What a study at Vanderbilt University teaches us about fitting Spheric Speech Clarity to adolescents

Children and adolescents with hearing loss face listening demands that differ from those of adults. Throughout a typical day they move between classrooms, hallways, cafeterias, sports activities, and social gatherings. These environments are often noisy, dynamic, and unpredictable. Even with amplification, many young listeners require more favorable signal-to-noise ratios than their peers with typical hearing to achieve comparable speech understanding.

For hearing care professionals (HCPs), this raises an important question: can the latest generation of AI-powered noise management technologies help adolescents navigate these environments more effectively?

A recent study conducted at Vanderbilt University explored exactly that question, evaluating how adolescents with hearing loss used and perceived Spheric Speech Clarity (SSC), Phonak’s deep neural network-based noise reduction technology.¹ The findings offer valuable insights into both performance and fitting considerations for this age group.

Why adolescents present a unique challenge

Noise management features have been extensively researched in both adults and children. The research shows that traditional directional microphone and noise reduction systems can provide meaningful benefit in many situations, particularly when speech originates from the front.

However, real-world listening environments are often dynamic, with speech and noise coming from multiple directions and changing rapidly over time. This is where deep neural network (DNN) technology may offer an advantage.

How Spheric Speech Clarity differs

Artificial intelligence has become a common term in hearing healthcare, but not all AI applications are the same. For many years, machine learning has been used in hearing aids to train classification systems, like AutoSense OS and AutoSense Sky OS. More recently, advances in large deep neural networks have enabled different benefits.

In Phonak Infinio Sphere devices, Spheric Speech Clarity uses a large DNN trained on extensive sound samples from challenging listening environments. The system extracts the speech from background noise, then integrates it with heightened contrast for enhanced speech clarity in a location-independent manner.

This approach is particularly relevant for adolescents, who often move through environments where multiple people are talking, conversations shift rapidly, and speech is coming from different directions.

Study with adolescents at Vanderbilt University

Vanderbilt University researchers enrolled 23 adolescents between 10 and 17 years of age with bilateral mild-to-severe symmetrical sensorineural hearing loss. All participants were experienced hearing aid users and were fitted bilaterally with Audéo Infinio Sphere 90 devices for the study.

The researchers set out to answer three key questions:

• Does SSC improve speech intelligibility for adolescents in challenging listening environments?
  
• Do adolescents prefer SSC over other available noise management options?
  
• If SSC is preferred, what level of SSC do adolescents choose?

Participants completed laboratory testing, preference evaluations, and real-world field trials.

Speech understanding: Benefits beyond the front-facing listener

When speech originated from the front, SSC and StereoZoom 2.0 produced comparable benefits and were significantly better than with Real Ear Sound. However, when speech originated from behind the listener, SSC significantly outperformed StereoZoom 2.0.

For clinicians, this finding is particularly relevant because many real-world adolescent listening situations involve speech coming from multiple directions. Whether talking with friends in a cafeteria or interacting during extracurricular activities, communication rarely occurs with everyone positioned directly in front of the listener.

Adolescents clearly preferred SSC

The preference findings were equally compelling. In blinded-laboratory A/B comparison testing, adolescents selected SSC7 more frequently than any other noise management option. Real Ear Sound was chosen least often, and SSC1 was the least preferred among the SSC settings.

When participants adjusted the SSC control themselves using the myPhonak app, none selected settings equivalent to SSC1 or SSC2 as their preferred option. Instead, the majority chose settings between SSC5 and SSC7.

Interestingly, these preferences closely mirrored what has previously been observed in adults.

Real-world validation

Laboratory findings are valuable, but real-world experiences often determine whether a technology ultimately succeeds.

During field trials conducted in challenging listening environments, 67% of participating adolescents preferred SSC5 over StereoZoom 2.0. Participants reported that listening was easier and communication was more comfortable when SSC was active.

For HCPs, this is encouraging because it suggests that the benefits observed in controlled testing translate into situations adolescents encounter in everyday life.

Clinical implications

The Vanderbilt findings provide practical guidance for fitting SSC with adolescents.

• Consider setting SSC at position 5 (moderate) within the Spheric Speech in Loud Noise program. This setting aligns with both performance outcomes and user preferences observed in the study.
  
• Adolescents may benefit from having access to a manual Spheric Speech in Loud Noise program. Unlike younger children, many teenagers are developing greater independence and can recognize when additional support is needed in challenging listening environments.
  
• The study highlights the value of personalization. Adolescents demonstrated a remarkable ability to identify their preferred SSC settings and adjust the technology to meet their listening needs. Encouraging them to explore settings through myPhonak and discuss their experiences during follow-up appointments can help create more individualized fittings.
  
• Involving adolescents in the fitting process can support ownership and engagement with their hearing technology.

Looking ahead

The study at Vanderbilt reinforces an important message: adolescents are not simply smaller adults, but neither should they be excluded from benefiting from advanced hearing aid technologies.

The findings demonstrate that adolescents not only benefit from Spheric Speech Clarity in specific challenging listening situations, but also strongly prefer it in both laboratory and real-world environments.

To read the full Phonak Insight, we invite you to visit the Phonak Evidence Library.

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Reference:

1. Nelson, J., Picou, E., & Rich, S. (2026). Spheric Speech Clarity for adolescents: Optimizing preference and real-world experience. Phonak Insight available at https://www.phonak.com/evidence.