Modulation detection, modulation masking, and speech understanding in noise in the elderly

Area of Science:

• Auditory Neuroscience
• Psychoacoustics
• Gerontology

Background:

• Temporal processing is crucial for understanding speech, especially in noise.
• Aging and hearing loss can affect auditory temporal abilities.
• Sensorineural hearing loss is common in older adults and may impact sound perception.

Purpose of the Study:

• To investigate temporal processing of suprathreshold sounds in normal-hearing and hearing-impaired older adults.
• To determine the effects of age and hearing loss on modulation detection, modulation masking, and speech understanding.
• To assess the impact of modulated noise backgrounds on speech perception.

Main Methods:

• Three experiments were conducted: modulation detection, modulation masking, and speech understanding in noise.
• Participants included young normal-hearing adults and older adults with normal hearing or mild sensorineural hearing loss.
• Sinusoidal amplitude modulation (SAM) detection and masking were tested across various frequencies; speech in noise was evaluated in modulated and unmodulated backgrounds.

Main Results:

• Age showed a modest correlation with modulation detection at low frequencies, but hearing loss was a more significant factor.
• Subjects with mild sensorineural hearing loss exhibited difficulties in the modulation masking task.
• Hearing-impaired subjects demonstrated poorer speech understanding in modulated noise compared to normal-hearing subjects.

Conclusions:

• Mild sensorineural hearing loss significantly impacts temporal processing, particularly in challenging listening conditions like modulation masking.
• Auditory temporal processing deficits in older adults are primarily linked to hearing loss rather than age alone.
• Impaired temporal processing due to hearing loss can reduce speech intelligibility in modulated noise environments.