Tympanometry equipment used to measure the movement of the eardrum (tympanic membrane) and assess the condition of the middle ear. A probe (not seen) is inserted into the ear through which a sound is produced. As the pressure in the ear canal is varied, the amount of sound reflected by the eardrum is recorded on a tympanogram. An audiologist can tell whether the Eustachian tube (which connects the pharynx and middle ear, allowing for equalisation of pressure across the eardrum) is functioning properly. Tympanometry helps with diagnosis of glue ear (middle ear inflammation due to blockage of the Eustachian tube), which commonly affects hearing in children.