Locating Sounds in the World with Over-the-Counter Hearing Aids

Pinar Erturk – perturk@bu.edu

Speech, Language and Hearing Sciences, Boston University, Boston, Massachusetts, 02215, United States

Virginia Best – ginbest@bu.edu
Speech, Language and Hearing Sciences
Boston University

Popular version of 3aPP6 – Spatial Perception with Over-the-Counter Hearing Aids
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Hearing aids help millions of people hear speech more clearly. But they may quietly reshape something else: your sense of where sounds are coming from. A new wave of affordable, over-the-counter (OTC) hearing aids is now available and they come in a wide variety of shapes and sizes and styles. Our study aims to understand what characteristics of hearing aids support (or disrupt) sound localization.

The ability to localize sound (knowing whether a car is approaching from the left or right, whether a voice is coming from in front of you or behind) is something most people take for granted. This spatial awareness relies on subtle acoustic cues available at the two ears. These cues can easily be disrupted by devices placed in or around the ear. Listeners with mild hearing loss, the very group that OTC devices are designed for, may be particularly vulnerable to these distortions, since they have relatively good sensitivity to sounds and their detailed characteristics.

To investigate, 14 adults with normal hearing were fitted with four different OTC devices representing a range of styles currently on the market: Lexie B2 Plus (a traditional behind-the-ear style), Eargo (an invisible in-the-canal style) and Apple Air pods Pro 2 (representing the growing category of consumer earbuds that can function as hearing aids).

Each participant completed a set of spatial listening tasks while wearing each device, and also without any device as a baseline. The tasks were designed to probe three distinct aspects of spatial perception: (1) Azimuth identification tests whether a listener can accurately judge the horizontal direction of a sound source; (2) Front-back discrimination asks whether listeners can tell whether a sound is coming from in front of them or behind; (3) Sound externalization refers to whether sounds are perceived as coming from the outside world, or from inside the head like when listening over headphones.

The results were clear: every OTC device tested disrupted spatial perception (Figure 1). However, the specific aspects of spatial perception that were affected, and the extent of the disruption, depended on the device and on the individual. By examining these patterns, we are able to make inferences about which features of OTC hearing aids support spatial perception and which features have a disrupting effect.

Figure 1. Mean absolute externalization ratings across hearing aid conditions, with individual participant data overlaid.

As the market for consumer hearing devices continues to grow, it is important to understand how they affect all aspects of hearing, not just speech clarity. This will be essential for helping people make informed choices about hearing aids and for designing more natural-sounding hearing aids in the future.