Updated: Sep 12, 2018
We’ve all been there. You come out of a club or a gig and everything sounds muffled, and there's an irritating ringing inside the head or ears. Or sometimes, after a day of working with machinery, or power tools, or being around noisy engines you can experience that same blocked feeling. The reason you have this is because you have just damaged your hearing by exposure to loud noise. Read on to find out why it happens and what you can do about it.
Why does my hearing feel muffled after being in loud noise?
It’s muffled because you have hearing loss. However, don’t panic. This is normally what we call a temporary threshold shift (TTS). The hairs (we call them hair cells) in the inner ear are temporary stunned or flattened by the high sound pressure levels, causing them to stop vibrating as they normally do when sound waves hit them. This means sound is not conducted through the hearing system as it should be, therefore giving us a deficit or shift in our normal threshold of hearing. It can last up to 72 hours but often returns within 24-48 hours. The hairs will gradually perk back up again and start to function normally, they just need a bit of time (and also peace and quiet).
Why are my ears ringing?
Because you have tinnitus. Tinnitus is defined as any sound you perceive where there is no external sound source. It doesn’t have to be ringing, it can be any sound; rushing, humming, buzzing. Normally, the hairs in the inner ear vibrate with sound waves and then produce an electrical impulse to tell the brain what the sound is. When hair cells are damaged (from the noise), they can start to misfire and emit incorrect signals to the brain, giving the perception of a sound when actually there isn't one. It is a common symptom of TTS and should disappear within 72 hours as the hearing improves.
What’s the difference between a temporary threshold shift (TTS) and permanent noise-induced hearing loss?
Noise-induced hearing loss normally occurs over time and doesn't improve, whereas a temporary threshold shift is, well, temporary. It normally takes years of abuse (of the loud sound variety) and noise exposure to actually permanently damage the inner ear hairs. Essentially, if you have TTS over and over again, you end up with noise-induced hearing loss, and permanent noise-induced hearing loss is not reversible. You can have permanent noise-induced loss from a sudden acoustic trauma, but it would be from something extremely loud, like an explosion, and it occurs rarely.
The hair cells in the inner ear are sensitive to specific frequencies or pitches of sound. There’s a bundle of hair cells in the ear that are responsible for processing a certain frequency or pitch of sound – 4kHz. This particular bundle of hairs is, for anatomical reasons, susceptible to damage from sound pressure waves. In a hearing test, someone presenting with TTS or noise-induced hearing loss will likely have a distinct ‘notch’ in their hearing at 4kHz. With TTS, other frequencies often tend to be heard at normal levels but there’s a dip at 4kHz where the sound has to be amplified in order for it to be heard – this is where the damage is. In the case of TTS, this ‘notch’ improves after a few days, whereas with permanent noise-induced loss, it doesn’t.
How do I know it’s too loud?
Health & Safety guidelines in the UK state that loudness levels over 85dB(A) is damaging to the ears. Work places are lawfully obliged to measure levels of noise and provide ear protection accordingly. Noise levels are measured using a sound-level meter. You can measure an environment yourself if you’re not sure if something is too loud. A proper, calibrated sound-level meter costs a lot of money, so I would recommend the next best thing – a smart phone app. Search for ‘sound level meter’ in your app store and download a free version. It uses the microphone in your phone to pick up and measure the sound pressure levels and this will give you a rough idea of the levels you are exposed to at that point in time. If you’re at a music concert or working in loud noise, try and measure the volume of sound around you. If it’s over 85dB(A) then you need some ear plugs asap.
It doesn’t necessarily have to be loud music. Any sound over 85dB(A) for a protracted amount of time can cause a loss. For example, power tools and operating machinery. Now, one period of noise exposure does not a permanent hearing loss make. BUT if you repeatedly expose yourself to loud sounds over time, that temporary threshold shift will become permanent, and speed up your natural rate of deterioration. Where most people naturally start to lose their hearing around the age of 60, we often see an earlier age of onset in people who have worked in noise or been exposed to loud noise repeatedly in their lifetime.
The moral of the story
Protect your hearing. A permanent, noise-induced ‘notch’ in your hearing is annoying because it affects the clarity of speech and makes it harder to hear in background noise – but it’s also difficult to help with a hearing aid because the rest of the hearing tends to be okay, and sometimes a hearing aid (even the really good ones) just can’t be that frequency-specific with the amplification. Also, no one wants a hearing aid. I wish that weren’t the case, and I’d do anything to make them more socially acceptable but there we are. Also, hearing aids are far more expensive than custom-ear protection. So it’s cheaper to protect your hearing than to not.
How do I protect my hearing from noise?
You need ear plugs and you have two options; custom or non-custom made ear plugs. Custom-made ear plugs are obviously more expensive but because they are designed to fit your ear perfectly (they require an impression of your ear first) they are super comfortable, can be worn all day, never fall out, block all damaging sound levels, and have special filters to reduce certain types of noise depending on what environment you are in. I would say they are ESSENTIAL if you are a professional musician or work in noise. I personally use and recommend the ACS Pro series. ACS make excellent quality ear plugs with a great range of filters. They are priced at £139 and require ear impressions. Click here to book an appointment with myself to get some custom ear plugs if you’re in the North West of England.
The other option is non-custom ear plugs, and these are a lot less spenny. Don’t bother with the really cheap foam or silicone ear plugs that you buy from chemists; they fall apart, get dirty easily, don’t stay in the ear well and don’t protect your hearing properly. For about £15-20 you can get some decent, medical-grade silicone, filtered ear plugs that are easier to keep clean. They’re not custom-made so may not fit everyone’s ears, and will not attenuate loud noises as accurately as the custom moulds, but they are an excellent option if you’re not in a position to purchase custom ear plugs. My favourite brand for non-custom ear plugs is Ear Peace. They’re excellent quality, have good research behind them, and they’re well designed. They come with a case you can put on a keyring so you don’t forget them and there are three in a pack just in case you lose one. There are 3 versions: music, industrial noise, and motorcycle. Also, I just love the name! Great name. You can buy them directly from their website https://www.earpeace.co.uk.
I hope this has encouraged you to think seriously about protecting your ears. If you know someone who works in noise, share this article with them and encourage them to take care of their ears. As always, if you have any queries or comments, feel free to ask them in the comment section or you're welcome to contact me directly. Email firstname.lastname@example.org for direct inquiries.
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