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A Method for Tracking the Time Evolution of Steady-State Evoked Potentials
Published on: May 25, 2019
Does the 40-Hz auditory steady-state response show the binaural masking level difference?
Ieda Maria Ishida1, David R Stapells
1School of Audiology and Speech Sciences, The University of British Columbia, Vancouver, BC, Canada.
Ear and Hearing
|August 25, 2009
Summary
The binaural masking level difference (BMLD) is observed behaviorally but not in 40-Hz auditory steady-state responses (ASSRs). However, reduced ASSR amplitudes in dichotic conditions suggest a precursor to BMLD effects in other auditory responses.
Area of Science:
- Auditory Neuroscience
- Neurophysiology
- Psychoacoustics
Background:
- The binaural masking level difference (BMLD) is a key auditory phenomenon.
- Cortical responses (<20 Hz) show BMLD, but transient and steady-state brain stem responses do not.
- Investigating BMLD in the 40-Hz auditory steady-state response (ASSR) is crucial for understanding auditory processing.
Purpose of the Study:
- To determine behavioral and 40-Hz ASSR BMLDs.
- To examine the effect of signal and noise interaural inversions on BMLD.
- To explore the relationship between ASSR amplitude changes and BMLD.
Main Methods:
- Behavioral BMLD measurements were obtained.
- 40-Hz auditory steady-state responses (ASSRs) were recorded.
- Stimuli involved various interaural configurations (diotic and dichotic).
Main Results:
- A clear behavioral BMLD was observed.
- No significant 40-Hz ASSR BMLD was found.
- ASSR amplitudes were significantly reduced under dichotic conditions compared to diotic conditions.
Conclusions:
- 40-Hz ASSR thresholds do not reflect the BMLD phenomenon.
- Amplitude suppression in 40-Hz ASSRs under dichotic listening may indicate early neural processing related to BMLD.
- This suppression could be a precursor to BMLD observed in later cortical responses and behavior.
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