| Grading scale | Description | Target population | Features | Limitations |
| Brock (Brock 1991)[1] | Designed to grade hearing loss progression from high to low frequencies in the configuration commonly associated with ototoxic cancer therapy; hearing loss is graded on 5-point scale | Pediatric | Widely used; baseline assessment not required | Does not capture hearing loss <40 dB, misses significant functional deficits |
| ASHA (1994)[2] | Hearing is compared with baseline in absolute terms (ie, presence/absence of hearing loss in comparison with baseline) | Pediatric and adult | Designed for early detection of hearing loss | Does not classify severity of hearing loss; baseline assessment is required |
| Muenster (Schmidt 2007)[3] | 8-point scale accounts for minimal hearing loss (>10 to 20 dB), subgroups within major classifications, and tinnitus | Pediatric | Designed for early detection of hearing loss | Complexity of use |
| Chang (Chang & Chinosornvatana 2010)[4] | Modification of Brock scale with similar configuration and expansion to 7-point scale; grades hearing loss >20 dB and measures interval frequencies (ie, 3000 and 6000 Hz) | Pediatric | Addresses functional deficits; baseline assessment not required | Complexity of use |
| NCI CTCAE, version 5 (2017)[5] | 4-point scale includes both objective and subjective criteria; grades are assigned based on threshold shift from baseline and actual hearing loss | Pediatric and adult | Familiar to oncologists; widely used in NCI-sponsored clinical trials | Baseline assessment required |
| SIOP Boston (Brock 2012)[6] | 5-point scale designed to grade hearing loss progression from high to low frequencies; grades hearing loss >20 dB; uses absolute hearing levels | Pediatric | Proposed through consensus of international working group; potential application across clinical trials worldwide; baseline assessment not required | Limited reliability and validity testing to date |
| TUNE grading system (Theunissen 2014)[7] | 7-point scale designed to provide insight into the effect of hearing loss on specific daily life situations (such as speech intelligibility and ability to appreciate ultrahigh sounds) | Adults | Includes subjective symptoms and threshold shifts at higher frequencies (up to 12.5 kHz); uses air conduction thresholds only; designed to represent the auditory system's real-world functionality | Time-consuming to use; feasibility testing completed; needs external validation |
