How does aging affect recognition of spectrally degraded speech?

Area of Science:

• Audiology and Neuroscience
• Gerontology
• Speech-Language Pathology

Background:

• Cochlear implants (CIs) benefit patients with sensorineural hearing loss, but speech recognition outcomes vary.
• Advancing age is a significant factor in this variability for CI users and normal-hearing individuals.
• Older adults with normal hearing also show reduced performance in recognizing spectrally degraded speech.

Purpose of the Study:

• To investigate the role of auditory spectral resolution and cognitive functions in age-related declines in speech recognition.
• To test the hypothesis that age-related speech recognition deficits are mediated by both auditory and cognitive factors.

Main Methods:

• A case-control study comparing cochlear implant users and normal-hearing controls.
• Speech recognition assessed in clear (CI users) and spectrally degraded (normal-hearing controls).
• Auditory spectral resolution measured using the Spectral-Temporally Modulated Ripple Test; cognitive skills assessed via non-auditory visual tasks.

Main Results:

• Older age was associated with poorer sentence and word recognition in both groups.
• The negative impact of age on speech recognition was partially explained by reduced spectral resolution.
• Cognitive function declines also partially mediated the age-related effects on speech recognition.

Conclusions:

• Advancing age impairs speech recognition in both CI users and normal-hearing individuals due to decreased auditory spectral resolution and cognitive abilities.
• Enhancing spectral resolution and cognitive functions may improve speech recognition outcomes for cochlear implant recipients.
• These findings highlight potential therapeutic targets for optimizing cochlear implant rehabilitation.