more precise postural control for patients. The rationale for sitting training is that two-thirds of the total bodyweight is centered in the upper body, and improved upper
body balance is expected to result in stable balancing during
walking.9) Consequently, we speculated that tailor-made,optimized, and unpredictable VR-guided training tasks
might make a greater contribution to more effective posturaland trunk balance than conventional approaches, even when
performed in a sitting position.
Likewise, conventional dual-task training is provided byasking patients to talk with the therapist, to count backwardfrom 100 by a specific number, or to perform tasks suchas the paper–scissors–stone game simultaneously withwalking.7,8) However, we consider that these conventional

dual-task training schemes do not directly emulate the cognitive functions needed while walking in a city or town.
Although the current patient could walk steadily inside thehospital with a 6MWD of 430 m at baseline after 1 monthof conventional rehabilitation at our institution, his walking
ability remained unstable with the risk of falling or colliding
with obstacles outside the hospital. This may have resulted
from information overload or attention deficits. One of thestrengths of VR-guided training is the controllability ofcognitive stimulation in a uniform environment in a waythat mimics the cognitive processes needed during walking
in a city or town as described in the case presentation section above.5) During VR-guided rehabilitation, the patient
continuously had to think about the next task, i.e., when andwhere the next falling object will appear, followed by timely
reaching tasks, emulating the conditions of hazard perception and avoidance. As a result, in the current patient, several
parameters, including the 6MWD, the TUG test with andwithout dual tasking, the dual-task 10-m walk test, the BBS,
and the likelihood of falling outside the hospital improved
even without improvements in the MMSE or FIM scores or
the lower-extremity muscle strength. VR seems to be a more
appropriate technology than augmented or mixed reality
technologies when trying to provide patients with uniform
and replicable environments for cognitive stimulation or
evaluation. This is because the landscape or environmental
information changes when augmented or mixed reality technologies are used in different locations.
Because of improvements in several CAT indices in thecurrent patient, we speculated that VR-guided attention
training contributed to improved walking ability outside of
the hospital. TMT or components of CAT have been used
to evaluate attention deficits for decades.10,11) Attention
deficits are historically categorized into five components,
as proposed by Sohlberg et al., namely, focused, selective,
sustained, alternating, and divided attention.12) The patient’s
general attention might have improved; however, we also
understand that his focused and selective attention were
profoundly impacted by the VR-guided training because
the digit span backward test, the time required to complete
visual cancellations of a triangle or symbol, and the correct
rate of memory updating (four span) markedly improved.11,12)
Regrettably, for nonmedical reasons, the current patient
was discharged after 2 weeks of VR-guided training; consequently, additional improvement could not be attempted,
even though longer intervention is considered to be more effective.13) Furthermore, the advantages and disadvantages of
VR-guided rehabilitation have not yet been clearly identified.

Copyright © 2019 The Japanese Association of Rehabilitation Medicine

6Omon K, et al: VR-guided Dual-task Walking Training

It appears that VR-guided training safely increases motivation, although the majority of evidence has been obtainedin the upper limb rehabilitation of stoke patients.14–16) VRguided training can make rehabilitation more enjoyable andit is expected to contribute to effective training in this casereport.13)
There are several two-dimensional programs available fortrunk balance training in clinical settings. For example, theNintendo Wii Fit (Nintendo, Kyoto, Japan) is reportedly effective in improving BBS or TUG.17,18) However, some physicians have suggested that VR, which is three-dimensionalin nature, has additional advantages in providing accurate
instructions and quantitative assessments compared to twodimensional programs.5) Consequently, the differences
between two- and three-dimensional VR-guided training isanother pertinent subject for research in the field of rehabilitation.
In conclusion, we presented an interesting case in which
VR-guided, dual-task, body trunk balance training withthe subject in the sitting position helped improve walking
ability. However, the nature of this single case report limits
the reliability of the identified efficacy of VR-guided training and also limits the external validity. Because the numberof patients with walking disability is increasing worldwide
in this era of super-aged societies and because VR-guided
training in the sitting position can be provided safely without additional human resources, the clinical efficacy of thistype of training warrants further evaluation in prospectively
designed studies.
CONFLICTS OF INTEREST
Masahiko Hara is the chief executive officer and a stockholder of mediVR, Inc., a company that holds several patents
on VR-guided, dual-task rehabilitation. However, this casereport received no specific grant from any funding agency
in the public, commercial, or not-for-profit sectors. Kyohei
Omon and Hideo Ishikawa have no conflicts of interest to
declare.
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