Verification of an Amplification Strategy to Enhance Soft Speech for Adults With Severe-to-Profound Hearing Loss

This study investigated the effects of a soft speech enhancement algorithm on distant speech perception for adults with severe-to-profound hearing loss (SPHL), examining speech intelligibility, listening effort, and sound quality.

Participants were 16 Mandarin-speaking adults (13 men, 3 women; M_age = 58 years) with symmetrical severe-to-profound sensorineural hearing loss. They had at least 1 year of hearing aid experience. A within-subject experimental design compared two hearing aid conditions: with the Speech Enhancer algorithm activated and deactivated. Speech intelligibility was assessed using the Mandarin Chinese matrix sentence test at individual speech reception thresholds. Subjective listening effort was measured using a categorical rating scale for speech presented at three distances (2, 4, and 8 m). Sound quality ratings were collected for loudness, speech understanding, and overall impression using a visual analog scale.

Activation of the speech enhancement algorithm led to a notable increase in speech intelligibility from 45% to 67%. Subjective listening effort decreased significantly with the algorithm activated at all distances, with greater benefits observed at farther distances. Similarly, sound quality ratings were significantly higher with the algorithm on for all attributes across all distances, with the largest improvements in overall impression ratings at greater distances.

The soft speech enhancement algorithm significantly improved speech intelligibility, reduced listening effort, and enhanced sound quality for distant speech perception in Mandarin-speaking adults with SPHL. These findings suggest that targeted signal processing for soft speech can provide substantial benefits for individuals with SPHL, including speakers of tonal languages, potentially improving communication in challenging listening situations.