Audiology Training Course ——Marketing Dept
Configuration of the ear • Pinna • Ear canal • Eardrum • Malleus • Incus ⑥Eustachian tube ⑦Stapes ⑧Semicircular canals ⑨Cochlea ⑩Auditory nerve
Configuration of the ear The outer earconsists of the pinna, or auricle, and the ear canal (external auditory meatus). The pinna – the part of the "ear" that we see on each side of our heads – is made of cartilage and soft tissue so that it keeps a particular shape but is also flexible. The pinna serves as a collector of sound vibrations around us and guides the vibrations into the ear canal. It helps us decide the direction and source of sound.
Configuration of the ear The middle ear begins with the eardrum at the end of the ear canal. The middle ear contains three tiny bones, called the ossicles. These three bones form a connection from the eardrum to the inner ear. As sound waves hit the eardrum, the eardrum moves back and forth causing the ossicles to move. As a result, the sound wave is changed to a mechanical vibration. The inner earcontains the sensory organs for hearing and balance. The cochlea is the hearing part of the inner ear. The semicircular canals in the inner ear are part of our balance system.
malleus incus acoustic wave stapes footplate at oval window ear canal pinna eardrum outer ear middle ear endolympha and perilympha in cochlea auditory sense cortis' comprehensive analysis nerve impulse Air-conduction
Degrees of hearing loss Between “hearing well” and “hearing nothing” lies a wide range of different degrees of hearing loss. Experts distinguish between mild, moderate, severe and profound hearing loss. Most cases of hearing loss are categorized as mild or moderate.
Degrees of hearing loss The sound of speech Human speech consists of vowels and consonants at different loudness and frequency levels. They are recorded on the audiogram as a so-called “speech banana”. It is an easy way to check whether the entire spectrum of speech is still audible and how a person’s hearing changes with time.
Degrees of hearing loss Mild hearing loss (25-40dB) Soft noises are not heard. Understanding speech is difficult in a loud environment Moderate hearing loss (41-60dB) Difficulty understanding speech, especially in the presence of background noise. Higher volume levels are needed for hearing TV or radio. Severe hearing loss (61-80dB) Conversations have to be conducted loudly. Group conversations are possible only with a lot of effort Profound hearing loss (>81dB) Some very loud noises are heard. Without a hearing aid, communication is no longer possible even with intense effort
Types of hearing loss Conductive Hearing Loss This type of hearing loss is caused by problems in the ear canal and/or the structures in the middle ear. It occurs when sounds from the outside world cannot be transmitted normally through the ear canal and/or middle ear to the inner ear. The most common causes of conductive hearing loss can be a buildup of wax in the ear canal, perforated eardrums, fluid in the middle ear (common in children), or damaged or effective ossicles (middle ear bones). A person with conductive hearing loss may notice their ears seem to be full or plugged. Most conductive hearing losses can be medically or surgically treated. If, for some reason, the hearing loss cannot be corrected, hearing instruments can provide benefit.
Types of hearing loss Sensorineural Hearing Loss This type of hearing loss is the most common type of hearing loss. More than 90 percent of all hearing instrument wearers have sensorineural hearing loss. It results from a combination of problems in the inner ear and the auditory nerve. They then become unable to convert sound vibrations into the electrical signals needed by the auditory nerve. The nerve pathways in the auditory nerve itself can also become damaged, preventing the signals from reaching the brain. Although this damage can be caused by exposure to loud noise - through working in a noisy environment for too long - the primary reason is aging. People with sensorineural hearing loss typically report they can hear people speak, but can't understand what they're saying. Hearing instruments and assistive devices can help.
Types of hearing loss Mixed Hearing Loss This kind of hearing loss is caused by a combination of problems in the middle and the inner ear or the auditory nerve. For example, the person may have a noise induced hearing loss from noise exposure and a perforation in the eardrum. The combination of sensorineural and conductive hearing therefore the loss is mixed.