![]() It would be better to have an “objective” test, which doesn’t need input from the patient in order to get a good measure, and is independent from their language ability.Īt the University of Nottingham, we’re working on an objective test using MRI scans. This isn’t a great way of testing hearing ability as it depends a lot on the ability of the patient to understand and cooperate with the test. They will then ask the patient to repeat back what the recording said. These kinds of hearing losses are not detectable when measuring the ability to hear a quiet sound in a quiet room and so are often referred to as “hidden hearing loss”.Īudiologists can measure this by playing the patient a recording of speech and mask this with some background noise. You use your supra-threshold hearing to understand conversations in a noisy room or hear someone talk over the sound of a blaring television. Yet the damage mentioned above can affect not just the ability to hear quiet sounds in a quiet environment, it can affect the ability to hear subtle changes in loud sounds – what we call “supra-threshold” (above the hearing threshold). ![]() The test, however, only measures one aspect of the complex system of highly tuned equipment that provides you with the ability to hear. This is not a complicated test – the brain doesn’t need to perform any tricks to hear, understand and respond to these sounds. In a soundproof room, the patient wears headphones and the audiologist plays beeps at a number of different frequencies to determine the threshold at which the person can hear “in quiet”. The audiologist measures hearing by finding the quietest sound a person can hear in a quiet environment. People with suspected hearing loss are usually referred to an audiologist. But animal studies show that even relatively moderate amounts of noise exposure can cause damage to the auditory nerve – the nerve connecting the inner ear to the brain. Until recently, it was believed that noise-induced hearing loss resulted from damage to the sound-sensing cells in the cochlea, the part of the inner ear that converts vibrations into electrical impulses. But mp3 players and mobile phones allow us to exceed that noise level with little more than a disclaimer from the manufacturers.Īnyone exposed to noises above 85dB at work must be monitored for hearing loss. For example, in the UK, anyone exposed to noise levels of 85dB or more in the workplace must be given hearing protection and be monitored for damage to their hearing. Many countries have health and safety regulations to prevent people from damaging their hearing at work. But you might be exposed to loud noises so constantly throughout the day that you don’t even realise they are there, perhaps from road works (75–105dB) or a noisy pub (around 90dB). People can be exposed to noise at work, such as a construction site (up to 96dB), or socially, such as a music festival or nightclub (up to 110dB). Prolonged exposure to anything above 85dB, without adequate ear protection, is assumed to be potentially damaging. ![]() A typical conversation is around 60dB, and anything you need to raise your voice to be heard over is probably above 87dB. It is the quietest thing someone with healthy hearing can hear above absolute silence (which is -9dB). Zero decibels is almost complete silence. A study published recently in The Lancet revealed that living in a noisy city increases your risk of hearing damage by 64%. ![]() It now accounts for more than a third of all cases of hearing loss in developed countries – and city dwellers are most at risk. Noise exposure is the main cause of preventable hearing loss worldwide.
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