brain areas also changes .
Our recent research review has identified a couple of brain mechanisms that underlie both tinnitus and sleep . Better understanding these mechanisms – and the way the two are connected – could one day help us find ways of managing and treating tinnitus .
Sleep and tinnitus When we fall asleep , our body experiences multiple stages of sleep . One of the most important stages of sleep is slow-wave sleep ( also known as deep sleep ), which is thought to be the most restful stage of sleep .
During slow-wave sleep , brain activity moves in distinctive “ waves ” through the different areas of the brain , activating large areas together ( such as those involved with memory and processing sounds ) before moving on to others . It ’ s thought that slow-wave sleep allows the brain ’ s neurons ( specialised brain cells which send and receive information ) to recover from daily wear and tear , while also helping sleep make us feel rested . It ’ s also thought to be important for our memory .
Not every area of the brain experiences the same amount of slow-wave activity . It ’ s most pronounced in areas we use most while awake , such as those important for motor function and sight .
But sometimes , certain brain areas can be overactive during slow-wave sleep . This is what happens in sleep disorders such as sleep walking .
A similar thing may happen in people with tinnitus . We think that hyperactive brain regions might stay awake in the otherwise sleeping brain . This would explain why many people with tinnitus experience disturbed sleep and night terrors more often than people who don ’ t have tinnitus .
Tinnitus patients also spend more time in light sleep . Simply put , we believe that tinnitus keeps the brain from producing the slow-wave activity needed to have a deep sleep , resulting in light and interrupted sleep .
But even though tinnitus patients have less deep sleep on average than people without tinnitus , the research we looked at in our review suggests that some deep sleep is hardly affected by tinnitus . This may be because the brain activity that happens during the deepest sleep actually suppresses tinnitus .
There are a couple of ways the brain may be able to suppress tinnitus during deep sleep . The first has to do with the brain ’ s neurons . After a long period of wakefulness neurons in the brain are thought to switch into slow-wave activity mode to recover . The more neurons in this mode together , the stronger the drive is for the rest of the brain to join .
We know that the drive for sleep can get strong enough that neurons in the brain will eventually go into slow-wave activity mode . And since this especially applies to brain regions overactive during wakefulness , we think that tinnitus might be suppressed as a result of that .
Slow-wave activity has also been shown to interfere
The brain activity that happens during the deepest sleep may suppress tinnitus
with the communication between brain areas . During deepest sleep , when slow-wave activity is strongest , this may keep hyperactive regions from disturbing other brain areas and from interrupting sleep .
This would explain why people with tinnitus can still enter deep sleep , and why tinnitus may be suppressed during that time .
Sleep is also important for strengthening our memory , by helping to drive changes in connections between neurons in the brain . We believe that changes in brain connectivity during sleep are contributing to what makes tinnitus last for a long time after an initial trigger ( such as hearing loss ).
Treating tinnitus We already know that intensity of tinnitus can change throughout a given day . Investigating how tinnitus changes during sleep could give us a direct handle on what the brain does to cause fluctuations in tinnitus intensity .
It also means that we may be able to manipulate sleep to improve the wellbeing of patients – and possibly develop new treatments for tinnitus . For example , sleep disruptions can be reduced and slow-wave activity can be boosted through sleep restriction paradigms , where patients are told to only go to bed when they ’ re actually tired . Boosting the intensity of sleep could help us better see the effect sleep has on tinnitus .
While we suspect that deep sleep is the most likely to affect tinnitus , there are many other stages of sleep that happen ( such as rapid eye movement , or REM sleep ) – each with unique patterns of brain activity . In future research , both the sleep stage and tinnitus activity in the brain could be tracked at the same time by recording brain activity . This may help to find out more about the link between tinnitus and sleep and understand how tinnitus may be alleviated by natural brain activity . n
We believe that changes in brain connectivity during sleep are contributing to what makes tinnitus last for a long time after an initial trigger ( such as hearing loss ).
GlobalHealthAsiaPacific . com ISSUE 5 | 2022
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