Optimising the Fitting of Hearing Aids with Cochlear

Optimising the Fitting of Hearing Aids with Cochlear Implants Sarie Cross 1, Paula Greenham 2, Sarah Flynn 1, Catherine Broxholme 3, Maire Doran 4 1. ISVR, University of Southampton. 2. Cochlear Europe Ltd. 3. Great Ormond Street Hospital, London. 4. Glan Clwyd Hospital, North Wales. Introduction This paper describes a multi-centre UK initiative to investigate the benefits of fitting a contra lateral hearing aid with a cochlear implant in experienced paediatric users. Current published research shows the benefits of fitting a hearing aid in the contralateral ear using a special balancing procedure. 1 However this procedure is based on the NAL-RP fitting prescription. In the UK the most commonly used fitting prescription used for children is Desired Sensation Level (DSL i/o)2. The balancing procedure outlined in the published literature has been modified to produce a generic protocol (see handout). This modified procedure has been further reduced to make it clinically practical to perform with younger children. Aims Can the benefits of using a contralateral hearing aid be replicated using the loudness-balancing element only of the published procedure and the DSL i/o fitting prescription? Study Protocol Modified Paediatric Procedure Subjects: Experience: 1 and the gain The implant information. 6 years of age or over Stable MAP for 6 months and have not used hearing aid for 1 year Personnel: Experienced HA Audiologist Ear Moulds: Comfortable rather than tight/deep fit Equipment: HA Programming and Real Ear Measurement Equipment Hearing Aid: Phonak Supero 412 Fitting Protocol: Desired Sensation Level Balancing: Adjust the output of the HA to match the overall loudness of the CI Listening Trial: 8 weeks Speech Testing: IHR Sentences – adaptive procedure Functional Benefit: PEACH questionnaire Localisation Testing: 11 speakers in anechoic chamber Parallel Study: Study with Adult subjects to validate generic balancing fitting procedure with standard prescribed fitting Confirm fitting with real ear measurement. 2 characteristics the ear with ear at soft speech levels a) Adjusting G 50 with an input level of 55 d. B SPL b) Adjusting G 80 with an input level of 80 d. B SPL overall gain if Hearing Aid Administer Earmould Impressions c) Check balance at 65 d. B SPL by adjusting required Confirm new fitting with real ear 4 Finally check that the loudness of both Evaluate implant and HA together is comfortable with 80 d. B SPL input. Localisation Testing Speech Performance 11 speakers CI Alone and CI with HA Anechoic chamber Administer ISVR, Southampton Follow up Questionnaire Fit and Optimise Obtain Consent Adjust the overall gain and/or compression of the HA so that the loudness of speech in the HA is matched to that in the implanted (55 d. B SPL), average (65 d. B SPL) and loud (80 d. B SPL). This is achieved with the Supero by; 3 measurement. Identify Patients Fit the HA according to DSL targets for gain maximum output. Do not be concerned if targets above 1 k. Hz are not achievable. system will contribute the high frequency Baseline Questionnaire Experiences to Date References Comfort levels must be checked before the procedure is started 11 adults have been fitted and did not like the initial DSL fitting targets and were then fitted using NAL. 4/11 have preferred a base cut at the first fitting already moving away form the NAL-RP targets The full balancing procedure with frequency shaping is time consuming even with adults 1 Should Children Who use Cochlear Implants Wear hearing Aids in the Opposite Ear? Ching T, Psarros P, Hill M, Dillon H. & Incerti P. Ear and Hearing 2001: 22, 365 -380 2 The Desired Sensation Level Method for Hearing Aid Fitting in Infants and Children Seewald, R. Phonak Focus No 20 The Authors would like to acknowledge Phonak U. K. for their support with this study. Further information from: Sarie Cross, SOECIC, ISVR, University of Southampton sec@isvr. soton. ac. uk Geneva 2004