抄録
This Technical Report presents air conduction hearing thresholds measured for pure tones at conventional audiometric frequencies (CAFs) from 125 Hz to 8 kHz and extended high frequencies (EHFs) from 8 kHz to 16 kHz, using apparatus and procedures in accordance with relevant ISO and IEC standards. The subjects were 490 otologically normal Japanese adults aged 18–83 years. Descriptive statistics of their threshold levels are presented in graphical and tabular forms to show the age-related decline of hearing sensitivity and its individual differences. The change in hearing sensitivity of older adults at CAFs was smaller, in general, than the standard values according to ISO 7029:2000, in which the amount of hearing sensitivity decline is estimated as a function of age. The threshold data presented in this report may serve as a basis for revising the international standard. In addition, measurement results at EHFs revealed that the responses of older subjects could be unreliable at the highest frequencies because of an unwanted sound in a lower frequency region generated with test tone presentation. Threshold values at extended high frequencies should be treated with caution.
