The Impact of the use of FM systems with cochlear implants in the UK over the last 10 years

1. Subject at 10m with & without FM receiver Subject at 3m with and without FM receiver ATT Tx The Impact of the use of FM systems with cochlear implants in the UK over the last 10 years AIM 1 To establish compatibility of cochlear implant speech processors with commonly used FM systems Is interference an issue? Do all systems work equally effectively over distance? When new speech processors are released are there any new considerations? Radio Aids used in research studies AIM 3 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 What are the responsibilities of the CI centre and the local services? How and where should evaluation take place? What materials are available for fitting and evaluation? Phonak Microvox Connevans 220 Connevans Genie Sennheiser Microport Phonic Ear 471R/ 475T Phonic Ear Solaris Phonak MLxS /MLx SmartLink & Campus S Tx • Subjects • 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 • Research Methodology • 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 • 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 • Use of Soundfield FM • 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 Fitting and Verification 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 We liaise with local services about the optimum transmitting frequency and type of system requested Validation Methods Informal e.g. use of Ling sounds Speech in Noise (or quiet) Task e.g. ATT Electro-acoustic methods are being trialled Responsibilities AIM 2 To document the increasing use of FM and CI in the UK How often are FM radio aids being used in the UK with cochlear implants? Do Implant centres have a policy on when to fit an FM system? What age are FM systems fitted and if they are not used why not? Is a verification procedure used? Are there any concerns, or feedback from local professionals or staff at the CI centres? Elizabeth Wood and Sarah Flynn South of England Cochlear Implant Centre Speech discrimination in noise Speech discrimination over distance Method A survey was sent out to all UK cochlear implant centres in 2000, then again in 2005, asking these questions Results 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. 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 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 ATT • CONCLUSIONS • 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 Contact for further information ejw@isvr.soton.ac.uk