The 6 kHz acoustic dip in school-aged children in Finland.

In the present study, pure-tone audiometry was used in 687 Finnish school children, aged 6-15 years, to determine the prevalence of a 6 kHz acoustic dip and related factors among three age groups. Trained audiometricians tested air conduction thresholds in a sound-proof room. A total of 57 children (8.3%) had a clear-cut dip of at least 20 dB at 6 kHz. This dip was more pronounced in older children and in boys. A thorough case history was obtained by questionnaire, with logistic regression analysis showing that low birth weight (< 2500 g) and childhood measles were the only factors associated with occurrence of the 6 kHz dip in school-aged children.