Amplification bandwidth and speech intelligibility for two listeners with sensorineural hearing loss

Area of Science:

• Audiology
• Speech Perception
• Hearing Science

Background:

• Sensorineural hearing loss (SNHL) significantly impacts speech intelligibility.
• Understanding the relationship between speech bandwidth, audibility, and comprehension is crucial for hearing aid fitting.
• Previous research has explored various acoustic factors affecting speech perception.

Purpose of the Study:

• To investigate speech intelligibility as a function of bandwidth in listeners with SNHL.
• To determine the impact of speech energy levels relative to most comfortable listening levels (MCLs) on intelligibility.
• To assess the correlation between speech intelligibility scores and the articulation index.

Main Methods:

• Speech intelligibility was measured for two listeners with moderately severe SNHL.
• Speech spectrum was shaped to match individual MCLs, with energy levels set below, near, or above MCLs.
• A Limiting Master Hearing Aid (LMHA) was used to control nine half-octave bands, varying low and high-frequency cutoffs.

Main Results:

• Speech intelligibility scores increased with wider speech bandwidth.
• Higher scores were observed when more speech energy was audible above threshold.
• Listener performance showed strong correlations (0.7 and 0.8) with the articulation index.

Conclusions:

• Speech bandwidth and audibility are key determinants of speech intelligibility in SNHL.
• The articulation index effectively predicts speech understanding in this population.
• Findings support optimizing hearing aid settings for bandwidth and audibility to enhance communication.