6.2 Cochlear implants and auditory brainstem implants
3 min read•july 18, 2024
Hearing implants like and are game-changers for people with severe . They work by bypassing damaged parts of the ear and directly stimulating nerves to restore hearing. It's like giving someone a brand new way to experience sound.
These implants aren't for everyone, though. Doctors look at factors like the type and severity of hearing loss, as well as the person's motivation and support system. Once implanted, the devices need careful programming and lots of practice to get the best results.
Cochlear Implants
Functioning of hearing implants
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Top images from around the web for Functioning of hearing implants
Frontiers | Auditory Brainstem Implants: Recent Progress and Future Perspectives View original
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Auditory Pathways to the Brain – Introduction to Sensation and Perception View original
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Adaptive Pitch Transposition: Smart Auditory Spectral Shifts in Cochlear Implants View original
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- Cochlear implants bypass damaged or non-functional hair cells in the cochlea directly stimulate the auditory nerve
- External components include a , , and capture sound, convert it into digital signals, and transmit to the internal components
- Internal components consist of a and that convert digital signals into electrical impulses and stimulate auditory nerve fibers in the cochlea
- Auditory brainstem implants (ABIs) used when the auditory nerve is damaged or absent bypass both the cochlea and auditory nerve
- ABIs directly stimulate the cochlear nucleus in the brainstem
- External components (microphone, speech processor, transmitter) capture sound, convert it into digital signals, and transmit to internal components (receiver/stimulator, electrode array)
- Internal components convert digital signals into electrical impulses and stimulate the cochlear nucleus, bypassing the damaged or absent auditory nerve
Candidates for hearing implants
- Cochlear implant candidates have severe to profound sensorineural hearing loss in both ears, limited benefit from hearing aids, no medical contraindications for surgery, realistic expectations and motivation for rehabilitation, and adequate support system and access to post-implantation therapy
- Auditory brainstem implant candidates have (NF2) with bilateral , complete or near-complete destruction of auditory nerves due to tumor growth or surgical removal, severe to profound hearing loss not amenable to cochlear implantation, no medical contraindications for surgery, realistic expectations and motivation for rehabilitation, and adequate support system and access to post-implantation therapy
Programming of hearing implants
- Cochlear implant programming involves (setting threshold and comfort levels for each electrode), adjusting speech processor settings to optimize speech perception and sound quality, regular follow-up sessions to fine-tune settings based on patient feedback and performance, and auditory training and rehabilitation to help patients adapt to new auditory input
- Auditory brainstem implant programming is similar to cochlear implant programming but with fewer electrodes and more complex stimulation patterns
- Involves mapping, adjusting speech processor settings, regular follow-up sessions, and intensive auditory training and rehabilitation to help patients interpret new auditory sensations
Psychosocial impact of implants
- Improved communication and social interaction lead to increased ability to understand speech and participate in conversations, enhanced social confidence, reduced feelings of isolation, and better integration into the hearing world
- Educational and occupational opportunities expand with increased access to mainstream education, improved academic performance, and broader career options and job prospects
- Emotional well-being and self-esteem improve through reduced stress and anxiety related to communication difficulties, increased independence and autonomy, and enhanced overall psychological well-being
- Family dynamics and relationships benefit from reduced stress and frustration due to improved communication, enhanced bonding and emotional connection, and increased participation in family activities and decision-making
- Challenges and adaptations include adjusting to new auditory input, learning to interpret signals, dealing with unrealistic expectations and potential disappointment, coping with stigma and social attitudes towards implants and deafness, and balancing deaf identity with newfound connection to the hearing world
Key Terms to Review (22)
Auditory brainstem implants: Auditory brainstem implants (ABIs) are neuroprosthetic devices designed to provide hearing sensations to individuals with severe to profound hearing loss, particularly those who cannot benefit from cochlear implants due to damage in the cochlea or auditory nerve. These implants bypass the damaged structures of the ear and stimulate the brainstem directly, allowing for auditory perception. They are especially significant for patients with neurofibromatosis type II (NF2) and other conditions that compromise the auditory pathway.
Auditory perception: Auditory perception is the process by which the brain interprets and makes sense of sound information received from the environment through the auditory system. This process involves recognizing, organizing, and understanding sounds, allowing individuals to distinguish between different pitches, tones, and patterns. It plays a critical role in communication and interaction with the surrounding world, especially when considering devices that aid hearing.
Binaural hearing: Binaural hearing is the ability to perceive sound using both ears, allowing for better localization of sound sources and improved auditory perception. This process involves the brain integrating the signals received from each ear to determine the direction, distance, and nature of sounds, creating a rich auditory experience. Binaural hearing is crucial for understanding speech in noisy environments and plays a significant role in overall auditory processing.
Cochlear Implants: Cochlear implants are medical devices that bypass damaged hair cells in the inner ear to directly stimulate the auditory nerve, allowing individuals with severe to profound hearing loss to perceive sound. This innovative technology represents a significant advancement in neuroprosthetics, connecting the fields of medicine and engineering while offering current solutions and future possibilities for those affected by hearing impairment.
Electrode array: An electrode array is a structured arrangement of multiple electrodes designed to interface with neural tissues, enabling the recording of electrical activity or the stimulation of neurons. This technology is crucial for the development of neuroprosthetics, as it allows for the direct interaction between electronic devices and biological systems, facilitating various applications such as cochlear implants and brain-computer interfaces.
Graham Clark: Graham Clark is a prominent Australian otolaryngologist and a pioneer in the development of cochlear implants, devices that provide a sense of sound to individuals with severe hearing loss. His groundbreaking work in the 1970s led to the creation of the first multi-channel cochlear implant, significantly improving auditory perception for users. This innovation has profoundly influenced the field of auditory neuroscience and rehabilitation for those with hearing impairments.
Hearing loss: Hearing loss is a partial or total inability to hear sounds in one or both ears, which can result from a variety of causes including age, exposure to loud noises, genetic factors, or medical conditions. This condition can significantly impact communication, social interactions, and overall quality of life, often necessitating the use of assistive devices such as cochlear implants or auditory brainstem implants for those with severe cases.
Implantee: An implantee is an individual who receives a medical device, such as a cochlear implant or auditory brainstem implant, to restore or enhance sensory functions. These devices are surgically placed inside the body, directly interfacing with the nervous system to provide improved perception of sound for individuals with hearing impairments. The effectiveness of these implants can greatly influence the quality of life for the implantee, allowing them to engage more fully with their environment and social interactions.
Informed Consent: Informed consent is a legal and ethical process by which individuals are provided with information about a medical procedure or research study, allowing them to make an informed decision about their participation. This process is crucial in ensuring that individuals understand the risks, benefits, and alternatives before consenting to any neuroprosthetic intervention, highlighting its importance across various applications and interdisciplinary research.
Mapping: Mapping refers to the process of establishing a correspondence between external stimuli and the sensory responses generated by a neuroprosthetic device, particularly in the context of cochlear implants and auditory brainstem implants. This crucial process enables the devices to translate sound signals into electrical impulses that can be interpreted by the auditory system, facilitating hearing restoration for individuals with hearing loss. Accurate mapping is essential for optimizing the functionality of these devices and improving the user's auditory experience.
Michael Merzenich: Michael Merzenich is a renowned neuroscientist recognized for his pioneering work in the field of neuroplasticity, which refers to the brain's ability to reorganize itself by forming new neural connections. His research has fundamentally changed our understanding of how experience and learning can reshape the brain, influencing the development of neuroprosthetics that harness this plasticity for therapeutic purposes. By demonstrating that the brain is capable of change even in adulthood, he has laid the groundwork for innovative approaches in auditory devices like cochlear implants and other forms of brain-computer interfaces.
Microphone: A microphone is an electroacoustic device that converts sound waves into electrical signals, allowing for the amplification or recording of sound. In the context of auditory devices, microphones play a crucial role by capturing external sounds and transmitting them to electronic systems, such as cochlear implants and auditory brainstem implants, which then process and deliver these sounds to the auditory nerve.
Neural Stimulation: Neural stimulation refers to the process of using electrical impulses to activate or modulate nerve cells, which can result in sensory perception or the restoration of function in patients with neurological impairments. This technique is critical for devices that interface with the nervous system, such as cochlear implants and auditory brainstem implants, as it mimics natural sensory signaling to promote auditory processing and improve hearing capabilities.
Neurofibromatosis type 2: Neurofibromatosis type 2 (NF2) is a genetic disorder characterized by the development of noncancerous tumors in the nervous system, particularly bilateral vestibular schwannomas (also known as acoustic neuromas). These tumors primarily affect hearing and balance, leading to significant auditory and neurological challenges. NF2 is linked to mutations in the NF2 gene, which plays a role in tumor suppression, and can have implications for patients requiring cochlear implants or auditory brainstem implants for hearing restoration.
Neuroplasticity: Neuroplasticity refers to the brain's ability to reorganize itself by forming new neural connections throughout life, allowing it to adapt to new experiences, learning, and recovery from injury. This flexibility is crucial for the development of neuroprosthetic technologies as it enables the brain to adjust to artificial systems and potentially restore lost functions.
Quality of life: Quality of life refers to the general well-being of individuals and societies, encompassing various factors that contribute to happiness, health, and overall satisfaction. In the context of health technologies, such as cochlear implants and auditory brainstem implants, quality of life is often measured in terms of improved communication abilities, social interactions, and emotional well-being. Additionally, successful neuroprosthetic implementations can dramatically enhance quality of life by restoring lost functions and fostering independence, ultimately enabling individuals to lead more fulfilling lives.
Receiver/Stimulator: A receiver/stimulator is a critical component in cochlear implants and auditory brainstem implants that converts electrical signals into neural impulses for the auditory system. This device receives the encoded sound information transmitted from an external processor and stimulates the auditory nerve or relevant brain structures, enabling hearing sensations. Its function is essential for restoring auditory perception in individuals with significant hearing loss or deafness.
Speech Processor: A speech processor is a crucial component of cochlear implants and auditory brainstem implants that converts sound into electrical signals, which are then transmitted to the auditory nerve or the brain. It plays a vital role in interpreting speech and environmental sounds, allowing users to perceive auditory information. By filtering and analyzing sounds, the speech processor ensures that relevant sounds are transmitted effectively to provide the user with meaningful hearing experiences.
Surgical implantation: Surgical implantation is a medical procedure that involves placing an electronic device within the body, specifically designed to interface with the nervous system. This technique is crucial for creating functional connections between prosthetic devices and biological tissues, enabling the restoration or enhancement of sensory and motor functions. It is a key element in procedures like cochlear implants and auditory brainstem implants, where restoring hearing capability relies on directly stimulating auditory pathways.
Transmitter: In the context of neuroprosthetics, a transmitter refers to a device or substance that sends signals from one location to another, often functioning to relay information between the nervous system and external devices. These signals can be electrical or chemical, and in cochlear implants and auditory brainstem implants, transmitters play a crucial role in converting sound into electrical signals that stimulate the auditory pathways.
Vestibular Schwannomas: Vestibular schwannomas, also known as acoustic neuromas, are benign tumors that develop on the vestibulocochlear nerve (cranial nerve VIII), which is responsible for hearing and balance. These tumors arise from Schwann cells, which form the myelin sheath around nerves, and can lead to hearing loss, tinnitus, and balance issues due to their impact on nerve function.
Wireless connectivity: Wireless connectivity refers to the ability to transfer data without physical cables, using electromagnetic waves. This technology is essential for modern implantable devices, allowing them to communicate seamlessly with external systems or devices, enabling better monitoring and control of medical treatments. Wireless connectivity in neuroprosthetics enhances user experience by providing real-time data transmission and reducing the need for invasive procedures to update or adjust settings.