Tinnitus is a condition that causes someone to hear a sound without an external source. It is often associated with hearing loss.
The condition can cause stress and depression, and can also be annoying for sufferers. This is the case for patients who have been suffering from tinnitus for a long time.
There is no cure for tinnitus. Many millions of people worldwide could be helped by finding a way to better manage or treat it.
One area of research that may help us understand is sleep. There are a lot of reasons for this. Tinnitus is a phantom percept. Our brain activity makes us see, hear or smell things that are not there. People only experience phantom perception when they sleep. People with tinnitus hear phantom sounds while they are awake.
The second reason is due to the fact that the brain activity of certain areas of the brain can be more active than they should be. This could explain how phantom percepts happen. The activity in the same brain areas changes when we sleep.
A couple of brain mechanisms underlie both sleep and tinnitus. One day, better understanding these mechanisms and the way they are connected could help us find ways to manage and treat Tinnitus.
Our body experiences multiple stages of sleep when we fall asleep. Slow-wave sleep, also known as deep sleep, is thought to be the most relaxing stage of sleep.
During slow-wave sleep, brain activity moves in distinctive waves through the different areas of the brain before moving on to others. Slow-wave sleep helps the brain recover from wear and tear, while also making us feel rested. It is thought to be important for our memory.
The amount of activity in the brain varies from area to area. It is most pronounced in areas we use most while awake, such as those that are important for motor function and sight.
Slow-wave sleep can cause certain brain areas to be over active. This is what happens in sleep disorders.
There is a chance that this may happen in people with tinnitus. We think that the brain might be sleepy. This would explain why many people with tinnitus experience disturbed sleep and night terrors more often than other people.
Tinnitus patients spend more time in light sleep. We believe that the brain can't produce the slow-wave activity needed to have a deep sleep because of tinnitus.
The research we looked at in our review shows that some deep sleep is not affected by tinnitus. The brain activity that happens during the deepest sleep suppresses tinnitus.
The brain may be able to suppress the sound of ringing in the ears. The first thing to do is with the brain. After a long period of wakefulness, the brain is thought to switch into slow-wave activity mode. The stronger the drive is for the rest of the brain to join, the more neurons in this mode together.
The drive for sleep can get strong enough that the brain will eventually go into slow-wave activity mode. Since this applies to brain regions that are active during wakefulness, we think that it might be a factor in the suppression of tinnitus.
Slow-wave activity can interfere with the communication between brain areas, so it's important to sleep when it's strongest.
This would explain why people with tinnitus can still sleep.
It is important for us to sleep to strengthen our memory. Changes in brain connectivity during sleep are believed to be the reason for the long-term effects of hearing loss.
We know that the intensity of tinnitus can change throughout the day. Figuring out what the brain does to cause fluctuations in tinnitus intensity could give us a better idea of how sleep affects it.
It means that we may be able to improve the wellbeing of patients by manipulating sleep. Sleep disruptions can be reduced and slow-wave activity can be boosted through sleep restriction, where patients are told to only go to bed when they are actually tired. Increasing the intensity of sleep could help us better understand the effects of sleep.
We think that deep sleep is the most likely cause of tinnitus, but there are many other stages of sleep that occur with different patterns of brain activity.
The sleep stage and brain activity could be tracked at the same time in future research. It may help to understand how sleep and tinnitus can be related and how natural brain activity can help with tinnitus.
Victoria Bajo Lorenzana is an Associate Professor of Neuroscience at the University of Oxford.
This article is free to use under a Creative Commons license. The original article is worth a read.