A newly published study in Scientific Reports examined how an AI-based noise reduction feature used in Phonak hearing aids is associated with changes in cognitive processing during speech understanding in noisy environments.1 The research used functional near-infrared spectroscopy (fNIRS), a neuroimaging technique that measures changes in blood oxygenation in the brain, to evaluate listening effort among experienced hearing aid users.
The study compared brain activity when participants listened to speech in background noise with and without activation of Phonak’s AI-based noise reduction. Speech understanding in noisy environments is widely recognized as one of the most challenging listening situations for people who use hearing aids.
According to the findings, activating the noise-reduction settings was associated with reduced cognitive processing in specific regions of the brain while participants simultaneously demonstrated improved speech understanding. Neuroimaging data showed reduced blood oxygen concentration in the left prefrontal cortex, an area associated with effortful listening. Participants also reported lower subjective listening effort when the technology was enabled.
The image on the left illustrates the brain while listening without AI-based noise reduction; the red areas show more oxygen concentration, which is less efficient. The image on the right illustrates the brain while listening with AI-based noise reduction; the smaller red areas show lower oxygen concentration, which indicates more efficient processing of speech.
The study authors used visualizations to illustrate differences in brain activation. Images representing listening without AI-based noise reduction showed higher oxygen concentration, while images representing listening with the technology activated showed lower oxygen concentration, which the researchers interpreted as more efficient cognitive processing.
Stefan Launer, Vice President Audiology and Health Innovation, Sonova said: “This study provides important scientific evidence that Phonak’s AI-based noise reduction reduces listening effort and cognitive load when listening to speech in noise, aligning with wearers’ real-world experiences. We’re grateful for the support of collaborators like Dr. Frank Russo at Toronto Metropolitan University, who make work like this possible.”
“This study confirms what we have already learned from extensive feedback from hearing aid wearers and hearing care professionals alike – that Phonak Infinio Sphere delivers clearer speech in dynamic group conversations and noticeably reduces listening fatigue throughout the day. By validating real-world experiences with compelling clinical evidence, the findings reinforce Phonak Infinio Sphere’s unique role in helping people stay mentally energized, socially engaged, and connected for longer in challenging listening environments.”
–Oliver Frank, Vice President Phonak Marketing
Phonak’s Infinio Sphere hearing aids incorporate the company’s proprietary AI-based noise-reduction system, known as Spheric Speech Clarity™.2 Phonak states that, unlike approaches that classify the listening environment before processing sound, the system uses a dedicated real-time deep neural network chip designed to extract, enhance, and reintegrate voices from multiple directions simultaneously.
The authors note that findings such as these contribute to the growing body of research exploring how hearing aid technologies may influence listening effort and cognitive load during speech perception in noise.
- The full study, titled “Brain benefits of deep learning-based noise management in experienced hearing aid users using functional near infrared spectroscopy,” is available in Scientific Reports (2025).
**Readers interested to learn more about Phonak’s approach to hearing aid testing may want to check out this July 2025 discussion on the subject with Michael Preuss, Audiology Manager at Sonova
References
1. Brain benefits of deep learning-based noise management in experienced hearing aid users using functional near infrared spectroscopy. Sci Rep 15, 41815 (2025). https://doi.org/10.1038/s41598-025-25801-y
2. Raufer, S., Kohlhauer, P., Jehle, F., Kühnel, V., Preuss, M., Hobi, S. (2024). Spheric Speech Clarity proven to outperform three key competitors for clear speech in noise. Phonak Field Study News retrieved from https://www.phonak.com/evidence
About Phonak
life is on. Since 1947, Phonak has been dedicated to improving the quality of life for people with hearing loss. Seventy-five years later, our passion for creating life-changing hearing solutions that help people thrive physically, socially, and emotionally remains. By offering the industry’s broadest portfolio of hearing solutions, we’re committed to creating a world where “life is on” for everyone.
At Phonak, innovation is not limited to products. We work to change the conversations surrounding people with hearing loss. We do this by fighting the stigma of hearing aids and creating an understanding of how hearing is connected to the broader context of healthy living.
About Sonova
Sonova is a global leader in innovative hearing care solutions: from personal audio devices and wireless communication systems to audiological care services, hearing aids and cochlear implants. The Group was founded in 1947 and is headquartered in Stäfa, Switzerland. Sonova operates through four businesses – Hearing Instruments, Audiological Care, Consumer Hearing and Cochlear Implants – and the core brands Phonak, Unitron, AudioNova, Sennheiser (under license) and Advanced Bionics as well as recognized regional brands. The Group’s globally diversified sales and distribution channels serve an ever-growing consumer base in more than 100 countries. In the 2024/25 financial year, the Group generated sales of CHF 3.9 billion, with a net profit of CHF 547 million. Around 18,000 employees are working on achieving Sonova’s vision of a world where everyone enjoys the delight of hearing.
Sonova has a long-standing commitment to innovation and was ranked no. 12 among the most innovative companies in Europe in 2025 by Fortune magazine, selected from 300 companies across 21 countries and 16 industries. For more information, please visit www.sonova.com
Source: Phonak, SR
