Age Differences in the Effects of Speaking Rate on Auditory, Visual, and Auditory-Visual Speech Perception

Area of Science:

• Speech perception research
• Gerontology
• Auditory and visual neuroscience

Background:

• Speaking rate significantly impacts speech perception.
• Age-related changes can affect auditory and visual processing.
• Understanding how these factors interact is crucial for effective communication strategies.

Purpose of the Study:

• To investigate the effect of speaking rate on auditory-only, visual-only, and auditory-visual speech perception across the adult lifespan.
• To determine if unimodal speech perception performance predicts auditory-visual performance at various speaking rates.

Main Methods:

• 145 participants (aged 22-92) completed a closed-set speech perception test.
• Stimuli were presented in auditory-only, visual-only, and auditory-visual conditions.
• Five speaking rates (normal, 2 slower, 2 faster) were used, with signal-to-noise ratios adjusted for auditory conditions.

Main Results:

• Significant Age × Rate interactions were found for the fastest speaking rates in visual-only and auditory-visual conditions.
• Unimodal speech perception performance accounted for over 60% of the variance in auditory-visual performance across all speaking rates.

Conclusions:

• Older adults exhibit generalized difficulty with fast-rate speech perception across auditory, visual, and combined modalities.
• Unimodal performance is a strong predictor of auditory-visual speech perception, regardless of speaking rate.
• Findings have clinical implications for understanding age-related speech perception decline and the use of visual cues by older adults.