Around 15% suffer from tinnitus. Tinnitus is a condition that causes someone to hear a sound, such as buzzing or ringing, without external sources. It is often linked to hearing loss.
The condition can be frustrating for sufferers as well as cause stress and depression. Patients suffering from tinnitus for months or years are especially vulnerable.
Tinnitus is a condition that has no treatment currently. Many millions could benefit from a better treatment or management of tinnitus.
Sleep is one area that could help us understand tinnitus better. This is due to many factors. Tinnitus can be described as a phantom percept. When our brain activity causes us to see, hear and smell things that aren’t there, it is called a phantom percept. Phantom perceptions are most common in people who are asleep. Tinnitus sufferers can hear phantom voices while awake.
Tinnitus alters brain activity. This means that certain brain areas (such as those responsible for hearing) may be more active than necessary. This could also explain phantom perceptions. These brain areas are also affected by sleep.
A couple of brain mechanisms are at the root of both tinnitus (and sleep) according to our research review. Understanding these mechanisms and how they are interconnected could help us to manage and treat tinnitus.
Tinnitus and sleep
Our bodies go through multiple stages of sleep when we fall asleep. The most important stage of sleep is slow-wave sleep, also known as deep sleep. This stage is considered to be the most peaceful.
Slow-wave sleep is when brain activity moves in distinct “waves” through different parts of the brain. This activates large areas (such as those that are involved with memory or processing sounds) and then moves on to other areas. Slow-wave sleep is thought to allow the brain’s neurons (specialized brain cells that send and receive information) to recover from everyday wear and tear. It also helps us sleep better. It is also important for our memory.
Slow-wave activity is not the same in every part of the brain. It is most prominent in the areas that we use most frequently while awake, such as motor function or sight.
Sometimes, slow-wave sleep can cause brain activity to be too intense for certain areas. This is the case with sleep disorders like sleepwalking.
Tinnitus sufferers may experience a similar phenomenon. Our theory is that hyperactive brain areas might keep the otherwise asleep brain awake. This could explain why people with tinnitus have more frequent night terrors and disturbed sleeping than those without it.
Tinnitus suffers also tend to spend more time in light sleeping. We believe that tinnitus prevents the brain from producing slow-wave activity necessary for deep sleep. This results in light and interrupted sleeping.
Tinnitus sufferers have less deep sleep than those without the condition. However, our review of research shows that deep sleep is not affected by tinnitus. It could be that the brain activity during deep sleep suppresses tinnitus.
The brain might be able to suppress tinnitus in deep sleep in a few ways. The brain’s neurons are the first. The brain’s neurons switch to slow-wave activity mode after a prolonged period of wakefulness. This mode is more effective for the rest of your brain because there are more neurons.
It is known that sleep-seeking can be so strong that slow-wave activity mode in the brain may occur. This is especially true for brain regions that are overactive during sleep, so we believe that this might cause tinnitus to be reduced.
It has been demonstrated that slow-wave activity can also interfere with communication among brain areas. Deepest sleep is when slow-wave activity is at its strongest. This may prevent hyperactive brain regions from disrupting other areas or interrupting sleep.
This would explain why people suffering from tinnitus are able to go deep asleep and how tinnitus might be suppressed.
The brain’s connections between neurons and the brain are also affected by sleep, which is important for memory strengthening. Our research shows that tinnitus can last for many years after an initial trigger, such as hearing loss.
We know that the intensity of tinnitus fluctuates throughout the day. We might be able to determine the brain’s role in causing fluctuations in tinnitus intensity by studying how it changes during sleep.
This means we may also be able to manipulate sleep to improve patients’ well-being and develop new treatments for Tinnitus. With sleep restriction paradigms patients are instructed to go to bed only when they are actually tired. This can reduce sleep disturbances and increase slow-wave activity. We may be able to see how sleep intensity affects tinnitus by increasing its intensity.
We believe that deep sleep is most likely to cause tinnitus. However, there are other stages of sleep, such as rapid eye movements or REM sleep, each with its own patterns of brain activity. Future research could track both the sleep stage as well as the brain activity that causes tinnitus. Brain activity can be recorded to help with this. This could help us understand the relationship between sleep and tinnitus, and how natural brain activity can alleviate it.