High frequency audiometry. Clinical aspects.

For 2 years past a previously described quasi-free-field high frequency audiometer delivering pure tones from 4 to 20 kHz has been incorporated in the audiological test battery. By this technique it is possible to obtain reliable and reproducible thresholds above the age of 8--9 years. In several case histories it is illustrated how high frequency audiometry (HFA) contributes to a better audiological diagnostic and it is predicted that HFA is of value in research studies on presbycusis, ototoxicity, noise vulnerability, and in hereditary studies on deafness. The physiological presbycusis demands normative reference values for each age decade. Many other factors, however, can cause an impaired high frequency hearing which is a severe limitation to the diagnostic value of abnormal findings.