A.1.3.1StudentResourceSheet
Activity 1.3.1 Student Resource SheetPart I: The Physics of SoundSound, like electricity and light, is a form of energy that travels in waves. When a pebble is thrown into a pond, you will notice that the waves of water ripple out from the center. Think of sound waves as these ripples of water. Sound is generated by vibrations. The vibrations act as the pebble and push the molecules of air around them outward. These molecules then bump into their neighboring molecules, creating waves. Every sound has two main characteristics, pitch and intensity. Pitch is determined by a sound’s frequency, or how rapidly the sound waves vibrate each second. Frequency is measured in vibrations per second, or Hertz (Hz). The higher the frequency of the sound, the more frequently the waves vibrate, and the higher the sound’s pitch is. Sound intensity is determined by a sound’s amplitude, or the amount of energy in the wave. The more energy the sound wave has, the higher the amplitude, and the louder the sound seems. Sound intensity is commonly referred to as loudness. Sound intensity is measured as decibels (dB). The decibel scale begins at 0 dB, which is the intensity of the sound that is least perceptible by a normal human ear. Because the range of intensity that a human ear can register is so large, the decibel scale is a logarithmic scale. For example, a sound of 20 decibels is one hundred times louder than 0 decibels; a sound of 30 decibels is one thousand times louder than 0 decibels. A whisper has an intensity of around 40 dB; whereas, the music at a rock concert has an intensity around 140 dB. Frequent or prolonged exposure to sounds with intensities above 85 dB can damage hearing receptors and cause permanent hearing loss. Part II: Hearing Loss Case StudiesPatient One:Patient One is a 45-year-old machine operator at a local factory. Lately, he has been complaining of a constant ringing in his ears and has noticed that he has a difficult time following conversation. His wife convinced him to get his hearing tested, and an audiologist found that he has noise-induced hearing loss with moderate to severe sensorineural hearing loss in both ears at frequencies around 4000 Hz and mild sensorineural hearing loss in both ears at frequencies around 8000 Hz. The hearing loss is accompanied by tinnitus.Patient Two:Patient Two is a six-year-old male. He has been experiencing chronic middle ear infections (also known as chronic otitis media) since he was six months old. Because he has a very narrow, short Eustachian tube in his right ear, he is susceptible to bacterial infections. He has had ear tube surgery twice, where a small tube was placed in the eardrum to ventilate the area behind the eardrum, keep the pressure equalized and reduce infection. This surgery had little success. The last two ear infections resulted in a perforated eardrum with a pus-like drainage from his ear. Lately, his teacher informed his parents that his performance in school has declined, and suggested he be tested for hearing loss. An audiologist found that he has mild to moderate conductive hearing loss in his right ear.Patient Three:Patient Three is a 24-year-old female who was born with a cochlear abnormality in her left ear. This abnormality causes her to experience a difficult time understanding lower-pitch noises; often she has difficulty following conversation in a crowded room. She has been diagnosed with moderate low-to-mid frequency sensorineural hearing loss in her left ear.Patient Four (Sue Smith):Patient Four is an 18-year-old college freshman who just recovered from a bacterial meningitis infection. She has not noticed any difficulties hearing, but was referred to an audiologist by her primary care physician. An audiologist found that she has mild low frequency sensorineural hearing loss in both ears.Patient Five:Patient Five is a 71-year-old female. She began noticing that she had a difficult time understanding and hearing speech when she was in her early sixties. Lately, the condition has gotten worse. Hearing tests confirmed that she has presbycusis, a hearing loss caused by the natural aging of the human body, and as a result has severe mid-to-high frequency sensorineural hearing loss in both ears.Patient Six:Patient Six is a 44-year-old female. She was recently diagnosed with Meniere’s Disease, an abnormality of the inner ear associated with a change in fluid volume within the labyrinth. She constantly experiences episodes of severe vertigo (a feeling of spinning), imbalance, nausea, and severe low frequency sensorineural hearing loss in both ears. Sometimes the episodes are infrequent and other times occur more frequently. Patient Seven:Patient Seven is a 38-year-female rock star who just finished her twentieth international tour. Lately, she has noticed that she has trouble distinguishing between certain sounds and has a difficult time hearing the higher voices of women and children. An audiologist has confirmed that she has moderate high frequency sensorineural hearing loss in her left ear.Patient Eight:Patient Eight is a 68-year-old male who recently was treated for an upper respiratory viral infection which caused inflammation of the labyrinth, the part of the inner ear that helps control balance (a condition called labyrinthitis). This condition has caused vertigo, a feeling of dizziness and spinning, as well as a moderate sensorineural loss in his left ear at low frequencies and a mild sensorineural hearing loss in his left ear at medium frequencies. The audiologist also confirmed a mild sensorineural hearing loss in the patient’s right ear.Patient Nine:Patient Nine is a 21-year-old male staff sergeant who just finished a tour of duty overseas. Since he has been back, he has experienced a constant buzzing sound in his left ear. Hearing tests show a mild sensorineural hearing loss in his left ear with Tinnitus.Patient Ten:Patient Ten is a 24-year-old female. She has otosclerosis, an inherited disorder in which an abnormal sponge-like bone grows in the middle ear. Her mother also had otosclerosis and became deaf by the time she was 45. Both of Patient Ten’s ears have been affected by the disorder and an audiologist confirmed that she has progressive mild to moderate conductive hearing loss in both ears. ................
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