As the Queen wears a hearing aid in public 'for the first time', how does the device work?

The Queen arrived at a church service in Sandringham yesterday wearing a hearing aid. [Photo: PA]

The Queen has been snapped wearing a hearing aid.

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In what is believed to be the first time she has worn one in public, her Majesty arrived at a church service in Sandringham yesterday with a brown and red device in her right ear.

This comes after her husband the Duke of Edinburgh was spotted wearing a discreet behind-the-ear hearing aid when he was 93, the Queen’s age, in October 2014.

The Duke of Edinburgh adjusts his hearing aid during a trip to Birmingham in November 2015. [Photo: Getty]

The Queen is thought to have worn an in-the-canal hearing aid.

These are similar to the “typical” in-the-ear devices, which fill the area outside the opening of the ear.

In-the-canal aids are smaller and just fill the opening of the ear, according to the NHS.

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Both devices cannot be seen from behind but are visible from the side.

The one worn by her Majesty is more discreet than its alternatives but can be “trickier to use” and is not “usually powerful enough for people with severe hearing loss”, the NHS reports.

Its small size can make it difficult for users to adjust and remove, according to the National Institute on Deafness and Other Communication Disorders (NIDCD).

Canal aids also have less room for a battery.

How do hearing aids work?

Hearing aids are small electronic devices made up of a microphone, amplifier and speaker.

After receiving a noise via the microphone, sound waves are converted into electrical signals that get sent to the amplifier.

This then increases the power of the signals and sends them to the ear via the speaker.

Hearing aids largely benefit those with damage to the small sensory cells, hair cells, in the inner ear. This can come about due to disease, ageing or injury from loud noises.

Surviving hair cells detect vibrations entering the ear. These get converted into signals that are passed along to the brain.

The greater the damage to the hair cells, the more severe the hearing loss and the more amplification required.

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If the inner ear is too damaged, even large vibrations cannot be turned into signals and a hearing aid would be ineffective.

Whichever you opt for, hearing aids cannot completely reverse damage, but do make sounds clearer and louder.

This can enable people to hear the doorbell, have conversations, feel confident in busy environments and enjoy listening to music or watching TV again, without the volume at full blast.

Despite their benefits, only around one in five in the US who could benefit from a hearing aid actually wear one, NIDCD statistics show.

Hearing aids are available on the NHS; however, you may have to pay privately if you want a specific one or hope to dodge a waiting list.

Your GP can refer you to a specialist provider if they think you could benefit.