DIPS ON BEKESY OR AUDIOSCAN FAIL TO IDENTIFY CARRIERS OF AUTOSOMAL RECESSIVE NON-SYNDROMIC HEARING-LOSS

Bekesy and audioscan sweep audiometry tests were carried out in 24 pre sumed obligate carriers of autosomal recessive non-syndromic hearing l oss and 30 sex and age appropriate controls, with a view to defining t he most expedient criteria for dips on either test in respect of possi ble carrier detection. On Bekesy, dips with a minimum depth of 22.5 dB generated the greatest difference between carriers and non-carriers, while on audioscan, the criterion of a minimum dip depth of 15 dB prov ided the best discriminant. Using these criteria, the prevalence of di ps was also evaluated in 8 unaffected siblings and 24 age appropriate control subjects. The findings both in the adult and the paediatric gr oups do not support the hypothesis that the presence of dips, either o n Bekesy or audioscan, is linked to the carrier state in ARNSHL.