Masking level difference for speech: effects of ear dominance and age

Area of Science:

• Audiology
• Psychoacoustics
• Speech Perception

Background:

• Auditory processing abilities, particularly speech discrimination in noise, vary with age.
• Masking Level Differences (MLDs) are a measure of binaural hearing, reflecting the brain's ability to use interaural cues to improve signal detection in noise.

Purpose of the Study:

• To compare right and left ear speech discrimination in noise across different age groups.
• To investigate the effects of monaural versus binaural noise presentation on MLDs in children and adults.
• To examine age-related differences and inter-subject variability in MLDs.

Main Methods:

• Monosyllable discrimination in a 'cocktail party' noise was assessed in 20 children (5-6 years), 40 young adults, and 20 older adults (66-76 years).
• Conditions included signal monaural-noise monaural and signal monaural-noise binaural in-phase interaurally.
• Right and left ear MLDs were measured and compared across age groups.

Main Results:

• MLDs were present in all age groups, indicating binaural processing.
• Young and older adults showed a right ear advantage in monaural noise conditions, significant only in young adults.
• Children did not exhibit an interaural difference in performance.
• Significant variability in MLD magnitude was observed within each age group.

Conclusions:

• Speech-in-noise perception and binaural masking release develop differently across the lifespan.
• Age and noise presentation conditions influence interaural asymmetries in auditory processing.
• Individual differences in binaural hearing are substantial, regardless of age.