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An Automated System for Sound Localization Testing in Hearing-Impaired Listeners
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Amplitude modulation detection by listeners with unilateral dead regions
1Department of Experimental Psychology, University of Cambridge, Cambridge, England. bcjm@cam.ac.uk
Journal of the American Academy of Audiology
|May 28, 2010
Summary
Amplitude modulation (AM) detection is poorer for carrier frequencies above the dead region edge frequency (fe) in individuals with sensorineural hearing loss. This finding impacts understanding sound discrimination in damaged cochlear regions.
Area of Science:
- Auditory Neuroscience
- Audiology
- Signal Processing in Hearing
Background:
- A dead region in the cochlea signifies severe dysfunction of inner hair cells and/or neurons.
- Previous research indicated lower amplitude modulation (AM) detection thresholds for carriers below the dead region's edge frequency (fe) in sensorineural hearing loss.
Purpose of the Study:
- To measure AM-detection thresholds in subjects with unilateral dead regions.
- To investigate AM detection for carrier frequencies both below and above the dead region's edge frequency (fe).
Main Methods:
- Tested ten subjects with bilateral high-frequency hearing loss and unilateral high-frequency dead regions.
- Presented sinusoidal carriers at 5, 10, or 15 dB sensation levels.
- Utilized edge frequencies (fe) near 1000, 1500, or 2000 Hz.
Main Results:
- Replicated previous findings: AM-detection thresholds were lower for ears with dead regions for carriers below fe.
- Observed higher AM-detection thresholds for ears with dead regions when carriers were presented above fe.
Conclusions:
- The poorer AM detection above fe in dead regions remains unexplained.
- Findings align with prior reports of impaired sound discrimination for frequencies within dead regions.
- Results suggest implications for how individuals with dead regions utilize auditory information within these damaged cochlear zones.
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