Where does tinnitus originate?

For a long time, the causes of tinnitus were solely sought within the ear, without considering the primary location where all our perceptions take place—the brain!

Tinnitus is often colloquially referred to as “ringing in the ears.” This terminology might suggest that tinnitus originates in the ear, but in reality, the true origin of tinnitus is in the brain.

In the normal hearing process, sound enters through the external ear and is transmitted as an electrical signal through the eardrum, cochlea, and hair cells, then forwarded via the auditory nerve to the brain. Within the brain, there are auditory regions responsible for processing and creating sound.

However, with tinnitus, the peculiar aspect is the experience of sound without an external source. Structures such as the cochlear nerve, the dorsal nucleus in the brainstem, and the auditory cortex in the cerebral cortex become overactive, generating auditory impulses on their own.

When perceiving a tinnitus sound, these specific areas in the brain become overactive and/or altered. Studies indicate changes in the auditory cortex, the brain region that processes sound into awareness. Additionally, there are demonstrable connections between tinnitus and dysregulation of the limbic system, the brain regions that regulate emotion, attention, and memory.

The significant challenge lies in directing our focus to these brain areas where actual changes occur. The ultimate goal is to gain control over them, all with the singular aim of altering your experience of tinnitus.

Emotional brain

There is consensus regarding the role of the limbic system in tinnitus, also known as the emotional brain. It is observed that when becoming conscious and experiencing tinnitus, the emotional brain reacts with overactivity, responding with an intensity as if there is an acute threat. As a metaphor, tinnitus can be seen as an alarm system, where the beep, noise, or hiss serves as the warning signal. Negative thoughts such as “This sound is driving me crazy” or “With such a beep, something serious must be wrong with me” can also negatively influence the emotional brain. The emotional brain senses even more threat, leading it to feel the need to amplify its ‘warning signal,’ or the tinnitus, even more clearly. 

Additionally, changes can be observed in the hippocampus, a brain region involved in storing memories. These new memories relate to events in personal life, including danger messages from the amygdala. The amygdala, a small structure no larger than an almond, is where the danger message originates. The hippocampus holds our memories for threatening things, storing the event, context, and emotional experience. This creates an ongoing connection between something that can happen in a specific setting and the emotional experience. In the case of tinnitus symptoms, it may be that you suddenly became aware of a sound that did not come from the surroundings. 

Despite this occurrence being common and often temporary, you may suddenly recall that newspaper article where someone mentioned having immense difficulties with their tinnitus symptoms. Your internal reaction likely moves towards stress, anxiety, or panic. Your first experience with emotional involvement is from that moment on, becoming a fact. 

In cases of tinnitus symptoms, the association is often made between becoming aware of the beep, noise, or hiss and an intense negative emotional reaction.

Auditory system

Demonstrated changes in the auditory brain regions are observed in tinnitus. These brain areas are related to everything concerning sound, and in the literature, this is referred to as maladaptive reorganization—an undesirable reorganization of the brain. It is fascinating to note that the auditory system likely uses visual feedback to partially or completely reverse this reorganization. The visual representations from the Freequency app may potentially assist in this process!

A study suggests that auditory training involving auditory object identification, dynamically engaging the patient’s attention and active participation, might reduce tinnitus perception. The Freequency app serves as a means of auditory training by presenting your tinnitus sound within the app. You hear the sound in the space, and then, you are allowed to search for where the bird is located, representing a form of object identification. Additionally, the app demands your attention and an active role in finding and freeing the birds. All the elements highlighted in the study are incorporated into the Freequency app.

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Exposure therapy

In the new European guidelines for treating tinnitus, exposure therapy is a proven and recommended treatment. Exposure therapy involves exposing individuals to their tinnitus sound but placing it in a less threatening context. The hippocampus, the brain part responsible for memories, plays a crucial role in this process. Through exposure to the feared context and experiencing firsthand that the anticipated doomsday scenarios do not materialize, the hippocampus ultimately stores new memories—with less or no negative emotional charge.

Literally, you do this in the Freequency app as well. You choose your own tinnitus sound to hear through your headphones. This allows the brain to specifically recognize it as yours. The environment you see is far from threatening; it is, in fact, a very pleasant visual setting. The hippocampus also gathers information from the visual aspect. In the Freequency app, your brain visually receives feedback that nothing threatening is happening, while you are consciously dealing with your tinnitus, which was previously perceived as threatening. Through repeated practice, this is intended to reduce the overactive, negative response of the emotional brain.

The goal is to overwrite old memories that triggered an automatic stress response.

Mirror therapy

Many studies highlight the similarities between chronic pain and chronic tinnitus. Chronic does not imply that it cannot improve or diminish; it simply means that it has been present for an extended period, often exceeding three months. In chronic pain and chronic tinnitus, similar brain areas are overactive.

An example of such a pain scenario in the brain is phantom pain, where pain is felt in a limb that is no longer present, such as due to amputation. From the literature, the concept arises that the brain, in response to the missing information from the amputated limb, starts to fill in the gaps itself. The brain works harder and generates impulses, ultimately leading to the actual experience of pain.

Similar brain regions are overactive in both phantom pain and tinnitus, with the literature often referring to tinnitus as phantom sound. In some cases, hearing loss may be the apparent cause of tinnitus. With fewer auditory impulses reaching the brain through the ear, the brain may start filling in the missing auditory stimuli, resulting in the perception of sound.

Effective treatment methods have been available for phantom pain for many years. As early as 1996, mirror therapy was first used for phantom pain, where a patient would have a mirror placed between, for example, both legs. The patient would look at the reflection of the intact leg in the mirror. For the brain, it seemed as if the amputated leg was present again. The regained sense of agency and control proved sufficient in many cases to reduce pain.

If phantom pain and tinnitus bear such resemblance in the brain, it is conceivable that the solution might also be similar. With the Freequency app, we provide the ‘reflection’ of your tinnitus, giving you the agency and control to influence your tinnitus.

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Virtual reality

All the above scientific aspects were theoretically outlined in a framework in 2010, but using ‘virtual reality.’ In 2016, this was scientifically tested, yielding demonstrably positive effects on tinnitus loudness and the impact of tinnitus on a person’s life. 

Crucial elements in this study included ensuring that the sound heard through the earphones closely matched the player’s perception of tinnitus. Additionally, the environment where the sound is heard must simulate reality. Freequency deliberately opted for ‘augmented reality,’ adding the necessary treatment elements to your reality. This is in contrast to virtual reality, where you completely isolate yourself from reality with a VR headset. With the Freequency app, there is no need for an expensive VR headset, making it accessible to everyone.

All the elements highlighted in the studies have been incorporated into the Freequency app.

Literature

1 Tang et al. Advances in Understanding, Diagnosis, and Treatment of Tinnitus. 2019

2 Besteher et al. Chronic tinnitus and the limbic system: Reappraising brain structural effects of distress and affective symptoms. 2019

3 Zhang et al. Interactions between the hippocampus and the auditory pathway. 2022

4 Cima et al. A multidisciplinary European guideline for tinnitus: diagnostics, assessment, and treatment. 2019

5 Nicholas et al. The hippocampus as a visual area organized by space and time: A spatiotemporal similarity hypothesis. 2019

6 Londero et al. Auditory and visual 3D virtual reality therapy for chronic subjective tinnitus: theoretical framework. 2010

7 Lewald et al. Role of the posterior parietal cortex in spatial hearing. J Neurosci 22:1–5. 2002

8 Searchfield. Object identification and attention training for treating tinnitus. 2007

9 Colmenero et al.Effectiveness of mirror therapy, motor imagery, and virtual feedback on phantom limb pain following amputation: A systematic review. 2017

10 Malinvaud et al. Auditory and visual 3D virtual reality therapy as a new treatment for chronic subjective tinnitus: Results of a randomized controlled trial. 2016