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29 Cards in this Set
- Front
- Back
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What is the purpose of the human senses?
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To collect information about our environment (vision, hearing smell, taste and touch)
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Which sense may be the most important?
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Touch b/c it alerts you to pain and temperature and allows you to maintain balance when standing up, but it depends on what is important to the person (i.e., in communication, hearing is very important)
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What are acoustics?
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Descriptions of the physical properties of sound & vibration
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Applications to communication:
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o Speech production
o Measurement of hearing o Auditory Skills o Calibration o Ear function o Room acoustics o Hearing conservation |
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What is psychoacoustics?
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• Describes relationship b/t physical properties of sound AND perception of the sound
• detection • discrimination = can you tell the difference between high and low pitch? |
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What is a sound?
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• “Potentially audible disturbance of a medium produced by a vibrating source” (textbook def.)
• Form of energy that results from vibrations of molecules as the move through the medium (usually air) in which they are travelling. (alternate def.) |
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Vibrations result in areas of:
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• Compression
• Rarefaction |
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What is frequency?
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The physical parameter to describe sound
o Measured in cycles / second or Hertz (Hz) o High frequency – many cycles/second o Lower frequency – fewer cycles/per second |
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What is pitch?
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psychological correlate of frequency = our perception of sound
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Decible (sound pressure level, SPL):
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• 140 dB pain
• 120 dB (discomfort) • 110 dB (jackhammers, rock concerts) • 90 dB OSHA limit for industrial noise • 60 dB Normal conversation • 40 dB Weakest audible at 100 Hz (high frequency) • 20 dB audible at 10kHz • 0 dB weakest audible at 3 kHz (low frequency) |
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Relationship between frequency and decibels:
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We hear high frequencies better
Low frequency sounds need more decibels (loudness) to hear. The higher the frequency (Hz (pitch)), the lower sound pressure (dB (loudness)) needed to hear it. |
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How many decibels in normal conversation?
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60 db
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How many decibels cause discomfort?
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120 db
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How do we hear? (systems)
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• Peripheral System (outer, middle, inner ear,
• Central System (central nervous system, brain) |
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Outer ear parts and function:
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Pinna (hard cartilage)
concha (bowl of ear) auditory canal, tympanic membrane (eardrum), = • localize sound • amplify signals • Protect (produces wax) |
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Middle ear parts and process:
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Ossicles (malleus, incus, stapes) (and stepedius muscle contract to loud sounds)
Oval window = mechanical energy Function: • Amplify • transduce (change form) sound from acoustic to mechanical vibration) |
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Inner ear parts and process:
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cochlea (membranous tissue)
hair cells auditory nerve brain = electrochemical energy Function: • Convert mechanical into hydromechanical • Transmit balance info Auditory nerve Organizes sound based on o Pitch o Loudness o Timing • Organ of Corti o Transduce into an electrical signal for brain |
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Auditory development:
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• Ear fully developed during pregnancy – 2nd trimester (20 weeks)
• Fetus responds to sound in utero • Newborns – startle response at birth or eye blinking • 3rd 4th month – head turn to sound and mother’s voice • Hearing is better than adults |
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Main Reasons for hearing loss:
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• 1. Noise
• 2. Aging • 3. Infection |
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Prevalence of hearing loss by age:
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Prevalence
o In infants: 1/1000 o In school age: 5/1000 o In teenagers: 20/100 o In adults > 65: 33/100, >75: 50/100 |
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Range of hearing loss corresponding to dB HL:
up to 15 dB (children), up to 25 (adults) |
Normal hearing in children. In adults, the upper limit of hearing may extend to 25 dB.
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Range of hearing loss corresponding to dB HL:
16-40 dB (children), 25-40 (adults) |
mild hearing loss in children: children with hearing in this range experience difficulty hearing faint or distant speech. This hearing level may cause language delay in children. In adults, the range is 25-40 Db.
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Range of hearing loss corresponding to dB HL:
41-55 dB |
Moderate hearing loss: individuals with hearing in this range experience delayed speech and language acquisition, have difficulty in producing certain speech sounds correctly, and experience difficulty following conversation
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Range of hearing loss corresponding to dB HL:
56-70 dB |
Moderately severe hearing loss: individuals with hearing in this range can understand only amplified or shouted speech
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Range of hearing loss corresponding to dB HL:
71 to 90 dB |
Severe hearing loss: experience difficulty understanding even loud and amplified speech, and they have significant difficulty in learning and producing intelligible oral language.
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Range of hearing loss corresponding to dB HL:
91+ dB |
Profound hearing loss: described as deaf. For them, hearing does not play a major role in learning, producing, and understanding spoken speech and language.
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Conductive Hearing Loss (CHL)
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• CHL occurs when sound is not conducted efficiently through the outer ear canal to the eardrum and the ossicles of the middle ear.
• Results in reduction of sound level • Usually medically or surgically corrected |
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Sensorineural Hearing Loss (SNHL)
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--SNHL occurs when there is damage to the inner ear (cochlea) or to the nerve pathways from the inner ear (retrocochlear) to the brain.
--SNHL cannot be medically or surgically corrected (yet). --Results in reduction of sound level + ability to understand speech |
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Central Hearing Loss
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-Damage in the CANS not the peripheral structures
-Characteristics -Can hear but can’t understand -What your brain does with what the ear hears -Problems with perceptual processing verbal -information -Examples: -Auditory Processing -Degenerative conditions -Tumors |
