By Lim Wey Wen

IMAGINE talking to a few other people over lunch, and they are speaking a language you barely understand.

You could catch bits and pieces of the conversation, but you just could not put the whole story together.

To include you in the conversation, they look at you periodically and laugh in unison when someone cracks a joke.

You try to follow their facial expressions so you do not seem too out of place. Suddenly, one of them asks you a question.

Embarassed, you manage a feeble "Huh", leaving the rest of them feeling as if you are not taking them seriously.

Before you could explain, they resume their conversation and the guessing game begins again.

If this scenario has become a little too common in your daily life, and you feel the same even when people are speaking a language you understand, take heed because it is often the typical early sign of hearing loss.

"Hearing loss is a very debilitating condition. People are not very well informed and they really don't know much about it," says hearing aid audiologist Kieran McCarry.

"So, if they have the problem they don't understand it. All they do is feel its effects without knowing what the cause of it is.

"This leads to a lot of frustration, a lot of isolation and a lot of heartache, in many cases, for the people themselves, and of course, their families and those close to them."

But there is no need to wallow in despair or suffer in silence, because help is available.

As only a tiny fraction of people who need hearing aids are using them, it is important to let people understand that there are technologies that could help them hear clearly again, if only they would come forward to seek help, McCarry says.

Anatomy of a hearing loss

Out of 500 million people worldwide estimated to have some form of hearing impairment, the World Health Organisation (WHO) estimates about 278 million of them are living with moderate to profound hearing loss.

A broad definition of hearing impairment and hearing loss is the loss of hearing in one or both ears. However, the extent of hearing loss can be categorised into mild, moderate, severe or profound.

The complete loss of ability to hear from one or both ears is called deafness.

While some are born with it (congenital hearing loss), most people with hearing loss acquire it at a later age (acquired hearing loss).

Infants can develop hearing loss in the womb if they are deprived of oxygen or when their mothers were exposed to infections such as rubella (German measles) and herpes. They can also inherit hearing loss from their parents or develop it if their mothers consume ototoxic drugs (toxic to the ear) such as the antibiotic gentamicin during pregnancy.

Adults however, mostly acquire hearing loss due to prolonged exposure to loud noise and the natural deterioration due to ageing.

Regardless of the age of onset, there are two types of hearing loss: conductive and sensorineural.

People with conductive hearing loss lose their hearing due to problems with their outer and middle ear.

Ear wax or a rare tumour may get in the way of sound waves reaching the eardrums. A faulty eardrum or problems with tiny bones in the middle ear may impede the transmission of vibrations into the inner ear.

Middle ear infections can also cause swelling or fluid build-up in the ear canal, effectively blocking sound waves from proceeding further into the ear.

People with sensorineural hearing loss, however, lose their hearing due to a damaged auditory nerve or damaged hair cells - the cells in the inner ear that convert vibrations from the outer ear into electrical signals to be sent to the brain.

These hair cells can be damaged by repeated exposure to loud noises, ototoxic drugs, fluid buildup in the inner ear, tumours, infections, or simply by getting older.

Telltale signs

How can you tell if you are losing your hearing?

McCarry says that most people do not realise they have a hearing problem until someone tells them they do. However, according to an audiology clinic in New Zealand, it takes people an average of seven years after the onset of hearing loss before taking the first step to have a hearing test.

The reasons why people are reluctant to seek professional help for their hearing problems vary, but some of the common ones are due to ignorance, the association of hearing loss with ageing or the fear of being consigned to living a life with hearing aids.

Some of them simply do not know they can't hear very well because it happens gradually.

Many do not realise that hearing loss is not just a matter of losing the ability to hear sound at low volumes. A person may also have difficulty perceiving or identifying sound clearly.

"Most people with hearing loss (PHL) have problems with speech discrimination. They can hear the words, but they don't understand what the words are," McCarry says.

While a speaker may sound perfectly audible and clear to a person with normal hearing, he may sound all muffled and jumbled up to PHL. So, they can be sitting in a room full of chatter, and still be alone.

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