What causes hearing loss?

Let’s talk about how hearing loss occurs. When we talk about hearing, the first thing we think of is the ear. The scientific name is the auricle, which mainly plays the role of collecting sound. The process from sound to the brain for receiving signals is called hearing the sound, and this system is called the auditory system. Hearing loss means there is a problem with the auditory system. In order to understand the cause of hearing loss, first take a closer look at the hearing conduction pathway.

Sound waves enter our external auditory canal through the auricle, and are transmitted to the tympanic membrane through resonance. The tympanic membrane transmits the sound to the middle ear ossicles, to the vestibular window, and then to the inner ear. The perilymph and endolymph pass through the spiral organ and receive signals from our auditory nerve and auditory center. Then we hear the sound. This is a complete auditory route.

It can be seen that the entire outer ear + middle ear plays a conductive role in sound. In the cochlea, semicircular canals, and vestibule of the inner ear, one of its functions is to sense sounds, which we call sound perception. Of course, there is also the auditory nerve, which belongs to the nerve, which means that our hearing loss often involves two terms, one is conductive hearing loss. One is sensorineural hearing loss. When our hearing loss occurs in the outer ear, it may be due to cerumen embolism, or other reasons may block our ear canal. Such a problem is an external ear problem, then it is conductive hearing loss; then if we have hearing loss in the middle ear Problems such as adhesion of the ossicular chain or tympanic effusion in the middle ear are still conductive hearing loss; if the problem occurs in the inner ear, such as cochlear hair cell necrosis or cochlear deformity, these It is a sensorineural problem. If it occurs in the auditory nerve, acoustic neuroma, or some auditory nerve transmission disorders, it is neurological hearing loss. However, the latter two sensorineural and nerve are often difficult to separate during detection.So we collectively call it sensorineural hearing loss. However, some of our patients have hearing loss in both conductive and mixed parts, so we call it mixed hearing loss.