TABLE 5.

Age-appropriate auditory monitoring for aminoglycoside ototoxicity.

Age group	Primary assessment	Secondary assessment	Practical considerations	Monitoring frequency
Neonates (0–27 days)	ABR with frequency-specific tone burst stimuli (500–4,000 Hz); prioritize the highest feasible frequencies for early detection of basal cochlear changes	DPOAE with high-frequency emphasis (4–8 kHz)	Testing during natural sleep Portable equipment for bedside assessment Middle ear status verification	Baseline before therapy, when feasible Intensify for prolonged courses (>7–10 days), repeated courses, renal dysfunction, MT-RNR1 risk, or concurrent ototoxins Post-treatment follow-up for any detected change
Infants (28 days–12 months)	DPOAE (2–8 kHz); ABR for baseline	VRA (6–12 months); behavioral observation (supplementary only)	Testing during optimal alertness Parental assistance for VRA conditioning Objective measures when behavioral is unreliable	Baseline before therapy, when feasible Intensify for prolonged courses, repeated courses, renal dysfunction, MT-RNR1 risk, or concurrent ototoxins Post-treatment follow-up for high-risk or any detected change
Young children (1–5 years)	Conditioned play audiometry; DPOAE (2–8 kHz)	Immittance measures: ABR if behavioral testing is unreliable	Game-based conditioning approaches Brief session duration (15–20 min) Visual reinforcement	Baseline before therapy Intensify for prolonged or repeated courses, renal dysfunction, genetic risk, or concurrent ototoxins Post-treatment follow-up
Older children (≥5 years)	Conventional audiometry with extended high frequencies (where available)	Speech audiometry; DPOAE	Self-report of symptoms Extended high frequencies are most sensitive Functional assessment	Baseline before therapy Intensify for prolonged or repeated courses, renal dysfunction, genetic risk, or concurrent ototoxins Post-treatment follow-up

Age groupings are pragmatic, based on audiology and vestibular testing feasibility, and do not strictly follow ICH E11 (R1) categories used elsewhere in the manuscript. Audiological testing feasibility, rather than pharmacological classification, determines the monitoring strategy and, therefore, the age groupings used here. Monitoring frequency should be individualized based on cumulative exposure, course duration, renal function, genetic susceptibility, and concurrent ototoxic exposures rather than applied as fixed intervals.

Abbreviations: ABR, auditory brainstem response; DPOAE, distortion product otoacoustic emission; ICH, international council for harmonisation; MT-RNR1, mitochondrially encoded 12S ribosomal RNA; VRA, visual reinforcement audiometry.