Sensory - Hearing and Balance Development
Introduction
We use the sense of balance and hearing to position ourselves in space, sense our surrounding environment, and to communicate. Portions of the ear appear very early in development as specialized region (otic placode) on the embryo surface that sinks into the mesenchyme to form a vesicle (otic vesicle = otocyst) that form the inner ear.
This region connects centrally to the nervous system and peripherally through specialized bones to the external ear (auricle). This organisation develops different sources forming the 3 ear parts: inner ear (otic placode, otocyst), middle ear (1st pharyngeal pouch and 1st and 2nd arch mesenchyme), and outer ear (1st pharyngeal cleft and 6 surface hillocks).
This complex origin, organisation, and timecourse means that abnormal development of any one system can impact upon the development of hearing.
In Australia, there is now an early postnatal analysis of neonatal hearing as part of a NSW State Wide Infant Screening Hearing Program using Automated Auditory Brainstem Response (AABR).
