Table 1.

Hearing assessments used for ototoxicity monitoring

Test	Test description	Age range	Research applications
Pure tone audiometry	Behavioral measurement of hearing thresholds in decibels (dB) for the speech frequency range (250‐8000 Hz). Testing requires participation and cooperation of the subject. Assessment methods for young children include visual reinforcement audiometry (VRA) and conditioned play audiometry.	8 mo and older	Standard method for hearing measurement, detection of ototoxic damage and identification of communicatively significant hearing loss.
Extended high frequency audiometry	Behavioral measurement of hearing thresholds in decibels (dB) for frequencies above the speech range. Test frequencies include 9000 Hz up to 20 000 Hz. Testing requires participation and cooperation of the subject. Not available at all institutions.	4‐5 y and older	Provides a more sensitive and earlier signal of ototoxic damage because ototoxicity initially occurs at the highest audible frequencies.
Otoacoustic emissions (OAEs)	Objective measurement of cochlear outer hair cell function. Does not require active subject participation. In the presence of normal middle ear function, loss of OAEs suggests outer hair cell damage but additional testing is needed to quantify change in hearing sensitivity. Available at most institutions.	Any age	Typically provides a more sensitive and earlier signal of ototoxic damage. Available at most institutions.
Auditory brainstem response (ABR/BAER)	Objective measurement of neural responses to sound stimuli (auditory evoked potentials). For ototoxicity monitoring, tone burst stimuli are used to estimate hearing thresholds when behavioral audiometry is not possible due to age, development, or medical condition. The subject must be sleeping or lying completely still during testing. Useful for very young, medically debilitated or otherwise uncooperative patient (who may be sedated).	Any age	Standard method for hearing measurement, ototoxicity detection, and identification of communicatively significant hearing loss when behavioral testing is not possible.
Tympanometry	Objective measurement of middle ear pressure and function. Used to determine middle ear status.	Any age	Necessary for valid interpretation of OAEs and to identify conductive middle ear pathology.