Hearing Case Study: No More Loud Music
Directions: As you read the case study, CIRCLE any new or unfamiliar vocabulary you come across and Highlight what you determine to be the most important information.
Roger, age 40, goes to his doctor for a regular physical examination. In the course of the interview, the doctor asks him if his hearing is okay. Roger says that his wife sometimes accuses him of being “half deaf” because he turns the stereo and television up louder than she likes it. He also says he has been late for work a few times because he didn’t hear the high-pitched beeping of his alarm clock, so he bought a clock radio and set it to wake him up to music instead. The doctor examines Roger’s ears but sees no impacted cerumen (earwax buildup) or other abnormalities. He asks if Roger would like to be referred to an otolaryngologist (ear, nose, and throat doctor), and Roger agrees that it would be a good idea to have his hearing checked more thoroughly.
During his appointment with his otolaryngologist, the doctor tells Roger that his receptionist will make an appointment for him to see an audiologist (branch of science that studies hearing), but says that he can do a few simple tests in the meantime. Roger tells him the same things he told his regular doctor, but adds that he often finds it difficult to make out a person’s words—for example, when watching television or at the theater—making it hard for him to follow the plot of a movie. He says that he can still hear telephone conversations with both ears, however, Roger says that he has liked his music loud ever since college and often plays his car stereo loud and with heavy bass amplification. He also likes to go to drag races three or four times a year.
The otolaryngologist asks if Roger has ever worked in a loud environment such as a factory, ever used firearms without ear protection, ever served in combat, and other questions—to all of which Roger answers no. To other questions, however, he answers yes: He had frequent middle-ear infections when he was a child, and he had Mumps when he was 8 years old—both conditions that can cause hearing loss. The doctor performs a Rinne tuning fork test. (Description below)
The Rinne test is performed by placing a high frequency (512Hz) vibrating tuning fork against the patient's mastoid bone (part of temporal bone) and asking the patient to identify when the sound is no longer heard. Once the patient signals that they can't hear the sound, the doctor quickly positions the still vibrating tuning fork 1–2cm from the auditory canal (ear canal), and again asks the patient to tell if they are able to hear the tuning fork.
If a person has normal hearing, air conduction should be greater than bone conduction and so the patient should be able to hear the tuning fork next to the auricle (the visual part of the ear) after they can no longer hear it when held against the mastoid.
If a person has abnormal hearing they are not able to hear the tuning fork after it is removed from the mastoid bone. This means that their bone conduction is greater than their air conduction. This indicates there is something inhibiting the passage of sound waves from the ear canal, through the middle ear apparatus and into the cochlea (i.e., there is a conductive hearing loss). If they are not able to sense the sounds when the tuning fork is on the mastoid bone OR when it is in front of the ear canal, then both bone and air conduction is equally diminished. These patients can usually hear better on the mastoid process than air process, but indicate the sound has stopped much earlier than conductive loss patients.
Roger’s results are as follows:
With the tuning fork against his mastoid process (part of the temporal bone), Roger hears the hum for 16 seconds in the left ear and 18 seconds in the right ear (bone conduction times). With the tuning fork then moved in front of the auditory meatus (ear canal), Roger hears the hum for an additional 12 seconds with both ears (air conduction time). Roger’s doctor remarks that his Rinne test results suggest a sensorineural hearing loss, not a conductive hearing loss.
Sensorineural hearing loss is caused by one of three things: a problem in the vestibulocochlear nerve, which transmits sound and equilibrium (balance) information from the inner ear to the brain, a problem in the inner ear, or the a problem in the processing centers in the brain. It is usually caused by abnormalities in the hair cells in the Organ of Corti in the cochlea of the inner ear. Sensorineural hearing loss can be caused by noise trauma, infection, or genetic deafness. It can also be caused by prolonged exposure to a very loud noise while wearing no ear protection, or music being set to high volumes for long periods of time.
Conductive hearing loss occurs when there is a problem conducting sound waves anywhere along the route through the outer ear, tympanic membrane (eardrum), or ossicles (middle ear). This type of hearing loss may occur in conjunction (at the same time) with sensorineural hearing loss or alone. Common causes could be the buildup of earwax, ear infections, a perforated ear drum, or pressure on the eardrum. It can also be caused by fluid buildup behind the tympanic membrane (ear drum). Conductive hearing loss is uncommon in the inner ear. If infection is the cause, antibiotics will be prescribed by a doctor. Other treatment options might be hearing aids or if necessary, surgical repair or cochlear implants. A cochlear implant (CI) is a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf or extremely hard of hearing.
Roger sees the audiologist the following week. The audiometer (machine that evaluates hearing loss) plays pure tones at selected intensities and frequencies from 250 to 8,000 Hz. At frequencies from 300 to 3,000 Hz, the range of most conversation, Roger has a hearing loss in both ears ranging from 40 to 60 decibels (db). Specialized audiometric tests that distinguish bone conduction from air conduction confirm that Roger has sensorineural deafness rather than conductive deafness.
The otolaryngologist tells Roger that his earlier middle-ear infections probably haven’t affected his hearing. His Mumps could have something to do with it, but more likely, the loss is a result of inner-ear damage from the loud music. He advises Roger that he must be more careful to protect his hearing, and that if his hearing loss is too troublesome, he may want to consider a hearing aid and training in speech reading so that he will be able to better understand movies, conversations, and so forth.
Based on this case study, answer the following questions on pg. 58 in your interactive notebook.
- In a short paragraph summarize the case study. (What happened? What were the findings?)
- Using context clues (clues from the reading), define 3-4 of the new vocabulary words you circled.
- IN YOUR OWN WORDS, please describe the Rinne Test, and what it helps determine.
- Using evidence from the Rinne test that was performed on Roger, do you agree with the doctor’s diagnosis?
- Suppose Roger had been a hunter and regularly used a shotgun without using ear protection. Which type of hearing loss—conductive or sensorineural—would most likely result from this activity? Why?
- Why did the otolaryngologist not suggest cochlear implants for Roger?
- Why does the otolaryngologist conclude that Roger’s childhood middle-ear infections are not responsible for his hearing loss?
- What are some of Roger’s treatment options for his loss of hearing?