OSN_Pediatrics_Browning Research Flashcards
Open Sound Navigator (OSN)
What are the features?
Features of OSN includes -
- Holistic system that quickly and seamlessly identifies multiple dynamic speech and noise sources
- no modes or mode switch
- Rebalances the sound scene, preserving speech in all directions, while selectively reducing noise.
- It provides a ‘spatially-informed’ estimate of the environmental noise which enables a fast and accurate noise reduction.
- Consists of 3 modules
- Analyze
- Balance
- Noise Removal
Visual Graphic of OSN vs. Conventional Directional Microphones
Directional Microphone Evolution
How do traditional systems function?
Omnidirectional technology is used for quiet environments or 1 on 1 conversations. When a certain threshold of background noise is reached then the directional microphone is engaged with a forward-facing beam. This assumes that the speech is always coming from the front and noise from behind.
Automatic Program Switching
- Quiet = Omnidirectional
- Noise = Directional
Based on:
- Noise Floor
- SNR
- Time
What are the assumptions made by a directional microphone?
- The hearing device user always wants to hear the person directly in front of him/her
- The hearing device user is always facing the person he/she wants to hear
- Noise is always coming from behind the hearing device user
- All noise types should be treated the same
- People don’t live in either QUIET or NOISE
What is Environmental Scene Classification?
Environmental Scene Classifcation is the sampling of different acoustic parameters out of the environment, and matching it to a database of sound scenes.
Challenges of Environmental Scene Classifiers
- Unsophisticated Systems
- Lumps all noise types together
- Does the scene have speech and/or noise?
- Speech + Noise: Directional Microphone with beamformer to the front
- Speech Only: Omni
- Noise Only: Omni
- Sophisticated Systems
- Identificaction of noise types
- Where is noise and where is speech?
- Speech + Noise: Adaptive directional microphone with adaptive nulls
- Speech Only: Omni
- Noise Only: Omni
Smart environmental scene classifiers identify scene based on the noise type, direction of the noise, and amount of noise
Noise Statistics
- School-age children spend up to 80% of their time listening to speech in the presence of competing noise throughout the school day.
- Adults spend 60% of their time in noise.
- Infants and children hear multiple people talking at the same time about 50% of their day at home.
Solutions to overcome this are a) remote microphones, b) digital noise redution and c) directional microphones.
Real World Considerations regarding Children and Directional Microphones
- Children, ages 11 months - 78 months, face the target speaker only 40% of the time
- Children, 4-17 years, orientation to primary talker is highly variable.
- Reliance by the user for an automatic system to switch when appropriate.
- Speech can come from anywhere and situations are highly variable.
- Children learn up to 90% incidentally.
How is OSN different than an Environmental Scene Classifier?
- OpenSound Navigator™ is a spatially informed seamlessly adapting speech-enhancement algorithm - reducing noise, while also maintaining access to multiple talkers.
- OpenSound Navigator™ is designed to leave the user with the possibility to hear multiple speech sources and decide themselves where to attend
Does advanced signal processing matter for BAHS users?
YES!
Evidence show an improvement of 3.2 dB SNR for BAHS users (on average) with advanced signal processing vs. without, depending on location of speech and noise.
Open Sound Navigator for Pediatrics – Study 1
Effects of Adaptive Hearing Aid Directionality and Noise Reduction on Masked Speech Recognition for Children Who Are Hard of Hearing
- Jenna M. Browning, Emily Buss, Mary Flaherty, Tim Vallier, and Lori J. Leibolda*
- American Journal of Audiology*
- Vol. 28, 101–113, March 2019*
Purpose of the Study
- To evaluate speech-in-noise recognition associated with activation of a fully adaptive directional hearing aid algorithm (OSN) in children with mild to severe bilateral sensorineural hearing loss
- Compared to: Performance of children with normal hearing
- Compared to: Omnidirectional microphone (no noise reduction)
Open Sound Navigator for Pediatrics
Effects of Adaptive Hearing Aid Directionality and Noise Reduction on Masked Speech Recognition for Children Who Are Hard of Hearing
Who participated in this study?
Study Participants
2 Groups
Group 1:
- Fourteen children (5-14 years old) with hearing loss
- Pure-tone thresholds from 250-8000 Hz mild to severe
- Consistent users of bilateral amplification
Group 2:
- Fourteen children (5-14 years old) with normal hearing
- Thresholds ≤ 20 dB from 250 – 8000 Hz
- Age-matched within 6 months to the children with hearing loss
Open Sound Navigator for Pediatrics
Effects of Adaptive Hearing Aid Directionality and Noise Reduction on Masked Speech Recognition for Children Who Are Hard of Hearing
What were the methods used?
Methods:
- Fit all participants with Oticon OPN Devices
- Testing using 3 conditions with varied noise types and direction of speech
- Noise types: Steady-state and speech babble
- Condition 1: speech from front and steady-state noise from behind
- Condition 2: speech from side and steady-state noise from behind
- Condition 3: speech from front and behind and speech babble from front and behind (i.e. speech and noise coming from all directions)
Open Sound Navigator for Pediatrics – Study 1
Effects of Adaptive Hearing Aid Directionality and Noise Reduction on Masked Speech Recognition for Children Who Are Hard of Hearing
What are the results?
In both condition 1 and condition 2 the children with hearing loss performed significantly better with OSN than in Omni, regardless of whether the direction of the speech was coming from the front or the side. Keep in mind this is different than a traditional directional microphone would perform. A Traditional directional microphone would always assume the speech is coming from the front, and may even cancel out speech coming from the side.
Open Sound Navigator for Pediatrics – Study 1
Effects of Adaptive Hearing Aid Directionality and Noise Reduction on Masked Speech Recognition for Children Who Are Hard of Hearing
Results of condition 3
The results of condition 3:
- OSN and OMNI perform equally with the three talkers.
- OSN advanced signal processing maintains access to speech in a 360 degree environment.
- Access to speech from all angles is essential for incidental learning and listening.
- A traditional directional microphone would only focus on the speaker from the front
- OSN behaves like Omni with multiple speakers in the environment, keeping all speech available, no matter where it is coming from.
Results when comparing Children with Normal Hearing (CNH) vs. Children who are Hard of Hearing (CHH)
Overall Results
- Children with normal hearing performed better than children with heairng loss regardless of the condition.
- Condition 3 was a difficult task even for children with normal hearing.
- The gap between children with normal hearing and children with hearing loss in OMNI was 7-8 dB across all 3 conditions
- The gap does shrink to 3-4 dB when children with hearing loss use OSN in presence of steady-state noise.
Microphone Technology Scorecard
- Children using hearing technology are typically in an omnidirectional mode
- Directional technology is a great benefit only if the speaker is in the front
- Open Sound Navigator (OSN) demonstrates a strong benefit regardless of target location. Benefit is similar to that seen with an Omnidirecitonal system
