Can You Hear Me Now?Benefits of Frequency-

Modulated (FM) Systems for Adults and Children Using

Cochlear Implants: A Meta-Analytic Approach

Mary Pat Kleineck, Department of Speech and Hearing Sciences, College of Arts and Sciences & Honors College Faculty Mentor: Dr. Erin Schafer, Department of Speech and Hearing Sciences

Background

• What is a Cochlear Implant?– A cochlear implant

is a surgically implanted hearing device that can significantly improve hearing for people with severe-to-profound hearing losses Picture from www.uhhs.com

Background

• What is a Cochlear Implant?– However, these

devices do not restore hearing in noise and speech recognition abilities of the person with hearing loss often decline in the presence of background noise Picture from www.uhhs.com

Background

• What is an FM System?– An FM System is a type of assistive

listening device which allows the listener to hear the desired speech signal at a louder level

– It consists of a microphone, a receiver, and a transmitter, which carries the acoustic signal wirelessly from the microphone to the receiver

Background

• Types of FM Systems– Classroom soundfield

Picture from www.oticon.com

Background

• Types of FM Systems– Desktop soundfield

Picture from www.centrumsound.com

Background

• Types of FM Systems– Direct-Audio Input

Picture from www.phonak.com

Purpose

• To compare the improvements in speech recognition in noise for people who have cochlear implants when using classroom soundfield, desktop soundfield, and direct-audio input FM systems.

Methods

• Collected data from 8 studies from peer-reviewed journals and poster presentations from 1998-2006

• Inclusion criteria included: (1) testing done in Standard English, (2) testing of speech recognition, (3) testing of no-FM and FM conditions, (4) providing mean percent-correct and standard deviations for the data, and (5) a fixed intensity stimuli of +5 or +6 SNR.

MethodsTable 1. Description of Studies

Author (year)

N

Age (years)

CI Company

CI Processor

Stimulus/ Noise

Manufacturer/ FM Receiver

Conditions

Aaron et al. (2003)

12

4 - 12

CC

SPrint

Sentences/ Multibabble

Phonak/ MicroLink

DAI

Anderson et al. (2005)

6

7 - 13

CC

3G, SPrint, ESPrit

Sentences/ Hospital cafeteria

noise

PE/ 900R Vocalight, LS/ LES 390 Desktop

SoundPak, Phonak/ MicroLink CI+

C, D, DAI

Catlett et al. (2003)

18

17 - 18

ABC

Clarion 1.2, CII

Sentences/ Speech

Phonak/ MicroLink CI S

DAI

Crandell et al. (1998)

18

18 - 80

CC

Spectra

Words/ Multibabble

Audio Enhancement Omni Deluxe

C

Iglehart (2004)

14

6 - 16

ABC, CC

S-Series, SPrint, Spectra,

ESPrit 22, Clarion 1.2

Words/ Multibabble

PE/ Toteable, PE/ 210 Soundfield System

C, D

Schafer & Thibodeau

(2003)

10

7 - 12

CC, M

ESPrit 22, 3G, Tempo

Sentences/ Speech

PE/ Toteable, PE/ Easy Listener, AVR/ Logicom

CI, Phonak/ Microlink CI+

D, DAI

Schafer & Thibodeau

(2004)

8

20 - 58

CC

Spectra, SPrint, ESPrit 22/24

Sentences/ Speech

PE/ Toteable, PE/ Easy Listener, AVR/ Logicom CI

D, DAI

Thibodeau et al. (2005)

8

5 - 15

CC, ABC

S-Series, Platinum, SPrint, 3G

Words/ Speech

Phonak/ MLx, Microlink CI S, Comtek/ PR-72b

DAI

Note. N=number of participants; CI=cochlear implant; CC=Cochlear Corporation, ABC=Advanced Bionics Corporation; M=MED EL Corporation; PE=Phonic Ear; DAI=direct audio input; C=classroom soundfield; D=desktop soundfield.

Methods

• Calculated differences between no-FM and FM-system conditions; each score was treated as a separate experiment

• Calculated average percent-correct scores and corresponding 95% confidence intervals for each experiment and type of FM system

Methods

• Performed a meta-analysis using a random-effects model. A chi-square value was computed to test the null hypothesis.

• Post-hoc analyses explored if the age of the listener, type of background noise, and type of internal processor used by the listeners yielded better speech recognition in noise with certain types of FM systems.

Results

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

Figure 1. Forest plot of meta-analysis results

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

Figure 1. Forest plot of meta-analysis results

Results

• Classroom Soundfield– Mean Average Benefit:

• 3.66% (CI95 ± 7.29)

– Intersects with 0% line– Results are not significant

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

Figure 1. Forest plot of meta-analysis results

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

Figure 1. Forest plot of meta-analysis results

Results

• Desktop Soundfield– Mean Average Benefit:

• 21.6% (CI95 ± 7.4)

– Does not intersect with 0% line– Results are significant

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

Figure 1. Forest plot of meta-analysis results

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

Figure 1. Forest plot of meta-analysis results

Results

• Direct-Audio Input– Mean Average Benefit:

• 36.8% (CI95 ± 7.0)

– Does not intersect with 0% line– Results are significant

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

Figure 1. Forest plot of meta-analysis results

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

-100.0 -50.0 0.0 50.0 100.0

Mean Difference (%)

Stu

dy

Classroom SoundfieldIglehart (2004)Anderson (2005)Crandell (1999), ACrandell (1999), ACrandell (1999), CCrandell (1999), CCrandell (1999), CAverage

Desktop SoundfieldSchafer (2003)Schafer (2004)Iglehart (2004)Anderson (2005)Average

Direct Audio InputSchafer (2003)Schafer (2003)Schafer (2003)Schafer (2004)Schafer (2004)Anderson (2005)Catlett (2003), 50/50Catlett (2003), 30/70Catlett (2003), 10/90Thibodeau (2005)Aaron (2003), 10-12Aaron (2003), 6Aaron (2003), 7Aaron (2003), 8Aaron (2003), 9Average

Total

Group

CombinedClassroom SoundfieldDesktop SoundfieldDirect Audio Input

3.6% (CI95 7.3)

21.6% (CI95 7.4)

36.8% (CI95 7.0)

25.3% (CI95 7.3)

Figure 1. Forest plot of meta-analysis results

Results

Table 2Main Analysis

< 0.0001564.5336.78 ± 7.015DAI

< 0.000147.1321.56 ±

7.394Desktop SF

0.028012.813.66 ± 7.297Classroom SF

Probability LevelX2μ ± CI95DFStudy

Note: DF=degrees of freedom; μ/CI95=average difference with 95% confidence intervals; X2=Chi--Square value; SF=soundfield; DAI=direct-audio input

Table 2Main Analysis

< 0.0001564.5336.78 ± 7.015DAI

< 0.000147.1321.56 ±

7.394Desktop SF

0.028012.813.66 ± 7.297Classroom SF

Probability LevelX2μ ± CI95DFStudy

Note: DF=degrees of freedom; μ/CI95=average difference with 95% confidence intervals; X2=Chi--Square value; SF=soundfield; DAI=direct-audio input

• Both desktop and direct-audio input offer significant benefits

• Direct-audio input provides the greatest benefit of all FM systems

Post-Hoc Findings

• The age of the participant does not affect the amount of FM-system benefit with classroom soundfield or direct-audio input receivers

Post-Hoc Findings

• The internal implant used by the participant did not affect results with a desktop soundfield receiver but did influence results with the direct-audio input receivers.

• Participants with Cochlear Corporation Nucleus 24 internal implants had significantly greater gains in speech recognition than those using a Cochlear Corporation Nucleus 22 internal implant.

Post-Hoc Findings

• The type of noise stimuli used during testing did not affect the amount of FM-system benefit measured for desktop soundfield and direct-audio input receivers.

Summary & Clinical Implications

• Though classroom soundfield FM systems are relatively inexpensive and easy to troubleshoot, they do not provide significant benefits

• Therefore, classroom soundfield FM systems should not be used in the schools

Summary & Clinical Implications

• Desktop soundfield and direct-audio input FM systems provide significant benefit

• Direct-audio input FM systems are superior and should be routinely recommended for children and adults with cochlear implants

Summary & Clinical Implications

• The post-hoc analysis suggests newer internal implant technologies work better with direct-audio input FM systems

Special Thanks To…

• Dr. Gloria Cox, Dean of the Honors College

• Dr. Susan Eve, Associate Dean of the Honors College

• Dr. Warren Burggren, Dean of the College of Arts & Sciences

• Dr. Samuel Matteson, Chair of the Department of Speech and Hearing Sciences