Best Cochlear Locations for Delivering Interaural Timing Cues in Electric Hearing
Agudemu Borjigin1, Stephen R Dennison2, Tanvi Thakkar3
1University of Wisconsin-Madison (Madison, WI, USA).
Biorxiv : the Preprint Server for Biology
|January 7, 2025
Summary
Bilateral cochlear implants (BiCIs) improve hearing but not sound localization. Effective ITD perception with BiCIs requires stimulating specific cochlear sites, which may differ from acoustic hearing frequency maps.
Area of Science:
- Auditory Neuroscience
- Audiology
- Biomedical Engineering
Background:
- Cochlear implants (CI) offer sound access to deaf individuals.
- Bilateral CIs (BiCIs) are increasingly standard but have limitations in sound localization.
- Restoring interaural time differences (ITDs) is crucial for effective sound localization.
Purpose of the Study:
- To investigate the optimal cochlear stimulation sites for restoring ITD perception in bilateral CI users.
- To determine if ITD encoding sites in electrical hearing align with those in acoustic hearing.
Main Methods:
- Electrically evoked auditory brainstem responses (eABRs) were used to assess ITD sensitivity.
- Stimulation sites were varied along the cochlea in a simulated bilateral CI model.
- ITD perception was evaluated across different electrode positions and frequencies.
Main Results:
- Optimal cochlear sites for ITD transmission via electrical stimulation can vary significantly.
- These effective sites do not always correspond to the apical cochlear regions typically associated with low-frequency ITD encoding in acoustic hearing.
- ITD sensitivity can be enhanced by targeting specific, non-traditional cochlear locations.
Conclusions:
- Effective ITD perception with bilateral cochlear implants depends on precise targeting of cochlear stimulation sites.
- Current CI strategies may not optimally leverage these sites for sound localization.
- Further research into individualized electrode placement could improve bilateral CI outcomes for sound localization.
Related Concept Videos
01:13The Cochlea
44.5K
The cochlea is a coiled structure in the inner ear that contains hair cells—the sensory receptors of the auditory system. Sound waves are transmitted to the cochlea by small bones attached to the eardrum called the ossicles, which vibrate the oval window that leads to the inner ear. This causes fluid in the chambers of the cochlea to move, vibrating the basilar membrane.
44.5K
01:15Auditory Pathway
4.6K
Auditory pathways constitute the complex neural circuits responsible for transmitting and interpreting auditory information from the peripheral auditory system to the brain. Sound waves are initially captured by the outer ear, funneled through the ear canal, and reach the tympanic membrane (eardrum). These vibrations are transmitted via the middle ear's ossicles to the inner ear's cochlea.
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking...
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking...
4.6K
01:16Anatomy of the Ear
7.2K
Auditory sensation, commonly called hearing, involves the transformation of sonic waves into neural impulses facilitated by the structures of the auditory organ. The prominent, flesh-like structure on the side of the head, called the auricle, directs sound waves towards the auditory canal. The auricle is often mislabeled as the pinna, a term more aligned with mobile structures like a feline's external ear. The auditory canal penetrates the cranium via the external auditory meatus of the...
7.2K
01:22Hair Cells
40.0K
Hair cells are the sensory receptors of the auditory system—they transduce mechanical sound waves into electrical energy that the nervous system can understand. Hair cells are located in the organ of Corti within the cochlea of the inner ear, between the basilar and tectorial membranes. The actual sensory receptors are called inner hair cells. The outer hair cells serve other functions, such as sound amplification in the cochlea, and are not discussed in detail here.
40.0K
01:21Perceiving Loudness, Pitch, and Location
191
The human brain perceives pitch through two primary mechanisms reflected in place theory and frequency theory. Each mechanism describes how sound waves are interpreted as specific pitches by the brain, offering insights into the intricate processes of auditory perception.
Place theory, or place coding, suggests that different pitches are heard because various sound waves activate specific locations along the cochlea's basilar membrane. The brain determines the pitch of a sound by...
Place theory, or place coding, suggests that different pitches are heard because various sound waves activate specific locations along the cochlea's basilar membrane. The brain determines the pitch of a sound by...
191
01:31Hearing
51.8K
When we hear a sound, our nervous system is detecting sound waves—pressure waves of mechanical energy traveling through a medium. The frequency of the wave is perceived as pitch, while the amplitude is perceived as loudness.
51.8K