threshold sound conditioning

What is Threshold Sound Conditioning (TSC) and How Does it Work?

The idea of hearing loss is something that greatly concerns many people. The older we become, the more caution we take when it comes to our hearing quality. Rightfully so, since hearing loss is considered the third most common chronic physical condition in the world. Hearing loss can happen to anyone regardless of age. It is something that even individuals that are young and otherwise healthy, can be severely impacted by if they do not take caution with protecting their ears. 

The issue with loss of hearing

According to statistics from the Centers for Disease Control and Prevention (CDC), nearly 16% of adults in the U.S. are experiencing hearing issues. Furthermore, 15% of the general population has some form of tinnitus, often described as ringing in the ear. 

The National Institute of Deafness and Other Communication Disorders claims that one in three people in the U.S. between the ages of 65 and 74 have hearing loss and nearly half of those older than 75 struggle with hearing. Age is considered one of the more significant predictors for hearing loss among adults. A study conducted in 2014 shows that hearing loss increased as people aged, with 43% of adults 70 years or older reporting hearing loss, compared to 19% of adults aged 40 to 69 years and 5.5% aged 16-39 years. 

Furthermore, men are twice as likely to have speech frequency hearing loss among adults between the ages of 20 to 69. As women get older, they could have more trouble with hearing at lower frequencies. All in all, age-related hearing loss usually leads to hearing loss in the high frequencies. 

Furthermore, noise-induced hearing loss is one of the more common ways people tend to damage their hearing because of excessive noise exposure. The CDC has reported that 40 million U.S. adults between the ages of 20-69 years old have some form of noise-induced hearing loss. Plus, one in two U.S. adults that have experienced hearing damage from noise is not involved in a loud work environment, meaning the exposure is likely from recreational activities.  

The CDC reported that an estimated 12% of children and adolescents aged between 6 to 19 years suffered permanent hearing damage due to excessive exposure to noise. A significant amount of school children already have some degree of hearing loss.

Is there a treatment?

As you can see, taking care of your hearing is essential for keeping your hearing healthy as you age.  Exposing yourself to loud noises regularly will lead to a severe impact on your hearing. That damage will gradually increase over time in most cases and cause issues for you as you age. 

Unfortunately, there is no cure-all for hearing damage. Consulting with a doctor may reveal the possible causes of your hearing loss, such as inflammation from an ear infection or ear wax building up. However, if your doctor finds that your hearing issue is due to structural damage, that could complicate things.  Solutions like hearing aids exist, but not everyone wears them for a variety of reasons. It could be due to how expensive it can be to acquire them or the stigma attached to wearing a hearing aid.

There are alternative forms of hearing solutions out there that could assist a person with maintaining their hearing and giving relief for issues like tinnitus. The one we are going to touch upon is known as Threshold Sound Conditioning.

What is Threshold Sound Conditioning

Threshold Sound Conditioning (TSC) technology sends a series of acoustic signals at a person’s hearing threshold levels. The hearing threshold is a sound level below which a person’s ears are capable of detecting any sounds. This means the acoustic signals (sound therapy) are inaudible when they are delivered.

A lowering of thresholds for a specific range of frequencies would equal a boost in hearing capabilities. That means as hearing thresholds lower and sensitivity increases, it becomes easier for the listener to detect that particular range of sounds (frequencies) at a lower volume level. Threshold Sound Conditioning was made to lower the hearing threshold with sound conditioning in people with sensorineural hearing loss due to otoacoustic trauma. Threshold Sound Conditioning has the potential to activate auditory pathway plasticity and enhance basal frequency hearing as measured by pure tone audiometry. That said, it has been documented that Threshold Sound Conditioning has helped individuals suffering from tonal tinnitus (specific pitch) find various levels of relief.

Sensorineural hearing loss is considered to be one of the more common disorders people tend to experience. The disorder appears more often in elderly patients, severely restricting everyday actions and lowering the person’s quality of life. Utilizing a method like sound conditioning has the potential to improve basal frequency hearing.

TSC works by stimulating the cells inside of the ear with the idea being to assist them in connecting with nearby cells to form and support auditory pathways. The cells are there to help send sound signals through your auditory passage until they reach the areas of your brain where they are translated into meaningful sounds. Doing this on a regular basis will make these pathways far easier to locate and take so that these types of signals reach their destination to become processed as a sound.

How does TSC work?

The purpose of TSC is to use sound by stimulating the inner ear cells in hopes of improving (lowering) the pure-tone hearing threshold. During the late 1990s, researchers found that acoustic stimuli could slow progressive sensorineural hearing loss and exposure to an adequately augmented acoustic surrounding could improve age-related auditory transformations. These slowing effects were shown in several types of experiments done on mice, as long as the acoustic surrounding was provided before the circumstances of severe hearing loss.

Along with delaying progressive hearing loss, acoustic stimulation could also protect a person’s hearing capability against damage from traumatic noise. A method known as forwarding sound conditioning (which involves using acoustic stimuli before exposure to moderate levels of sound) was observed to reduce noise-induced hearing impairment in several mammalian species, including humans.

Furthermore, recent studies have shown that low-level sound conditioning can also reduce free radical-induced damage to hair cells by increasing antioxidant enzyme activity and reducing Cox-2 expression within the cochlear, which heightens cochlear sensitivity. In particular, the increased cochlear sensitivity was recorded when distortion product otoacoustic emission and compound action potentials were measured.

The inclusion of forwarding sound conditioning and backward sound conditioning (which is the use of acoustic stimuli after exposure to traumatic noise) has been shown to protect a person’s hearing capability against noise trauma. It may also prevent the cortical map reorganization induced by traumatic noise.

Researchers from Stanford University conducted a randomized controlled clinical study with significant results. They observed a significant improvement of pure-tone hearing thresholds of 10 dB or more in 78% of participants. Female participants show a notable difference in the first dependent variable from male subjects. However, older participants showed no significant difference from their younger counterparts.

Threshold Sound Conditioning has been identified as one of the more promising innovations in hearing health in recent years. The research that has gone into TSC has shown that it can positively impact a person’s hearing ability and help with enhancing their lives from the problems caused by hearing loss.

How AudioCardio uses TSC

AudioCardio aims to assist people who are suffering from various hearing ailments. AudioCardio has developed a mobile app that allows a person to use their smartphones or tablet devices paired with a set of headphones or hearing aids to assess their hearing to calibrate and generate a personalized sound therapy (TSC) at the threshold level. 

To personalize the sound therapy, the user needs to assess their hearing in a silent room with their headphones connected to the device to accurately calibrate their sound therapy. The user would adjust the volume slider on the screen to the barely audible level and set it there. The barely audible noise is defined by the final decibel level before the sound being played is undetectable. The app continues to repeat these steps nine more times for a total of five times for the left ear and five times for the right ear. 

AudioCardio has created an algorithm that generates a personalized sound therapy based on the person’s in-app assessment by pinpointing the frequency range with the highest hearing threshold (most hearing loss) for each ear. The Threshold Sound Conditioning technology utilized by AudioCardio continuously delivers a personalized sound therapy for one hour each day. 

As the individuals consistently use the app daily, the sound therapy may become noticeable enough to hear. The individual should retake their assessment to recalibrate their sound therapy and generate a new sound therapy based on recent progress in their hearing thresholds. Users need to continue repeating this process to further improve their progress. Best of all, this sound therapy is entirely passive, and it runs in the background while you go about your day. You will not need to remain actively engaged, so you can continue doing other activities without the need to take a break from them.  

These sound therapy sessions are supposed to assist with maintaining and strengthening the user’s capability to comprehend, differentiate, and recognize familiar sounds at a lower volume. AudioCardio has conducted clinical studies and research that shows that most individuals make a minimum change of 10 dB in as little as three weeks for the frequencies being targeted for each ear.

Furthermore, the data gathered from the mobile app shows that most people using the AudioCardio app experience even more progress and changes as they continue to use the app beyond the initial three to four weeks. Some individuals may take longer to notice an effect, but this could be due to the lack of adherence to the recommended usage from the individual, with them possibly skipping out on days or not reassessing their hearing thresholds with signs of progress as advised. 

Remaining consistent in your progress can differ based on varying factors, such as if someone is working in a noisy environment like a concert, sporting events, construction site, factory, or if they get sick or have an ear infection. However, existing users have reported that they are capable of maintaining their levels for months or even a year after entirely stopping use of the AudioCardio app.

Should you use it?

Sounds provide us with a powerful means of communication. These senses permit us to experience everything that happens around us through the power of sound. Our sense of hearing grants us the opportunity to gather, process, and interpret sounds continuously and without conscious effort. The unfortunate part is that there are so many people out there that take their sense of hearing for granted. 

There are so many ways for someone to lose their hearing that most do not take caution in protecting their ears. That is especially true among youths who believe that the loss of hearing is associated with age and are not considering the outside influences that could gradually damage their hearing. At this point, medical research has not discovered a way that can entirely recover a person’s hearing, only maintain it in some fashion.

AudioCardio is one of the many companies attempting to help people maintain their hearing and handle the difficult symptoms and situations associated with hearing loss. Ailments like tinnitus are known to impact a person’s health and interactions with the world. Most people don’t even want to confront the fact that they are suffering from hearing loss and will instead do their best to ignore the problem, which often leads to the symptoms worsening.

Using Threshold Sound Conditioning technology, you can help ensure that your hearing remains at optimal levels and get relief from issues like tonal tinnitus. Keeping a consistent schedule that includes your daily sound therapy can help in maintaining your hearing. TSC has become an increasingly popular solution for many audiologists and hearing health experts. 

Best of all, the therapy sessions are easy to follow through with and do not require much work on your part. All you need to do is find a quiet place, place headphones on, calibrate the settings and get your session started. The only thing you need to stay on top of is making sure you continue to conduct these sound therapy sessions daily and to retake your hearing assessment to recalibrate your sound therapy any time you start to notice your sound therapy when it is activated. 


Threshold Sound Conditioning has proven to be safe and effective thanks to the medical research conducted by a variety of medical centers. While it will not cure you of your hearing problems, it may assist in maintaining and improving thresholds. If you feel as if your hearing is getting worse or you simply want to maintain your current abilities, consider trying out AudioCardio today!