Infection of CNS spread in inner ear is through:

Cochlear aqueduct (Aqueduct of Cochlea) is a connection between scala tympani (containing perilymph) and the subarachnoid space (containing CSF). On occassions, paicularly in young children, the Cochlear aqueduct is large and open.Infection can spread to the inner ear from the infected CSF or vice versa, the cochlear aqueduct resulting in severe profound hearing loss (meningitic labyrinthitis).