A portable virtual reality balance device to assess mild traumatic brain injury symptoms: A pilot validation study

Abstract

Mild traumatic brain injury (mTBI) following a head impact or blast exposure can cause diffuse injury to the brain, which can affect sensorimotor, cognitive, and emotional processes. Among the most common sensorimotor symptoms of mTBI is balance impairment. A commonly used assessments of balance following mTBI is the sensory organization test (SOT). This test has shown that postural deficits following head injury may be due to visual-vestibular processing issues, but it is less sensitive to unremitting symptoms that do not spontaneously resolve within a week. Our current project involves demonstrating validity and reliability of a novel low-cost, portable virtual reality-based balance screening device that employs established principles of sensorimotor reweighting and visual-vestibular integration. The goal is to determine if it can replace existing tools that are either prohibitively expensive or lack reliability or sensitivity. Methods: Healthy adults with no known musculoskeletal or neurological injury (n=27; 17 males, 10 females; 22.1+3.9 years) were tested to establish healthy norms. Individuals with mTBI (n=8; 4 males, 4 females; 20.0+1.7 years) were compared to the healthy norms. The new VR-based balance assessment system consists of a Wii balance board (WBB), a large screen television, and a custom-designed software user interface used to collect and process data. Subjects performed six upright postural tasks (three visual conditions either standing directly on the WBB or on foam placed on the WBB). Subjects viewed a virtual reality scene displayed on a 60" television. The three visual conditions were Static Scene, Dark Scene, and Dynamic Scene (Roll at 60 deg/s). The WBB recorded COP at 100Hz for 30 sec. Dependent variables included COP velocity, root mean square, and sway area. Subjects also performed the sensory organization test (SOT), which can be used as criterion-measures for intraclass correlations with the new device. Results: Preliminary data on healthy subjects validates effectiveness of the device to reduce postural stability as sensory input reliability and availability decreases. Additionally, our results reveal that individuals with mTBI have significantly worse balance scores on the new VR-device (p<0.001). This highlights its sensitivity to balance disturbance even if when testing a small sample. Comparison of the new device to SOT shows good criterion validity with ROC curves revealing sensitivity/specificity equal or higher than the SOT. COP sway area, velocity, and standard deviation of medial-lateral and 7KLV UHVHDUFK LV VXSSRUWHG E\ WKH &RQJUHVVLRQDOO\ 'LUHFWHG 0HGLFDO 5HVHDUFK 3URJUDP ± 5DSLG ,QQRYDWLRQ )XQG :;:+& :*: 72 978-1-4799-8984-3/15/$31.00 ©2015 IEEE

Concussion Recovery Phase Affects Vestibular and Oculomotor Symptom Provocation

“…The subjectivity and variance of symptoms and lack of objective diagnostic criteria complicate efforts to accurately identify a concussion [12,19,21]. A multifaceted approach including not only signs and symptoms (S/S) but the inclusion of ocular-motor, cervical, and vestibular screenings has been suggested to overcome this obstacle [7,23,24,27,35,38]. Clinical evaluations incorporating advanced posture control analysis and oculomotor assessment have been shown to identify concussed athletes with 98.6 % accuracy [25].…”

“…Many diagnostic tests have been shown to reliably detect deficits in postural control in a concussed population [14,25,29]. Common tests include the Balance Error Scoring System (BESS) and the Sensory Organization Test (SOT) [6], while others include advanced technology such as the use of virtual reality [32,33,35,36]. Objective outcome measures with high sensitivity and specificity often require costly instruments such as high-resolution cameras and force plates that are not readily available on the sideline.…”

The Validity of an Oculus Rift to Assess Postural Changes During Balance Tasks

“…VBAL will be compared with a previously validated forceplate-based criterion measure for balance assessment (i.e., VETS device; see Wright et al, 2015Wright et al, , 2017. That original postural assessment device wirelessly collecting COP data from a WBB via a Bluetooth connection while presenting simulated VR motion on a large commercially available television monitor (e.g., VIZIO E-Series Razor LED 60 inches, Irvine, CA).…”

“…That original postural assessment device wirelessly collecting COP data from a WBB via a Bluetooth connection while presenting simulated VR motion on a large commercially available television monitor (e.g., VIZIO E-Series Razor LED 60 inches, Irvine, CA). The WBB has been validated for posturography (Bartlett, Ting, & Bingham, 2014;Young, Ferguson, Brault, & Craig, 2010) and has been validated with our VETS user interface in previous studies (Wright et al, 2015;. The WBB and HMD were synced through VETS and VBAL, respectively, using a custom code that sends a TCP/IP command to a local host, which then sends a common signal back to both programs to begin and end data collection.…”

“…Traditional measures of postural control, such as COP, have been shown to be susceptible to manipulations in visual and somatosensory input, suggesting that these systems are functionally linked in humans' control of balance (Horak, 2006;Schärli, van de Langenberg, Murer, & Müller, 2012;Wright, McDevitt, & Appiah-Kubi, 2015;Wright et al, 2017). Less is known, however, about how these measures impact head position and whether changes to COP occur independent of shifts in head position.…”