Which two frequencies are usually averaged to calculate the two-tone pure tone average?

The two-tone pure tone average is typically calculated using the frequencies of 500 Hz and 1000 Hz. These frequencies are selected because they fall within the range where human speech and hearing sensitivity are most critical, and they are used commonly in audiometric evaluations to assess hearing loss. By averaging these two frequencies, clinicians can gain insight into a patient's overall auditory function, particularly with regards to the speech frequencies that are most relevant in everyday communication.

The choice of 500 Hz and 1000 Hz reflects their significance in assessing hearing capabilities in populations, including those with potential noise-induced hearing damage or age-related hearing loss. These frequencies are also generally more sensitive to clinical changes in hearing compared to very high frequencies or less relevant low frequencies.