Neuropathology of the Inner Ear Flashcards

1
Q

What are the central (ascending) pathways ?

A

a complex network of cells in the brain that receive the signal from the ear sensory cells

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2
Q

What are the auditory reflexes (descending pathways)

A

the motor output of the auditory system. The idea of turning the head via neck muscles towards or away from sounds

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3
Q

What is the BAER and what is it used for.

A

Brainstem Auditory Evoked Response

used for investigating deafness
results appear on a graph as the 6 major wave forms. no perception of hearing at all appears as a flatline

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4
Q

What are the two types of deafness ?

A

conductive –> obstruction of the passage of sound or mechanical injury

sensorineural –> an abnormality in the receptor organ or neurons of the cochlear division of CV VIII, may be congenital or acquired

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5
Q

What is the vestibular disease and its function

A

It is made up of the extensor muscles, extra-ocular eye muscles, 2 receptors (crista ampulla and macula), sensory hair cells

maintains the body in equilibrium by …
- maintaining eye position despite head
- maintaining body position relative to the horizon
- maintaining body posture relative to the horizon

it works to regulate movement, keep objects in visual focus and respond to visual information.

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6
Q

Describe the CS of vestibular syndrome

A

falling, rolling, tilting of the head, circling, nystagmus, ataxia and vomiting

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7
Q

What is the difference between central and peripheral vestibular disease?

A

Central –> lesion of the brainstem.
- dull demeanour
- very quiet
- not correcting foot position
- tilting the head
- staggering to the side

Peripheral –> lesion of the neurological components or anatomic components
- walk just fine
- slight head tilt (spontaneously)
- spontaneous nystagmus
- mentally alert

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8
Q

Define paradoxical vestibular disease

A

a subset. the problem is inside the cerebellum, causing a loss of inhibitory influence - the animal leans the wrong way (away from the lesion instead of towards it)

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9
Q

Define bilateral vestibular disease

A

caused by metabolic, toxic or anomalous issues, leading to wide searching head movements with low body carriage

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