Results of hearing tests in 223 VLBW boys and expected numbers calculated from total population
| Group | Definition | Observed | Expected |
|---|---|---|---|
| 1 | Average hearing loss in best ear at 500, 1000, and 2000 Hz between 40–60 db | 1 | 0.1 |
| 2 | Average hearing loss in best ear at 500, 1000, and 2000 Hz between 20–40 db | 8 | 3.2 |
| 3 | Hears 20 db at 500, 1000, and 2000 Hz in best ear and loss 20–40 db worse ear | 6 | 3.5 |
| 4 | Hears 20 db at 500, 1000, 2000,and 3000 Hz both ears | 34 | 27.4 |
| 5 | Hears 20 db at 500, 1000, 2000, 3000, and 4000 Hz both ears | 174 | 189.9 |