When testing at usual audiometric frequencies, which difference prompts testing inter-octaves?

When testing at the usual audiometric frequencies, inter-octave testing is prompted by a significant difference of 20 dB or more between consecutive frequencies. This threshold indicates that the hearing loss can significantly vary between these frequencies, suggesting the need for additional testing at the inter-octave points to accurately define the hearing profile of the patient.

Inter-octave frequencies are measured to capture nuances in hearing ability that might be missed if the audiogram skips those ranges. For example, if a patient shows a hearing threshold of 60 dB at one frequency and 40 dB at the next octave frequency, this 20 dB difference could signify an important change in the patient's hearing capabilities, warranting extra investigation at the frequency lying in between.

This method helps clinicians provide a more comprehensive overview of an individual's auditory function, ensuring accurate diagnosis and effective treatment planning. Other threshold differences, such as 10 dB or more, might not indicate a significant enough change to require an inter-octave test.