balance and hearing

CAA Conference and Exhibition, October 17-20, 2018

Balance and Hearing: What Cochlear Implants Have Taught us

about the Developing Vestibular System

Sharon L. Cushing


Disclosures

⚫ Speaker’s Bureau

⚫ Interacoustics

⚫ Royalties

⚫ Plural Publishing

⚫ Editor: Balance Disorders in the Pediatric Population

⚫ Patent Holder: ⚫ Patents #: 7041-0: Systems And Methods For Balance Stabilization

⚫ Sponsored Research Agreement⚫ Cochlear Americas

⚫ Sharon Cushing

⚫ Paolo Campisi

⚫ Mark Crawford

⚫ Maureen Dennis

⚫ Gina Sohn

⚫ Naureen Sohail

Cochlear Implant Clinical/ Research Team

DIRECTORS

⚫ Blake Papsin

⚫ Karen Gordon

⚫ Vicky

Papaioannou

RESEARCH

ASSISTANTS

⚫ Stephanie Jewell

STUDENTS

⚫ Daniel Wong

⚫ Claire Salloum

⚫ Sho Tanaka

⚫ Patrick Yu

⚫ Brad Hubbard

⚫ Lauren Schofield

⚫ Brittany Harrison

⚫ Brooke Allemang

⚫ Laurie MacDonald

⚫ Mary Lynn Feness

⚫ Pat Di Santos

⚫ Nancy Greenwald-

Hood

⚫ Susan Druker

Local - external

⚫ Sandra Trehub

⚫ Frank Russo

International

⚫ Robert Cowan

⚫ Richard van Hoesel

FELLOWS

⚫ Talar Hopyan

⚫ Neil Chadha

⚫ James Ramsden

COLLABORATORS

Local - SickKids

⚫ Bob Harrison

⚫ Tracy Stockley

⚫ Susan Blaser

⚫ Adrian James

Unilateral Bilateral

Tien et al, 2002

distortion of the saccular

membrane

fibrosis of the vestibule

20-100% lose cVEMP

responses after CI

Vestibular Effects of Cochlear

Implantation (negative)

Vestibular Dysfunction is

Common in Children with SNHL

70% dysfunction

35-40% complete

areflexia

Otol Neurotol. 2013

Vestibular Dysfunction is

Common in Children with SNHL

70% dysfunction

35-40% complete

areflexia

vestibular impairment is the single

most common associated feature of SNHL

Otol Neurotol. 2013

Measuring Balance

Bruininks-Oseretsky (BOT2)

Balance Subtest

Balance subtest Items Max. Score

1. Standing with feet apart on a line Eyes Open 10 sec.

Eyes Closed 10 sec.

2. Walking forward on a line 6 steps

3. Standing on one leg on a line Eyes Open 10 sec.

Eyes Closed 10 sec.

4. Walking forward heel to toe on a line 6 steps

5. Standing on one leg on a balance beam Eyes Open 10 sec.

Eyes Closed 10 sec.

6. Standing heel-to-toe on a balance beam 10 sec.

N= 190 children with CI tested

*p= 0.0001

0

2

4

6

8

10

12

14

16

normal hearing hearing loss BVL

BO

T-2

Scale

Sc

ore

Bilateral Vestibular Loss

(BVL)

Vestibular Loss Impacts Balance

*p= 0.0001

0

2

4

6

8

10

12

14

16


BO

T-2

Scale

Sc

ore

Mean 4.4 years


(BVL)


balance deficits are not always apparent


⚫ static and dynamic balance – BOT-2

0

2

4

6

8

10

12

14

16

standardized normals (non CI) non-reimplanted re-implanted

BO

T-2

Bal

ance

Su

bse

t Sc

ore

16

14

12

10

8

6

4

2

BO

T-2

Bala

nce S

ubset

Score

Standardized

normals

(non - CI)

non-

reimplantedreimplanted

p = 0.00001

p = 0.0083

0

When Balance is Poor – Implants Fail

Otol Neurotol. 2015

p = 0.0002

0

0.2

0.4

0.6

0.8

1

non-reimplanted reimplanted

Pro

po

rtio

n o

f p

ati

en

ts

abnormal

normal

re-implantednon

re-implanted

bilateral

areflexia

When Vestibular Function is Poor –

Implants Fail

Otol Neurotol. 2015

vestibular & balance

dysfunctionrisk of CI failureα

Bilateral Areflexia

Odds ratio: 8.6

Implant failure

Otol Neurotol. 2015

When Vestibular Function is Poor –

Implants Fail


Screening

Vestibular & Balance Function

4 Easy Steps

1. motor milestones

2. motor function

3. horizontal canal

4. otoliths


Motor Milestones – Upper Limits

⚫ head control

⚫ 4 months

⚫ sitting

⚫ 9 months

⚫ walking

⚫ 18 months


Screening


4 Easy Steps

1. motor milestones

2. motor function

3. horizontal canal

4. otoliths

One Leg Standing

Age Duration (sec)

1 foot standing

30 months 1 (briefly)

36 months 2

4 years 5

5 years 10

One Leg Standing

Eyes Closed

One Leg Standing

Eyes Open

Otol Neurotol. 2016

One Leg Standing

One Leg Standing

Eyes Closed

One Leg Standing

Eyes Open

One Leg

Standing

Sensitivity Specificity

Eyes Open

< 8 seconds

100% 49%

Eyes Closed

< 4 seconds

90% 84%

Children age 5 and older

Otol Neurotol. 2016

One Leg Standing


Screening


4 Easy Steps

1. motor milestones

2. motor function

3. horizontal canal

4. otoliths

Assess Horizontal Canal Function

video Head Impulse Testing (vHIT)

(EyeSeeCam, Interacoustics)

video Head Impulse Testing (vHIT)

Synapsys

Infants < 6 months cannot visually suppress the VOR


Screening


4 Easy Steps

1. motor milestones

2. motor function

3. horizontal canal

4. otoliths


Subjective Visual Vertical (SVV)

⚫ Positive → tilt to the right

⚫ Negative → tilt to the left

⚫ Normal range: ± 2°(Brodsky 2015, 2016)

⚫ Bias →initial direction of

linear marker(Pagarkar 2008; Toupet 2015)

-2o +2o

Subjective Visual Vertical

Chronos System, Interacoustics


Screening

Vestibular & Balance Dysfunction

4 Easy Steps

1. motor milestones

2. motor function

3. horizontal canal

4. otoliths


• Cochleovestibular

anomalies

• Phelps

• Waardenburg

• Klippel Feil

• Pendred

• Ototoxicity

• Usher Syndrome

• Meningitis

• CMV

• ANSD

• Connexin

• Mitochondrial?

• Autoimmune?

Vestibular and Balance

Dysfunction Risk by Etiology


Ototoxicity in Cancer

cochleotoxicity ≈ vestibulotoxicity

platinum based therapy

aminoglycosides

cranial radiation

surgical therapy

25-90% ?

0

20

40

60

80

100

120

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Frequency (Hz)

Ototoxicity Related Hearing Loss

0

20

40

60

80

100

120

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Le

ve

l (d

B H

L)

Frequency (Hz)

Left Ear Right Ear

Conductive hearing loss

Cochlear implantn=26

Ototoxicity Related Balance Impairment

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15

seco

nd

s

participants

n=26

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20

seco

nd

s

participants

Eyes Open

n=26


0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20

seco

nd

s

participants

Eyes Open

<8 sec35%

(8/23)abnormal

n=26


0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20

seco

nd

s

participants

Eyes Open

Eyes Closed

<8 sec35%

(8/23)abnormal

n=26


0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20

seco

nd

s

participants

Eyes Open

Eyes Closed

<8 sec35%

(8/23)abnormal

65%

15/23abnormal

<4 sec

n=26


Horizontal Canal Dysfunction

50% Dynamic Visual Acuity

52% VOR loss vHIT

42% Utricular Dysfunction

Subjective Visual Vertical

N = 26

Vestibular Impairment from Ototoxicity


Ototoxicity in Cancer

cochleotoxicity ≈ vestibulotoxicity

platinum based therapy

aminoglycosides

cranial radiation

surgical therapy

25-90% 50%


Congenital Cytomegalovirus

photos courtesy of Dr. Robert Harrison



20-50% Sensorineural Hearing Loss


92% Vestibular end-organ Dysfunction

33% Complete Bilateral Loss

50% Progressive

Bernard et al. Pediatrics. 2015

50% Otolithic Dysfunction

cVempMaes, Ear & Hearing. 2016


20-50% Sensorineural Hearing Loss

Single Sided Deafness in Children

Consequences of SSD in Children

School

Performance

Behaviour

IEP &

Speech Therapy

Unilateral Hearing

Loss

Lieu et al.. Laryngoscope. 2012

Speech & Language

Quality of Life

Grade Failure

Measuring Balance Impairment

⚫ quantitative measurement of postural

control

Force

plates

Centre of Pressure

0

5

10

15

20

25

Unilateral Normal

P=0.004

BO

T-2

Scale

d S

core

Otol Neurotol. 2016

Unilateral Hearing

LossNormal Hearing

Balance is Impaired in SSD

0

5

10

15

20

25

Unilateral Normal

P=0.004

BO

T-2

Scale

d S

core

hearing loss

Otol Neurotol. 2016

Unilateral Hearing

LossNormal Hearing


0

5

10

15

20

25

Unilateral Normal

P=0.004

BO

T-2

Scale

d S

core

hearing loss

bilateral

vestibular

loss

Otol Neurotol. 2016

Unilateral Hearing

LossNormal Hearing


Vestibular Dysfunction in SSD

Horizontal Canal Dysfunction

48% Caloric Reduction

50% VOR loss vHIT

Otolithic Dysfunction

62.5%

Utricular 42% oVEMP

Saccular 25% cVEMP

N = 20

Consequences of SSD in Children

School

Performance

Behaviour

IEP &

Speech Therapy

Unilateral Labyrinthine

Loss

Lieu et al.. Laryngoscope. 2012

Speech & Language

Quality of Life

Grade Failure


Cognitive Decline


Cognitive Incline


Disclosures (cont'd)

Everything I have learned about brain development

in children I have learned from 2 people

Dr. Karen Gordon Xavier Sloan


Reduced

activity

Activity no

longer reduced

Lee, et al., Nature, 2001

Auditory Deprivation

Sensory Assembly

stimulus

Processing ReassemblySenses

pattern recognition

high fidelity representation of the environment

faithful representation

Sensory Assembly

stimulus


pattern recognition



"Ice Cream, yummy!"

Sensory Assembly - Cochlear Loss

stimulus


pattern recognition



Sensory Assembly - Restored

stimulus


pattern recognition



effort


How Do Humans Listen?


Jiwani et al., Submitted

Right Stimulation CI Experienced – Normal Hearing Dipole Differences

P1 - P1 N1 - N1 P2 - P2

How Do Humans Listen?


Cognitive Load

Spatial

Knowledge

Vision

Kinesthetic

InputVestibular

Hearing

Proprioception

Efference

Copy

Balance and Navigation

Cognitive Load

*p= 0.0001

0

2

4

6

8

10

12

14

16


BO

T-2

Scale

Sc

ore


(BVL)


Spatial

Knowledge

Vision

Kinesthetic

InputVestibular

Hearing

Proprioception

Efference

Copy


Cognitive Load

Control Strabismus Amblyopia

BO

T2

Ba

lan

ce

Sco

re

0

5

10

15

20

25

30

P = <0.001

P = <0.001

Balance is Impaired in

Developmental Visual Anomalies

Bachar et al in preparation

Control Strabismus Amblyopia

BO

T2

Ba

lan

ce

Sco

re

0

5

10

15

20

25

30

P = <0.001

P = <0.001

Balance is Impaired in

Developmental Visual Anomalies

hearing loss

bilateral

vestibular

loss

Bachar et al in preparation

Spatial

Knowledge

Vision

Kinesthetic

InputVestibular

Hearing

Proprioception

Efference

Copy


Cognitive Load

Sensory Assembly - Vestibular Loss

stimulus


pattern recognition



Sensory Assembly – Vestibular Loss

stimulus


pattern recognition



effort

Spatial

Knowledge

Vision

Kinesthetic

InputVestibular

Hearing

Proprioception

Efference

Copy


Cognitive Load


3

3.5

4

4.5

5

5.5

6

1 2

6

0

1

5

CI off CI on

Bala

nce s

co

re

(BO

T-2

)

*p= 0.029

Vestibular Effects of Cochlear

Implantation (positive)

Sensory Assembly – Restored?

stimulus


pattern recognition



effort

Spatial

Knowledge

Vision

Kinesthetic

InputVestibular

Hearing

Proprioception

Efference

Copy


Cognitive Load

Hypothesis

⚫ Electrical current from a cochlear implant can

spread to the vestibular system


VEMP Waveforms (same ear)

acoustic electric

P

1

P

1

N1N1

Laryngoscope. 2016

Electrically-Evoked VEMPs are Faster

P1 and N1 peak latencies of cervical VEMPs

N1 and P1 peak latencies of ocular VEMPs

p<0.01, paired t-test


Vestibular Abnormalities

Cause Functional Deficits

by Stephanie Jewell

Electrical Stimulation Shifts the Perception

of Vertical Back to CenterLeaning left

Leaning right

Shifted right

Shifted left

p<0.001

Sensory Assembly – Restored?

stimulus


pattern recognition



effort

TransCochlear Stabilization of Balance

⚫ accelerometer and

gyroscopic sensor

⚫ conversion to CI

stimulation

⚫ head referenced

⚫ deviation signalled

⚫ transferred electrically

to implant

⚫ 16 patients

OFF ON

P = 0.041

Mean S

cale

d B

OT

Score

0

1

2

3

4

5

6

7

8

9

CI off Head referenced CIstimulation

Hearing and Implants Help Balance


0

2

4

6

8

10

12

Tandem Eyesopen

One Foot EyesOpen

BB - One FootEyes Open

BB - TandemEyes Open

Tandem Eyesclosed

One Foot EyesClosed

BB - One FootEyes Closed

Max time

Tim

e t

o F

all (

s)

NORMAL

HEARING

Time to Fall Approaches Normal


0

2

4

6

8

10

12

Tandem Eyesopen

One Foot EyesOpen



Tandem Eyesclosed

One Foot EyesClosed


Max time

Tim

e t

o F

all (

s)


NORMAL

HEARING

CI


0

2

4

6

8

10

12

Tandem Eyesopen

One Foot EyesOpen



Tandem Eyesclosed

One Foot EyesClosed


Max time

Tim

e t

o F

all (

s)


NORMAL

HEARING

CI

HEAD

REFERENCED

CI STIMULATION

Summary

⚫ vestibular & balance dysfunction

⚫ common

⚫ matters

⚫ screening is feasible

⚫ performance impaired by labyrinthine

⚫ implants can stimulate an impaired

vestibular system

What Drives Development in Children?

balance and hearing

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