MANY old people are being exposed to danger because they don't know how deaf they are. They are not aware their hearing has failed until their situation has deteriorated to the point where it threatens their safety. A Hong Kong University survey found the problem was more serious in Hong Kong than overseas because of poor resources, education and cultural differences. Almost all of the 130 respondents, aged 50 to 80, claimed they did not have any hearing defect. But screening revealed 70 per cent of them did. Most could hear sounds of 35 decibels while others could only hear sounds of 50 decibels or above. A jet landing or taking-off is 90 decibels or above and a normal conversation about 50 decibels. A healthy person can hear sounds of 25 decibels or above. 'That's why sometimes one has to shout at the top of his voice before the elderly can hear because the elderly fail to hear sounds of 50 decibels or below,' said researcher Lena Wong Lai-nar. Ms Wong, lecturer with Hong Kong University's speech and hearing sciences, said many elderly should wear a hearing aid but they did not because they were unaware of their problem. 'This could be very dangerous. An old person may not hear the sound of vehicles or warnings from passers-by when crossing the road,' she said. 'Old people in Western countries realise their hearing defects at an earlier stage. But such awareness in Hong Kong is very low. 'Chinese culture is one of the reasons. Chinese traditionally are unwilling to consult doctors. They do not admit defects and believe they can recover by taking medicine. But late treatment will only make their hearing worse.'