ABSTRACT

NORMATIVE DATA OF THE SENSORY ORGANIZATION TEST, THE MOTOR CONTROL TEST, AND THE

ADAPTATION TEST ON THE BERTEC BALANCE ADVANTAGE® IN

HEALTHY ADULTS

Objective: The purpose of this study was to determine test-retest reliability

and obtain normative values in healthy adults age 20-69 during computerized

dynamic posturography using the Bertec Balance Advantage®. Bertec values were

compared to published NeuroCom® normative values and across age groups to

determine any differences.

Methods: 50 healthy adults divided into 5 age groups were tested during the

3 test protocols for CDP: Sensory Organization Test (SOT), Motor Control Test

(MCT), and Adaptation Test (ADT). Five different subjects were tested on 2 days,

1 week apart, to determine between day reliability.

Results: Majority of conditions had moderate to good reliability on the

Bertec® (r = .55-.99). Differences between age groups occurred on SOT condition

2 and somatosensory ratio score and ADT toes down. When compared to

NeuroCom®, largest differences occurred on condition 4 of SOT and ADT test.

Conclusion: Bertec Balance Advantage® may be used to test whether or not

a person’s balance is impaired. MCT and SOT composite and equilibrium scores

for conditions 3-6 were comparable to the NeuroCom® normative values.

Keywords: Bertec Balance Advantage®, Sensory Organization Test, Motor

Control Test, Adaptation Test, Computerized Dynamic Posturography

Christian Lopez May 2017

NORMATIVE DATA OF THE SENSORY ORGANIZATION

TEST, THE MOTOR CONTROL TEST, AND THE

ADAPTATION TEST ON THE BERTEC

BALANCE ADVANTAGE® IN

HEALTHY ADULTS

by

Christian Lopez

A project

submitted in partial

fulfillment of the requirements for the degree of

Doctor of Physical Therapy

in the Department of Physical Therapy

College of Health and Human Services

California State University, Fresno

May 2017

APPROVED

For the Department of Physical Therapy:

We, the undersigned, certify that the project of the following student meets the required standards of scholarship, format, and style of the university and the student's graduate degree program for the awarding of the doctoral degree. Christian Lopez

Project Author

Peggy Trueblood (Chair) Physical Therapy

Monica Rivera Physical Therapy

Nancy Wubenhorst Physical Therapy

For the University Graduate Committee:

Dean, Division of Graduate Studies

AUTHORIZATION FOR REPRODUCTION

OF DOCTORAL PROJECT

X I grant permission for the reproduction of this project in part or in

its entirety without further authorization from me, on the

condition that the person or agency requesting reproduction

absorbs the cost and provides proper acknowledgment of

authorship.

Permission to reproduce this project in part or in its entirety must

be obtained from me.

Signature of project author:

ACKNOWLEDGMENTS

I would like to thank my committee members Dr. Peggy Trueblood, Dr.

Monica Rivera, and Nancy Wubenhorst for all of their help and support through

out the development of this research project. This could not have been

accomplished without their guidance. I want to give a special thanks to my friends

and family who have always believed in me. I would like to thank the entire

Fresno State Physical Therapy Department for accepting me into the program and

providing me the opportunity to become a physical therapist. And most of all, I

would like to thank my 29 classmates who have been on this journey with me

every step of the way.

TABLE OF CONTENTS

Page

LIST OF TABLES .................................................................................................. vi

LIST OF FIGURES ................................................................................................ vii

BACKGROUND ...................................................................................................... 1

METHODS ............................................................................................................... 6

Pilot Study ......................................................................................................... 6

Normative Study ............................................................................................... 6

Data Analysis .................................................................................................. 10

RESULTS ............................................................................................................... 11

Reliability Pilot Study ..................................................................................... 11

Subjects ........................................................................................................... 11

Comparison Between Age Groups .................................................................. 12

Comparison to NeuroCom® Normative Values .............................................. 13

DISCUSSION ......................................................................................................... 14

Limitations ...................................................................................................... 17

Conclusion ....................................................................................................... 18

REFERENCES ....................................................................................................... 20

TABLES ................................................................................................................. 26

FIGURES ............................................................................................................... 30

APPENDICES ........................................................................................................ 34

APPENDIX A: STUDY IRB ................................................................................. 35

APPENDIX B: HEALTH QUESTIONNAIRE ..................................................... 42

LIST OF TABLES

Page

Table 1. Reliability Values of the SOT from Initial Pilot Study ............................ 27

Table 2. Reliability Values of MCT and ADT from Pilot Study ........................... 28

Table 3. Reliability Categories of Initial Pilot Study for All Conditions ............... 28

Table 4 Means ± SD for SOT Equilibrium and Ratio Scores, MCT Latencies, and ADT Averaged Sway Energy Scores for All Age Groups ................ 29

LIST OF FIGURES

Page

Figure 1. Sensory organization test condition 2 means and standard deviations comparing age groups ............................................................................. 31

Figure 2. Somatosensory equilibrium scores given in means and standard deviations comparing age groups ........................................................... 31

Figure 3. SOT Bertec® means compared to NeuroCom® norms7 .......................... 32

Figure 4. MCT Bertec® means and standard deviations compared to NeuroCom® norms7 ................................................................................. 32

Figure 5. Comparison of toes up means and standard deviations of sway energy scores on Bertec® compared to NeuroCom® norms7 .................. 33

Figure 6. Comparison of toes down means and standard deviations of sway energy scores on Bertec® compared to NeuroCom® norms7 .................. 33

BACKGROUND

Balance is a critical, yet underappreciated and complex part of everyday

life. It can be defined as the ability to control upright posture under different

conditions, and the ability of an individual to sense their limitations of stability.1

Deficits in balance is a risk factor for falls and can lead to serious injury such as

hip fractures, hospitalization, and even death.2 Falls are also responsible for a

significant amount of health care spending, as they account for over $31 billion in

direct medical cost annually.3 Various methods have been introduced in order to

measure balance, however, tests commonly used in the clinic are not always

consistent due to their variable execution and subjective scoring systems.4,5

Therefore, there is a need to have procedures and protocols that can help

determine fall risk, as well as monitor improvements through rehabilitation.

In the 1980s, computerized dynamic posturography (CDP) devices were

developed. These devices are capable of measuring the ability of a person to shift

their center of pressure (CoP) within their base of support (BoS) and towards the

perimeter under various manipulations of the environment, which is known as

dynamic balance.6 It was during this time that Nashner and associates developed

the NeuroCom EquiTest®, which is capable of measuring and quantifying how a

person utilizes various sensory information in order to remain balanced under

different conditions. The CDP is composed of 3 test protocols, the sensory

organization test (SOT), the motor control test (MCT), and the adaptation test

(ADT).7 Computerized dynamic posturography has been used to measure and

monitor progress in patients who are undergoing balance rehabilitation, evaluate

balance after a trauma, have a history of falls or aging disequilibrium, have

2 2

vestibular or neurological disorders such as multiple sclerosis, Parkinson’s

disease, or have suffered a sports-related concussion.8-13

In order to maintain balance, the nervous system relies on input from 3

different subsystems, which are known as the visual, vestibular, and

somatosensory systems.14 The human body’s balance system continually receives

input from these subsystems, however, depending on the environmental

conditions, typically one predominates over the other.15 By providing disruptive

information that facilitates sensory conflict, the SOT can quantitatively assess the

patient’s ability to utilize each of the subsystems and maintain balance.16 The

ability of the SOT to detect impairments in these balance systems has been

documented in the literature.17-19 Yardley et al. has demonstrated that in patients

who complained of dizziness, tests of auditory, vestibular, and oculo-motor

function could not differentiate between dizzy subjects and matched controls,

while the SOT was capable of detecting impairments in these individuals.17

The MCT measures the patient’s ability to recover from unexpected

external perturbations. This movement induces an automatic postural response and

the onset timing, strength and lateral symmetry of responses are then recorded.7

This test measures the speed of a person’s reactions to external translations that

are provided by the force plate underneath the subject. There are 3 measures of

perturbations for this test rated as small, medium, large, which are always

performed in that order. The software tailors the size of each translation based on

the height of each patient. Lockhart et al. has demonstrated that those with longer

latency scores on the MCT have a less effective recovery method after

encountering a sudden slip.20,21

The ADT assesses if the patient can ignore disruptive somatosensory input

that occurs when a sudden and unexpected change in their support surface arises.

3 3

The patient follows a normal learning curve during the 5 trials of this test, with

each successive trial demonstrating a decrease in sway energy, due to the

habituation of the automatic postural response and suppression of postural reflexes

by implementation of higher cognitive processes.7,22

Since the introduction of the NeuroCom EquiTest®, the literature has

confirmed the validity and utilization of the device in the diagnosis of balance

disorders in adults, making it the “gold standard” when testing balance on a

dynamic device.23-25 With the recent advances in technology, an alternative CDP

system by Bertec has become available. However, the normative data has yet to be

established.

One of the features integrated in Bertec’s new system making it appealing

to clinicians and researchers is the ability to use virtual reality (VR) in treatment

protocols, which has become an increasingly popular method of intervention.26 A

systematic review by Corbetta et al. found that rehabilitation which incorporates

VR is more effective than standard neurologic rehabilitation for improving

walking speed, balance and mobility after stroke.27 Virtual reality has also shown

promise in balance rehabilitation of patients with traumatic brain injury, diabetic

neuropathy, and those with peripheral vestibular disorders.28-30 Bertec’s new

platform is also capable of producing optokinetic stimuli, which when performed

with head tilts, has been demonstrated to be capable of readapting the vestibulo-

ocular reflex and improving debilitating conditions such as mal de debarquement

syndrome.31

The Bertec Balance Advantage® system utilizes a spherical dome that

immerses the user into a virtual surround environment through a projection.

During CDP testing, a major addition to the Bertec® is the virtual surround

environment to produce vection, which depicts the movement of large visual

4 4

scenes in peripheral vision to cause an illusion of self-motion. Moreover, the

CDP’s virtual surround environment has the capability to create conflicting

sensory information within the body’s balance systems.32 One of the key features

of this surrounding spherical dome is its strong sense of presence of the

environment, which can help make a patient’s response in the virtual world similar

to their response in the real world.33 This sense of presence cannot be produced in

the NeuroCom®, as there is a lack of overhead projection within the device, thus

providing visual reference points, potentially providing the individual with visual

stability. The use of virtual surround environments to challenge balance and cause

postural sway has been documented in the literature, however, comparing it to the

NeuroCom EquiTest® sway reference to a visual surround on postural control has

not been studied.34

Normative values are currently available for the NeuroCom EquiTest® CDP

protocol from the ages of 20 to 79.7 Due to the Bertec’s platform differing from

NeuroCom® by using a virtual environment, it is unknown if the values between

the 2 devices are comparable. Currently to date, there is no normative data

available for the Bertec® Balance Advantage®. Therefore, the purpose of this study

is to report results on the CDP for healthy adults aged 20-69 using the Bertec®

Balance Advantage®.

Postural stability has been demonstrated to decline with age, while muscle

onset latency times have been shown to increase with age in studies using the SOT

and MCT performed on the NeuroCom EquiTest®, resulting in statistically

significant differences between age groups.20,35,36 To the best of our knowledge,

there are no studies that have investigated age differences on the ADT. We

hypothesize that there will be similar results using the new Bertec® Balance

Advantage®. Therefore, the null hypothesis is that there will be no differences

5 5

between age groups on the SOT and MCT results using the Bertec® Balance

Advantage®. The alternative hypothesis is that there will be a significant

difference between age groups on the SOT and MCT results using the Bertec®

Balance Advantage®.

METHODS

Pilot Study

To help in determining test-retest reliability of the Bertec Balance

Advantage®, we tested 5 subjects aged 23-30 years of age who met the inclusion

criteria that is listed below on the SOT, MCT, and ADT. They performed all 3

tests for the CDP protocol, and then were retested 7 days later. Statistical analysis

was then completed with IBM SPSS version 24 software. Due to the large amount

of trials between ADT, the trials were combined into an averaged score in order to

compare between age groups.

Normative Study

Subjects

A total of 50 subjects were recruited for testing using non-probability quota

sampling. Subjects were recruited through the use of flyers, social media, and

word of mouth. An age range from 20 to 69 years of age was used. The subjects

were then stratified into 5 age groups, with 10 subjects in each group. Age groups

ranged from 20 to 29 years of age, 30 to 39, 40 to 49, 50 to 59, and 60 to 69.

This study was approved by the California State University, Fresno,

Committee on Protection of Human Subjects, and is in compliance with the

governmental regulations specified by the Office for Human Research Protection.

All subjects gave their informed consent prior to participation in this study (see

Appendix A).

Inclusion criteria consisted of any individual between 20 and 69 years of

age who did not have any significant medical history or known neurological or

musculoskeletal disorder or impairments that could impact balance. Exclusion

7 7

criteria included the presence of dizziness, inner ear, or other balance or vestibular

disorder, open head injury, cervical injury, assistive device use or inability to stand

for periods shorter than 20 minutes, visual impairments that were worse than

20/40 with corrective lenses, a concussion within the past 10 years after which the

subject experienced headaches and/or other symptoms, diabetes, peripheral

vascular disease, any significant lower extremity joint disorder or injury, or

abnormal motion sickness and sensitivity.

All participants prior to testing were required to fill out a detailed subject

questionnaire to identify any potential conditions that would exclude them from

participation. Upon completion of the questionnaire, the subject’s height, age, and

sex were then recorded and inputted into the Bertec software (see Appendix B).

Procedure

The study used the new Bertec Balance Advantage® – Dynamic CDP

platform. Three tests were conducted on the Bertec system, the SOT, the MCT,

and the ADT. To reduce error, the same tester was used to conduct all 3

examinations.

Participants were equipped with a one-size-fits-all harness that was

adjusted to fit their body-type comfortably. They then were asked to remove their

socks and shoes and step onto the forceplates barefoot. The harness was then

attached to the safety straps that were hanging overhead, and the researcher then

aligned the participant’s medial malleolus into the standardized position, parallel

to the horizontal line on the forceplate. The lateral calcaneus of each foot was then

aligned to the small, medium, or large lines. The position of the lateral calcaneus

was dependent on the participant’s height, and the software instructed the

researcher where to align each participant’s feet. Detailed explanations of each test

8 8

or trial was provided to each participant from a standardized script prior to

beginning any test, explaining what the test consisted of and to notify the

researcher if they began to feel dizzy or nauseous. Breaks were provided for each

patient between trials and conditions if they reported any of the aforementioned

symptoms and were not allowed to resume testing until symptoms subsided.

Participants were also instructed to wear their corrective visual lenses or contacts

if a physician prescribed them.

Sensory Organization Test

The SOT was the first test performed. This test records the movements of

the body’s CoP in 6 conditions, with 3 trials per condition. The tasks of each

condition are as follows; Condition 1: Participant’s eyes are open and there is a

fixed base of support and a fixed virtual environment. Condition 2: Participant’s

eyes are closed and a fixed base of support. Condition 3: Participant’s eyes are

open with a sway-referenced virtual environment and fixed base of support.

Condition 4: Participant’s eyes are open with a fixed virtual environment and a

sway-referenced mobile base of support. Condition 5: Participant’s eyes are closed

with a sway-referenced mobile base of support. Condition 6: Participant’s eyes are

open with a sway-referenced virtual environment and a sway-referenced mobile

base of support. The subject is placed on the platform and aligned in the position

as indicated by the software. Each trial lasted 20 seconds. The test then calculates

equilibrium scores for each trial, which is based on the displacement of the

subject’s COG over their BOS. A ratio score is then provided for each of the

sensory systems, as well as a composite score that provides a global determination

of normal versus abnormal results.7

9 9

Motor Control Test

The MCT was performed immediately following the SOT unless

participants were feeling fatigued, dizzy, or requested a break. The MCT measures

the participant’s ability to quickly and automatically recover from unexpected

external provocations. The test used sequences of small, medium, or large

platform translations in either the forward or backward direction, however only the

medium and large translations are used for calculating test results. 3 trials of each

translation were performed. The participants first performed 3 small backward

translations, 3 medium backward translations, and 3 large backward translations.

The subjects then performed 3 small forward translations, 3 medium forward

translations, and 3 large forward translations. Each translation is automatically

scaled by the software according to the subject’s height. The software then

provides data on the time in milliseconds between the onset of the translation and

the force response in the subject’s legs, which is defined as latency, as well as an

overall composite score of the test.7 The subject’s foot alignment did not change as

compared to the SOT.

Adaptation Test

The ADT was performed last and immediately following the SOT and

MCT, unless the participants reported dizziness, fatigue, or requested a break. This

test assesses the participant’s ability to modify motor reactions and minimize sway

when the support moves in a toes-up or toes-down direction. The test includes 5

trials of the platform moving into an incline in the “toes up” direction, and then 5

trials of the platform moving into a decline or “toes down” direction. The

participants did not know when the platform was going to move during testing but

they were told in what direction it would be moving. For each of the trials, a sway

energy score quantifies the magnitude of the force response required to overcome

10 10

the postural instability.7 The subject’s foot alignment remained the same as it was

on both the SOT and the MCT.

Data Analysis

Results of the SOT, MCT and ADT were analyzed using a one-way

analysis of variance (ANOVA) comparing age groups. All conditions, equilibrium

scores, ratio scores, and composite scores were analyzed for the SOT. MCT scores

were entered by averaging left and right scores together to be consistent with the

NeuroCom® normative values. ADT trials were averaged to determine differences

between age groups. Statistical significance of P < .05 was set for the ANOVA

analyses. If significance was found, a post hoc Tukey HSD was conducted to

determine which groups were different.

RESULTS

Reliability Pilot Study

Results for the test-retest reliability study were analyzed using a Pearson’s r

correlation coefficient and are listed in Tables 1 and 2 for the SOT, MCT, and

ADT. Using the Portney and Watkins guidelines, we defined values of less than

0.5 having poor reliability, 0.50 to 0.75 as having moderate reliability, and greater

than 0.75 as having good reliability.37 The results of the pilot study and the

category of each condition is summarized in Table 3.

Subjects

A total of 50 participants were used in the analysis of this study. Testing

began in January of 2016 and concluded in July of 2016. After a thorough

screening of the results of the 3 tests and subjective questionnaires, it was

determined that a total of 6 participants of the original 50 that were recruited were

not eligible to be included in the normative study due to previous major lower

extremity injuries such as ACL tears (2/6), a history of concussions (2/6), cervical

fusion (1/6), and prior unspecified lower back surgery (1/6).

An additional 6 participants were then recruited and testing began in

August of 2016 and concluded in November of 2016. Of the 50 participants, 17

were male and 33 were female. Less than half (19/50) participants had visual

impairments that were corrected with prescription lenses, while 14/50 participants

reported experiencing motion sickness at some point in their life, but follow up

questions helped determine it was not of enough concern to interfere with testing.

Nearly half (23/50) participants reported a prior LE injury and/or having a surgical

procedure done which included stress fracture repair, knee arthroscopy,

hysterectomy, caesarian section and appendectomy, while 15/50 participants

12 12

reported using over the counter drugs such as multi-vitamins, ibuprofen,

probiotics, antihistamines and/or prescription drugs such as singular and zyrtex for

allergies, Lipitor and simvastatin for cholesterol; estrogen; thyroid medications,

Ventolin for bronchospasm, omperzole for gastroesophageal reflux disease,

Advair for COPD, and blood pressure medications such as Lisinopril and

Spurnolactin.

Comparison Between Age Groups

Normative values for all tests on the Bertec® can be found in Table 4. A

significant difference was found among the 5 age groups for condition 2 (P= .028)

and somatosensory ratio scores (P= .013) on the SOT using a one-way ANOVA.

The post hoc Tukey HSD revealed the differences were between the 20-29 age

group and the 50-59 age group for condition 2 (P= .037) and somatosensory ratio

scores (P=.009). Additionally, the 40-49 age group and 50-59 age group was also

significant for somatosensory ratio score (P= .037). Means and standard deviations

of groups for condition 2 and somatosensory ratio scores can be seen in Figures 1

and 2. The ANOVA analyses were not significant for all other SOT conditions,

ratio, or composite scores.

ANOVA analysis for MCT composite scores, medium and large forward

and backward translations were all determined to be insignificant between age

groups. No significant differences were found between age groups for toes up

average (P=.359), whereas the toes down average was determined to be

statistically significant (P=.025). A post hoc Tukey HSD revealed differences were

between the 20-29 age group and 50-59 age group (P=.048) and the 20-29 age

group and 60-69 age group (P= .029) All other age groups were determined to

have insignificant differences.

13 13

Comparison to NeuroCom® Normative Values

To determine if the SOT, MCT, and ADT scores using the Bertec® system

were comparable to those same scores on the NeuroCom®, we compared the

values against the published norms for NeuroCom®.7 Analyses comparing the

mean Bertec® scores in our sample to the reported mean value for each of the 3

measures will be performed by using the one-way t test.

When reviewing the results of the SOT and subsequently compare the 2

systems, the 60-69 age group was removed from the study and were grouped into

a 20-59 age group (n=40). A one-way t test comparing the 2 systems revealed

significant differences on condition 1 (P< .001), 4 (P< .001), 6 (P= .003) and

composite scores (P< .001) of the SOT. Means and standard deviations from

individual ADT trials were also calculated in order to directly compare to

NeuroCom® normative values.7 All MCT and ADT toes up scores were

determined to be significantly different (P < .05). Trials 2 through 5 of ADT toes

down were significantly different (P < .001), while trial 1 had no significant

difference. Comparison graphs are listed in Figures 3, 4, 5 and 6.

DISCUSSION

This is the first study to report normative values using the Bertec® Balance

Advantage® CDP platform. Test-retest reliability was moderate to good for all of

the results of our initial pilot study with the exception of the SOT on conditions 1

and 2 equilibrium scores, and somatosensory and vision ratio scores, along with

the ADT in the toes down direction. The ratio scores are calculated using the

results of condition 1, therefore having low reliability on condition 1 could

directly affect these scores.7 The most reliable conditions of the SOT were the

ones that are the most difficult, which is consistent with what has been reported.38

After reviewing the literature and to the best of the author’s knowledge, there are

no reliability studies currently available reporting on the MCT or ADT.

Significant differences were found in our normative study between age groups on

some equilibrium and ratio scores of the SOT, along with the toes down direction

of the ADT. Other authors have also reported differences across age groups in

healthy populations on the SOT using the NeuroCom® 35,36 There were no

significant differences found in any measures of the MCT, therefore, the

alternative hypothesis that there will be differences between age groups using the

SOT and MCT on the Bertec® Balance Advantage® is partially accepted.

The greatest differences between age groups were for condition 2 on the

SOT, as well as the somatosensory ratio score (condition 2/ condition 1). In part

this may be due to the poor reliability found for conditions 1 and 2 from our pilot

study.39 A study from Cohen et al. found that Condition 2 scores had low

variability among young subjects, but was demonstrated to decrease with age, and

it is known that older adults use different strategies to maintain balance when

compared to their younger counterparts.36,40 The fact that there were no significant

15 15

differences between the 60-69 age group and younger age groups is an unexpected

finding. Condition 2 is known to challenge the somatosensory system, and it is

possible that some participants had underlying conditions that may have been

unknown to them and thus were unable to report, such as peripheral neuropathy,

which is a risk factor for falls and postural instability.41 It is also possible that

some subjects were more physically active or participated in hobbies that

improved balance, as studies have demonstrated that these can have positive

effects on their balance.42-44 For example, our sample of 60-69 year olds actually

performed better across all conditions in the SOT as compared to the 50-59 year

old group.

The data gathered indicate similar values to that reported in the in the

NeuroCom® system, however, statistical significance was found between our

mean values and those reported for the NeuroCom® using a one-way t-test.7 These

include conditions 1, 4, 6 and composite scores of the SOT, along with all of the

MCT and ADT scores.

When compared to the NeuroCom® SOT, the equilibrium scores in our

sample for conditions 1, 2, and 3 and 5 are nearly identical to the reported

NeuroCom® normative values.7 The greatest differences between systems occurred

on condition 4 in the SOT. Although significant differences were found on other

conditions when testing with a one-way t-test, the differences are not clinically

important considering the learning effects that have been reported on the

NeuroCom®. A study conducted by Wrisley et al. found that the minimal

detectable change on the NeuroCom® SOT was 8 points due to the learning

effects, and all of the scores that were found to be significantly different with the

one-way t-test were below 8 points, with the exception of condition 4.38 A possible

explanation for this finding is that this condition is more posturally challenging on

16 16

the Bertec® as compared to the NeuroCom®, because of the introduction of the

virtual surround. Condition 4 involves the subject’s eyes being open, heavily

relying on visual and vestibular input.

There were no significant differences in the overall composite scores of the

MCT or any of the latency translation scores in the forward or backward directions

across age groups in our normative study. This differs from a study conducted by

Lockhart et al., where they found significant differences between young, middle,

and old age groups when using MCT latency scores.20 However, in Lockhart et

al’s study, medium and large translation scores were combined.

To be consistent with the NeuroCom® normative data for comparisons, we

chose to analyze the medium and large translations separately. When comparing

the Bertec’s® MCT means to the established NeuroCom® norms, they are

relatively close to each other, with never more than 10 msec of a difference,

however all were determined to be significantly different with the one-way t-test.

One difference is between the platforms, as informed by the Bertec® corporation,

is that the Bertec® scores latencies within 5 msec, whereas the NeuroCom® system

is not that sensitive, and therefore, affects the latency score as much as 10 msec.

Thus, differences less than 10 msec between the 2 systems would be considered

comparable.

There was a significant difference in the toes down direction of the ADT

scores between age groups of the normative study. These differences occurred in

the 20-29 age group and 50-59 age group, as well as between the 20-29 age group

and 60-69 age group. It is known that if subjects have problems that are unrelated

to balance, such as anxiety, decreased ankle strength, and limited ankle range of

motion, the results of the ADT can be altered.7 The reliability of the ADT in the

toes down direction should also be taken into account when analyzing this finding,

17 17

as it had the poorest reliability score (r= 0.04) of all of the tests in the initial pilot

study.39 The ADT also demonstrates a high degree of variability, as is noted by the

large standard deviations that occur on each trial. This implies that this test should

be reviewed on more of a case-by-case basis, and should be examined by the

overall trend of the trials and not the exact score. There were no significant

differences between groups in the toes up direction of the ADT. The toes up

direction is the more researched component of the ADT, and it has been used in

the past to associate with certain neurological pathologies such as multiple

sclerosis.45,46

When comparing the means acquired on the ADT from the Bertec® to the

NeuroCom® norms, the intended trend can be seen. On both toes up and toes down

directions, there is normal suppression of the automatic reflexes across trials that

should occur during testing.7 In the toes down direction, the Bertec’s® standard

deviation values are within the norms of the NeuroCom®. When looking at the

toes up direction, there is a clear difference between both the Bertec® means and

the NeuroCom® norms. In order to fully understand this phenomena, more

information is required from the Bertec® corporation about the hardware. It is

known that the NeuroCom® rotates at a rate of 50º/second, while the Bertec’s® rate

of rotation was not known. Furthermore, there is a difference in the weight of the

forceplates between platforms, which could directly affect the amount of force that

is produced between both systems during the ADT test.

Limitations

For this study, a population of “healthy” individuals was required, and this

proved to be difficult to obtain. Many people today have had numerous surgeries,

conditions, or on medications that could impact or impair balance, especially when

18 18

dealing with elderly populations. In our sample for this study, we included 2

participants that had meniscal surgeries, as these were determined to be minimally

invasive arthroscopic surgeries and not impact proprioception or balance.

A quick sensory screen, such as a monofilament test or vibratory threshold

test, should have been conducted on patients to ensure proper proprioception of

lower extremities.47 If subjects had unknown underlying neuropathies or

conditions, it would have provided information to the researchers and they could

have excluded them from participating.

More information about lifestyle should also have been taken during the

questionnaire to give the researchers an idea of each subjects overall level of

fitness. It could have been asked in the form of how many hours per week subjects

participated in certain exercises and hobbies that have a positive effect on

balance.42-44 If a majority of the subjects in the 60-69 age group were actively

participating in such activities, and the 50-59 age group were less active, it could

have helped explain the differences in scores.

Conclusion

The results of this study indicate that the Bertec® Balance Advantage® can

remain consistent in detecting which individuals may be considered as “healthy”

and not have any balance deficits. The MCT and several conditions of the SOT are

comparable to the NeuroCom®, with the biggest differences occurring on

condition 4 of the SOT. Future research with healthy older adults should take into

account activity level of subjects, as some may be more physically active or have

hobbies that enhance balance and can create differences between age groups that

are not real.

19 19

Further studies are also necessary to determine the learning effects of the

SOT on the Bertec Balance Advantage® to determine its minimal detectable

change (MDC), as there may be a learning effect with repeated administration as is

seen on the NeuroCom Equitest.38 With the findings of significant differences on

conditions between both systems, the MDC’s could be different between platforms

as well. Test-retest reliability should also be established, as our initial pilot study

included a small sample size of only 5 subjects.

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7. EquiTest® System Version 8.0 Data Interpretation Manual. NeuroCom®

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11. Nelson SR, Di Fabio RP, Anderson JH. Vestibular and sensory interaction

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12. Beckley D, Bloem B, Van Dijk J, Roos R, Remler MP.

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13. Guskiewicz KM. Assessment of postural stability following sport-related

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15. Shumway-Cook A, Woollacott MH. The growth of stability: postural

control from a developmental perspective. J Motor Behav. 1985;17(2):131-

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16. Clendaniel RA. Outcome measures for assessment of treatment of the dizzy

and balance disorder patient. Otolaryngol Clin North Am. 2000;33(3):519-

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17. Yardley L, Burgneay J, Nazareth I, Luxon L. Neuro-otological and

psychiatric abnormalities in a community sample of people with dizziness:

a blind, controlled investigation. J Neurol Neurosurg Psychi.

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18. Di Girolamo S, Di Nardo W, Cosenza A, Ottaviani F, Dickmann A, Savino

G. The role of vision on postural strategy evaluated in patients affected by

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19. Guskiewicz KM. Postural stability assessment following concussion: one

piece of the puzzle. Clin J Sport Med. 2001;11(3):182-189.

20. Lockhart TE, Smith JL, Woldstad JC. Effects of aging on the biomechanics

of slips and falls. Hum Factors. 2005;47(4):708-729.

21. Shepard NT, Janky K. Computerized postural control assessment.

Handbook Clin Neurophys. 2010;9:238-251.

22. Nashner L. Adapting reflexes controlling the human posture. Exp Brain

Res. 1976;26(1):59-72.

23. Ionescu E, Dubreuil C, Ferber-Viart CC. Physiological changes in balance

control of adults aged 20 to 60 years assessed with Equitest. Ann

Otolaryngol Chir Cervicofac. 2005;122(5):231-235.

23 23

24. Dodd K, Hill K, Haas R, Luke C, Millard S. Retest reliability of dynamic

balance during standing in older people after surgical treatment of hip

fracture. Physiother Res Int. 2003;8(2):93-100.

25. Furman JM. Posturography: uses and limitations. Baillieres Clin Neurol.

1994;3(3):501-513.

26. User Manual Version 1.0. Bertec® Balance Advantage®; 2014:76-81.

27. Corbetta D, Imeri F, Gatti R. Rehabilitation that incorporates virtual reality

is more effective than standard rehabilitation for improving walking speed,

balance and mobility after stroke: a systematic review. J Physiother.

2015;61(3):117-124.

28. Cuthbert JP, Staniszewski K, Hays K, Gerber D, Natale A, O'Dell D.

Virtual reality-based therapy for the treatment of balance deficits in patients

receiving inpatient rehabilitation for traumatic brain injury. Brain Inj.

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29. Grewal GS, Sayeed R, Schwenk M, et al. Balance rehabilitation: promoting

the role of virtual reality in patients with diabetic peripheral neuropathy. J

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30. Bergeron M, Lortie CL, Guitton MJ. Use of Virtual Reality Tools for

Vestibular Disorders Rehabilitation: A Comprehensive Analysis. Adv Med.

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31. Dai M, Cohen B, Smouha E, Cho C. Readaptation of the vestibulo-ocular

reflex relieves the mal de debarquement syndrome. Front Neurol.

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32. Thurrell AE, Bronstein AM. Vection increases the magnitude and accuracy

of visually evoked postural responses. Exp Brain Res. 2002;147(4):558-

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33. Sadowski W, Stanney K. Presence in virtual environments. Handbook of

Virtual Environments:Design, Implementation, and Applications. Manwah,

NJ: Lawrence Erlbaum; 2002:791-806.

34. Piponnier J-C, Hanssens J-M, Faubert J. Effect of visual field locus and

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Vis. 2009;9(1):13-13

24 24

35. Borah D, Wadhwa S, Singh U, Yadav SL, Bhattacharjee M, Sindhu V. Age

related changes in postural stability. Indian J Physiol Pharmacol.

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36. Cohen H, Heaton LG, Congdon SL, Jenkins HA. Changes in sensory

organization test scores with age. Age Ageing. 1996;25(1):39-44.

37. Portney LG, Watkins MP. Foundations of Clinical Research: Applications

to Practice. Vol 2: Prentice Hall Upper Saddle River, NJ; 2000.

38. Wrisley DM, Stephens MJ, Mosley S, Wojnowski A, Duffy J, Burkard R.

Learning effects of repetitive administrations of the sensory organization

test in healthy young adults. Arch Phys Med Rehabil. 2007;88(8):1049-

1054.

39. Lopez CO, Trueblood PR, Rivera M, Wubenhorst N. Normative data of the

sensory organization test, motor control test, and adaptation test on the

Bertec® Balance Advantage® in healthy adults. Paper presented in partial

fullfilment of the requirements for the degree of Doctor of Physical

Therapy; March, 2017; Fresno, California.

40. Alexander NB, Shepard N, Gu MJ, Schultz A. Postural control in young

and elderly adults when stance is perturbed: kinematics. J Gerontol.

1992;47(3):M79-M87.

41. Richardson JK, Hurvitz EA. Peripheral neuropathy: a true risk factor for

falls. J Gerontol Series A: Biol Sci Med Sci. 1995;50(4):M211-M215.

42. Douris P, Southard V, Varga C, Schauss W, Gennaro C, Reiss A. The

Effect of Land and Aquatic Exercise on Balance Scores in Older Adults. J

Geriatr Phys Ther. 2003;26(1):3-6.

43. Schmid AA, Van Puymbroeck M, Koceja DM. Effect of a 12-week yoga

intervention on fear of falling and balance in older adults: a pilot study.

Arch Phys Med Rehabil. 2010;91(4):576-583.

44. Jeter PE, Nkodo A-F, Moonaz SH, Dagnelie G. A systematic review of

yoga for balance in a healthy population. J Alt Comp Med. 2014;20(4):221-

232.

45. Lawson GD, Shepard NT, Oviatt DL, Wang Y. Electromyographic

responses of lower leg muscles to upward toe tilts as a function of age. J

Vest Res. 1994;4(3):203-214.

25 25

46. Diener H, Dichgans J, Hülser P-J, Buettner U-W, Bacher M, Guschbauer B.

The significance of delayed long-loop responses to ankle displacement for

the diagnosis of multiple sclerosis. Electroencephalo Clin Neurophysiol.

1984;57(4):336-342.

47. Sorman E, Edwall LL. Examination of peripheral sensibility. Vibration test

is more sensitive than monofilament test. Lakartidningen.

2002;99(12):1339-1340.

TABLES

27 27

Table 1. Reliability Values of the SOT from Initial Pilot Study

SOT r-value (P<.05)

Condition 1 0.21

Condition 2 0.15

Condition 3 0.55

Condition 4 0.89

Condition 5 0.76

Condition 6 0.99

Somatosensory Ratio (2/1) 0.34

Vestibular Ratio (5/1) 0.52

Vision Ratio (4/1) 0.34

Preference Ratio (3+6/2+5) 0.83

28 28

Table 2. Reliability Values of MCT and ADT from Pilot Study

MCT and ADT Results r-value (P<.05)

MCT Back Medium 0.76

MCT Back Large 0.65

MCT Forward Medium 0.60

MCT Forward Large 0.88

MCT Composite 0.95

ADT Toes up 0.71

ADT Toes Down 0.04

Table 3. Reliability Categories of Initial Pilot Study for All Conditions

Category Tests

0.75 and up (Good) SOT: Condition 4, 5, 6, Composite, Preference

MCT: Composite Score, Forward Large, Backward

Medium

0.5-0.75 (Moderate) SOT: Condition 3, Vestibular

ADT: Toes Up Direction

MCT: Backward large, Forward medium

Less than 0.5 (Poor) SOT: Condition 1, Condition 2, Somatosensory, Vision

ADT: Toes Down Direction

29 29

Table 4 Means ± SD for SOT Equilibrium and Ratio Scores, MCT Latencies,

and ADT Averaged Sway Energy Scores for All Age Groups

Tests 20-29 y.o. 30-39 y.o. 40-49 y.o. 50-59 y.o. 60-69 y.o.

SOT 1 92.47±2.20 93.37±1.74 92.27±1.74 92.97±1.48 92.33±1.67

SOT 2 92.97±1.32* 92.83±2.18 92.30±1.09 90.50±2.43* 91.80±1.93

SOT 3 91.70±1.67 92.10±2.30 90.10±4.48 89.03±4.19 91.37±2.85

SOT 4 76.63±5.60 73.13±9.68 70.67±11.30 68.77±9.50 70.40±5.56

SOT 5 70.50±10.52 67.10±11.30 62.87±10..47 63.93±9.38 65.27±8.41

SOT 6 68.50±9.45 60.47±13.17 54.17±9.60 61.50±9.86 62.33±10.23

SOT Comp 79.18±4.67 76.05±7.06 72.58±6.09 73.85±6.62 75.12±4.32

SOM 100.60±2.55* 99.40±2.17 100.10±1.79* 97.40±2.12* 99.50±1.35

Vestibular 76.60±11.60 71.90±11.51 68.10±10.59 68.70±9.33 70.60±8.77

Vision 82.90±5.36 78.40±9.37 75.80±13.31 73.80±9.22 76.20±5.33

Preference 103.61±7.50 101.49±3.48 98.84±8.22 100.34±9.01 102.95±5.64

ADT Up 86.44±14.03 77.40±20.06 78.14±23.47 82.40±13.49 92.84±22.07

ADT Down 47.58±6.80* 58.84±24.00 60.04±9.62 70.66±21.27* 72.28±21.61*

MCT Comp 130.50±5.91 125.5±3.89 132.80±7.51 130.90±8.18 128.20±7.21

MCT B Med 127.35±9.74 124.35±6.52 131.40±9.15 131.05±7.85 127.85±7.59

MCT B Lrg 124.75±6.26 124.10±3.58 131.30±6.78 128.90±6.20 127.50±6.79

MCT F Med 135.50±6.32 128.00±7.49 135.70±6.57 131.40±10.62 130.90±10.66

MCT F Lrg 134.65±6.96 124.80±6.02 132.20±11.42 130.25±10.14 126.80±8.94

p values for comparing age groups *Asterisks indicate significant differences (p<.05) between age groups

FIGURES

31 31

Figure 1. Sensory organization test condition 2 means and standard

deviations comparing age groups

Figure 2. Somatosensory equilibrium scores given in means and standard

deviations comparing age groups

75

80

85

90

95

100

20-29 y.o. 30-39 y.o. 40-49 y.o. 50-59 y.o. 60-69 y.o.

Sensory Organization Condition 2

**

*Asterisks indicate significant differences

75

80

85

90

95

100

105

20-29 y.o. 30-39 y.o. 40-49 y.o. 50-59 y.o. 60-69 y.o.

SOT Somatosensory Equilibrium Scoresø*

ø*

ø Symbols represent groups that were significantly different from each other. *

32 32

Figure 3. SOT Bertec® means compared to NeuroCom® norms7

Figure 4. MCT Bertec® means and standard deviations compared to

NeuroCom® norms7

*

**

*

0

10

20

30

40

50

60

70

80

90

100E

qu

ilib

riu

m S

core

SOT Means 20-59 year old

Bertec (N=40)

NeuroCom (N=112)

*Asterisks indicate significant differences between platforms

0

20

40

60

80

100

120

140

160

180

M Back L Back M Forward L Forward

Tim

e (

mse

c)

MCT Latencey Means 20-59 y.o.

Bertec N=40

NeuroCom=29

***

*

*Asterisks indicate significant differences between platforms

33 33

Figure 5. Comparison of toes up means and standard deviations of sway

energy scores on Bertec® compared to NeuroCom® norms7

Figure 6. Comparison of toes down means and standard deviations of sway

energy scores on Bertec® compared to NeuroCom® norms7

0

20

40

60

80

100

120

140

T1 Avg T2 Avg T3 Avg T4 Avg T5 Avg

Sw

ay

En

erg

y S

core

Toes Up Means 20-59 years old

Bertec (N=40)

NeuroCom(N=64)

*

* *

*

*

*Asterisks indicate significant differences between platforms

0

20

40

60

80

100

120

T1 Avg T2 Avg T3 Avg T4 Avg T5 Avg

Sw

ay

En

erg

y S

core

Toes Down Means 20-59 years old

Bertec (N=40)

NeuroCom (N=64)

*

* **

*Asterisks indicate significant differences between platforms

APPENDICES

APPENDIX A: STUDY IRB

36 36

I.D.#

FRESNO STATE PHYSICAL THERAPY DEPARTMENT

PARTICIPANT CONSENT FORM

Project Title: Computerized Posturography using the Bertec in Healthy

Adults

Principal Investigator: Peggy R. Trueblood, PhD, PT

Professor and Chair

Department of Physical Therapy

Co-Investigators: Marcia Thompson, DSc, DPT

Assistant Professor, Department of Physical Therapy

Leslie Zarrinkhameh, PT, DPT, GCS

Lecturer, Department of Physical Therapy

Toni Tyner, MHL, PT

Assistant Professor, Department of Physical Therapy

Student Investigators: Carolyn Bentley, SPT

Christian Lopez, SPT

PURPOSE OF RESEARCH

I have been informed that the overall purposes of this project are to collect normative

data on a new posturography system that measures a person’s balance and to compare

this system to the gold standard system, also measuring your balance or postural control.

More specifically, we will 1) collect normative data using the Bertec Computerized

Dynamic Posturography (CDP) system using virtual reality with images projected in a

specially modified dome and 2) compare this data with the sway-referencing used by

EquiTest systems developed by NeuroCom International. The images used in the Bertec

system are controlled by the system’s computer and move in correspondence to your

postural sway detected by a force plate that you will stand on during the protocols. The

image is concentric ovals leading to a grey oval shape, creating the perception of a tunnel

with no definable end or horizon during the Sensory Organization test. In the case of the

37 37

EquiTest system by NeuroCom, the dome is referenced by your postural sway on the

forceplate.

I acknowledge that my participation is voluntary and will include a 60 minute collection

period (approximately 30 minutes with each system). The project will be conducted in

McLane 104 and 111, the Department of Physical Therapy at California State University,

Fresno.

CRITERIA FOR PARTICIPATION

I am eligible to participate in this study if I meet the following criteria: 1) age 20-59

years old without any significant medical history or known neurological or

musculoskeletal disorder/impairment that can impact my balance. I am aware that I will

be ineligible to participate in this study if I do not meet the criteria noted above and/or

have a prior history of any of the following: 1) dizziness, inner ear, or other balance or

vestibular disorder, 2) closed or open head injury, 3) cervical injury, 4) assistive device

use or inability to stand for 20 minutes, 5) visual impairment (worse than 20/40 with

corrective lenses), 6) concussion after which I experienced headaches and/or other

symptoms, 7) diabetes, 8) peripheral vascular disease, 9) any significant lower extremity

joint disorder or injury, 10) motion sickness/sensitivity.

PROCEDURE

I am aware that I will be:

1. Screened using a questionnaire to determine my eligibility before testing.

2. If eligible for testing, my name will be entered as a code name, eg Fresno 101,

102, etc into the computerized systems that test your balance

3. My age, sex, height information will be entered in the systems. These parameters

are used to determine proper foot placement.

4. I will be provided standard instructions prior to the start of each test condition

including the start of each test. During the recordings, I will maintain a steady

standing position.

5. I will be tested on two different computerized systems, each using 3 different tests

to measure balance: Sensory Organization Test (SOT); Adaptation Test (ADT)

and the Motor Control Test (MCT).

6. I will be tested without shoes. The investigator will align my feet properly at the

beginning of the tests.

7. I am allowed to rest as often as necessary throughout the testing.

8. During some of the tests the support surface and or the visual surround may move

gently during some of the recording trials. My task will be to remain as steady as

possible. The investigator will inform me when this may occur.

9. During all of the testing, I will be in a restraining harness and the investigator will

remain in close proximity in case I lose my balance.

38 38

10. The entire session will take approximately 30 minutes on each system. I will have

a 15 minute rest period between testing on the two balance systems.

11. I will first perform all of the standing balance tests on the Bertec System in the

following order:

a) First, I will complete the Sensory Organization Test (SOT) This balance test

systematically tests our three sensory systems: vision, vestibular or inner ear, and

somatosensory or our sensation of our feet. During the SOT, I will complete 3, 20

second trials of six different test conditions (18 total trials) during the Sensory

Organization Test. I will be allowed to rest between conditions as needed. The

order of testing is as follows:

i. Eyes open with a fixed (i.e. not moving) surface and visual

surround

i. Eyes closed with a fixed surface

ii. Eyes open with a fixed surface

iii. Eyes open with a fixed surface and sway-referenced (i.e., moving)

visual surround

iv. Eyes open with a sway-referenced surface and fixed visual

surround

v. Eyes closed with a sway-referenced surface

vi. Eyes open with a sway-referenced surface and visual surroundings.

b) Next I will perform the Motor Control Test (MCT). This test is designed to assess

my ability to recover automatically from external perturbations or slight

movements under my feet. The scale of the movement is based on my height.

This test will also include six different conditions, 3 trials each, which are as

follows:

i. Backward translation, small

ii. Backward translation, medium

iii. Backward translation, large

iv. Forward translation, small

v. Forward translation, medium

vi. Forward translation, large

c) The final test I will perform is known as the Adaptation test (ADT). This test

measures my ability to counteract a movement of the surface that I am standing

on in a toes up or toes down direction. I will be given 5 trials of each condition

(toes up and toes down).

2) I will have a 15 minute rest period before repeating these tests on the NeuroCom

System.

39 39

BENEFITS

I understand that there is no benefit in my participation in this project except to have my

balance tested on two different, but similar computerized systems. My participation will

add to the normative database for a new computerized balance system on the market and

will help determine if there are differences in the balance scores as compared to the gold

standard system already in use.

RISKS AND DISCOMFORTS

Risks associated with the balance tests are minimal. I am aware that participation in this

project may lead to fatigue or dizziness. To avoid this, rest breaks will be allowed. I

understand that there is a possibility that I may lose my balance at times during the

assessments. To prevent a fall or loss of balance, I will wear a safety harness for all

testing and will be guarded by trained investigators.

CONFIDENTIALITY

I understand that the findings of this study will be kept confidential and will be stored in

a secure location. Should the data be used for publication in medical literature or for

teaching purposes, I understand that only the investigators will know my identity and I

will not be identified by my name in any publication. I further understand that

photographs and videotapes will be used only with my written permission.

REQUEST FOR MORE INFORMATION

I understand that I have the right to ask and have answered questions concerning this

study at any time. Dr. Peggy Trueblood, the principal investigator, is available to answer

my questions or concerns at 278-3008. I will receive a copy of this consent form to refer

to for further reading or clarification if needed.

REFUSAL OR WITHDRAWAL OF PARTICIPATION

I understand that my participation is voluntary and that I may refuse to participate or

withdraw consent and discontinue participation in this study at any time. I also

understand that the investigators may terminate my participation in this study at any time

after they have explained the reasons for doing so.

INJURY STATEMENT

I understand that in the event of any physical injury resulting from my participation in

this study, my physician will be notified and treatment will be available at my own

expense. There will be no form of legal or monetary compensation available from the

California State University, Fresno, my referring physician, or the above listed

investigators.

40 40

I have explained to ______________________________ the purpose of this study, the

procedures, and the possible risks and benefits to the best of my ability.

______________________________ ______________________

Investigator Date

CONSENT

I confirm that the investigators have explained to me the purpose of the project, interview

process, screening, and procedures that I will undergo. I also understand the possible

risks and benefits that I may experience as a result of this study. The procedures for this

research have been reviewed and approved by California State University, Fresno,

Committee on Protection of Human Subjects. I have read and understand this consent

form. Therefore, I agree to give my consent to participate as a subject in this project.

______________________________ ______________________

Participant Date

______________________________ ______________________

Witness to Signature Date

I do/do not authorize the taking of photographs or videotapes of myself for either

publication or use as educational materials.

_____________________________ ______________________

Participant Date

_____________________________ ______________________

Witness to Signature Date

41 41

I.D.#

MEDICAL RESEARCH PATIENT’S BILL OF RIGHTS

California law requires that any person asked to take part as a subject in research

involving a medical experiment, or any person asked to consent to such participation on

behalf of another, is entitled to receive the following list of rights written in a language in

which the person is fluent. This list includes the right to:

1. Be informed of the nature and purpose of the experiment.

2. Be given an explanation of the procedures to be followed in the medical experiment

and any drug or device to be utilized.

3. Be given a description of any attendant discomforts and risks reasonably to be

expected from the experiment.

4. Be given an explanation of any benefits to the subject reasonably to be expected from

the experiment, if applicable.

5. Be given a disclosure of any appropriate alternative procedures, drugs, or devices that

might be advantageous to the subject, and their relative risks and benefits.

6. Be informed of the avenues of medical treatment, if any, available to the subject after

the experiment if complications should arise.

7. Be given an opportunity to ask any questions concerning the experiment or the

procedures involved.

8. Be instructed that consent to participate in the medical experiment may be withdrawn

at any time and the subject may discontinue participation in the medical experiment

without prejudice.

9. Be given a copy of the signed and dated written consent form.

10. Be given the opportunity to decide to consent or not to consent to a medical

experiment without the intervention of any element of force, fraud, deceit, duress,

coercion, or undue influence on the subject’s decision.

APPENDIX B: HEALTH QUESTIONNAIRE

43 43

Subject Questionnaire Computerized Posturography using the Bertec in Healthy Adults

1) Have you experienced dizziness or been diagnosed with inner ear or any other

balance or vestibular disorder?

[ ] Yes [ ] No

If Yes, please explain

_________________________________________________________

2) Have you a prior head injury, open or closed?

[ ] Yes [ ] No

If Yes, please explain

_________________________________________________________

3) Have you had any prior cervical injury?

[ ] Yes [ ] No

4) Do you currently use an assistive device (e.g cane)?

[ ] Yes [ ] No

5) Are you able to stand unsupported for a minimum of 20 minutes?

[ ] Yes [ ] No

6) Do you have any visual impairments?

[ ] Yes [ ] No

If Yes, please explain

_________________________________________________________

7) Have you had a concussion after which you experienced headaches and/or other

symptoms?

[ ] Yes [ ] No

If Yes, please explain

_________________________________________________________

8) Have you been diagnosed with diabetes?

[ ] Yes [ ] No

9) Have you been diagnosed with peripheral vascular disease?

[ ] Yes [ ] No

10) Have you had any significant lower extremity joint disorder or injury?

[ ] Yes [ ] No

If Yes, please explain

_________________________________________________________

44 44

11) Have you experienced any motion sickness or sensitivity?

[ ] Yes [ ] No

12) History of any neurological disease?

[ ] Yes [ ] No

13) Any history of surgeries?

[ ] Yes [ ] No

If Yes, please explain

_________________________________________________________

14) Any recent illnesses or ear infections?

[ ] Yes [ ] No

If Yes, please explain

_________________________________________________________

15) Have you consumed any alcohol in the past 12 hours?

[ ] Yes [ ] No

16) Please list (or provide) your current prescribed and/or over-the-counter medications.

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

________________________

I, _____________________________, confirm that the above information is true to my

knowledge.

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Participant Date

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Witness to Signature Date