The Effect of Binasal Occlusion on Balance Following a Concussion
Phase: NA
Conditions: Concussion Post Syndrome
Sponsor: University of Ottawa

 
 
 
 
 
 
 
 
 
Title:  The Effect of Binasal Occlusion on Balance Following a Concussion: a 
Randomized Controlled Trial Protocol 
 
 
NCT number: not available 
 
 
Document Date:  November 16, 2017 
 
 
 

THE EFFECT OF BINASAL OCCLUSION ON BALANCE FOLLOWING A 
CONCUSSION: A RANDOMIZED CONTROLLED TRIAL PROTOCOL 
 
ABSTRACT 
 
Introduction 
 
While most individuals will recover within the first month after concussion, a 
significant number will continue to experience dizziness, balance problems, 
cognitive deficits, and vision problems.  Single-task measures of static balance may 
not be sensitive enough to capture mild postural changes still associated with 
incomplete recovery.  Increasingly there is an interest in dual-task paradigms of 
balance assessment as a more accurate representation of functional postural control 
associated with activities of daily living and sport participation.  Binasal occlusion 
(BNO) has been proposed as a means of providing visual stabilization to improve 
postural control in individuals with vision-related balance problems following a 
concussion.  The purpose of this study is to assess the efficacy of BNO during the 
performance of both single and dual-task conditions in adults who continue to 
experience dizziness one month or longer following a concussion.  It is hypothesized 
that BNO will improve balance and saccadic eye function, and reduce symptoms.  
This article presents the research protocol for this study. 
 
Methods and analysis 
This study is a randomized crossover design balanced with respect to first-order 
effects.  Participants will be recruited and randomly assigned to one of two 
treatment sequences, binasal occlusion (BNO) or non-occluded vision.  Both groups 
will perform the same static balance tasks, including quiet stance performed during 
target-focused vision and a visually based cognitive dual-task.  Following a short 
washout period, participants will repeat the balance tasks under the alternate 
treatment condition.  The primary outcome measure is centre of pressure (COP) 
velocity in both the medial-lateral (M/L) and anterior-posterior (A/P) planes and 
95% ellipse.  Secondary outcome measures include saccadic eye function and self-
report measures of symptoms and disability (neck and dizziness related). 
Ethics and dissemination: 
Results of this randomized controlled trial (RCT) will allow clinicians to make 
evidence-informed decisions regarding the management of persistent balance 
problems post-concussion.  Ethics has been obtained through the University of 
Ottawa Research Ethics Board (REB #H06-17-20).  Results will be disseminated at 
professional conferences and in manuscripts to peer-reviewed journals. 
 

INTRODUCTION 
 
Concussion is defined as a traumatic brain injury induced by biomechanical forces 
that can result in a transient neurologic impairments (McCrory et al., 2017).  While 
most individuals recover within the first month after injury (McCrory et al., 2017), 
up to 30% will continue to experience persistent post-concussion symptoms beyond 
the expected period of normal recovery (Zemek, Farion, Sampson, & McGahern, 
2013).   A significant number of these individuals will experience dizziness, balance 
problems, cognitive deficits, and vision problems after concussion, which have been 
associated with prolonged recovery (Lau, Kontos, Collins, Mucha, & Lovell, 2011; 
Lovell et al., 2006; McCrory et al., 2017).  The pathophysiologic process underlying 
prolonged recovery is not yet clearly defined.   
 
As such, a multimodal assessment representing the multiple systems involved in the 
injury is recommended, including symptoms, cognition, balance and a clinical exam.  
Most research investigates the impact of concussion on these measures 
independently.  While each of these objective measures is an integral component in 
the acute diagnosis of concussion, they may not independently demonstrate 
sufficient sensitivity to monitor recovery from the injury.  A growing body of 
evidence suggests that physiologic recovery extends beyond current measures of 
clinical recovery (Kamins et al., 2017; Levac, DeMatteo, Hanna, & Wishart, 2008).  
This suggests that single-task measures of static balance may not be sensitive 
enough, however, to capture the complex demands of integrating cognition with 
postural strategies associated with sporting activities and functional daily tasks.  
Therefore, testing balance alone may not be sensitive enough to mild postural 
changes still associated with incomplete recovery.  Increasingly there is an interest 
Article Summary  
Article focus 
 This article describes the protocol for an RCT to measure the effect of BNO 
on balance in adults with persistent balance problems one month or more 
following a concussion. 
Key messages 
 Disturbed balance is common post-concussion, and associated with 
prolonged recovery. 
 High quality evidence for the use of BNO does not exist for patients with 
persistent balance deficits post-concussion. 
Strengths and limitations of study 
 This is the first RCT to examine the effect of BNO in this population. 
 The results of this study will allow clinicians to make evidence-informed 
decisions regarding the management of persistent balance problems post-
concussion. 
 Other pathophysiologic mechanisms responsible for balance deficits post-
concussion may affect the generalizability of results. 

in dual-task paradigms of balance assessment as a more accurate representation of 
functional postural control.  Dual-task is defined as the simultaneous performance 
of cognitive and a motor task, such as balance.  Higher-level cognitive effort required 
in dual-task performance is thought to divert attention away from postural 
strategies, resulting in postural sway changes.  This is of clinical significance, given 
that return to clinically normal balance is considered a prerequisite prior to 
returning to sports participation (McCrory et al., 2017),which typically demands the 
simultaneous integration of cognitive and postural tasks.  While studies on 
concussed athletes have demonstrated a reduction in cognitive and/or static 
balance tasks using dual-task paradigms (Broglio, Tomporowski, & Ferrara, 2005; 
Rochefort et al., 2017), these paradigms are not widely used in the clinical decision-
making process for return to sport. 
 
Within both the clinical and research setting, measurement of balance provides 
valuable information.  Force plates are considered the “gold standard” for assessing 
balance by measuring centre of pressure (COP) generated from foot pressure during 
stance (O’Connor, Baweja, & Goble, 2016).  Centre of pressure is considered a proxy 
measure for postural sway, a common strategy for maintaining balance.  Studies of 
postural control in individuals 3 months or more post-concussion demonstrate a 
significant increase in COP displacement compared with controls (Degani et al., 
2017).  These changes in COP during quiet stance are primarily reflective of the 
vestibulospinal reflex, which relies heavily on proprioceptive input.  This may not be 
an adequate representation of demands placed on the postural system during 
activities of daily living and sport, since maintenance of balance requires the 
complex interaction between the proprioceptive, vestibular, and visual systems.  
 
Given that approximately half of the brain’s pathways are linked to vision (Galetta, 
Morganroth, et al., 2015; Rizzo et al., 2016), it’s not surprising that there has been 
increasing interest in assessing vision pathways to further our understanding of the 
pathophysiology of concussion.  Research has identified impairments in oculomotor 
function, including saccades, in individual immediately after concussion and up to 3 
months and more post-injury (Master et al., 2016).  Saccades, the ability of the eyes 
to move rapidly and accurately between two targets, such as when reading, is 
typically measured objectively using video-oculography (VOG) or using clinical tests 
of rapid eye movement.  Knowledge of the number of saccades generated or 
pathology in saccadic characteristics would contribute to our understanding of the 
underlying mechanism of prolonged reading times (Rizzo et al., 2016).  This is 
possible by capturing objective metrics of eye movement obtained through infrared-
based video-oculography. 
 
Vision problems are common post-concussion, including subjective complaints of 
double or blurred vision, oculomotor problems, visual information processing, and 
visual attention (Yadav, Thiagarajan, & Ciuffreda, 2014).  Clinical tests of oculomotor 
function, have been recently identified as an important component of the initial 
screening exam in the acute diagnosis of concussion (McCrory et al., 2017; Patricios 
et al., 2017).  According to a recent systematic review on oculomotor assessment in 

mild traumatic brain injury, saccadic eye movements are most frequently 
investigated (Hunt, Mah, Reed, Engel, & Keightley, 2016).  Among measures of 
oculomotor vision, the King-Devick Test (KDT) has become a popular sideline 
screening tool for concussion, due to its ability to tap into the domain of oculomotor 
function not otherwise assessed by best practice diagnostic tools, such as the 
Standardized Concussion Assessment Tool-5 (SCAT5).  The KDT is a reading test of 
rapid number naming speed that assesses saccadic eye movement, attention, and 
cognitive function.  In addition to its ability to diagnose an acute concussion with 
high sensitivity and specificity (Galetta, Liu, et al., 2015), emerging evidence 
supports the use of the KDT as an indicator of recovery in patients with persistent 
post-concussion symptoms (Rizzo et al., 2016; Subotic, Ting, & Cusimano, 2017).  
Previous studies have shown that the KDT test times correlate with complex 
cognitive processes, providing evidence of convergent validity (Subotic et al., 2017).  
This supports its use in a dual-task paradigm to assess balance in a concussed 
population.   
 
Vision therapy is commonly prescribed for oculomotor problems prevalent 
following a concussion.  Binasal occlusion is a safe and minimally invasive technique 
that has been proposed in the symptomatic management of vision-related problems, 
including dizziness (Ciuffreda, Yadav, & Ludlam, 2017; Gallop, 2014; Proctor, 2009).  
However, little is known regarding the efficacy of binasal occlusion (BNO) in vision 
therapy for the management of persistent balance problems in this population.   
The application of BNO involves blocking the middle of the binocular visual field by 
placing narrow strips of opaque occlusive material on the nasal portion of both 
lenses of a pair of glasses (Ciuffreda, 2014, Gallop 1998). The width of the tape may 
vary according to the individual, angled nasally inferiorly, with the width between 
the inner canthi recommended as a sufficient distance to provoke a subtle, yet 
effective response, without disrupting functional vision (Gallop, 2014).   
 
Potential mechanisms for the effect of BNO on symptoms and subjective balance 
have been proposed, including stabilizing one’s sense of orientation by providing a 
“visual anchor”, improving the ability to filter out irrelevant visual information and 
suppress visual motion, increasing the use of ambient vision, and improving visual 
attention by reducing the integration of information between the two central visual 
fields (Ciuffreda, Yadav, & Ludlam, 2017; Gallop, 2014; Padula, Capo-Aponte, Padula, 
Singman, & Jenness, 2017).  Visual attention in the visual cortex using visual-evoked 
potentials (VEP) has been shown to be impaired post-concussion (Yadav et al., 
2014).  Thus, improvements in visual attention and stability with BNO may allow an 
individual to allocate more attention to postural control.  Evidence of this would be 
seen as improved balance during visually-based cognitive dual-task conditions.  
 
 High quality studies in the field of vision therapy in the management of concussion 
are lacking, as research has been limited to case studies and extrapolations from 
other pathologies (Ciuffreda, Yadav, & Ludlam, 2013; Ciuffreda et al., 2017; Gallop, 
1998, 2014; Proctor, 2009).  These studies suffer from methodological limitations 
such as lack of randomization and comparison groups, small sample sizes, and lack 

of standardized protocols.  While some of these studies did report an immediate and 
significant improvement in subjective symptoms and functional balance during gait, 
objective measures of postural sway and oculomotor function were not investigated.   
 
Studies have compared single- with dual-task performance on COP post-concussion, 
(Degani et al., 2017) or the presence of saccadic dysfunction post-concussion, using 
visually-based cognitive dual-tasks (Rizzo et al., 2016; Subotic et al., 2017). 
However, to date, no study has directly compared the effect BNO as an intervention 
on measures of COP velocity, objective metrics of saccadic eye movement, and 
symptoms during the performance of single- and visually-based cognitive dual-task 
balance conditions in a concussion population.  This makes it difficult for clinicians 
to make evidence-informed choices in the management of individuals who 
experience persistent balance deficits beyond the expected period of normal 
recovery following a concussion.  This study aims to address this gap by assessing 
the efficacy of a BNO intervention trial in adults with persistent post-concussion 
balance problems compared with a control condition using both single and visually-
based cognitive dual-task balance paradigms. The study is designed as a randomized 
controlled crossover test with a sample size calculated a priori to ensure the 
contribution of high quality evidence to a nascent body of literature. 
 
OBJECTIVES 
 
Purpose 
 
The overarching research question is the following: What is the effect of BNO 
compared with no binasal occlusion on measures of static balance, saccadic eye 
movement functions, and symptoms in adults who continue to experience dizziness 
one month or longer following a concussion?  The specific objectives of this study 
are (1) to measure the effect of BNO on postural sway, compared with non-occluded 
vision during quiet stance on a force plate; (2) to examine the impact of BNO on 
postural sway while performing a visually based cognitive dual-task compared with 
target-focused vision, as measured during quiet stance on a force plate; (3) to 
compare the effect of BNO on saccadic eye function, compared with non-occluded 
vision during a timed reading task.  Saccadic eye function will be quantified as time 
to completion during the KDT and the total number of saccades; (4) to determine 
the relationship between a rapid number naming task and observable saccadic eye 
function; (5) measure the association between self-reported symptoms, disability, 
and objective measures of balance in adults who continue to experience dizziness 
longer than one month after concussion. 
 
It is hypothesized that BNO will improve postural sway during a visually based 
cognitive dual-task more than during quiet stance. We also hypothesize that time to 
completion of a timed reading task will correlate positively with saccadic eye 
function, and that both will show improvement with BNO.  It is further hypothesized 
that perceived disability due to dizziness and neck pain would be greater in 

individuals with increased postural sway.  This article presents the research 
protocol for this study. 
METHODS 
Design 
This cross-sectional study will examine the effect of BNO on balance in adults aged 
18-65 years who continue to experience symptoms one month or more following a 
concussion.  A 2-task, 2-period, 2 treatment condition randomized crossover study 
design will be used in order to be balanced with respect to first-order effects, as 
each condition will precede the other condition only once.  Potential participants 
will be screened for eligibility during a telephone interview.  Following enrollment, 
they will be randomized to one of two condition sequences and act as their own 
control group.  Participants will perform two different balance tasks repeated under 
both treatment (BNO) and control (no BNO) conditions.  The treatment/control 
conditions will be the same for each participant with only the order of each 
treatment/control sequence randomized.  Post-concussion syndrome is considered 
chronic and stable, and thus suitable for a crossover study design.  Likewise, the 
application of BNO is intended to improve immediate functional balance and 
saccadic eye movement, rather than cure the concussion.   No evidence of the effect 
time of BNO has been reported in the literature.  Based on clinical experience of two 
of the authors, the treatment effect is limited to the time of application, so there 
should be no carryover effect between conditions and a negligible washout period 
between trials is considered sufficient.   To minimize any risk of potential carryover 
effects, patients will also be asked to wait the greater of 1 minute, or until all 
symptoms return to their pre-test baseline before performing the subsequent task.  
A summary of the study design is available in Figure 1.  All study procedures will be 
conducted at one of two private rehabilitation clinics in Ottawa, Canada. 
 
 
Participants  
Patient selection 
Participants will be recruited by advertisement posters placed in a visible location 
within citywide multidisciplinary medical and rehabilitation centres.  All 
recruitment materials will direct individuals interested in participating to contact 
the research coordinator directly to provide further details about the study and to 
screen for eligibility by a telephone interview.    
 
Inclusion criteria 
Forty adults with persistent symptoms one month or more following a concussion 
will be recruited for the study. Individuals will be considered eligible if they have 
been diagnosed with a concussion as defined in the 2016 Berlin consensus 
statement (McCrory et al., 2017) as a traumatic brain injury induced by 
biomechanics forces, which was caused by either a direct or indirect blow to the 
head, face, neck or elsewhere on the body with an impulsive force transmitted to the 
head,  which may or may not have involved loss of consciousness, and included one 
or more of the following clinical domains: 

 Symptoms (e.g. headache, nausea, fatigue, feeling like in a fog, difficulty 
concentrating or remembering, and/or emotional lability) 
 Physical signs (e.g. loss of consciousness, amnesia, neurological deficit); 
 Balance impairment (e.g. gait unsteadiness) 
 Behavioural changes (e.g. irritability) 
 Cognitive impairment (e.g. slowed reaction times) 
 Sleep/wake disturbance (e.g. somnolence, drowsiness) 
Participants must also meet the following inclusion criteria: (1) aged 18-65 years; 
(2) sustained the concussion 4 or more weeks ago; (3) report persistent dizziness or 
balance problems not accounted for by a pre-existing musculoskeletal, neurological, 
or vestibular condition; (4) have normal vision or visual impairments that can be 
corrected with contact lenses; (5) are proficient in English or French; (6) are able to 
provide informed consent. 
 
Figure 1. Study design 
 
ENROLLMENT     ALLOCATION 
 
 
INTERVENTION 
 
 
 
 
 
 
 
 
 
 
 
Informed consent 
During a telephone screening interview, potential participants will speak with a 
member of the research team to confirm study eligibility, to review details of the 
study protocol, and to enroll in the study if deemed suitable.  During this discussion, 
potential participants will be given the opportunity to request an electronic copy of 
the informed consent form to review prior to meeting with the study team.  Once 
enrolled, participants will attend an in-person testing session at one of the two trial 
locations.  At this session, the research team will review: (1) the purpose of the 
study; (2) how the randomization process works; (3) a general overview of the 
testing conditions, and the self-report outcome measures.  A thorough discussion of 
potential risks and benefits associated with participation in the study will then take 
place, as well as the assurance that participants may withdraw from the study or 
request a rest at any time during the study without consequence or without effect 
on the medical care that they receive.  Each participant will be given a hard copy of 
Randomized 
Group A 
Control (no-
BNO) 
Assessed 
for 
Eligibility 
Group B 
Intervention 
(BNO) 
Washout 
period (≥1 
min) 
Group A 
Control  
(no-BNO) 
Group B 
Intervention 
(BNO) 
Excluded 

the informed consent form for signature and an extra copy to take home.  
Participants will be given as much time as required to re-read and complete the 
informed consent form, as well as the opportunity to ask for and receive clarification 
for questions as necessary. 
 
Sample size 
 
40 participants will be recruited for the present study.  A power analysis based on 
COP excursion using a force plate with adults following a concussion has been 
calculated to determine the number of participants that need to be recruited for the 
present study.  A change in COP excursion by more than 5cm will be considered to 
be significant, as this represents the minimal detectable change with a 90% 
confidence interval (Goble, Manyak, Abdenour, Rauh, & Bawega, 2016).  A two-tailed 
analysis will be made with alpha level set at 0.05 and power set at 80%.  
Due to the nature of this crossover design, loss to follow-up is not expected, and 
therefore not accounted for in the sample size determination. 
 
Randomization 
Participants will be randomly assigned to one of two groups for a crossover study 
design.  Each group will complete both arms of the study, randomized to sequence, 
starting with either the control condition or the intervention condition.  The 
intervention condition consists of performing the identical balance tasks while 
wearing glasses overlaid with BNO.  Researchers performing the intervention will 
not be blinded to group allocation due to the crossover design. 
 
 
OUTCOME MEASURES 
 
For each arm of the study, participants will complete two trials of static balance 
while standing on a force plate that will record movement of the center of pressure 
(COP) under their feet. Sensors from an electromagnetic tracking system will also be 
attached to each participant at the base of the skull, T5, and L5 along the spine, 
collecting acceleration of movements, angular velocity of movements, and angular 
rotation of the earth.  The sensors will record accelerations of movements, angular 
velocities, and angular rotations. Throughout each trial condition, Tobii™ eye 
tracker glasses will be worn to measure and record saccadic eye movements and 
time to task completion. 
 
Primary outcome 
 
Balance – COP 
Measurement of postural sway as an indicator of persistent balance impairment 
post-concussion builds upon previous studies demonstrating increased postural 
sway in the acute period following a concussion (Goble et al., 2016).  The primary 
outcome of interest is the mean M/L and A/P velocity of COP, in addition to the 95% 
ellipse during different conditions of static balance.  The minimal clinical difference 

considered to demonstrate a change in postural sway is 5cm based on a previous 
validation study in a concussed population (Goble et al., 2016). 
 
Postural stability will be assessed using the BTrackS (BTS) Balance Plate and 
Explore Balance software (BTrackS, Balance Tracking Systems Inc., San Diego, CA, 
USA) that is easily portable.  The BTS Balance Plate is an FDA registered Class 1 
Medical Device designed to measure static balance by calculating the centre of 
pressure (COP) excursion and velocity of an individual during quiet stance(Goble et 
al., 2016).  Centre of pressure is a proxy measure for postural sway, which is a 
common measure of balance impairment following concussion (Chang, Levy, Seay, & 
Goble, 2014; Goble et al., 2016; Kleffelgaard, Roe, Soberg, & Bergland, 2012; 
Rochefort et al., 2017).  Decreased COP displacement can be used as an indicator of 
recovery or improved postural strategies used to maintain balance after a 
concussion.  The BTS Balance Plate calculates COP using four-sensor technology 
within a lightweight (<7kg), 0.4m by 0.6 m rectangular platform that is highly 
accurate and reliable compared with a laboratory-grade force plate (O’Connor et al., 
2016). 
The Explore Balance software is an application-based program that will be 
customized to the current study protocol.  All balance testing will be performed by 
members of the research team trained in BTS technology. 
 
 
Secondary outcomes  
Prior to postural sway data collection, participants will be asked to complete 4 
questionnaires, including a participant demographic questionnaire, the post-
concussion symptom scale (PCSS), the dizziness handicap inventory (DHI), and the 
neck disability index (NDI).  
 
Baseline Patient Characteristics 
Baseline patient characteristics will be collected on pre-prepared data collection 
forms, and will include age, gender, height, weight, race, marital status, level of 
education, employment status, mechanism of concussion, and previous history of 
concussion. 
 
The Post-Concussion Symptom Scale (PCSS) 
The use of symptom scales plays an important role in the diagnosis of concussion 
and in monitoring recovery.  International consensus statements (McCrory et al., 
2017), position papers (McCrea, Nelson, & Guskiewicz, 2017), and clinical guidelines 
(Marshall et al., 2015) recommend symptoms as part of a multimodal assessment 
that includes measures of neurocognitive status, balance, and cranial nerve function. 
Clinical best-practice standards recommending the complete resolution of 
symptoms prior to medical clearance for return to sport highlight the importance 
symptom evaluation in the management of concussion. 
The PCSS is a standardized and easily administered 22-item self-report symptom 
scale that measures the severity of each symptom experienced that day (Lovell et al., 
2006).  Symptoms are reported on a 7-point Likert scale, with 0 and 6 representing 

anchoring points from the absence of symptoms to the presence of severe 
symptoms.  Results are conveyed as the total symptom score and range from 0-132, 
with a higher score associated with a higher level of symptoms.  Total scores 
demonstrate high internal consistency in a concussion population (α=0.93), with a 
6.8 point change (CI80) associated with a clinical change in symptoms (Lovell et al., 
2006). 
 
The Dizziness Handicap Inventory (DHI) 
Dizziness is commonly reported post-concussion (Rochefort et al., 2017), and 
associated with prolonged recovery (Lau et al., 2011).  The presence of dizziness has 
the ability to significantly impact an individual’s quality of life by limiting an 
individual’s activities and raising their anxiety.  Developed as a standardized 
measure to evaluate the self-perceived impact of dizziness on everyday life 
(Jacobson & Newman, 1990), the DHI is a self-report scale that represents the 
functional, physical, and emotional domains.  Internal consistency is high for total 
scores (α = 0.89) and satisfactory for the three subscales (α =0.72 to 0.85).  The 
presence of dizziness-related disability is scored as no (0), sometimes (2), or yes (4).  
Scores range from 0-100, with a higher score reflecting a greater disability 
associated with dizziness.  Cut-off scores exist for mild (16-34), moderate (36-52), 
and severe (54+) disability, with an 18-point change in score considered clinically 
meaningful (Jacobson & Newman, 1990). 
 
The Neck Disability Index (NDI) 
A force to the head or body that results in a concussion is of sufficient force to injure 
the soft tissue and joints of the cervical spine.  Altered proprioception from injured 
cervical spine structures can contribute to symptoms of dizziness commonly 
associated with concussion.  The NDI is the most commonly used self-report 
outcome measure for neck pain (MacDermid et al., 2009).  The index is a simple and 
quickly administered 10-item questionnaire measured on a 6-point Likert scale 
from 0=no disability to 5 = full disability.  Scores range from 0-50, with 50 
representing the highest level of disability.  Psychometric properties of scores 
demonstrate highly stable test-retest reliability (r=0.94-0.95) in patients with neck 
pain longer than 3 weeks (MacDermid et al., 2009).  Clinically important difference 
have been reported with a 5-7 point change in score depending on whether the pain 
was of musculoskeletal or neural origin (MacDermid et al., 2009).   
 
 
Saccadic eye function  
Saccadic eye function will be assessed with two measures, a Tobii™ Pro wearable 
eye tracker and the KDT.  Tobii™ Pro wearable eye tracker uses infrared video-
oculography to analyze patterns of eye movement in terms of fixations and saccades 
(www.tobiipro.com).  Longer, more complicated visual tasks, such as rapid number 
naming, require longer processing times.   The number of saccades completed 
during each balance condition will be recorded by the Tobii™ Pro.   
The KDT is a vision-based test of rapid number naming speed that acts as a proxy 
measure for saccadic eye movement (Galetta, Liu, et al., 2015).  The KDT consists of 

a demonstration card, plus a series of 3 increasingly more difficult test cards of 
variably spaced single digit numbers (Subotic et al., 2017).  Following completion of 
the demonstration card, participants are asked to read each test card from left to 
right, top to bottom, as quickly as possible without errors.  A summary score of the 
test is recorded as the total time to complete all 3 test cards, measured in seconds.  
Time to completion for the KDT will be recorded by the Tobii™ Pro.  A meta-analysis 
demonstrated high test-retest reliability (ICC=0.92; CI95%: 0.91, 0.94) in baseline 
trials (Galetta, Liu, et al., 2015). 
 
 
Table 2: Outcome measures 
Domain 
Measure 
Outcome of Interest 
Baseline 
Disability 
Primary 
Secondary 
Cervical spine 
Neck Disability 
Index 
X 
 
 
Dizziness 
Dizziness 
Handicap 
Inventory 
X 
 
 
Postural sway 
M/L COP 
excursion 
 
X 
 
 
A/P COP 
excursion 
 
X 
 
 
95% ellipse 
COP 
 
X 
 
Eye tracking 
Saccades 
 
 
X 
 
King Devick 
Test 
 
 
X 
Symptoms 
Post-
Concussion 
Symptom 
Scale 
 
 
X 
(M/L=medial/lateral; A/P= anterior/posterior; COP,=centre of pressure) 
 
Interventions 
 
Balance Testing Protocol 
All participants will be asked to perform a repeated measure of 2 different balance 
tasks under 2 different treatment conditions as outlined below.  Each trial of balance 
will take 2 min to administer, and will be performed with the participant wearing 
socks.  Before and after each trial, participants will be asked to rate if they are 
experiencing any headache, dizziness, nausea, or fogginess on a scale of 0 to 10.  
Following each trial, a washout period will be given as the greater of a minimum of 1 
minute of rest or until symptoms aggravated by the task return to their pretrial 
baseline.  A time period of two minutes was chosen as a sufficient interval over 

which to collect stable COP data according to the International Society for Posture 
and Gait Research (Scoppa, Capra, Gallamini, & Shiffer, 2013), while aligning with 
time required to complete the KDT. 
 
For balance task A, participants will be asked to stand with their feet shoulder width 
apart on the BTS with their hands placed on their hips. They will be asked to hold 
this position for two minutes with their eyes open, vision fixed on a small target 
(dot), and to focus on standing as still as possible.  
 
For balance task B, participants will be asked to stand shoulder width apart on the 
BTS with their hands on their hips. Participants will be asked to complete a 
cognitive task while they maintain their balance.  The visually based cognitive dual-
task will involve the participants performing the King-Devick Test (KDT).  Test 
cards will be fixed to a wall and positioned 12 inches from the participant’s face at 
eye level.  Participants will be asked to read the numbers out loud as quickly and as 
accurately as possible, from left to right, beginning at the top left corner of each test 
card.  The total time to read all 3 test cards and the total number of errors 
committed will be recorded.  If a participant makes an error, they will be asked to 
restart the test. The test usually takes less than two minutes to complete.  
Participants who complete the KDT in less than 2 minutes will be asked to restart 
the test from the beginning and continue reading for the remainder of the test 
period.  Those individuals who require more than the allotted 2 minutes to complete 
the KDT will continue with the rapid number naming task until completion, and COP 
data will stop being collected at 2 min. 
 
Throughout each trial, participants will be fitted with a pair of Tobii™ eye tracking 
glasses that will record their eye movements.   
 
Control condition: normal vision 
During the control arm of the trials, the eye tracking glasses will remain 
unobstructed and vision will not be occluded. 
 
Experimental intervention: BNO 
During the intervention arm of the trials, strips of occlusive material will be placed 
on the medial portion of each lens of the Tobii™ eye tracking glasses to occlude 
central integrated vision. 
 
Planned statistical analyses 
Baseline characteristics for participants will be compared with descriptive statistics 
(mean, SD, n, %).   
The primary objective, the effect of BNO on postural sway, will be addressed by 
using a dependent t-test to compare differences between treatment conditions for 
each COP variable.  A similar analysis using a dependent t-test (groupxKDTtime to 
completion) will be performed to assess the secondary objective, the effect of BNO on 
reading.  Additionally, a Wilcoxon Signed Rank test will be used to determine if there 
is a significant difference in the number of saccades completed on the KDT between 

the control and intervention conditions.  Finally, correlations among self-report 
measures of disability (DHI and NDI) and symptoms (PCSS), and the 3 dependent 
measures will be calculated using Spearman’s rho for non-parametric data. 
 
 
Ethics and Dissemination 
The possibility of fatigue, an increase in post-concussion symptoms, and problems 
with balance while completing the trials of balance will be disclosed to potential 
participants.  Participating in this study is very low risk and does not constitute 
more as compared with usual care that a patient would receive.  Participants will be 
required to provide informed consent, and may withdraw from the study at any 
time without explanation.   
Results from this study will be shared with healthcare professionals and academics 
at professional conferences and through manuscripts to peer-reviewed journals. 
Publication topics include the efficacy of BNO on postural sway and saccadic eye 
function; the impact of a cognitive dual-task on balance; the relationship between 
KDT time and observable saccadic eye function; and the association between self-
reported measures of symptoms, disability, and objective measures of balance.  
 
Conclusion: Impact on clinical practice 
 
The assessment and treatment of vision related issues has been identified as an 
integral part of the rehabilitation of patients who have suffered a concussion.  The 
efficacy of BNO as a treatment modality in the management of individuals with post-
concussion syndrome is currently poorly understood.  This article describes the 
protocol for a randomized controlled trial that tests the efficacy of BNO on static 
balance for adults with persistent dizziness and balance problems one month or 
more after concussion.  Results from primary and secondary outcome measures will 
contribute to our understanding of the efficacy of BNO in relation to postural sway, 
saccadic eye function, symptoms, and disability.  This study will begin to fill in the 
gaps with respect to evidence-based vision therapy to manage persistent dizziness 
post-concussion.  
 
 
Current Study Status 
This trial is set to begin recruitment in November 2017. 
 
 
 
 
 
 
 
 
 
REFERENCES 

 
 
Broglio, S. P., Tomporowski, P. D., & Ferrara, M. S. (2005). Balance performance with 
a cognitive task: A dual-task testing paradigm. Medicine and Science in Sports 
and Exercise, 37(4), 689–695. 
https://doi.org/10.1249/01.MSS.0000159019.14919.09 
Chang, J. O., Levy, S. S., Seay, S. W., & Goble, D. J. (2014). An Alternative to the Balance 
Error Scoring System: Using a Low-Cost Balance Board to Improve the Validity/ 
Reliability of Sports-Related Concussion Balance Testing. Clin J Sport Med, 24, 
256–262. https://doi.org/10.1097/jsm.0000000000000016 
Ciuffreda, K. J., Yadav, N. K., & Ludlam, D. P. (2013). Effect of binasal occlusion (BNO) 
on the visual-evoked potential (VEP) in mild traumatic brain injury (mTBI). 
Brain Injury : [BI], 27(1), 41–7. 
https://doi.org/10.3109/02699052.2012.700088 
Ciuffreda, K. J., Yadav, N., & Ludlam, D. P. (2017). Binasal occlusion (BNO), visual 
motion sensitivity (VMS), and the visually-evoked potential (VEP) in mild 
traumatic brain injury and traumatic brain injury (mTBI/TBI). Brain Sciences, 
7(8), 1–14. https://doi.org/10.3390/brainsci7080098 
Degani, A. M., Santos, M. M., Leonard, C. T., Rau, T. F., Patel, S. A., Mohapatra, S., & 
Danna-dos-Santos, A. (2017). The effects of mild traumatic brain injury on 
postural control. Brain Injury, 31(1), 49–56. 
https://doi.org/10.1080/02699052.2016.1225982 
Galetta, K. M., Liu, M., Leong, D. F., Ventura, R. E., Galetta, S. L., & Balcer, L. J. (2015). 
The King-Devick test of rapid number naming for concussion detection: meta-
analysis and systematic review of the literature. Concussion, 15(1), 1–15. 
https://doi.org/10.2217/cnc.15.8 
Galetta, K. M., Morganroth, J., Moehringer, N., Mueller, B., Hasanaj, L., Webb, N., … 
Balcer, L. J. (2015). Adding Vision to Concussion Testing: A Prospective Study of 
Sideline Testing in Youth and Collegiate Athletes. Journal of Neuro-
Ophthalmology, 35(3), 235–241. 
https://doi.org/10.1097/WNO.0000000000000226 
Gallop, S. (1998). A variation on the use of binasal occlusion glasses - a case study. 
Journal of Behavioural Optometry, 9(2), 31–35. 
Gallop, S. (2014). Viewpoint 4 Binasal Occlusion – Immediate , Sustainable 
Symptomatic Relief. Optometry & Visual Performance, 9(2), 31–35. 
Goble, D. J., Manyak, K. A., Abdenour, T. E., Rauh, M. J., & Bawega, H. (2016). An initial 
evaluation of the BTrackS balance plate and sports balance software for 
concussion diagnosis, 11(2), 149–155. 
Hunt, A. W., Mah, K., Reed, N., Engel, L., & Keightley, M. (2016). Oculomotor-Based 
Vision Assessment in Mild Traumatic Brain Injury. Journal of Head Trauma 
Rehabilitation, 31(4), 252–261. 
https://doi.org/10.1097/HTR.0000000000000174 
Jacobson, G. P., & Newman, C. W. (1990). The development of the Dizziness 
Handicap Inventory. Archives of Otolaryngology - Head & Neck Surgery, 116(4), 
424–427. https://doi.org/10.1001/archotol.1990.01870040046011 
Kamins, J., Bigler, E., Covassin, T., Henry, L., Kemp, S., Leddy, J. J., … Giza, C. C. (2017). 

What is the physiological time to recovery after concussion? A systematic 
review. British Journal of Sports Medicine, 51(12), 935–940. 
https://doi.org/10.1136/bjsports-2016-097464 
Kehbein, K. A. (2010). Literature Review 4 Cognitive Functioning and Eye 
Movements Neuro-Visual Processing Rehabilitation : An Interdisciplinary 
Approach, 39–40. 
Kleffelgaard, I., Roe, C., Soberg, H. L., & Bergland, A. (2012). Associations among self-
reported balance problems, post-concussion symptoms and performance-
based tests: a longitudinal follow-up study. Disability and Rehabilitation, 34(9), 
788–794. https://doi.org/10.3109/09638288.2011.619624 
Lau, B. C., Kontos, A. P., Collins, M. W., Mucha, A., & Lovell, M. R. (2011). Which On-
field Signs/Symptoms Predict Protracted Recovery From Sport-Related 
Concussion Among High School Football Players? The American Journal of 
Sports Medicine, 39(11), 2311–2318. 
https://doi.org/10.1177/0363546511410655 
Levac, D., DeMatteo, C., Hanna, S., & Wishart, L. (2008). Intra-individual variability in 
recovery from paediatric acquired brain injury: relationship to outcomes at 1 
year. Developmental Neurorehabilitation, 11(3), 195–203. Retrieved from 
http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=reference&D=med6&NEWS=
N&AN=18608358 
Lovell, M. R., Iverson, G. L., Collins, M. W., Podell, K., Johnston, K. M., Pardini, D., … 
Maroon, J. C. (2006). Measurement of Symptoms Following Sports-Related 
Concussion: Reliability and Normative Data for the Post-Concussion Scale. 
Applied Neuropsychology, 13(3), 166–174. 
https://doi.org/10.1207/s15324826an1303_4 
MacDermid, J. C., Walton, D. M., Avery, S., Blanchard, A., Etruw, E., McAlpine, C., & 
Goldsmith, C. H. (2009). Measurement Properties of the Neck Disability Index: A 
Systematic Review. Journal of Orthopaedic & Sports Physical Therapy, 39(5), 
400-C12. https://doi.org/10.2519/jospt.2009.2930 
Marshall, S., Bayley, M., McCullagh, S., Velikonja, D., Berrigan, L., Ouchterlony, D., & 
Weegar, K. (2015). Updated clinical practice guidelines for concussion/mild 
traumatic brain injury and persistent symptoms. Brain Injury, 29(6), 688–700. 
Master, C. L., Scheiman, M., Gallaway, M., Goodman, A., Robinson, R. L., Master, S. R., 
& Grady, M. F. (2016). Vision Diagnoses Are Common After Concussion in 
Adolescents. Clinical Pediatrics, 55(3), 260–267. 
https://doi.org/10.1177/0009922815594367 
McCrea, M. A., Nelson, L. D., & Guskiewicz, K. (2017). Diagnosis and management of 
acute concussion. Physical Medicine and Rehabilitation Clinics, 28(2), 271–286. 
McCrory, P., Meeuwisse, W., Dvorak, J., Aubry, M., Bailes, J., Broglio, S., … Castellani, 
R. J. (2017). Consensus statement on concussion in sport—the 5th international 
conference on concussion in sport held in Berlin, October 2016. Br J Sports Med, 
bjsports-2017. 
O’Connor, S. M., Baweja, H. S., & Goble, D. J. (2016). Validating the BTrackS Balance 
Plate as a low cost alternative for the measurement of sway-induced center of 
pressure. Journal of Biomechanics, 49(16), 4142–4145. 
https://doi.org/10.1016/j.jbiomech.2016.10.020 

Padula, W. V., Capo-Aponte, J. E., Padula, W. V., Singman, E. L., & Jenness, J. (2017). 
The consequence of spatial visual processing dysfunction caused by traumatic 
brain injury (TBI). Brain Injury, 0(0), 1–12. 
https://doi.org/10.1080/02699052.2017.1291991 
Patricios, J., Fuller, G. W., Ellenbogen, R., Herring, S., Kutcher, J. S., Loosemore, M., … 
Schneider, K. J. (2017). What are the critical elements of sideline screening that 
can be used to establish the diagnosis of concussion? A systematic review. 
British Journal of Sports Medicine, 2000(April 2016), bjsports-2016-097441. 
https://doi.org/10.1136/bjsports-2016-097441 
Proctor, A. (2009). Traumatic brain injury and binasal occlusion. Optometry and 
Vision Development, 40(1), 45–50. Retrieved from 
http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=reference&D=psyc6&NEWS=
N&AN=2009-04473-005 
Rizzo, J. R., Hudson, T. E., Dai, W., Birkemeier, J., Pasculli, R. M., Selesnick, I., … 
Rucker, J. C. (2016). Rapid number naming in chronic concussion: eye 
movements in the King–Devick test. Annals of Clinical and Translational 
Neurology, 3(10), 801–811. https://doi.org/10.1002/acn3.345 
Rochefort, C., Walters-Stewart, C., Aglipay, M., Barrowman, N., Zemek, R., & 
Sveistrup, H. (2017). Balance Markers in Adolescents at 1 Month 
Postconcussion. Orthopaedic Journal of Sports Medicine, 5(3), 
232596711769550. https://doi.org/10.1177/2325967117695507 
Scoppa, F., Capra, R., Gallamini, M., & Shiffer, R. (2013). Clinical stabilometry 
standardization. Basic definitions - Acquisition interval - Sampling frequency. 
Gait and Posture, 37(2), 290–292. 
https://doi.org/10.1016/j.gaitpost.2012.07.009 
Subotic, A., Ting, W. K.-C., & Cusimano, M. D. (2017). Characteristics of the King-
Devick test in the assessment of concussed patients in the subacute and later 
stages after injury. Plos One, 12(8), e0183092. 
https://doi.org/10.1371/journal.pone.0183092 
Tobii(tm) Pro. (n.d.). Retrieved October 17, 2017, from www.tobiipro.com 
Yadav, N. K., Thiagarajan, P., & Ciuffreda, K. J. (2014). Effect of oculomotor vision 
rehabilitation on the visual-evoked potential and visual attention in mild 
traumatic brain injury. Brain Injury, 28(7), 922–929. 
https://doi.org/10.3109/02699052.2014.887227 
Zemek, R. L., Farion, K. J., Sampson, M., & McGahern, C. (2013). Prognosticators of 
Persistent Symptoms Following Pediatric Concussion. JAMA Pediatrics, 167(3), 
259. https://doi.org/10.1001/2013.jamapediatrics.216