Effects of age, stimulus degradation, and sentence context on auditory temporal processing

Area of Science:

• Auditory Neuroscience
• Speech Perception
• Psychoacoustics

Background:

• Age-related hearing loss can impact speech understanding.
• Temporal processing deficits are common in older adults.
• Stimulus degradation, like that experienced with cochlear implants, can further challenge auditory perception.

Purpose of the Study:

• To investigate how age, stimulus degradation, and sentence context influence the perception of speech temporal cues.
• To determine if age-related deficits in temporal processing are modulated by linguistic context or auditory input quality.

Main Methods:

• A phonemic categorization task was used with adults aged 20-72.
• Stimuli included unprocessed and 8-channel vocoded speech sounds (dent/tent contrast) with varying voice-onset times.
• Sentence contexts were manipulated to be neutral, dent-biased, or tent-biased.

Main Results:

• Older age was associated with reduced sensitivity to voice-onset time differences.
• This age-related decline in temporal sensitivity was observed across all sentence contexts.
• The negative impact of age on temporal sensitivity was less pronounced for vocoded stimuli compared to unprocessed stimuli.

Conclusions:

• Age-related deficits in processing speech temporal cues, specifically voice-onset time, are significant.
• Top-down linguistic influences from sentence context do not appear to mitigate age-related temporal processing declines.
• Stimulus degradation may interact with age-related effects on temporal cue sensitivity, suggesting complex interactions in auditory processing.