Case 4 - Audition Flashcards

1
Q
  1. What are some of the social consequences of hearing loss?
  2. What are some of the psychological consequences of hearing loss?
  3. What aspects of social exclusion do they suffer from?
A
  1. Social and behavioral difficulties, dependency, restricted opportunities
  2. Victims of abusive language, higher levels of stress, higher levels of mental health problems
  3. Social isolation, lack of education, and poverty
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2
Q
  1. What is attention?
  2. What are the 3 elements of attention?
  3. What is alerting?
  4. What is orienting?
  5. What is selection?
A
  1. Selecting for active processing of specific aspects of your environment
  2. Alerting, orienting, and selection
  3. Change in internal state of individual in preparation for perceiving a stimulus
  4. Selection of information from sensory input i.e. moving towards the target etc.
  5. Choosing among multiple conflicting actions or responses
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3
Q
  1. What are the 4 different types of attention?
  2. What is sustained attention?
  3. What is Selective attention?
  4. What is alternating attention?
  5. What is divided attention?
A
  1. Sustained attention, selective attention, alternating attention, divided attention
  2. Ability to keep focus for long periods of time even if exposed to repetitive actions or activity e.g. learning
  3. Selecting aspects when confronted with multiple stimuli
  4. Ability to switch or transfer focus from one activity to another
  5. Ability to focus on 2 or more stimuli simultaneously
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4
Q

Define the following:

  • Sound
  • Frequency
  • Hertz
  • Pitch
  • Intensity(Amplitude)
A
  • Variations in air pressure which are audible
  • Number of compressed pathces that pass by an object (ear) each second
  • Number of cycles per second
  • Tone - determined by the frequency
  • Difference in pressure between compressed and rarefied patches of air. Determines loudness.
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5
Q
  1. What is the range of sound humans can hear?
A
  1. 20Hz to 20,000Hz
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6
Q

Identify the following:

  • Pinna
  • Auditory canal
  • Ossicles (M,I,S)
  • Oval window
  • Cochlea
  • Tympanic membrane
  • Round window
  • External acoustic meatus
  • Helix
  • Antihelix
  • Auricular lobe
  • Semicircular canals
  • Eustachian tube
  • CN VIII
  1. Where is each found?
A

Outer ear

  • Pinna
  • Auditory canal

Middle ear

  • Ossicles (M,S,I)

Inner ear

  • Oval window
  • Cochlea
  • Tympanic membrane
  • Round window
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7
Q
  1. What moves in the ear to start the process of audition?
  2. After the TM is moved what happens?
  3. What do the Ossicles do to sound waves?
  4. Which is larger the TM or the oval window?
A
  1. Tympanic membrane
  2. Ossicles vibrate, and move the oval window
  3. Amplify them
  4. Tympanic membrane
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8
Q
  1. What is the attenuation reflex?
  2. Which muscles are involved?
  3. Why do we need the attenuation reflex?
  4. Is it instantaneous?

Identify:

  • Stapedius muscle
  • Tensor tympani muscle
A
  1. Muscle contraction in the middle ear, making the ossicles rigid.
  2. Tensor tympani & Stapedius muscles
  3. To protect the inner ear from damage
  4. No, takes time so damage can occur with fast and very loud sound
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9
Q
  1. What is the function of the eustachian tube?
  2. How is it kept closed?
  3. What can be done to equalise middle ear pressure?
A
  1. To maintain the pressure in the middle ear, as it is continuous with the nasal cavities
  2. Valve
  3. Yawning or swallowing - opens the ET
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10
Q

In the inner ear, identify:

  • Oval window
  • Round window
  • Scala vestibuli - what does this contain?
  • Scala media - what does this contain?
  • Reissners membrane
  • Basilar membrane
  • Scala tympani - What does this contain?
  • Helicotrema - what is this?
  • Organ of Corti
  • Tectorial membrane
  • Stria Vascularis
  • Spiral ganglion
A

Scala vestibuli & tympani - contain perilymph

Scala media - contains endolymph

Helicotrema - Where the scala tympani becomes continous with the scala vestibuli

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11
Q
  1. What makes endolymph and periplymph different?
  2. What maintains the ionic content?
A
  1. Endolymph has a high K+ content
    1. Perilymph has a high Na+ content
  2. Stria vascularis
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12
Q
  1. Where is the base of the basilar membrane?
  2. Which part of the basilar membrane is wider?
  3. Which part is more stiff?
  4. Movement of which fluid causes the BM to bend?
  5. High frequency waves cause what?
  6. Low frequency waves cause what?
  7. What does this establish for the brain?

Identify:

  • Base of basilar membrane
  • Apex of basilar membrane
A
  1. Base is closest to the oval window
  2. Apex
  3. Base
  4. Endolymph
  5. Base of the membrane vibrates a lot, dissipates energy
  6. Wave travels all the way to the apex, before energy dissipated
  7. Tonotopy - place code
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13
Q

In the organ of corti, identify:

  • Outer hair cells
  • Inner hair cells
  • Rods of corti - what is their function?
  • Supporting cells
  • Spiral ganglion
  • CN VIII
A

Rods of corti - provide structural support

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14
Q
  1. What happens in the organ of corti?
  2. What do hair cells do?
  3. What are hair cells (Type of cell)?
  4. How is sound transduced?
A
  1. Where auditory receptor cells (Hair cells) are found
  2. Convert mechanical energy into change in membrane potential
  3. Specialised epithelial cells
  4. Bending of hair stereocilia leads to sound transduction
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15
Q

On the hair cells, identify:

  • Stereocilia
    1. What differentiates inner hair cells from outer hair cells?
A
  1. IHC - stereocilia are just below the tectorial membrane
    1. OHC - stereocilia are within the tectorial membrane
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16
Q
  1. What do the hair cells synapse with?
  2. What does CN VIII project to?
A
  1. Spiral ganglion
  2. Cochlear nuclei in Medulla (Brainstem)
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17
Q
  1. Movement of which membrane is necessary for transduction?
  2. What is found on the tip of the hair cells?
  3. Which position makes it generate a hair receptor potential?
A
  1. Basilar membrane
  2. Specialised ion channel, which opens and closes by bending of sterocilia
  3. Ion channel is open
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18
Q
  1. What does movement of the tip link lead to?
  2. What ion moves into the cell?
  3. What does this lead to?
  4. What NT is released? To what cell?
A
  1. Increased tension, and rate of channel openings
  2. K+ (Depolarisation)
  3. Activation of Ca+ voltage gated channels - entry of Ca+
  4. Glutamate - to the spiral ganglion cells
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19
Q
  1. When the movement of the tip link is in the opposite direction?
  2. What does this lead to?
  3. What happens to the ions?
  4. What kind of channel is the tip link channel?
A
  1. Relieves tension on tip link
  2. Channels spend more time closed
  3. Reduced inward movement of K+
  4. Mechanically gated (Physically opened)
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20
Q
  1. How many hair cells does a spiral ganglion synapse with? (Inner and outer)
  2. How do OHC’s amplify sounds?
  3. What are the 2 motor proteins?
A
  1. Inner - 1 hair cell, Outer - Numerous
  2. Motor proteins change length of the hair cells to amplify the movement of the basilar membrane
  3. Prestin & Myosin
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21
Q
  1. Where do the afferents from the spiral ganglion go?
  2. Which nuclei do they go to? On which side?
A
  1. Via CN VIII to the medulla
  2. Ipsilateral cochlear nuclei (Dorsal & Ventral)
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22
Q
  1. Where do the axons from the ventral cochlear nucleus go to?
  2. Where do the olivary nuclei axons go?
  3. Where is the inferior colliculus?
A
  1. Superior olivary nucleus bilaterally
  2. via Lateral leminiscus to the Inferior colliculus
  3. Midbrain
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23
Q
  1. Where do the axons of the Dorsal cochlear nucleus go?
  2. Where does the inferior colliculus send axons to?
  3. Where is this found?
A
  1. straight to the inferior colliculus of midbrain
  2. Medial geniculate nucleus
  3. Thalamus
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24
Q
  1. Where does the MGN project to?
  2. What are the accessory projections?
A
  1. Auditory cortex (Temporal lobe)
  2. Superior colliculus & Cerebellum
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25
Q
  1. How are the inner hair cells selective?
  2. What is the characteristic frequency?
A
  1. They are found at a particular location on the basilar membrane, and only fire AP’s in response to sound in a limited frequency range
  2. Frequency that the neurons are most responsive to
26
Q
  1. How is stimulus intensity coded? (2)
  2. What do more intense stimuli cause?
  3. What is loudness percieved correlated with?
A
  1. Firing rate of neurons and number of active neurons
  2. More intense stimulus causes more BM vibration and so increased membrane potential change
  3. Number of active hair cells as more are activated
27
Q
  1. What frequencies are characteristic of the apical basilar membrane?
  2. What frequencies are characteristic of the basal basilar membrane?
A
  1. Low frequency
  2. High frequency
28
Q
  1. What is Tonotopy?
A
  1. Different frequencies lead to different maximal deformations of the basilar membrane so this allows for recognition of frequency
29
Q
  1. What is created in the cochlear nuclei by tonotopy?
  2. What is phase locking?
A
  1. Organised pattern based on characteristic frequencies
  2. Consistent firing of a cell at the same phase as the sound wave
30
Q
  1. When do phase locked neurons fire AP’s?
  2. What is the maximal level for phase locking?
  3. What happens after this level?
  4. What is then used?
A
  1. At peaks or troughs of the waves, to convey the timing of the wave
  2. 5000 Hz
  3. AP’s generated randomly as too fast for AP’s to represent timing
  4. Tonotopy
31
Q
  1. What is Interaural time delay?
  2. When is this not effective?
A
  1. Localisation based on the time at which the sound arrives in each ear
  2. When the sound frequency is so high that 1 cycle of sound is smaller than distance between ears
32
Q
  1. What is interaural intensity difference?
  2. What is the frequency the human ear is most sensitive to?
A
  1. Using the head shadow to locate sound, used for higher frequency sounds
  2. 2000 to 5000 Hz
33
Q
  1. What is the function of the vestibular system?
  2. What is the function of the otolith organs?
  3. What is the function of the semicircular canals?
A
  1. Identify the location of our head in space
  2. Detecting linear acceleration
  3. Detecting angular acceleration
34
Q
  1. What 2 organs make up the Otolith organs?
  2. What is the macula?
  3. What are Otoconia?
A
  1. Utricle & Saccule
  2. Contains hair cells which are used for orientation
  3. Crystals of Calcium Carbonate
35
Q
  1. Identify:
  • Macula
  • Otoconia
  • Kinocilium
A

1.

36
Q
  1. When force is exerted which direction do the otoconia move?
  2. What moves?
  3. What does this do to the cilia?
A
  1. Same direction as the force
  2. Gelatinous cap
  3. Bends them
37
Q
  1. What happens when the hair cells are bent toward the kinocilium?
  2. What happens when they bend away from the kinocilium?
  3. What is significant about each macula?
A
  1. Depolarisation
  2. Hyperpolarisation
  3. Each one is direction specific, so allows to differentiate movement
38
Q
  1. What happens to the hair cells in the opposite ear?
  2. What does the Utriccle detect?
  3. What does the saccule detect?
A
  1. The hairs bend in the opposite direction, so you have the opposite effect
  2. Horizontal acceleration
  3. Vertical acceleration
39
Q
  1. What is the angle between each semicircular canals?
  2. What movements do they detect?
  3. What is the organ here called?
A
  1. 90 degrees
  2. Pitch, roll, yaw (Rotational movements)
  3. Ampulla & Cupulla
40
Q
  1. What happens when there is angular movement?
  2. What does this cause?
  3. What happens when there is deflection towards the kinocilium? And away from it?
A
  1. Endolymph displaces the gelatinous mass displacing the cupula
  2. Change in K+ concentration, due to opening or closing of channels
  3. Increased firing so increased K+, Decreased firing
41
Q
  1. What is NT used by these neurons?
  2. What happens when the canal is rotated round its axis?
A
  1. Glutamate
  2. Canal and cupula spin, and endolymph stays due to inertia (Exerting force on cupula)
42
Q

Identify:

  • Crista
  • Ampulla
  • Cupula
  • Kinocilium
  • Endolymph
A
43
Q
  1. Which movement is perceived by the superior SC? Posterior? Horizontal?
  2. Where do the vestibular axons from CN VIII go to? Which side?
  3. What are the relevant tracts?
A
  1. Roll, Yaw, Pitch
  2. Vestibular nuclei (Ipsilateral)
  3. Vestibulospinal tract & Medial longitudinal funinculus
44
Q
  1. What is the vestibulo-occular reflex?
  2. Which input is it triggered by?
A
  1. Keeps eyes oriented in direction, when body is moving in another
  2. Vestibular input
45
Q
  1. Where does the afferent signal originate?
  2. Where does it go to?
  3. Which nerve controls the eye muscle?
  4. Which tract is relevant?
A
  1. Scarpa’s ganglion
  2. Medial vestibular nucleus
  3. Abducens nerve (Contralateral)
  4. Medial longitudinal fasciculus to CN III
46
Q
  1. What is Nystagmus?
  2. What would dysfunction in the slow phase mean?
  3. What would dysfunction in the fast phase mean?
A
  1. alternatiting slow eye movement, with rapid saccadic movement
  2. Lesion in the vestibulo-occular pathway
  3. Lesion in the higher brain centers
47
Q
  1. What is Menieres disease?
  2. What is benign paroxysmal positional vertigo?
A
  1. Increase in endolypmh pressure which causes disruption of signal transduction - Tinnitus, nausea, and nystagmus
  2. Disloged otolith which causes vertigo
48
Q
  1. Can a person with post lingual deafness hear again with a cochlear implant?
  2. Can a person with pre lingual deafness hear again with a cochlear implant?
A
  1. Yes
  2. No
49
Q
  1. What does the gene DFNB1 lead to?
  2. How is it inherited?
A
  1. Non-syndromic hearing loss and deafness, congenital. Causes sensorineural hearing loss
  2. Autosomal recessive
50
Q
  1. What are the tonsils?
  2. What is tonsilitis?
  3. Which pathogens usually cause it?
  4. Treatments?
A
  1. Lymphoid tissue
  2. Inflammation of the pharyngeal tonsils
  3. Group A haemolytic streptoccous, or herpes simplex
  4. Corticosteroids or Tonsilectomy (If chronic)
51
Q
  1. What is otitis media?
  2. What is it caused by?
  3. Which tonsil can also cause it?
A
  1. Inflammation of middle ear
  2. Dysfunction of the eustachian tube due to edema or negative tympanic pressure
  3. Enlarged adenoid
52
Q
  1. What test is used to measure air conduction?
  2. What test is used to measure bone conduction?
  3. What dB range is normal hearing?
A
  1. Pure tone audiometry or vibrating tuning fork in front of ear
  2. Tuning fork placed on the head
  3. 0-25 dB
53
Q
  1. What is conductive hearing loss?
  2. What is the result?
  3. What can cause it?
A
  1. Normal bone conduction, Poor air conduction
  2. Reduced effectiveness of air conduction, but doest affect bone conduction as the middle ear can be bypassed
  3. OM or blockage of the external auditory meatus
54
Q
  1. What is sensorineural hearing loss?
  2. What causes it?
A
  1. Bone conduction and air conduction are very close to each other but reduced, higher than 25dB
  2. Cochlear abnormalities, or problem with transmission of sound to brain.
55
Q
  1. What is mixed hearing loss?
  2. What will be the result if tested?
A
  1. Where there is both conductive and sensorineural loss
  2. Air conduction is lower than bone conduction, and bone conduction threshold is less than 25dB
56
Q
  1. What is a tympanogram?
  2. What do the following show?
  • A
  • B
  • C
  • AD
  • AS
A
  1. Tests middle ear function, and compliance of the tympanic membrane to changing air pressures
  • Normal middle ear
  • Middle ear effusion, blocked
  • Eustachian tube dysfunction
  • Highly compliant middle ear system (Flaccid)
  • Less compliant middle ear system (Less mobility)
57
Q
  1. What is the Webers test?
  2. What must the patient report?
  3. What is a normal result?
A
  1. Place tuning fork in middle of forehead equidistant from ears.
  2. Which ear the sound is louder in?
  3. Sound is = in both ears
58
Q
  1. If the defective ear hears it louder?
  2. If the normal ear hears it louder?
  3. Can this test be used if the defective ear is not known?
A
  1. Conductive hearing loss in the defective ear
  2. Sensorineural hearing loss in the defective ear
  3. No, use Rinne’s test
59
Q
  1. What is the Rinnes test?
  2. What is a normal result (Positive)?
  3. What is an abnormal result (Negative)?
A
  1. Tuning fork placed on mastoid process behind each ear, when sound not heard. Move outside the ear. Patient reports when they cant hear the sound
  2. Sound heard outside ear is louder than head when on bone (AC>BC)
  3. Sound is louder on bone than in air (BC>AC)
60
Q
  1. What is the Rhinne’s test used for?
  2. What is the Webbers test used for?
A
  1. Conduction testing
  2. Localisation of the defect
61
Q
  1. What are otoacoustic emissions?
A
  1. Used to check cochlear function, objectively