What do Steve Martin, David Letterman, Sylvester Stallone, Eric Clapton, Sting and Cher have in common with Charles Darwin, Ronald Regan and Bill Clinton? Very little, is one answer. Fame is another. And hearing impairment, believe it or not, is a third.

Today marks the beginning of Hearing Awareness Week, an initiative designed to encourage the one in 10 of us who has difficulty hearing to go for a test.

And we do need encouragement it seems. Astonishingly, most people delay for around 10 years before bothering to get checked out. Maybe it's because we believe that ignoring the niggling symptoms won't do any harm, but if that's the reason, then we're either misinformed or kidding ourselves.

Apparently, the ongoing strain can cause further deterioration, which is irreversible. And if that isn't motivation enough to make an appointment, then I don't know what is.

Excessive noise is one of the most common causes of hearing damage, which is unfortunate, given that listening to music on the move is becoming increasingly popular and that recent MRBI research shows that while 41pc of adults wear earphones regularly, the corresponding figure for 15-24 year olds is a massive 82pc.

Keith Ross, an audiologist with Hidden Hearing, a hearing aid supplier, believes that these figures are alarming, given that most people listen to iPods and MP3 players with the sound up too high.

"The damage is caused gradually, so it could be years before these young people realise the irreparable harm they're causing," he cautions. "To be safe, volume should be kept at a level where outside sounds can still be heard by the person wearing headphones."

According to Keith, we are the worst judges of our own hearing, as naturally we think what we hear is normal.

"A client once told me how sad it was that the birds had been driven away from her area by building projects," he says.

"In reality, the birds were there. Her husband heard them singing every day, but as she could no longer hear them she thought they had gone."

TV3 anchorman Mark Cagney found out recently that his hearing wasn't what it should be. "I went for a test because I had occasional difficulty hearing what my kids were saying," he explains.

"Some of my colleagues were surprised that I would go public about it. They seemed to think there was some sort of associated stigma and that my admitting to it might make me less of a man or something, but I don't see it that way.

"Anyway, the aids I wear are tiny and, as I chose a grey pair to blend in with my hair, they're practically invisible.

"In my view I don't have a hearing problem. Instead, I see it positively: I hear better with my hearing aids, just as I see better with my glasses.

"I've spent more than 30 years wearing earphones and earpieces for a living and quite often the volume would be higher than it should be. Add to that, the wear and tear that goes with being 51 and it's to be expected that things might start to go."

So does he always wear his aids at home? "Not always, as there are times in every man's life when he likes to indulge in a little selective hearing."

Background noise in pubs and clubs poses problems for many people attempting to hold conversations with friends, and 25-year-old 2FM DJ, Jenny Greene is one of them.

"My hearing has always been okay, but I do have difficulty with conversation in noisy places," she says. "Last year when I noticed that my hearing wasn't up to scratch, I got scared, so I went for a check-up and found out that while my hearing levels had dropped a little, I didn't need aids."

While that was good news, Jenny was still terrified that she'd do any more damage, so to maintain her hearing she cut back on the amount of DJ work she does and she got special filters to protect her ears while she's working.

"I love music and want to be able to continue to enjoy it right through my life, so it's up to me to look after my hearing as best I can," she says.

Jenny's experience is shared by 55-year-old Olien Nelson (right) from Kilmacanogue, Co Wicklow, who used to feel embarrassed when she couldn't hear what friends were saying at parties.

"To avoid having to continually ask them to repeat themselves, I finally didn't let on that I hadn't heard. That was dreadful, so four months ago I got a hearing aid, and I'm sorry I didn't do it sooner," she says.

Hearing difficulties manifest in different ways and, while the social isolation caused by being unable to talk freely with friends is difficult, tinnitus can cause a lot of problems too.

This is something that 24-year-old language interpreter, Lisa Harvey has had for as long as she can remember.

"I had measles as a baby, and that may have caused my condition," she says. "When I was 14, I was told at school that the noises in my head were psychological, but thankfully, I knew that was rubbish.

" To cope, I learned how to lip-read. Then, last August, I got some hi-tech hearing aids that block out the ringing in my head. And of course, I hear it again when I take them out at night, but I don't mind as I'm so used to it."

However slow we may be to react to hearing impairment today, it was worse years ago.

Joyce Kenny (59) from Loughshinny, Co Dublin, suffered ongoing hearing problems and earaches as a child, but nothing was done about it.

"Growing up, I often got the impression that people thought I was stupid when I couldn't hear what they had said," she recalls. "They saw me as some sort of idiot who couldn't cop on.

"When I was in my teens I got an ear infection, which resulted in total hearing loss for a day, which was terrifying.

"Luckily my hearing returned, but tests revealed a hole in my ear drum, which made the sounds inside my head seem louder to me than those outside.

"My mother wouldn't allow me to have surgery because she thought it too risky, so when I married at the age of 20, my husband signed a permission slip which enabled me to have an operation, which helped enormously.

"These days, I wear tiny aids which are absolutely fabulous, and I no longer shy away from talking with people."

Like Joyce, many people have hearing problems all their lives, but for others it comes on suddenly.

Don't be one of the majority who wait 10 years to get help. Make an appointment for a hearing test today.

Could you have a hearing problem?

Do you:

- Strain to hear when you are in company?

- Ask others to speak up because you think they are mumbling?

- Have difficulty hearing conversations clearly bec-ause of background noise?

- Find that your TV/radio needs to be louder now than previously?

- Find a particular type of sound (female voices, for example) more difficult to recognise than others?

- Often ask others to repeat themselves?

If you answered 'yes' to two or more of the questions, you need to have your hearing checked. Tests at Hidden Hearing are free of charge. To find a centre near you, contact 1800 882 884 or email hearingaware@hiddenhearing.ie. Ask for the free information booklet, Have you Heard?, which is also available from GPs.

Sound is too loud if:

- You can't talk to people who are about two metres away without shouting

- Having visited a club or concert, you find that you cannot hear properly for a few hours afterwards, or you experience ringing in your ears.

- The level of sound hurts your ears.

What can I do to protect my hearing?

- Take regular breaks from the dance floor.

- Stand away from speakers at clubs.

- Wear ear plugs.

- Turn down the volume on your MP3 player.

I don't want everyone to know I'm wearing a hearing aid...

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Some are so tiny that they're barely noticeable. Others look really sporty, and come in vibrant colours.

Check them out -- you'll be surprised.