Vestibular Rehabilitation using a Wide FOV Virtual Environment

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Vestibular Rehabilitation using a Wide FOV
Virtual Environment

• PJ Sparto, JM Furman, SL Whitney, LF Hodges, MS
  Redfern

Sponsors Eye and Ear Foundation NIH P30DC005205,
R21DC005372, K23DC005384, K25AG001049
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Rationale for use of VR

• Inner ear disorder will result in dysfunction of
  the vestibulo-ocular reflex (VOR), which allows
  us to maintain stationary gaze position during
  head turns
• Recovery of abnormal VOR requires visual input
  and head movement
• Viirre et al. (1996) and Kramer et al. (1998)
  proposed use of VR for vestibular rehab
• Stimuli can be delivered in controlled manner

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Rationale for use of VR

• Greater incidence of anxiety and panic disorders
  in people with dizziness
• Dizziness/anxiety often induced by complex visual
  environments
• Grocery stores, shopping mall
• Driving through tunnels
• Head movements and optic flow
• Habituation/exposure therapy is a common
  treatment strategy for these patients

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Rationale for wide FOV

• Wide FOV
• Peripheral motion cues provide greater sense of
  vection, which is important for postural control
• Higher cost and greater space
• HMD
• Cost-effective
• Eyestrain, headache, binocular vision changes
• Maladaptive response because of extra inertia

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Balance NAVE (BNAVE) 3 back-projected screens 1
front-projected floor 180o Horiz x 90o Vert
FOV Surface rotate and translate
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Clinical research flow chart

• Development of environments
• Determine if user interfaces are safe
• wide FOV
• HMD
• What is efficacy of rehab?

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Development of environments

• Extract elements from real grocery store
• Design geometric models
• Model virtual grocery store

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Virtual grocery store

• Complexity of store can be easily changed
• Size of product
• Height of shelves
• Width of aisle
• Pattern on floor
• Reflection of light on floor

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Device safety

• Can subjects perform coordinated head/eye
  movements without getting sick
• 9 healthy subjects performed 8 different
  coordinated head and eye movements on each visit
• 6 visits, consisting of a different background
• 1 Solid background
• 1 Geometrical elements (stripes), stationary
• 4 Optic flow (moving stripes)

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Show box target
Clinical research flow chart
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Device safety

• Subject Tolerance
• Subjective Units of Discomfort (SUDS)
• 0 to 10
• Simulator Sickness Questionnaire (SSQ, Kennedy et
  al.)
• 16 items rated 0 to 3 (none, slight, moderate,
  severe)
• Disorientation (blurred vision, dizziness,
  vertigo)
• Nausea (e.g. sweating, nausea, concentration)
• Oculomotor stress (e.g. fatigue, headache,
  eyestrain)

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Gaze coordination

• Motion Analysis
• Postural Sway
• Head and eye movements (gaze)
• Timing and accuracy of movements

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Head movements 6 DF Electromagnetic sensor Eye
movements Horizontal and vertical
Video-oculography (VOG)
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Next steps

• 3 subjects with dizziness have begun trials to
  determine safety
• Run experiment in virtual grocery

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Show store target
Clinical research flow chart
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Next steps

• Run experiment using HMD
• Add treadmill
• Clinical trials - efficacy

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University of Pittsburgh Depts of Physical
Therapy, Otolaryngology, BioEngineering UNC-Charlo
tte Dept of Computer Science Invaluable
contributors Jeffrey Jacobson, Leigh Mahoney,
Sabarish Babu, Chad Wingrave, many others
www.mvrc.pitt.edu