Age effects in temporal envelope processing: speech unmasking and auditory steady state responses.

Area of Science:

• Auditory Neuroscience
• Gerontology
• Speech Perception

Background:

• Aging affects auditory processing, including temporal envelope perception.
• Understanding age-related changes in speech unmasking and auditory steady-state responses is crucial for hearing health.

Purpose of the Study:

• To investigate age-related differences in temporal envelope processing.
• To determine if older listeners have reduced speech unmasking at higher modulation rates.
• To assess if auditory steady-state response (ASSR) amplitudes decrease in older adults at high modulation rates.

Main Methods:

• Two groups (younger, mean age 25; older, mean age 69) with normal hearing participated.
• Experiment 1: Speech unmasking in modulated noise (16/32 Hz) with normal and time-compressed speech.
• Experiment 2: ASSR amplitudes measured at modulation rates of 32 and 128 Hz.

Main Results:

• Older listeners showed reduced speech unmasking for normal-rate speech.
• No age effect on speech unmasking for rapid speech.
• ASSR amplitudes were reduced in older listeners at 128 Hz, but not 32 Hz.

Conclusions:

• Reduced speech unmasking in older adults at slow rates is linked to speech redundancy, not envelope processing deficits.
• Deficits in temporal envelope processing are apparent in older age, specifically at high envelope frequencies (128 Hz).