Effect of Open fittings May, 2004 Johnny H. Hansen Director, Global Technical Operations GN ReSound as.

What’s the problem? M&M Hearing Uppsala Sweden – Experienced problems 6 months after fitting – Based on 1361 responses

It’s all about occlusion…

Occlusion 1k 8k 2k 4k 500 250 Frequency (Hz) dB SPL in ear canal CIC with pressure vent BTE with 1.5 mm vent Open mold Sound pressure measured in ear for own vocalization of vowel /ee/

…..and feedback

The dilemma.. and the solution Effect of Stabilizer DFS

Why ResoundAIR and Canta7/Open are so revolutionary? Because we have combined: state-of-art technology in earmould design/venting signal processing in ComforTech .

ComforTech: WarpOpen

Stabilizer™ DFS Technology Feedback path S WarpOpen Compression system Static filter bank Adaptation Adaptive filter - The feedback path is measured and stored in the static filter bank which is a “mirror” of the actual acoustic feedback path

The proof….

Hearing threshold level (dB HL) The occlusion research project in Giessen Germany… 20 40 60 80 100 120 125 1k Frequency (Hz) Hearing threshold level (dB HL) 250 500 2k 4k 8k AC HTL BC HTL NH group (n = 9) HI group (n = 10)

FlexVent and ResoundAIR Ear Tip (front) FlexVent (rear) ResoundAIR ear tip

Occlusion measure (dB) Measured occlusion: SPL increase in ear canal at low frequencies when reading a standard text -5 5 10 15 20 Occlusion measure (dB) Test Retest Flex- Vent 1.6 mm Earmold vent 2.4 mm ReSound AIR ear tip Un- occluded all subjects (n = 19)

Experienced occlusion: NH group (n=9) -2 2 4 6 8 10 Occlusion rating (arb. units) Flex- Vent 1.6 mm Earmold vent 2.4 mm ReSound AIR ear tip Un- occluded Test Retest HI group (n = 10) -2 2 4 6 8 10 Occlusion rating (arb. units) Flex- Vent 1.6 mm Earmold vent 2.4 mm ReSound AIR ear tip Un- occluded Test Retest

The challenge: Open fitting in custom (CIC) products

Stepped vent in CIC device Here you see an example of how the stepped vent looks like in a CIC device.

Feedback path response 10 2 3 4 -80 -70 -60 -50 -40 -30 -20 -10 Frequency, Hz Feedback path response, dB Stepped Not stepped Stepping makes the vent shorter and shifts the peak of the high frequency resonance, reducing the likelihood of feedback and optimizes Stabilizer function. A vent produces a low frequency peak at the cut off frequency which is evident on a coupler measurement and is largely damped in a real ear. This resonance produces gain (insertion gain) and reduces the amount of attenuation for the frequencies in the region of the peak. That is, the attenuation slope is not a straight line. The stepped vent have a significant effect in reducing the risk of feedback in the high frequencies by shifting the high frequency resonant vent peak up in frequency - beyond the useful bandwidth of the aid. The effect of the Stabilizer is thereby increased

The Challenge..

The Challenge…. Stepping optimize the work conditions for Stabilizer-DFS but don’t create significant occlusion reduction To obtain full Open comfort benefits in CIC’s we need very large vent diameter combining new skills and mindset challenge with dispenser, the sales force and the Lab More in the next sessions……….

Vents….

How do Vents work ? Sound bore Dampers Vents Vents affect the low frequencies 125 250 500 1000 2000 4000 8000 Vents Dampers Sound bore (Dillon, 2001)

What determines the vent effectiveness Acoustic Mass determines the vent effect The lower the Acoustic Mass the higher the vent effect (occlusion relief) Formula Vent Length ------------------------ x Constant Vent diameter2

Effects of Ventilation Low frequency sounds can enter and leave the ear canal through the vent. Transmission of low frequency sounds is easier the smaller the acoustic mass of the vent. The acoustic mass of the vent is calculated from the length & diameter of the vent. Increasing the diameter reduces the acoustic mass Decreasing the length reduces the acoustic mass

Openness of vents Non-occluding Non-occluding Open Closed Closed

How open are our instruments ReSoundAir rating 1 FlexV (L) rating 3 FlexV (M) rating 4 Tmold (2.4) rating 6 Tmold (1.6) rating 7 S.CIC (2.3) rating 5 T.CIC (2.3) rating 5 FV(M):4 FV(L):3 Air:1 IROS SCIC:5 Here you see the subjective occlusion rating (HI subjects) from the Giessen trial. Explain why the stepped vent doesn’t alleviate occlusion. Venten kortes af, men kun ud til et hulrum som ikke er åbent, idet resten af apparatet fylder en del af øregangen ud. Vent length in custom products: 19 x 2 (right and left) CIC devices vent length (stepped vent): average of 1,48 cm 19 x 2 (right and left) CIC devices vent lengh (traditionel vent): average of 1,99 cm. Vent length of tradional earmold vents: 6 Earmolds 2,4 mm:average of 1,9 cm (vent length) 6 Earmolds 1,6 mm: average of 1,8 cm (vent length). TCIC:5 Tmold:7 Tmold:6

Sound Demo´s Speak Crunching

Custom Products

Problems in the Lab Custom products with open fittings, especially CIC’s often cause trouble for the Lab. To get room for the vent canal you occasionally have to compromise. You can focus on either Cosmetics or Comfort. You can compromise on either vent diameter or instrument size.

Full cosmetic benefits Custom Open Products Vent diameter Small Large Full cosmetic benefits Small Select cases* * Cases of larger ear canals Instrument size Full comfort benefits No perceived benefits Large Ø 1.6 mm (~2.0 mm2) Ø 2.6 mm Ø 3.0 mm (~7.0 mm2) <-Closed Open ->

Vents on Custom Products Non-occluding Non-occluding Open Custom Closed Closed

The conscious choice Compromise on instrument size. Risk of Return due to protrusion Comfort Limited room for vent Cosmetics Compromise on vent diameter. Risk of Return due to occlusion. Keep in mind that 40% of users experience Occlusion as the primary problem

Venting Process 1

Large vent issues Faceplate Module Battery Hybrid Receiver

Large vent issues Faceplate Module Battery Hybrid Receiver

Large vent issues Faceplate Module Battery Hybrid Receiver

Lab Training America Asia Europe North Europe South 4 Lab training sessions to be co-ordinated with Product/Mkt/Sales training America (Bloomington) March 3rd US – CND Asia (DanaJapan) March 9th JPN – CHI – AUS - NZ Europe North (Taastrup) March 9th GER – HOL – FRA DEN - SWE – NOR - BRA Europe South (Madrid) March 12th SPA – ITA – U.K. BEL - SWI - A

Thank you. Questions ?