Spectrum of congenital inner ear malformations as proposed by Sennaroglu and Saatci13
| Time of Insult (week) | Malformation | Features |
|---|---|---|
| Third | Labyrinthine aplasia (Michel deformity) | Complete absence of cochlea and vestibule |
| Third-to-fourth | Cochlear aplasia | Complete absence of cochlea; vestibule present |
| Fourth | Common cavity | Single cystic cavity representing cochlea and vestibule, without any differentiation |
| Fifth | Cystic cochleovestibular anomaly (IP-I) | Cystic-appearing cochlea lacking entire modiolus and cribriform area; large cystic vestibule |
| Sixth | Cochlear hypoplasia | Cochlea and vestibule are separate but are smaller than normal; hypoplastic cochlea resembles small bud off the IAC |
| Seventh | Incomplete partition type II (IP-II) | Cochlea consists of 1.5 turns, in which middle and apical turns coalesce to form a cystic apex; vestibule and VA may be enlarged |