Cochlear implants stimulate nerves inside the ear to provide the sensation of sound

A cochlear implant stimulates parts of the cochlea directly, with limited pitch and timbre capabilities

People with these devices have to learn or relearn how to train their brains to interpret nerve signals as sound. The range of the type of sounds that the brain can distinguish with a cochlear implant is limited and consequently it's difficult to understand a tonal language or distinguish individual speakers in a crowd.

The first neural devices were cochlear implants, designed to treat hearing loss

Neural interfaces connect with our nervous system to restore or enhance abilities, such as hearing or movement. These neuroprostheses have enabled the restoration of mobility, communication, and activities of daily living that might otherwise require a caregiver.

Cochlear implants are raising questions about deaf identity and culture

The rise of cochlear implants, which are usually covered by insurance and can enable hearing for many patients, raises questions about what it means to be deaf, the effects on deaf individuals learning American Sign Language, and about deaf culture. Watch this video that discusses the controversies and spotlights a little girl who hears for the first time with her cochlear implant.

736,900 cochlear implants had been implanted by 2020 worldwide

In the United States, roughly 118,100 devices had been implanted in adults by that point and 65,000 in children. These estimated figures come from the US Food and Drug Administration, which first approved cochlear implants for adults experiencing hearing loss in the mid-1980s, and collected reports from cochlear implant manufacturers approved for the US market.

The three smallest bones in the human body—the malleus, incus, and stapes—amplify the vibrations of sound waves by almost 20 times to help enable hearing.

Mind-controlled bionic arms use nerve implants to restore sensation and movement

Unlike traditional prosthetics that rely on surface electrodes or mechanical parts, this system uses implanted titanium and nerve-connected electrodes to enable a seamless brain-to-arm connection. Patients train in virtual reality with their implanted signals before using the physical prosthesis.

Brain implants can help colorblind people hear colors

Colorblind artist Neil Harbisson was born into a world of grey. In 2004, he had a chip installed connected to an external color frequency sensor. Once the sensor "reads" a color, it sends a signal to the chip and plays an associated sound both in and outside Harbisson's head.

If hearing is damaged, the brain may amplify remaining sounds, perhaps causing tinnitus.

Brain-reading devices are helping paralyzed people to touch

In clinical trials, implanted brain-computer interfaces are allowing dozens of individuals with paralysis to control prosthetics that are restoring a range of skills, including drinking coffee and feeding oneself. One area of related prosthetic research is creating a synthetic sense of touch—coupling the brain implant with pressure sensors in prosthetic robotic fingertips to enable an approximation of a sense of touch.

We hear because soundwaves are converted into electrochemical signals in our ears

This science teacher video systematically walks through the biology of the outer, middle, and inner ear. The explanation starts with the auricle, an external part that funnels sound through the auditory canal, and the tympanic membrane (the ear drum), which vibrates when sounds hit it. Beyond that, as the video details, is the eustachian tube, which is connected to the back of our throats and allows air to pass in and out to equalize ear pressure.

Watch how your nervous system's efforts to process silence can contribute to tinnitus

Cochlear cells can be damaged in numerous ways, including aging or exposure to loud noise. If enough cells die, the auditory system can become less sensitive, prompting the brain to compensate by amplifying sound, which is likely to contribute to tinnitus.

Brain implants are restoring movement and communication in early human trials

Several companies developing brain-computer interfaces have begun testing on humans with promising results. These implants have helped reanimate paralyzed limbs and enable communication, though ethical concerns remain about data privacy.

Most custom earmolds for in-ear hearing aids are made using 3D printing

The technology has also been utilized for behind-the-ear and receiver-in-canal hearing aids, allowing for the creation of structures tailored to the patient's anatomy for enhanced effectiveness. 3D printing has also been used to print retinal eye cells and custom eyeglass frames.

Elon Musk's Neuralink's N1 chip can wirelessly read brain signals from over 2,000 electrodes

The device is a battery-powered brain implant that transmits data via Bluetooth. Neuralink's near-term objectives for the device focus on unlocking new treatments for paralysis, neurological disorders, and some psychiatric conditions.

Using brain implants to restore vision

Several companies are attempting to create brain-computer interfaces that skip over retinas and optic nerves to allow visual input to go straight to the brain, potentially restoring some sight to the blind. Clinical trial findings suggest restored sight is sparse and manifests differently than a sighted person might expect, appearing as specks of "light" clusters called phosphenes to help differentiate one's surroundings.

Neural implants blur the line between personal intention and machine execution

A key ethical dilemma—the contemplation conundrum—explores whether implants might misinterpret mere imagination as intent to act. Neuroscientists have found no brain signal that clearly marks when someone decides to act, making intent hard to detect in neurotechnological systems.

An essay exploring how living day-to-day with a brain implant helps restore a sense of identity

Companies like Neuralink are experimenting with volunteers who have lost control over their bodies. Many of the program's participants claim the most significant benefit from the tool is the ability to perform simple, mundane tasks, such as playing video games or shaking hands, rather than more obvious milestones like walking or eating. This essay explores what it's like, day to day, to use a brain implant.

Gene therapy is restoring hearing among kids with genetic deafness

Gene therapy for profound genetic deafness has been advancing in recent years, with multiple clinical trials enabling hearing at normal levels for the first time without hearing aids or cochlear implants. The therapies target hearing loss caused by mutations in the OTOF gene that codes for a protein called otoferlin. That protein normally plays a key role in relaying sound signals in synaptic transmission between the ear's inner hair cells and the auditory nerve.

See what loud noises do to inner ear hair cells

This animation illustrates how louder music can affect inner ear hair cells. Damage to these cells is generally considered permanent. Hearing protection like ear plugs can reduce the level of sound entering into the ear and help protect those cells.

Open brain surgery is not required for BCIs inserted via blood vessel injection

Synchron's brain-computer interface, the Synchron Switch, takes advantage of preexisting medical devices, such as stents and catheters. Cells grow over the device over a 90-day period, incorporating it into the vessel wall and minimizing clots.

A novel tinnitus therapy, called Lenire, involves mild electric tongue shocks and sound exposures.

Neuralink brain implants have enabled a paralyzed person to play video games

As one of twelve test subjects in Neuralink's PRIME study, Rob Greiner's implant translates his brain's activity into digital commands for the 'Battlefield 6' game. He can now also design 3D models and 3D-print objects using his thoughts.

We may be using Q-tips in our ears—even when we shouldn't—because they can stimulate pleasure nerves

People continue to use Q-tips inside their ears even though we know it's risky. Some clinicians suggest that beyond the desire to get water out, this may be because the nerve bundle called the vagus nerve, which spans from the brain to the large intestine, can be stimulated that way, causing a pleasurable sensation in other body parts including the heart, belly, or genitals.

Brain-computer interfaces create a direct link between the brain and external devices

The technology enables users to control prosthetics, computers, or even games using only their thoughts. In 2021, a monkey played table tennis using only its brain, thanks to a Neuralink device, marking a major milestone before human trials began in 2024.

Interface device implanted into ALS patients restored some of their abilities

Most people with amyotrophic lateral sclerosis, or Lou Gehrig's disease, require assistance with daily life due to loss of motor control. The electrode-coated, stent-like device used motor mapping data and machine learning to translate brain activity into actions.

Some animals possess sensitive hearing to help pinpoint prey and map the world

Bats and dolphins produce sound to reflect off surfaces and create a mental image of their surroundings. Owls' faces are dish-shaped to help funnel sounds to their ears, including that of mice moving along leaves or snow. Pinnipeds, such as seals and walruses, hear in both air and water.

Using AI to restore speech 30 years after a stroke

Through a novel surgical procedure involving electrodes implanted in the brain, along with the help of artificial intelligence, a stroke patient is regaining her ability to speak. This technology converts her thoughts into speech through a digital avatar, allowing her to verbally express herself for the first time in decades.

Predictive brain implants raise ethical concerns about patient autonomy after surgery

These devices can accurately forecast neurological events like seizures and suggest or even automatically deliver responses. Their constant monitoring and prescriptive functions may blur the line between patient choice and device influence.

An experimental bionic knee has been directly integrated into the user's muscle and bone—not an external socket—marking a significant prosthetic advancement.

New eye implant clinical trial recruiting in 2026

University of Southern California researchers have launched a phase 2b clinical trial of a stem cell implant designed to restore vision in people with advanced dry macular degeneration. Patients will be randomized to receive the stem cell implant or a simulated procedure and placebo implant. This type of larger, second-stage clinical trial is designed to confirm efficacy and dosing and to look for side effects. It's one of the stages that precedes the US Food & Drug Administration approval of a device.

Scientists are learning to guide your dreams using sound and touch.

Interacting sound waves can create regions where the pressure from each wave combines, allowing objects to levitate in place against gravity or be manipulated for touch-free construction.

An ear doctor with hearing loss seeks to help those with hearing loss enjoy music

Alex Chern, an ear doctor who has hearing loss himself, dreams of restoring the ability to experience "all the richness and the beauty of the sound of music" for patients—not just functional hearing. Hearing aids amplify sound waves and aren't designed to work well with music that may have varied pitch and volume. Chern is studying how hearing loss and engaging with music may affect cognitive decline.

See why wearing earbuds—instead of over-the-ear headphones—can cause ear infections

Earbud headphones can heighten the risk of ear infections. They can lead to earwax buildup and create a dark, moist environment as you sweat—ideal conditions for germs to thrive. Wearing external over-the-ear headphones or ones that don't enter deep into the ear canal can help.

Tinnitus estimates vary, but may occur in 10%-15% of the population

This video discusses the mechanisms underlying tinnitus and explores the knowns and unknowns about the condition. Tinnitus most commonly occurs among those with hearing loss, suggesting that cochlear damage may be a factor.

Steps for buying your first hearing aids

Hearing aids have advanced in aesthetics, simplicity, and cost in recent years, but acquiring them can be daunting for first-timers. Experts suggest finding a high-quality audiologist and knowing your rights with medical services. They also recommend buying them sooner rather than later, as hearing issues can compound and grow more costly over time.

Surfer's ear, from repeated cold water exposure, leads to new bony protrusions in the ear

Frequent exposure to icy cold water, typical in surfing, can cause tiny bony growths to develop in the ear canal, informally called surfer's ear. While the exact cause for these growths is unknown, it may be the body's protective response to shield the ear drum from the cold. These protrusions can heighten the risk of swimmer's ear, lead to wax buildup, and result in hearing loss.

Deep brain stimulation helps manage movement in patients with neurological disorders

DBS is a surgical procedure that uses implanted electrodes to send electrical signals to targeted areas in the brain, interrupting abnormal neural activity. It may be implemented when medications lose effectiveness or cause disruptive side effects.

A stand-in 'nose' may help people with anosmia to smell certain odors

In a 2025 paper, researchers reported they'd created a proof-of-concept device that bypasses typical olfactory pathways and instead exploits an alternative—the trigeminal nerve in the nose—to detect a few strong scents. The nerve typically helps detect the temperature of inhaled air or the presence of irritants. (Some users may experience a paywall.)

Notch music therapy may filter out some tinnitus frequencies

Researchers in Germany have developed a smartphone app-based therapy for individuals with tinnitus associated with hearing loss. Some people with tinnitus can use this Notch app with their hearing aids to at least partially block sound frequencies matching their tinnitus pitch—turning down the volume of their tinnitus.

Why surgeons implant teeth into eyes

What if the thing that restored your vision… was your own tooth? That’s exactly what happened to Brent Chapman. After 20 years without sight, a bizarre surgery using his tooth as a lens restored his vision.

Explore why swimmer's ear will not go away on its own

This infection is typically treated with ear drops to reduce inflammation and fight the bacteria or fungus that led to the issue. But without treatment, complications can arise, including a deep tissue infection, bone or cartilage damage, or—very rarely—spreading beyond the ear into the skull bones and surrounding areas.

In the womb, a fetus may begin to hear at 18 weeks

Though little indentations form on the side of the fetus's neck at roughly nine weeks—with some formations taking place even before then—developmentally, these indentations don't become ears that allow a little one to hear until around 18 weeks.

Hearing loss is linked with brain volume reductions

The brain looks different as a result of hearing loss, with reductions in brain volume overall and in specific areas, and these changes are hypothesized to impact cognition. Exactly why hearing loss alters cognition is an active area of research, but theories include that the elevated cognitive load of straining to hear affects brain power available for thinking and memory and that hearing loss leads to social isolation which boosts dementia risk.

Doctors explain that most ear infections—but not swimmer's ear—affect the middle ear

A typical ear infection occurs in the area behind the eardrum, but swimmer's ear is an infection of the ear canal. Its characteristic symptom is pain whenever the ear is moved, though it can also include itching and a sense of fullness. Symptoms typically begin within a few days or a week of a water buildup not being addressed.

Gene therapy for a rare type of deafness is allowing deaf children and adults to hear for the first time, according to research results reported in April 2026.

Individuals with synesthesia experience involuntarily overlapping sensations

Tasting words or seeing colors in music results from the brain retaining extrasensory connections from infancy. While most lose these neural pathways during development, about 4% of people are synesthetes, maintaining them without realizing it's unusual.

Hear examples of what tinnitus can sound like to those suffering from it.

Losing a brain-computer interface can trigger lasting psychological distress

A clinical trial participant with severe epilepsy described becoming “one” with her implant after it gave her unprecedented control over her seizures. When the device was removed due to the company shutting down, she experienced deep emotional trauma and a sense of personal loss.

Medical imaging allows 3D printers to create patient-matched devices

With imaging data on a person's anatomy, external prostheses and implants, such as cranial plates or hip joints, can be custom-printed to better match a patient's body. Fabrication of porous structures can promote bone growth, leading to longer-lasting implants.