The Optimal Speech-to-Background Ratio for Balancing Speech Recognition With Environmental Sound Recognition

Area of Science:

• Auditory Perception
• Psychoacoustics
• Speech Processing

Background:

• Understanding speech in complex auditory environments is crucial for communication.
• Hearing impairment affects the ability to segregate speech from background noise.
• Environmental sounds provide important contextual information and alerts.

Purpose of the Study:

• To determine speech-to-background ratios (SBRs) for optimal recognition of speech and environmental sounds by normal-hearing (NH) and hearing-impaired (HI) listeners.
• To investigate the influence of attention (divided vs. selective) on auditory recognition tasks.
• To assess the masking effects of environmental sounds on speech recognition.

Main Methods:

• Conducted experiments with NH and HI listeners performing concurrent speech and environmental sound recognition (ESR) tasks.
• Utilized psychometric functions to determine performance ranges and optimal SBRs.
• Varied attention conditions (divided vs. selective) to evaluate their impact on recognition.

Main Results:

• NH listeners demonstrated high accuracy (>95%) over a 20 dB SBR range, with an optimal SBR of +12 dB.
• HI listeners had a significantly smaller range (1 dB) and an optimal SBR of +5 dB.
• Environmental sounds were more effective maskers of speech than vice versa, irrespective of hearing status.

Conclusions:

• A defined range of SBRs allows for simultaneous recognition of speech and environmental sounds, but this range is constrained in HI listeners.
• Optimal SBRs for balancing speech and environmental sound recognition differ between NH and HI listeners.
• Findings may inform the design of assistive listening devices to improve speech intelligibility while preserving environmental sound awareness.