Pilot Project on External Vestibular Prosthesis in Chronic Subjective Dizziness

Purpose:

Hypothesis: #1The use of the BalanceBelt™ will provide differential information about body
sway movements during specific clinical balance and gait tasks in patients with CSD that is
not currently available through routine measures.

Hypothesis: #2 The use of the BalanceBelt™ will provide for a more rapid rate of reduction
in patient symptoms compared to the historical data from the traditional habituation therapy
method.

Aims, purpose, or objectives: #1 Motion detectors contained in the BalanceBeltTM will be
used to record information about the subtle changes in posture and gait that are thought to
occur in patients with CSD with the tactors turned off. The goal of this portion of the
study will be to improve diagnostic strategies for CSD.

Aims, purpose, or objectives: #2 In this second portion of the study the investigators will
test the benefits of a one week intensive rehabilitation program using the BalanceBeltTM
with tactors activated in 10 patients with CSD. The goal of this study will be to develop a
treatment that is quicker and more effective than current therapies.

Background:

Chronic subjective dizziness (CSD) is the second most common condition identified in
patients referred to Mayo Clinic for persistent dizziness. The investigators manage nearly
500 patients with CSD each year. CSD is a syndrome of persistent non-vertiginous dizziness
and unsteadiness that may be worsened by patients' own motion, exposure challenging visual
stimuli such as busy shopping areas, or performance of precision visual tasks such as
reading. CSD develops in about 25% of patients following medical events that acutely disrupt
balance. Once established, CSD may last for many years, even if the problems that triggered
it resolves. As a result, CSD causes considerable distress and functional impairment, even
to the extent of work disability and disruption of family and social life.

Over the last decade, the Mayo Clinic Integrated Neurotology team, and other investigators
around the world have developed two treatment strategies for CSD. One uses serotonergic
medications such as sertraline (Zoloft) and venlafaxine (Effexor). The other is a variation
of vestibular and balance exercises known as vestibular habituation. These therapies reduce
symptoms for 60-80% of patients when administered by experts in the field. However, they
have important shortcomings. They are time-consuming, taking a minimum of 2-3 months of
diligent treatment to achieve best results. They usually achieve a partial reduction in
symptoms, which improves patients' functioning, but falls short of a cure. They can make
patients worse, rather than better, when used by clinicians who are unfamiliar with them.

A new theory about altered postural control mechanisms in CSD suggests that it could be
diagnosed more accurately and treated more quickly by using an external vestibular
prosthesis to enhance sensory feedback during vestibular exercises. A suitable prosthesis is
the BalanceBeltTM, which is currently in final beta testing by BalanceTek, the company that
developed it. This device has been shown to have efficacy in reducing sway behavior in
patients that have bilateral vestibular hypofunction. For those patients with deficient
vestibular systems the belt provides information that is missing from the lack of vestibular
system cues for detecting sway or leaning behavior, hence drawing attention to the
information that is missing. The BalanceBeltTM is a comfortable, self-contained unit worn
over a light weight shirt around the waist. It has sensitive motion detectors and small
tactors that vibrate against the skin at four locations to provide information about posture
and motion. Patients with CSD do not have permanent vestibular deficits, but underutilize
vestibular signals because they develop visual or somatosensory dependence. The
investigators expect the BalanceBeltTM to reset this error by providing patients with
reliable motion stimuli.

The investigators propose two preliminary studies using the BalanceBeltTM in patients with
CSD. In the first study, the investigators will use the motion detectors contained in the
BalanceBeltTM to record information about the subtle changes in posture and gait that are
thought to occur in patients with CSD. This goal of this study will be to improve diagnostic
strategies for CSD. The investigators will compare postural movements recorded with
BalanceBeltTM with tactors turned off during quiet stance, normal walking (Dynamic Gait
Index), functional reach test, and the Sensory Organization Test in 10 patients with CSD and
10 age and gender matched normal individuals. In the second study, the investigators will
test the benefits of a one week of intensive rehabilitation program using the BalanceBeltTM
with tactors activated in 10 patients with CSD. The goal of this study will be to develop a
treatment that is quicker and more effective than current therapies.

Study Design:

For Hypothesis and aim #1: Ten consecutive patients, ages 25-70 years, diagnosed with CSD
after completion of their routine evaluation in the Dizziness and Balance disorders
laboratory and their evaluation by the Behavioral Medicine program for dizziness, would then
be recruited for participation in the study. If patients agree to participate patients will
individually be placed through the following evaluations while the wearing the BalanceBelt™
with the tactors turned off but the recording elements turned on. Each of these tests is a
standard evaluation tool used in the Vestibular and Balance Laboratory on a routine basis:

1. Dynamic Gait Index - evaluates gait under normal walking and under conditions of head
turns, walking around two objects on the floor, stepping over a shoe box, walking at
different speeds, walking with a stop and 180 degree turn, walking up and down 3
standard steps with hand rails. During the evaluation the physical therapist or the
audiologist guards the subjects at all times walking with the subject and the subject
wears the harness used for the test in #3 that has a hand grab to prevent falls.

2. Functional Reach Test - the subject stands in a stationary position and reaches out
with a single arm as far as they can without taking a step. Here again the physical
therapist or the audiologist is guarding the patient during the performance of the
test, again with the subject in the harness used in #3 with the hand grab to prevent
falls.

3. Sensory Organization Test - this is a 6 condition standard evaluation of balance
control performed on a dynamic platform that can record sway movement in the A/P
dimension while the sensory inputs from proprioception and vision are varied through
the platform and visual surround movements. The subject wears a full chest harness that
is fastened to a roll bar above the subject to prevent any falls.

For each of the patients an age and gender matched normal (± 5 years) volunteer will go
through the same evaluations. The time for testing will take 45 minutes. Normal subjects
will be recruited through written advertisements from visitors and / or accompanying persons
for patients to Mayo Clinic. Each of the normal subjects will go through an office
vestibular examination that will consist of direct monitoring for nystagmus in all positions
of gaze with and without visual fixation present. Patients will also undergo the head thrust
test with visual fixation present and headshake test with visual fixation absent. Pursuit
and saccade office examination will be performed with a hearing screening by pure tones
only. If any abnormalities are revealed with the screening the normal volunteer will be
advised as to formal testing that should be performed via their primary care physician also
being notified.

For Hypothesis and aim #2: Ten consecutive patients, ages 25-70 years, diagnosed with CSD
who live within a 30 minute drive time of the Rochester Mayo campus will be asked to
participate in the habituation therapy activities typically used as treatment of CSD but
with an intensive treatment program using the exercises at home for the first week. The
patients will be using the BalanceBelt™ with the tactors activated. The typical therapy
evaluations pre-therapy will be taken in addition to Visual Analog Scales related to the
intensity of symptoms provoked by visual motion, head movements and walking in visually
complex environments. These same measures will be taken at the end of the first week of
intensive therapy at a return visit to check their exercise activities prior to continuing
their progressive home treatment. The one week of intensive therapy will be performed prior
to starting any recommended medications or medication changes for the CSD. The therapy will
be conducted by one of the Physical Therapists certified in Vestibular and Balance therapy.

Following the intensive therapy the patient will continue with the therapy activities and
medication trials as is standard currently for the CSD patients.

Data Analysis:

Statistical Considerations

Power Statement: Power analyses not used as this is a pilot study.

Data Analysis Plan:

For Hypothesis and aim #1: The outcome parameters from the BalanceBelt™ that represent the
total amount of sway and sway activity in the A/P and M/L directions will be compare between
the CSD patients and the normal age matched volunteers via the Wilcoxon rank-sum test for
mean comparisons.

For Hypothesis and aim #2: The visual analog scale scores pre & post the the one week of
intensive therapy will be compared for the 10 subjects using also the Wilcoxon test for mean
comparisons.

Endpoints As this is a pilot study no fixed endpoints will be used.

Subject population: 20 patients with diagnosis of Chronic Subjective Dizziness (CSD) and
10 normal volunteers.

Inclusion Criteria:

- Subjects will be 25-70 years of age inclusive and pregnant women may participate.

- Patients will have CSD as their primary diagnosis for the cause of their balance and
dizziness complaints provided by the Behavioral Medicine Program for Dizziness, a
division of the Department of Psychiatry & Psychology.

- Normal volunteers will have a negative history of otologic & neurologic disorders and
no history of dizziness and balance problems.

- Normal volunteers will have normal findings on a screening office examination for
peripheral and central vestibular system involvement (see methods for details of the
examination) and screening for normal or symmetrical hearing loss of explainable
origin.

Exclusion Criteria:

- Patients with positive indications from testing of peripheral and/or central
vestibular system involvement that is felt to be influencing the symptoms reported
beyond the CSD alone.

- Patients with mobility restriction that would prevent participating in the tests or
the intensive therapy trials.

- Subjects with hearing impairment that interferes with oral communication.