Table 1. Chang Ototoxicity Grading Scale.
Chang Grade | Sensorineural Hearing Threshold (dB HL) bone conduction or air conduction with normal tympanogram |
---|---|
| |
0 | ≤ 20 dB at 1, 2, and 4 kHz |
| |
1a | ≥ 40 dB at any freq 6 to 12 kHz |
1b | > 20 and < 40 dB at 4kHz |
| |
2a | ≥ 40 dB at 4 kHz and above |
2b | > 20 and < 40 dB at any freq below 4kHz |
| |
3 | ≥ 40 dB at 2 or 3 kHz and above |
| |
4 | ≥ 40 dB at 1 kHz and above |