The Impact of the use of FM
systems with cochlear implants
in the UK over the last 10 years
Elizabeth Wood and Sarah Flynn
South of England Cochlear Implant Centre
AIM 1
Radio Aids used in research studies
AIM 3
Is interference an issue?
To develop training and resources to
enable those who have day to day
contact with the user to maintain,
monitor and evaluate effective use of the
FM system
Do all systems work equally effectively over distance?
What are the responsibilities of the CI centre and the
local services?
To establish compatibility of cochlear
implant
speech
processors
with
commonly used FM systems
Phonak Microvox
When new speech processors are released are there
any new considerations?
Connevans 220
Phonic Ear 471R/ 475T
Phonic Ear Solaris
Phonak MLxS /MLx SmartLink & Campus S Tx
Research Methodology
Subject at
3m with and
without FM
receiver
Subject at
10m with &
without FM
receiver
Noise
speaker
CI Centre
Initial fitting and validation
Provision of lead/adaptor
& troubleshooting guidance
Training
Do Implant centres have a policy on when to fit an
FM system?
Family
Support and encourage
Liaise with school and
CI centre
User
Report on sound quality
Provide feedback
What age are FM systems fitted and if they are not
used why not?
Is a verification procedure used?
Fitting and Verification
Are there any concerns, or feedback from local
professionals or staff at the CI centres?
We recommend that the initial fitting takes places at
the CI centre when the user has a stable map and can
report on sound quality
Method
Tx
2 metres
A
T
T
A survey was sent out to all UK cochlear implant
centres in 2000, then again in 2005, asking these
questions
2 metres
20 cm
To document the increasing use of FM
and CI in the UK
Speech discrimination over distance
With implant and FM aid
Noise
speaker
Local Services
Provision and
Maintenance of FM
Day-to day management
Liaison with school, family
and CI centre
Training for staff
How often are FM radio aids being used in the UK
with cochlear implants?
The McCormick Automated Toy Test (ATT) was used
to evaluate speech discrimination in noise and quiet.
The format was modified to give a fixed noise level of
55dB(A) with the speech level varying, or with a fixed
speech level of 70dB(A) and the noise level varying. In
both formats the level at which the subject scores 71%
correct is recorded
Speech discrimination in noise
What materials are available for fitting and evaluation?
Responsibilities
AIM 2
Older children and adults who were experienced CI
users took part in the studies. A range of Nucleus
speech processors were evaluated with radio aids
Speech
speaker
Sennheiser Microport
How and where should evaluation take place?
Subjects
With implant only
Connevans Genie
FM
Speech
speaker
Results
Results
• Speech discrimination scores in quiet and in noise
improved on average when all FM systems were used
• Sound quality at distance was rated as good by all
subjects with all radio aids except the MLx at 10m
when subjects reported a slight reduction in quality.
• Interference-free transmission was achieved with all
systems but inter-subject variability was observed
• MicroLink MLxS radio aid receivers can be used
successfully with the ESPrit 3G
• Optimal gain levels for MLxS with the ESPrit 3G are
between +6 to +12
• The optimal transmitting frequency differs for the
CI22 and CI24 implants
In 2000 data was received from all 21 implant
centres on 1241 children. In 2005 13/18 centres
provided full information on 1763 children and 2
provided partial information on another 415
children.
Use of Soundfield FM
Validation Methods
Informal e.g. use of Ling sounds
Speech in Noise (or quiet) Task e.g. ATT
Electro-acoustic methods are being trialled
In 2005 almost 30% of children with cochlear
implants are fitted with a personal FM system.
Numbers of FM radio aids used in the UK
CONCLUSIONS
250
Numbers of CI users
A
T
T
We liaise with local services about the optimum
transmitting frequency and type of system requested
200
150
235
225
100
114
113
50
61
38
0
41
66
9
9
0
Connevans
220 & Genie
Phonic Ear
Solaris
Phonak
Microvox
4
0
0
2005
2000
Oticon
Lexis
Type of FM Radio Aid
In 2002 a small study looked at subjective and
objective ratings of sound quality when using a radio
aid in a soundfield treated room.
Results
Problems of compatibility were described particularly if
the room had not received any acoustic treatment.
However, results from the 2000 FM survey showed
that only 3% centres reported the use of soundfield
FM with CI’s in schools, whereas in 2005 this had
risen to 25%, suggesting some of the previous
problems have been addressed
The biggest increase is the introduction and use of
the ear-level plug-in FM systems (from 3% of CI
users in 2000 to 22% in 2005). Users are generally
older children
All centres said that a user should be able to report
on sound quality and give feedback before fitting
Concerns reported were the fragile leads and
cables, the size of the adaptors, and the need for a
fitting protocol
At SOECIC 59% of children are fitted with personal
FM radio aids
Contact for further information ejw@isvr.soton.ac.uk
• Radio Aids can be successfully
used with cochlear implants
• User feedback to report on sound
quality and interference is essential
• Training and setting up of
appropriate gain and default
frequency when using a radio aid is
necessary
• Fitting and verification procedures
are needed
• Close liaison between CI clinic and
local serrvices is essential
• Liaison with radio aid and cochlear
implant manufacturers has assisted
and advanced our understanding