Using Tympanometry to Evaluate Middle Ear Function in Children and Adolescents with Signs of Peripheral Facial Nerve Palsy
Facial nerve is the seventh paired cranial nerve. The main trunk of CN VII consists of motor fibers and the intermediate nerve which is a part of CN VII has parasympathetic and sensory fibers. One of the branches of CN VII is the chorda tympani which may play a significant role in responses related to normal Eustachian tube function. Other branches of CN VII, such as the greater petrosal nerve and tympanic branch, have motor fibers that open the Eustachian tube, which connects the tympanic cavity with the nasopharynx. It is located at the base of the cranium and consists of bone and cartilage. To evaluate the Eustachian tube and middle ear function, impedance audiometry (IA) is used. It is specifically used in hearing organ evaluation in children. The impedance audiometry consists of tympanometry, registration of reflex from the stapedius muscle and evaluation of Eustachian tube function. Tympanometry is an examination, evaluating response of the tympanic membrane and related structures of the middle ear on artificially induced pressure changes in the external auditory meatus. The main aim of the article is to evaluate middle ear function in children and adolescents with peripheral facial nerve palsy using results obtained in tympanometry and comparing the values for pressure, amplitude, and tympanometric curve gradient between the side with CV VII palsy (affected side) and the opposite side (healthy side).