Elevated hearing thresholds degrade speech perception by rendering key cues inaudible

Evidence

An obvious correlate of elevated auditory thresholds (poor audibility) is an inability to hear low-level sounds in the environment. Poor audibility can impact the ability to have a conversation, particularly if the conversation is relatively quiet. In these cases, a listener will miss the low-level elements of speech, commonly unvoiced fricatives, but other speech sounds may be rendered inaudible by hearing loss as well. For listeners who do not have flat losses, differences in the threshold across the frequency range of hearing can also cause deficits in perception, particularly for speech cues that require an across-frequency representation. A listener with a sloping, highfrequency hearing loss cannot take advantage of acoustic information in the high-frequency range. If certain formants in speech are rendered inaudible, a listener may confuse speech sounds that contain similar low-frequency formants. In cases of particularly severe hearing loss, listeners may confuse vowel sounds with each other if formants are not audible (Nábělek, 1988). In addition, robust audibility across a wide range of frequencies has been implicated in maintaining an ability to determine which elements of sounds belong together (i.e., auditory scene analysis; Bregman, 1990). For example, the ear best utilizes acoustic cues for sound segregation, such as onsets and offsets, when their representation across frequency is full and robust (e.g., Valentine & Lentz, 2012). — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1688

Categorization

• DEFINE: Introduces auditory scene analysis and how robust audibility supports sound segregation—a usable definitional anchor.