Case 4 - Hearing and Speech Development Flashcards
when do structures of the neurosensory ear develop
around 20 weeks gestation
what happens at 25 weeks
we have a functional auditory system
at 25 weeks to 5-6 months we have what
hair cells of the cochlea
axons of the auditory nerve
neurones of the temporal lobe auditory cortex are tuned to receive signals of specific frequencies and intensities
what is the organ of hearing
cochlea
what is the organ of balance
the vestibular system
what can we see through a healthy tympanic membrane
the malleus, and the incus
what is the cord of tympani important in
taste
what is the role of the middle ear
conduction
protection
transducer
amplifier
conduction in the middle ear
conduct sound form the outer part of the ear to the inner ear
protection in the middle ear
creates a barrier to protect the muddle and inner ear structures from foreign bodies
transduction in the middle ear
converts acoustic energy to mechanical energy
converts mechanical energy to hydraulic energy
amplification in the middle ear
transformer action of the middle ear
only about 1/1000 of the acoustic energy in air would be transmitted to the inner ear fluid without the middle ear function
what is another name for the inner ear
the labyrinth
where is the inner ear found
the petrous portion of the temporal lobe
what is the inner ear made up of
the cochlea and vestibular system
how many turns foes the cochlea have
2 and a half
what does the saccule do
helps with balance when not moving and standing still
what do the semicircular canals do
help when we are in movement
what is the function of the cochlea
is to propagate sound waves from the base which is situated near the middle ear
physiology of hearing
sound waves will travel down the external auditory canal and hit the tympanic membrane
the tympanic membrane will move which will cause some vibrations of the ossicles
this will create some mechanical energy which will in turn move towards the stapes
this vibrates and this then creates some movement in the fluid in the cochlea
this energy is transducer into electrical energy which then goes on to the nerve of hearing
why do different parts of the cochlea pick up different frequencies
because there is movement of fluid against the basilar membrane which has stiffness at different parts
what is Wernicke’s area
temporal
speech comprehension
what is Broca’s area
frontal
production of speech
what is sound measured in and what Is the scale measured in
sound measured in decibels
the decibel scan itself is logarithmic
what is severe hearing loss
70-90dB
what is profound hearing lossn
90-120d
what is normal range of hearing
10-20dB
what is the hearing test used at 6-24 months
visual reinforcement audiometry
what is the hearing test used after 24 moths
conditional play audiometry
what is the hearing test used for after 36 months
conventional audiometry
when are objective measures used
less than 6 months
what is included in the visual reinforcement audiometry
toy is put in front of a child to keep their attention and they are focusing on that and they produce a sound to the side
if the child hears the sound they will turn toward the sound and will get positive reinforcement
conditioning them to turn their head if they hear another sound
what is included in conditioned play audiometry
ear specific audiometry white is quite useful
they are conditioned to perform a task when they hear a sound
what is conventional audimetry
ear specific audtimetry
we can test air conduction and also bone conduction
what does bone conduction test
the nerve of hearing
what does air conduction test
the conductive element of hearing
what is speech audiometry
tests the ability to recognise and understand speech
what is the HINT test
hearing in noise test
what is the SPRINT test
speech recognition in noise test
what is the WINT test
words in noise test
what hearing test is performed on a new born
automated otoacoustic emission OAE
how does an OAE work
the normal cochlea has a sound amplification mechanism, whereby the outer hair cells amplify basilar membrane movement in response to sound.
you put a probe in a baby’s ear and when the cochlea reacts it is picking up that reaction
robust result considered to be about 20dB hearing or better
what happens if baby fails initial OAE
they will have another OAE in the next few days or weeks and if they fail again they will go on to have an ABR which is an auditory brainstem response test
what does the auditory brainstem responses test test
eighth nerve
cochlear nucleus
superior olivary nucleus
lateral leminiscus
inferior colliculus
what is amplitude
the number of neurones fired
what is latency
the speed of transmission
what is inter peak latency
the difference in wave 5 latency between the two ears
what is speed
the way we say something
what is language
the form, meaning and use of the words and utternace
what is neuroplasticity
the brains ability to change through experience
under 6 months
pre verbal
- crying, gestures
- hungry, tired, hot, cold, pain
2 months:
coos and gurgles
3 months
fixed on sound and calms to familiar voices
6-10 months
able to express pleasure and displeasure. child can distinguish sounds of any language and reproduce this. (lost by age 11)
commutations by sounds and intonations
6-12months
begin by detecting very small differences between speech and speech sounds (phonemes)
at 6 months they can contract different vowel phonemes
1 year
one word stage - mainly morphemes
at end of first year, should be able to understand about 50 words and say around 5
learns words which produce effect - again and more etc
18 months
- two word phrases
- should have 20-50 words
- naming
- demanding
-questioning
2.5 years
- simple sentences
- lack tenses
- error in syntax
- recognition of rhyme and intonation
- 200-300 words
2.5-5 years
- improvements in phonemes
- development of pronunciation and articulation
6-10 years
- master syllable stress to distinguish between similar words
when do pre-lingually deaf children get implants
- prescribe hearing aids before 3 months
- implant before 4 years, ideally at 12 months
post-lingually deaf adults
have sound memory
have used hearing aids to optimise hearing
already know how to speak and use language
what happens after the period of neuroplasticity
the cochlear implantation does not improve hearing or speech
