SLHS 21500 Study Guide - Midterm Guide: Interaural Time Difference, Sound Localization, Auditory Masking
25 Aug 2016
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Test 2 Review Sheet
Psychoacoustics:
•What is psychoacoustics?
obehavioral measurement of perception, study of perception of sound
•What are the perceptual correlates of frequency and intensity?
opitch and loudness
•What is a discrimination procedure? A scaling procedure? A matching procedure?
odiscrimination: used to assess the smallest difference between two conditions that
is detectable by the listener, just noticeable difference
oscaling: attempt to measure sensation directly using a scale (i.e. 1-10)
omatching: listener adjusts signal to match another sound (i.e. tinnitus), usually
used to quantify pitch or loudness
oWhat are the three discrimination procedures discussed in class?
▪Method of limits: stimulus is altered in small steps until the listener’s
response changes (hearing to not hearing or vice versa)
▪Method of adjustment: the listener adjusts the stimulus so it is just
detectable (absolute threshold) or just noticeable change is detectable
(difference threshold)
▪Method of constant stimuli: each of a fixed set of stimuli are presented in a
random order
oWhich is used in standard hearing testing?
▪Methods of Limits
•What is binaural hearing?
oprocessing of sound using two ears
•What are the two cues used for localization?
oInteraural Time Difference
oInteraural Intensity Difference
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•What is auditory masking?
owhen the perception of one sound is affected by another sound
oSimultaneous masking, forward and backward masking?
▪Simultaneous: when both the stimulus and the masking noise occur at the
same time
▪Forward: when the masking noise occurs before the stimulus
▪Backward: when the masking sound occurs after the stimulus
Guest speaker: Dr. Elizabeth Strickland:
•“Sensory systems adapt” – what does this mean? Give an example using the visual
system.
oas senses are exposed to a given stimulus, they become used to it or “immune” —
pupillary response: the pupils adapt to different amounts of light
•What is the medial olivocochlear reflex (MOCR or efferent feedback loop) in the
auditory system?
oit’s a reflex in the auditory system that allows adaptation to background noise
•What happens when this MOCR is activated?
oturns down the amplification of the outer hair cells
•In what kind of environment might this be helping us?
oenvironment with lots of background noise
•What does a typical experiment in her lab involve?
oa listener in a sound booth with headphones they are asked to report if they detect
given stimuli/differentiating which set is different, etc.
•Is a short tone easier to hear when it is near the onset of the masker or when it is delayed
from the onset of the masker?
odelayed from the onset of the masker so the auditory system has time to adjust
•What happens to this “temporal effect” with increasing hearing loss?
ono temporal effect with cochlear hearing loss, make ears less adjustable
Auditory development:
•What is the difference between an embryo and a fetus?
oembryo: first 8 weeks
ofetus: 8 weeks to birth
•What are the three primitive tissue layers?
oectoderm: outer layer, inner and outer ear
oendoderm: inner layer, middle ear
omesoderm: middle layer
•When does the development of the ear begin?
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o3rd gestational week
•When is the cochlea fully developed and functional?
o20 weeks
•Which parts of the ear are formed from
oThe ectoderm: inner ear, outer ear
oThe endoderm: middle ear
oThe mesoderm: bone, cartilage, muscle, organs
•When is the middle ear fully developed?
o32-37 weeks
•When is the outer ear fully developed?
o20 weeks
•When do babies start hearing?
o20 weeks
•What is the evidence that they hear in utero?
ofetal heart rate increases with sound stimulus
•How do newborns respond to sounds?
oarousal, gross body movements, orienting behavior (head turn, eye widening,
pupillary dilation), motor reflexes (facial grimaces), crying
•How do auditory behaviors develop over the first two years of life?
obirth-6 weeks: eye widening, blinking, stirring/arousal from sleep, startle
o6 weeks-4 months: quieting, rudimentary head turn
o4-7 months: head turn to side, listening attitude
o7-9 months: direct localization of sounds to the side
o21-24 months: direct localization of sounds at all angles
•How do speech and language develop over the first three years of life?
obirth-3 months: recognizes/soothes to voices, hears differences in speech sounds,
communicates through cooing and crying, reacts to sound sounds
o4-6 months: turns eyes to sound, recognizes own name, vocalizes to excitement
and displeasure, watches face of speaker, makes noise when talked to
o7-12 months: understands “no-no”, babbles, uses gestures to communicate, tries
to repeat sounds, begins using single words
o12-17 months: attention span a few minutes, follows simple directions
accompanied by gestures, points to objects/pictures/family members, says two or
three words to label things, tries to imitate simple words
o18-23 months: enjoys being read to, follows simple commands w/o gestures,
points to simple body parts, understands simple verbs, says 8-10 words, asks for
common foods, animal sounds, word combinations, begins using pronouns
o2-3 years: knows about 50 words by a year, speech is more intelligible, answers
simple questions, 2-3 word phrases, uses question inflection
•Why is it important for audiologists to be knowledgeable about typical speech and
language development?
oin order to make appropriate referrals and monitor language development because
hearing loss may delay language acquisition
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find more resources at oneclass.com
