Evaluating ME Function via an Acoustic Power Assessment Patricia - - PowerPoint PPT Presentation

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Evaluating ME Function via an Acoustic Power Assessment Patricia - - PowerPoint PPT Presentation

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Evaluating ME Function via an Acoustic Power Assessment Patricia Jeng, Ph.D., Jont Allen, Ph.D. Mimosa Acoustics Mel Gross, Au.D., Starkey Laboratories psj wbMEPA the device PC board Ear probe Lap-top computer MEPA

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SLIDE 1

Evaluating ME Function via an Acoustic Power Assessment

Patricia Jeng, Ph.D., Jont Allen, Ph.D. Mimosa Acoustics Mel Gross, Au.D., Starkey Laboratories

psj

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SLIDE 2

wbMEPA – the device

  • PC board
  • Ear probe
  • Lap-top

computer

  • MEPA

program

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SLIDE 3

A clinical diagnostic tool - wbMEPA

  • Mimosa’s middle ear power analyzer (MEPA)

– RMS – reflectance measurement system – WBR – wideband reflectance – Otoreflectance

  • Sponsored by NIH SBIR grant R43/44

DC03138

  • FDA 510(k) #053216
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SLIDE 4

MEPA

  • Principles of the wbMEPA measurement
  • Demonstration of wbMEPA measurement
  • Clinical applications
  • Hands-on demonstration
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SLIDE 5

The middle ear is the gateway to the auditory system

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SLIDE 6

ME – Gateway to the auditory paths

  • Audiogram
  • OAE
  • ABR
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SLIDE 7

What is the Problem?

  • The ME is the window into the cochlea

– ME diagnostic tools are few

  • Key application areas:

– Neonate hearing screening

  • The “False-positive” problem

– Middle ear disease diagnosis – Predicting the conductive component of hearing-loss vs. frequency, in dB

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SLIDE 8

How can we evaluate the ME?

  • In a normal ear the acoustic power is

absorbed by the cochlea.

– Power reflectance is a measure of ME inefficiency

  • Acoustic power measurement objectively

quantifies ME function and malfunction.

jba

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SLIDE 9

What is “acoustic power flow?”

  • Demonstration: a wall

that reflects the ball

  • A middle ear with

OME is like the wall.

  • The ball is like the

sound energy

  • Demonstration: a cloth

absorbs the ball’s energy

  • A normal middle ear is

like the cloth

  • Some of the ball’s

energy is transferred through the cloth

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SLIDE 10
  • Sound enters ear canal, propagates down

the ear canal, and is partially reflected from the ear drum.

– Power reflectance = energy reflectance

What is Power Reflectance?

Reflected power Incident power Reflectance =

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SLIDE 11

Reflectance = Reflected Power Incident Power Transmittance = Absorbed Power

What is Power Reflectance?

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SLIDE 12

Wideband Reflectance |R(f)|

Hunter, AAA convention 2005

R(f) depends on frequency

Like a wall Like a cloth 100% 20% 250 Hz 4 kHz

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Reflectance Measurement

  • 1. Probe calibration
  • 2. Obtain patient measurement
  • 3. Evaluation of results

psj

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SLIDE 14
  • 1. Probe Calibration

Characterize the probe acoustics properties via four cavities

L3 Earphone L1 L2 L4 FOUR CAVITIES

Cavity pressures Calibration pass Cavity set

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SLIDE 15
  • 2. Obtain patient measurement

a. Select the probe tip

  • b. Place the probe in the

patient’s ear canal c. Specify the probe tip size

  • d. Initiate the canal pressure

measurement e. Parameters:

– Stimulus type (Chirp or tone) – Stimulus duration (sec)

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SLIDE 16

Measure Reflectance

  • Ear tip size
  • Stimulus type
  • Ear to be

measured

  • Reflectance

plot

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SLIDE 17

Application – UNHS Why Reflectance?

mg

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Why Reflectance?

A central goal of any UNHS (Universal Newborn Hearing Screening) program is to correctly identify ears with hearing loss and correctly identify ears with normal hearing.

Keefe, Ear and Hearing 2000

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SLIDE 19

PASS REFER Normal Hearing Hearing Loss 100% 0% 0% 100%

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SLIDE 20

Why Reflectance?

In the newborn population, the incidence of conductive hearing loss is greater than sensorineural hearing loss. Usually, the conductive component is transient.

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Why Reflectance?

Boone, R.T, et al (2005) review 76 newborns whom failed the UNHS. Approximately 66% had OME and only 33% required

  • BMT. SNHL was confirmed via EP in 11%

following resolution of OME. SNHL was confirmed in the majority of patients without OME.

(International Journal. Of Ped. Otorhinolarygoloy)

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Why Reflectance?

  • Boone, 76 newborns whom failed the UNHS.
  • 50 (66%) had OME

– 17 (33%) required BMT. – SNHL was confirmed via EP in 5 (11%) following resolution of OME.

  • Of the remaining 26, SNHL was confirmed in the

majority of patients without OME.

(Boone, R.T., International Journal. Of Ped. Otorhinolarygoloy 2005)

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Why Reflectance?

Boone, R.T, et al (2005) review 76 newborns whom failed the UNHS. Approximately 66% had OME and only 33% required BMT. SNHL was confirmed via EP in 11% following resolution of OME. SNHL was confirmed in the majority of patients without OME.

OME is a common cause of a ‘false positive’ failed UNHS, but the presence in the face of a failed hearing screening does not necessarily rule out a SNHL.

(International Journal. Of Ped. Otorhinolarygoloy)

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SLIDE 24

Why Reflectance?

Keefe, Gorga,et al tested 2638 neonatal ears and these authors concluded that information on the middle ear status improves the ability to correctly predict hearing status

Keefe, JASA 2003

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SLIDE 25

Why Reflectance?

  • Keefe et al tested 2638 neonatal ears
  • Concluded that information on the

middle ear status improves the ability to correctly predict hearing status

Keefe, Gorga, JASA 2003

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SLIDE 26

Why Reflectance?

Keefe, Zhao, et al, evaluated 1405 neonatal

  • ears. OAE levels decreased and ABR

latencies increased with increasing high frequency reflectance. Up to 28% of the variance in OAE levels and 12% of the variance in ABR wave V latencies where explained by these factors

Keefe, JASA, 2003

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Why Reflectance?

  • Keefe evaluated 1405 neonatal ears.
  • High frequency reflectance approaching 1

implies abnormal OAE levels and abnormal ABR latencies.

  • Up to 28% of the variance in OAE levels

and 12% of the variance in ABR wave V latencies where explained by these factors

Keefe, Zhao, JASA, 2003

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Why Reflectance?

It is possible to obtain abnormal 220 Hz. tympanograms in infants less than 4 months when indeed their middle ear system is normal.

  • Keefe, 1996
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Why Reflectance?

Tympanometry results where normal (Type A) in infants below 4 months of age even though middle ear effusion was present.

Paradise 1976, Meyer 1997

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Why Reflectance?

In newborns with “normal” middle ear systems (as defined by normal TEOAE results) has an error rate of 8% for the 1000 Hz tympanogram.

Kei, JAA

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Why Reflectance?

To decrease the false positives Cost (Testing and Patient’s Opportunity Cost) Validity of UNHS

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Why Reflectance?

  • The problem with tympanometry is that

static pressurization of the ear canal produces large changes in the ear canal volume due to changes in the ear canal diameter.

Keefe, Ear and Hearing 2000

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Why Reflectance?

  • There does not currently exist a clinically accepted

acoustic test of middle ear status applicable to the neonatal population.

  • The problem with tympanometry is that static

pressurization of the ear canal produces large changes in the ear canal volume due to changes in the ear canal diameter.

  • In a compliant infant ear canal, the diameter can

change as much as 70% (Holte, 1991)

Keefe, Ear and Hearing 2000

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Why Reflectance?

With proper calibration techniques WBR can be measured to 6 kHz. WBR does not require the use of a pressurized E.A.C.

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HERTZ Reflectance Ratio 0.0 1.0 All Power Reflected All Power Absorbed

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Application – ME pathology Why Reflectance?

mg

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Feeney, ASHA Leader, 2005

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  • The group mean one-

twelfth-octave ER for the 75 ears of the young-adult participants (solid line) as a function of frequency. The shaded area represents the 5th percentile to the 95th percentile of the ER values. The group mean one- third-octave ER for 10

  • adult ears (thick dashed

line) from Keefe et al. (1993) and the group mean

  • ne-sixth-octave ER for 20

adult ears (thin dashed line) from Margolis et al. (1999) are shown for

Feeney, JSHR, 2003

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SLIDE 39

Feeney, JSHR, 2003

Normal

Reflected Absorbed

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Bilateral SNHL

Feeney, JSHR, 2003

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Feeney, JSHR, 2003

Normal

Reflected Absorbed

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Four Ears with OME

Feeney, JSHR, 2003

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SLIDE 43

Feeney, JSHR, 2003

Normal

Reflected Absorbed

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Two Ears with Otosclerosis

Feeney, JSHR, 2003

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Feeney, JSHR, 2003

Normal

Reflected Absorbed

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Ossicular Discontinuity

Feeney, JSHR, 2003

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SLIDE 47

Feeney, JSHR, 2003

Normal

Reflected Absorbed

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Two Hypermobile TM with normal hearing

Feeney, JSHR, 2003

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Feeney, JSHR, 2003

Normal

Absorbed

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Tympanic Membrane Perforation

Feeney, JSHR, 2003

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Feeney, JSHR, 2003

Normal

Reflected Absorbed

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Negative Pressure Ears

Feeney, JSHR, 2003

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Why Reflectance?

Hunter, AAA convention, 2005

Well Baby Clinic

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Why Reflectance?

  • “No significant differences were

found in WBR based on gender”

Hunter, AAA convention, 2005

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Why Reflectance?

  • “No significant differences were

found in WBR based on gender”

  • “No significant correlation was

found between WBR and age, except at 6000 Hz.”

Hunter, AAA convention, 2005

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Why Reflectance?

A central goal of any NHS program is to correctly identify ears with hearing loss and correctly identify ears with normal hearing. Evoked otoacoustic emissions (EOAE) and Auditory Brain stem Responses (ABR) becomes difficult to assess without verifying the status of the middle ear system through independent means

Keefe, Ear and Hearing 2000

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RMS results - normal

(Allen et al., JRRD, 2005) Power Reflectance Power Absorption Power Transmittance Resistance Reactance Impedance Magnitude

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RMS results – perforated ear drum

(Allen et al., JRRD, 2005) Power Reflectance Power Absorption Power Transmittance Resistance Reactance Impedance Magnitude

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RMS results – Otosclerosis

(Allen et al. JRRD, 2005) Power Reflectance Power Absorption Power Transmittance Resistance Reactance Impedance Magnitude

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RMS results - OME

(Allen et al., JRRD, 2005) Power Reflectance Power Absorption Power Transmittance Resistance Reactance Impedance Magnitude

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Application -Transmittance Predicting the conductive component hearing loss vs. frequency, in dB

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Energy Transmittance across all subjects

  • 10 adult subjects

– normal hearing – normal tympanometry

  • 15
  • 12
  • 9
  • 6
  • 3

100 1000 10000 Frequency (Hz) (10*log(1-R

2))

n=10

  • High pass cut-off frequency ~

1.2 kHz in all subjects

  • Low pass cut-off frequency

varies across subjects

(Hazlewood et al., AAS, 2006)

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Reflectance vs. audiogram in dB

Audiogram shows

similar frequency response as middle ear transfer function

*Audiograms smoothed up to 3 kHz using a 3 point moving average. Audiogram (dB) 10*log(1-|R2|) Frequency (Hz)

SQR

  • 30
  • 20
  • 10

100 1000 10000 7 17 27 37

Audiogram (dB) 10*log(1-R2|) Frequency (Hz)

LMR

  • 30
  • 20
  • 10

100 1000 10000

  • 2

8 18 28

energy transmittance audiogram

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Reflectance vs. audiogram in dB

Audiogram does not show the same frequency response as middle ear transfer function

– High frequency disagreement

Frequency (Hz) 10*log(1-|R2|) Audiogram (dB)

energy transmittance audiogram

SML

  • 20
  • 10

10 100 1000 10000

  • 10

10 20 Frequency (Hz) 10*log(1-|R2|) Audiogram (dB)

KCR

  • 25
  • 15
  • 5

5 100 1000 10000

  • 5

5 15 25

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LMR

  • 30
  • 20
  • 10

100 1000 10000

  • 2

8 18 28 LML

  • 30
  • 20
  • 10

100 1000 10000

  • 5

5 15 25 MSR

  • 30
  • 20
  • 10

100 1000 10000

  • 3

7 17 27 MSL

  • 25
  • 15
  • 5

5 100 1000 10000

  • 10

10 20 SML

  • 20
  • 10

10 100 1000 10000

  • 10

10 20 SMR

  • 25
  • 15
  • 5

5 15 100 1000 10000

  • 10

10 20 30 WHL

  • 30
  • 20
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100 1000 10000 10 20 30 WHR

  • 30
  • 20
  • 10

10 100 1000 10000

  • 10

10 20 30 JDL

  • 25
  • 15
  • 5

5 100 1000 10000

  • 5

5 15 25 JDR

  • 30
  • 20
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100 1000 10000 10 20 30 SQR

  • 30
  • 20
  • 10

100 1000 10000 7 17 27 37 MCL

  • 20
  • 10

10 100 1000 10000 10 20 30 MCR

  • 30
  • 20
  • 10

100 1000 10000

  • 3

7 17 27 SLL

  • 30
  • 20
  • 10

100 1000 10000 3 13 23 33 SLR

  • 25
  • 15
  • 5

5 100 1000 10000 10 20 30 KCL

  • 20
  • 10

10 100 1000 10000

  • 10

10 20 KCR

  • 25
  • 15
  • 5

5 100 1000 10000

  • 5

5 15 25 ABL

  • 30
  • 20
  • 10

100 1000 10000 5 15 25 35 ABR

  • 25
  • 15
  • 5

5 100 1000 10000

  • 5

5 15 25 SQL

  • 25
  • 15
  • 5

5 100 1000 10000 5 15 25 35

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Does the middle ear transfer function determine hearing sensitivity?

  • 90% agreement between low-frequency slope of

audiogram and low-frequency slope of middle ear transfer function

  • Reflectance may provide “objective air-bone gap”

– Conductive hearing loss in children typically occurs in low frequencies

  • Changes to energy transmittance estimate of the middle ear

function (low frequency slope and plateau region) should correlate with changes to the audiogram

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SLIDE 67

Take Home Message

Energy transmittance data suggests Cochlea is an acoustic detector of power over the frequency range 200-5000 Hz

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Hands-on demo

  • 3 stations to try out
  • Exhibits at Starkey’s booth – for more

questions and demo

  • Contact information

– mimosa@MimosaAcoustics.com – mel_gross@starkey.com

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SLIDE 69

Question?

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SLIDE 70

Evaluating ME Function via an Acoustic Power Assessment

Thank you