The Effects of Virtual Reality on Visual Neglect

The Use of Virtual
Reality with
Unilateral Spatial
Presented By: Angela Hall, MOTS
March 24, 2012
 Background Information on CVA, Unilateral Spatial
Neglect, and Virtual Reality
 Objective of the Systematic Review
 Search Strategies
 Summary of Study Procedures
 Methodology
 Results
 Implications for OT practice and future research
Cerebrovascular Accident
Cerebrovascular Accident
CVA Complications
 Hemiplegia
 Apraxia
 Impaired
 Impulsivity
 Impaired Spatial
 Unilateral Spatial
 Impaired Balance &
 Poor Attention Span
 Weakness
 Aphasia
National Stroke Association
Unilateral Spatial Neglect
Weiss, Naveh, & Katz, 2003
USN and Function
 Impaired ability to perform self-care activities
 Poor mobility
 Difficulty feeding oneself
 Impaired reading comprehension
 Impaired safety
Buxbaum et al, 2008; Weiss et al, 2003
Current Assessment
 Behavioral Inattention Test
 Line bisection
 Cancellation
 Drawing
 Reading/Writing
Buxbaum et al, 2008; Pierce & Buxbaum, 2002
Current Treatment
photos:, Harding & Riddoch, 2008
Buxbaum et al, 2008; Pierce & Buxbaum, 2002
Virtual Reality
Weiss et al, 2003
Benefits of VR
 Experience real-life situations in safe environment
 Simple to change environment & grade activity
 Provides immediate feedback
 Repeated learning trials
 Produces computer generated output
 May provide information on head and eye
Weiss et al, 2003
The objective of this review is to
examine the extent to which the
research literature supports the use
of virtual reality as an effective
assessment tool and treatment
technique for patients experiencing
USN following a CVA
Search Terms
 stroke
 virtual technologies
 cerebrovascular
 left visual neglect
 visual neglect
 unilateral spatial
 virtual reality
 unilateral neglect
 hemineglect
Summary of Study
Study Sizes
 Groups
 Eight studies included a patient group with 2-12
participants and a control group with 3-21
 Two studies used only one group
 Four participants
 Eight participants
 Gender
 Four studies included more men
 One study included more women
 Three studies included equal amounts of men and
 Two studies did not specify participant gender
 Patient Groups
 Eight of ten studies included participants ranging in age
from 34-77
 Eight of ten studies included participants with a right
hemispheric lesion
 Eight of ten studies required participants to exhibit clinical
visual neglect
 All ten studies required participants to understand
directions and have functional use of at least one limb
 Exclusion criteria: Substance abuse and prior history of
neurological or visual impairment
 Control Groups
 Included participants ranging from 34-77
 Seven studies used groups of neurologically healthy
 One study used patients with right hemispheric
 Exclusion criteria: Substance abuse and prior history
of neurological or visual impairment
Interventions &
VR as an Assessment
Study One
 The star cancellation portion of the Behavioral Inattention
Test (BIT) and baking tray test
 Cancellation test in the VR environment
Study Two
 Completed the line and star cancellation subtests of the
 Same tests using two lenses on a head-mounted display
Study Three
 3D neglect test consisting of a city environment
Broeren et al., 2007; Tanaka et al., 2005; Jannink et al.,
VR as an Assessment (2)
Study Four
 Used a “VREye” system to differentiate between eye
tracking patterns of the control and patient groups
by asking participants to identify 10 objects and the
time on a clock
Study Five
 Participants navigated wheelchair along a virtual
path with a variety of conditions
 Moss-Magee Wheelchair Navigation test, several
subtests of the BIT, and the Bell test
Gupta et al., 2000; Buxbaum et al., 2008
VR as an Intervention
Study One
 Practiced street crossing in a virtual environment twelve
times over a 4-week period.
Frequency, order and direction of subjects’ search
Number of trials and length of time it took to complete each level
Highest level successfully completed at the end of training.
Ability to cross a real street safely
Study Two
 Patients trained on virtual street crossing,
Deviation angle
Reaction time
Visual and auditory cues required
Failure rate of missions.
Weiss et al., 2003; Kim et al., 2007
VR as an Intervention (2)
Study Three
 Compared group receiving VR street crossing to a group
receiving visual scanning training.
 Outcome measures: Star cancellation from the BIT,
Mesulam Symbol Cancellation test, ADL checklist, virtual
reality street crossing test, and a real street crossing test.
Study Four
 Participants received six weeks of VR training consisting of
“Birds and Balls” and “Soccer” games.
 Outcomes measured by comparing pre-post test scores on
the Bell’s test and BIT.
Katz et al, 2005; Smith; 2007; Ansuini et al, 2006)
VR as an Intervention (3)
Study Five
 Participants reached for real objects located at 1 of
the 3 locations while viewing the real-time virtual
representation of their hand.
 Outcome results were measured based on the
percentages of trials in which the object was
successfully detected.
Common Limitations
Lack of randomization
No blinding of test administrator
Short duration of treatment
None of the patient groups had more than 12
 Only one study had significant number of participants
(n=50; Kim et al., 2007)
 Unequal groups
 Failure to mention psychometric properties of
 Failure to use all subsections of a test
Assessment Results
 Study One (Broeren et al., 2007)
 Showed that VR testing yielded more sensitive results
 6 of 8 patients demonstrated a difference in search patterns
 Patients had more hand deviation when moving from
 Study Two (Tanaka et al., 2005)
 Significant difference between conventional neglect
assessments and virtual reality assessments on the left side
Assessment Results (2)
 Study Three (Buxbaum et al., 2008)
 Patients scored below the control group in four
 Significant differences within the patient group with
complexity of object array (p<0.01) and side of object
presentation (p<0.05)
 Study Four (Jannink et al., 2009)
 Significant differences exist between groups in total time
spent at the test (p=0.049) and mean response time in
left field of view (p=0.037).
 No significant differences were found at level 3.
Assessment Results (3)
 Study Five (Gupta et al., 2000)
 Control patients were able to identify and count all
objects and view the entire display.
 Patient with left neglect identified only 3 of 10
objects and reported the wrong time.
 Patient with right neglect was only able to identify
one of the objects and reported an incorrect time.
Intervention Results
 Study One (Kim et al, 2007)
 Significant differences (p<0.05) found in deviation
angle, reaction time, visual cues, auditory cues, and
failure rate of mission.
 Study Two (Weiss et al, 2003)
 Patient group took longer to complete street crossing
levels and had more total accidents.
 Control group had more accidents in level 3, but the
patient group had more accidents in level 5.
Intervention Results (2)
 Study Three (Katz et al, 2005)
 Improvements (p<0.05) for the group receiving VR
training and the group receiving computerized
scanning on and ADL checklist.
 The VR group made significant improvements in
looking left (p<0.05) and number of accidents
(p<0.035) in virtual street crossing.
 No significant difference in real street crossing
Intervention Results (3)
 Study Four (Smith, 2007)
 Found no significant differences in the scores of these
patients after 6 weeks of intervention.
 Qualitative remarks suggest that the clients found the
interventions helpful.
 Study Five (Ansuini et al., 2006)
 Patients with a fronto-parietal lesion demonstrated
significant improvements in response to left targets
(p<0.01) and on the sensory task (p< 0.01) while patients
with a temporo-parietal lesion did not show
 Virtual reality may be an effective assessment
tool that can provide more information and
more sensitive results compared to conventional
neglect assessments.
 Studies have compromised validity
 Results showed differences in search patterns in
two studies, but the authors did not address
whether this may be due to visual scanning
deficits (Broeren et al., 2007; Gupta et al., 2000).
Discussion (2)
 Many of the studies showed statistical differences
between the patient groups and control groups
 Expected result because control groups were primarily
composed of healthy individuals.
 Two studies presented evidence suggesting that VR may
be more sensitive at detecting mild neglect (Broeren et al.,
2007; Jannink et al., 2009).
 Some patients who were considered “clinically recovered” by
conventional assessments demonstrated at least mild neglect
on VR assessments especially with complex environments
Discussion (3)
 In one study, patients improved performance in the
VR environment, but this did not translate to a reallife setting.
 May indicate that VR training has limited carry over for
functional improvements.
 The vast array of VR technology utilized limits
 Evidence demonstrates the emerging potential for
virtual reality in the assessment and treatment of
visual neglect following a CVA.
Implications for OT
 VR can help patients and families become more
aware of the deficits and safety challenges
 May help improve space deficits and maximize
compensation of the contralateral visual side to
help patients maximize performance in ADLs.
 Offers OTs the opportunity to provide the patient
with real-time performance feedback and detailed
recordings of kinematics of the hand allowing for
more in-depth tracking of the progress
Implications for OT
Practice (2)
 Potential to detect and measure USN in sub-acute
and chronic stages of stroke recovery.
 Help clients become aware of what they are
missing in the real-world and develop strategies to
compensate for the neglect.
 VR test was also sensitive to mild neglect that is
often difficult to detect with conventional neglect
Implications for Future
 Improved studies using larger sample sizes, different
virtual environments, and patients with various
motor and cognitive impairments to generalize
specific training skills.
 Focus on increasing the array of complexity of
objects presented to the clients.
 Test the effect of dynamic objects versus static
objects on subjects’ eye movements and to
determine if this technique can be used to train
subjects to visualize information on the neglected
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M. (2007). Neglect assessment as an application of virtual reality. Acta Neurologica Scandinavica,
116(3), 157-163.
Buxbaum, L., Ferraro, M., Veramonti, T., Farne, A., Whyte, J., Ladavas, E., Frassinetti, F., Coslett, H.
(2004). Hemispatial neglect: Subtypes, neuroanatomy, and disability. Neurology, 62(5), 749-756.
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