Parameters for clinical description of the hearing impairment
| (1) Hearing impairment in dB HL (averaged on 0.5-1-2 kHz) | |
|---|---|
| Moderate | 40–69 dB HL |
| Severe | 70–94 dB HL |
| Profound | >95 dB HL |
| (2) Age of onset | |
| Congenital | Present at birth |
| Uncertain | When it was difficult to ascertain the real congenital onset |
| (3) Symmetrical/asymmetrical involvement | |
| Asymmetrical | >15 dB difference between ears in at least two frequencies |
| (4) Steady/progressive deficit | |
| Progressive | >15 dB of progressiveness in at least two frequencies or >10 dB for average of 4 frequencies (0.5-4 kHz) |
| (5) Configuration of audiogram | |
| Low frequencies | >15 dB from the better to the poorer hearing threshold at the low frequencies to the mid frequencies |
| Sloping | >15 dB difference between 1000 and 4000 Hz |
| Flat | <15 dB difference from 500 to 4000 Hz |
| U shaped | With >15 dB difference between the better hearing thresholds and the poorer hearing threshold(s) |
| None of the above configurations | |