A study to determine the extent of epilepsy in the city is expected to go ahead this year thanks to the lifeline thrown to Enlighten Hong Kong. World Health Organisation figures put the number of sufferers in the city at about 30,000, but the taboo and secrecy surrounding the condition mean the true number could be higher. Enlighten Hong Kong believes the city may have as many as 100,000 epileptics - one in 68 of the population - and that many sufferers keep their condition a secret. The group, whose estimate is based on projections by medical experts, plans to organise a detailed study to try to discover the true number of sufferers and to dispel some of the myths and prejudices surrounding the condition. As with asthma and diabetes, there are no obvious signs of the illness and people often only discover a friend, classmate or colleague has epilepsy if they witness a seizure. Enlighten says secrecy about the condition is particularly prevalent in schools.