| Postnatal factors | No. of patients | Percentage | |
| Viral infection | - | - | |
| Infection and ototoxic drug history | 4 | 40 | 80 |
| Infection with ototoxic drug history and hyperbilirubenemia | 2 | 20 | |
| Hyperbilirubenemia requiring phototherapy | 2 | 20 | |
| Delayed milestones + ototoxic drug history | 2 | 20 | |
| Total | 10 | 100 | |