Scoring System
Category Definition Points
Koos Grading Koos 4 0
Koos 3 1
Koos 2 2
Koos 1 3
Extension Transmodiolar extension 0
Infiltration of modiolus 1
Contact with modiolus 2
No contact, no infiltration of modiolus 3
Hearing ≥ 100 dB 4-PTA 0
80 < 100 dB 4-PTA 1
< 79 dB 4-PTA 2
> 0% monosyllables, any PTA 3
PS EABR No response 0
Unclear wave V 1
Stable wave V 2
Total Score Class IV 0 - 3
Class III 4 - 5
Class II 6 - 8
Class I 9 - 11