chapter 1 Flashcards
Audiology
the healthcare profession devoted to
The prevention, identification, and evaluation of hearing disorders (including balance disorders)
Educational preparation
Doctoral entry-level degrees
Clinical PhD/ScD
Professional doctorate AuD
PhD
Professional certification
American Speech–Language Hearing Association (ASHA): the national organization that certifies audiologists and speech–language pathologists in the United States
Certificate of Clinical Competence (CCC)
American Academy of Audiology (AAA)
Professional licensure
State licensing board
Most states model their regulatory rules in audiology after the ASHA standards for the certificate of clinical competence
Continuing Education Units, around 30 per 3 years
Required by most states to maintain licensure
Often, separate licenses for audiology and hearing aids
Less schooling required to become a hearing aid dispenser (i.e., associate’s degree)
Evolution of the profession
Relatively new profession
Began in 1940s
Roots took hold in the United States following WWII
Clinics set up to rehabilitate veterans with hearing loss
Non-VA diagnostic clinics (both independent and within physician offices) set up later
Hearing aids dispensed by dispensers (not audiologists)
Scope of practice
Comprehensive audiometric evaluation (CAE)
Includes evaluation of middle ear function using immittance measures (tympanometry, acoustic reflex)
Auditory brainstem response (ABR) evaluation
Intraoperative monitoring of CN VII and CN VIII
Otoacoustic emission (OAE) evaluation of outer hair cell function
Electronystagmography (ENG) evaluation and vestibular rehabilitation
Cochlear implant programming/mapping of speech processor
Prescriptive fittings of hearing aid and assistive listening devices
ACOUSTICS
1) the properties or qualities of a room or building that determine how sound is transmitted in it.
2) the branch of physics concerned with the properties of sound.
PSYCHOACOUSTICS
Interdisciplinary science of the perception of sound.
2) Audiology
Prevalence
Prevalence refers to proportion of persons who have a condition at or during a particular time period,
Incidence
Incidence refers to the proportion or rate of persons who develop a condition during a particular time period.
Sound
Sound: the movement of a disturbance (vibration) through an elastic medium (liquid/solid/gas) without permanent displacement of the particles
◦We are generally concerned with AIR
Hearing
Hearing: the perception of sound
Mass
Mass: quantity of matter present
•Not identical to weight (because weight is affected by gravitational force)
•For our purposes, mass ~ weight
Force
Force: a push or a pull on an object; a vector
Inertia
Inertia: tendency to resist any change in motion (Newton’s First Law)
•Outside force must be applied to change this tendency
•The greater an object’s mass, the greater its inertia
Elasticity
–Elasticity: tendency to resist deformity of an object and to return to its rest position
Nature of sound
Initial impact starts movement (displacement) away from rest
2)Elasticity in the fork allows displacement, but also generates a restoring force that stops the movement
3)Restoring forces push the fork back to rest position
4)Inertia carries the tines past rest position (overshoot)
5)Restoring force builds up in the other direction
6)Fork returns to rest position again (one full cycle)
7)Overshoots . . . builds up restoring force . . . the pattern repeats
In an elastic medium such as air, the molecules next to the sound source move first. Then, they pass the movement to adjacent molecules. This motion is propagated, or transferred, through the air to the ear.
Compression
Compression: occurs when air particles are pushed together, resulting in an increase of air pressure; aka condensation
Rarefaction
Rarefaction: occurs when air particles are separated, resulting in a decrease of air pressure
Sound in air: longitudinal
Sound in air: longitudinal (pressure) wave
◦Particles vibrate alternately in the same direction of propagation (away from/toward the source) so that propagation is parallel to energy source
◦Particles approach and recede from each other to create pressure variations
Simple harmonic sound
Simple harmonic motion: the symmetrical to-and-fro motion of a body over a rest position
◦When the amplitudes of the vibrating body are plotted as a function of time, the resulting pattern is a sine wave
◦Pure tones, sounds with definite tonal quality, are produced by simple harmonic motion
Frequency
Frequency: a measurable characteristic of acoustic signals that is described by the number of complete cycles that a periodically vibrating source passes through in a 1-second time period
◦Measured in units called Hertz (Hz)
In a pure tone, only one frequency is described (e.g., 1000 Hz)
◦A sinusoid—forms a sine wave when graphed
◦Periodic in nature—repeats at regular intervals over time
Octave
Octave: twice the frequency of a given frequency
◦Octaves assessed via audiometer:
◦250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, 8000 Hz
Pitch
◦Pitch: related to the listener’s perceptual response mainly to frequency (and, to a degree, intensity)
◦Frequency and pitch are related
◦Higher perceived pitch results (mostly) from higher frequency
◦However, this relationship is non-linear, especially at frequencies > 1000 Hz
Amplitude
Amplitude: a derived unit of measurement that describes the distance that the sound-producing body moves during vibration
◦The greater the distance from the point of rest, the greater the amplitude
◦In general, the greater the amplitude, the louder the sound
◦Decreases over time as energy is lost to damping (friction and other outside forces)
