Hi, I'm Anita Vereb, an audiologist here at Michigan Medicine. And we're going to talk to you today about the basics of hearing physiology, and the prevalence of hearing loss in children. Hopefully through this lecture series, you will feel more empowered instead of feeling frustrated and confused about how to identify hearing loss. How to interpret an audiogram and understand the different types of hearing loss that children may encounter. So think about the incidence of hearing loss in infants, in the newborn population, what would you guess the incidence of hearing loss is? Is it one in a hundred, one on a hundred thousand, five in ten thousand, or two in a thousand? If you guess two and a thousand, you're correct. That is the incidence of hearing loss in the newborn population. However, take into consideration those children who are in the neonatal intensive care unit, their incidence is a little bit higher. So if you're looking at these two children here, can you tell me which one has a hearing loss? Really you can't, and that's the point is that hearing loss in children is an invisible disability. And often times, this is why the importance of early identification and intervention when we're coming and talking about hearing loss in children. So the incidence of hearing loss in children increases as children become school-aged. And six in a thousand school-aged children will have some type of educationally significant hearing loss. And if left untreated, this can lead to significant deficits in their speech and language, communication and behavioral development, and overall socialization. But the good news is, early identification of hearing loss with timely and appropriate intervention can minimize these impacts? In week one, we reviewed a little bit about the different parts of the ear. So we're going to talk about you have the outer ear which is the pinna or the auricle, and then you have the ear canal here. So this here is what we call the outer ear. And then in the middle ear, you have the eardrum here, which is the tympanic membrane. The three middle ear bones also called the ossicles, and then the Eustachian tube. That's the components of the middle ear. In the inner ear, you have the cochlea with the semicircular canals, and then the auditory, and vestibular nerve leading to the brain. So let's discuss how do we actually hear? here, we hear the sound of the car horn. [SOUND] And what happens is the sound waves then are collected through the pinna or the auricle, the outer ear. They travel down through the ear canal, going into the middle ear, hitting the eardrum or the tympanic membrane, which causes that eardrum to move. Sending those vibrations then to the middle ear bones. The three middle ear bones, setting them in motion with then the last bone, the stapes. Pushing in on the cochlea, and setting a wave of the fluid in the cochlea into motion. Which then sends the basilar membrane, which is housed in the cochlea to move. And on the basilar membrane, we took a little slice here of what that organ of Corti, that part of the cochlea, see of the basilar membrane. And then you have the little hair cells, outer and inner hair cells. So as that traveling wave goes through the cochlea, it causes that membrane to move which causes those hair cells to shear back and forth. Kind of like seaweed in the water, when you see a wave go by and you can see the seaweed move back and forth. So as those hair cells shear, it changes that vibration or acoustical signal into an electrical signal or pulse that then is sent to the hearing nerve, then up to the brain. And then aha, we hear, I heard that sound, that car horn and I jumped out of the way. So this just gave you a basic overview of how we hear. Thank you for listening.