The eighth cranial nerve (vestibulocochlear nerve) has the dual function of sending input about noise and position to the brain.
Hearing is one of the 5 major senses. It is crucial for the ability to learn and interact with the environment we live in. The loss of hearing, whether partial or complete, can be devastating for development at any time. The loss of hearing in early development can be even more detrimental. Without the ability to hear a parent’s voice, one’s own cry, or one’s own babbling, the future ability to produce language and, ultimately, the ability to verbally communicate will be impaired. The many reasons for hearing loss vary across the neonate, infant, toddler, child, and adolescent. Hearing loss can be caused by a congenital defect from an infection, a toxic exposure, or a genetic cause. Hearing loss can be acquired from frequent ear infections or fluid behind the tympanic membrane (TM). Metabolic, traumatic, and compressive nerve injuries can also cause hearing loss.
Whether a child is brought in for concerns about hearing or being seen for a well-child check, screening for hearing function at every opportunity is crucial. The family will provide clues to help determine if there are concerns about hearing function. Knowledge of normal development is a necessity to be able to identify when development is abnormal. The exam is used to give additional clues to help determine the onset of the deafness and the severity.
Hearing Loss in Neonates and Infants
Expectations of normal development must be used to determine whether hearing is abnormal. The history should be used to screen if the baby has an intact Moro reflex. Since most parents may not know what that is, ask if the patient reacts to a dog barking, doors slamming, a car horn beeping, or sirens. Did the infant ever respond to any of those things? Does the baby turn to sound both ways? This will help determine if the hearing loss is unilateral or bilateral. It is possible for the hearing loss to be asymmetrical, so asking about response to different levels of noise is also important. Ask about the noises the baby makes. The age of the patient will guide the level of sound they should be making. Does the patient coo or babble? Does the baby have different cries? Are any consonant sounds being made? Do they say “dada,” “mama,” or any other consonant words? How many words do they have? Do they use 2-word sentences?
Hearing Loss in Toddlers and Older Children
Indicators that are suspicious of hearing loss in older children are similar to those in neonates and infants. Such clues include not turning to the source of a sound without a visual clue, not following commands, ignoring ...