Audiovestibular Flashcards
1
Q
what is the main function of outer hair cells?
They receive mostly efferent input, where does this come from?
A
amplify sound
superior olivary complex
2
Q
what are Tip links? Function?
A
- filamentous structures that connect the tips of adjacent stereocilia
- amplify the forces in the area of the molecular sensors
3
Q
How does sound enter cochlear
A
- Compression hits the tympanic membrane
- causing stapes to transfer force to the oval window
- sound travels down the scala vestibule (around helicotrima) to the scala tympani, allowing its fluid perilymph to mix
- from here sound moves to the round window
4
Q
Where are high/low frequency sounds encoded in the cochlear?
A
- high frequencies are encoded at the base
- low frequencies at the apex
5
Q
hair cells in ear are located between which membranes?
A
-basilar and tectorial
5
Q
hair cells in ear are located between which membranes?
A
-basilar and tectorial
6
Q
apex of hair cells are bathed in solution with ___ K+ content, whereas the base is ___ K+ content
A
- high K+ at apex
- low K+ at base
7
Q
apex of hair cells in in high K+ solution, base is low K+, how does the movement of these cells cause depolarisation? What does this depolarisation cause in turn at the basal end of the cell?
A
this causes opening of mechanosensitive channels allowing K+ to flow into the cell leading to depolarisation
- causes Ca2+ channels at base to open
- leads to vesicular neurotransmitter release that stimulates the nerve
8
Q
K+ is used for _____ by entering at the ___
and for ______ by leaving at the ___ in the hair cells of the ear
A
- depolarisation by entering at the apex
- repolarisation by leaving at the base
9
Q
Tuning fork frequency for rinnie and Weber’s test?
A
512 Hz
10
Q
Rinnie’s test normal finding when you ask, is the vibration louder in front of the ear or behind?
Normal is reported as what? normal result could also be due to what?
A
- normal is louder in front (i.e. air conduction is better than bone) could be a mild SNHL on that side
- normal is reported as Rinnie’s positive
11
Q
If on Rinnie’s test pt reports they hear the vibration louder behind the ear on mastoid than in front, what does this mean give 2 poss explanations and what you would say the result is?
A
=result is Rinnie’s negative
-conductive hearing loss on that side (or severe SNHL on that same side)
12
Q
Explain why a or severe SNHL on that same side can give a negative Rinnie’s test result (abnormal result, heard louder on bone than in front of ear)
A
- the ear tested is hearing nothing but
- the better hearing contralateral ear is picking up and hearing the sound as it is conducted through the skull bone
13
Q
Weber’s test, do you hear it louder on the left, the right or centre?
-If it lateralised to the left, give 2 poss explanations?
A
- left sided conductive hearing loss
- right sided (contralateral) SNHL
14
Q
Hearing loss in Db
- mild
- moderate
- severe
- profound
A
- mild 25-40
- moderate 45-70
- severe 75-90
- profound 95+
15
Q
What descriptive terms may we describe audiograms with?
A
- unilateral / bilateral
- symmetrical / asymmetrical
- degree of HL: mild/mod/severe/profound
- type: conductive, SNHL or mixed
16
Q
when can you say it;s asymettrical on an audiogram?
A
> 15dB difference in 2 consecutive frequencies
17
Q
4 RFs for age related presbycusis
A
- genetic predisposition
- low socioeconomic background
- noise exposure
- smoking
- HT
- DM
- Vascular disease
18
Q
3 ototoxic drugs
A
-quinine, aspirin, cisplatin, furosemide, macrolide antibiotics, iron chelators
19
Q
what doily noise level must ear protection be provided and worn by law
A
85 dBA
20
Q
What is temporary threshold shift(TTS)? What can repeated exposures to noises intense enough to cause this lead to ?
A
a form of noise-induced hearing loss (ringing in ears after=warning too loud) which is brief and occurs after noise exposure but completely resolves after a period of rest.
-can lead to a permanent threshold shift
21
Q
vestibular schwannomas
- describe
- how may present
- diagnosis
A
- benign, slow growing tumour from overproduction of schwann cells
- present: asymmetrical HL, tinnitus
- diagnosis: MRI of int. acoustic meatus
22
Q
define SSNHL (!)
A
-30dB HL over 3 consecutive frequencies occurring in <3days, most are unilateral and idiopathic, of these ~50% spontaneously recover
(bilateral often have identifiable cause)
23
Q
bilateral SNHL is a medical emergency, suggest an ix and a rx that may be trialled in someone presenting this way
A
- audiometry, MRI IAM, CT Petrous bones
- reducing course of high dose steroids
24
Tinnitus hx:
- characteristics
- bilateral, unilateral (!)
- how it affects patient
- triggers
25
Suggest 3 Exams for tinnitus:
- otoscopy and audiometry, bilat in associated with hearing impairment can refer for hearing aids if needed
- BP
- Auscultate for bruits, if pulsing in time with pulse could be vascular cause
- cranial nerve exam
- metabolic abnormalities
26
Red flags for tinnitus:
- Unilateral
- Pulsatile
- Asymmetrical hearing loss
- Dizziness
- Unexplained neurological symptoms
27
Tinnitus management:
- advice, reassurance
- sound enrichment
- relaxation/stress reduction techniques
- referral for hearing therapy
- hearing aids
28
2 ear conditions lead to notch like appearance (different types of notch) on audiometry, what are these?
- otosclerosis (poor quality spongy bone-more lucent on CT, doesn't send vibrations as effectively across) causing a conductive hearing loss with a characteristic notch
- noised induced hearing impairment --> notched hearing loss that starts ~3-4kHz
29
What is used to screen simply for hearing impairment in babys?
-Automated oto-acoustic emissions, quick simple, non-invasive
30
What does distraction testing in children use
-not having object permanence awareness
31
What happens in visual reinforcement audiometry
- boring distraction in front of child
| - teach child to turn to an interesting reward e.g. buzzing puppet
32
What autosomal dominant syndrome presents with mid-facial bone hypoplasia and external auditory atresia causing a _____ hearing loss?
- Treacher-Collins Syndrome
| - Conductive
33
Branchio-renal syndrome suggest 2 fts and what inheritence?
- Autosomal dominant (EYA1 gene mutation)
- progressive hearing loss
- preauricular pits
- branchial cysts/fistulae
- renal hypoplasia
- widened vestibular aqueducts
34
Pendred syndrome is associated with a widened _____ ____ and a euthyroid ____ develops in late teens
-hearing loss is usually
- vestibular aqueduct +/- cochlear hypoplasia
- goitre
- severe congenital bilateral sensorineural HL
35
What should children with Pendred syndrome avoid and why?
- avoid contact sports
| - minor head trauma can trigger a stepwise progression of the widened vestibular aqueduct,
36
Cleft lip doesn't affect hearing but cleft palate does, what pts is this common in, leading to what presentation?
- Down's Syndrome
| - Blocked Eustachian Tube leads to middle ear effusion so child presents with Glue Ear
37
Causes of SNHL in children can be non-syndromic or syndromic, name 1 non-syndromic cause:
CMV
Genetic
Idiopathic
38
Causes of SNHL in children can be non-syndromic or syndromic, name 2 syndromic causes:
Waardenburg Syndrome
Sticklers Syndrome
Jervell Lange Nielson Syndrome
39
What is the commonest cause of childhood SNHL
| -It is treatable, what is used?
Congenital CMV infection
| Valgancyclovir
40
CMV. If women infected for 1st time during pregnancy ~1/3rd pass the virus to their fetus, how do most women catch CMV?
How to avoid it?
- from the saliva and urine of small children passed to pregnant women
- don't share eg. food/drinks/cutlery/dummies
- avoid kissing on mouth
- wash hands/face/child with soap and water
41
How can congenital CMV be diagnosed in first 3weeks of life?
-saliva/urine/blood test, Guthrie blood spot test
42
Non-syndromic hearing loss is not associated with other signs/symptoms.
Numerous genes have been found to cause it, most are which inheritance pattern? Most common cause?
- Most are autosomal recessive pattern
| - connexin 26 AR non-syndromic deafness
42
Non-syndromic hearing loss is not associated with other signs/symptoms.
Numerous genes have been found to cause it, most are which inheritance pattern? Most common cause?
- Most are autosomal recessive pattern
| - connexin 26 AR non-syndromic deafness
43
-connexin 26 caused AR non-syndromic deafness causes HL how?
- connexin 26 codes for a gap junction in the outer hair cells, affects how K+ flows through the cell
- severity variable but often --> profound HL
44
What is the most common complication of meningitis esp bacterial? What should you refer for regardless?
What can occur as a sequela of inflammation of the inner ear that must be picked up asap or risk losing hearing speech for life?
- hearing loss
- refer for a hearing assessment asap post-discharge
NB: labyrinthitis ossificans (thickening of the cochlear bones -means can't insert an electrode for cochlear implant so time is of the essence)
45
Jevel and Lange-Nielsen (vestibular areflexia and delayed motor milestones) leads to congenital profound bilateral SNHL, what is screened for when children present with this HL and why, how can we treat?
-screen for a long QT interval
-with hope to treat to prevent sudden cardiac death
-treat with Beta-blockers and ICD
NB: it is autosomal recessive (KCNQ1 and KCNE1 genes)
46
Bilateral vestibular schwannoma's are associated with what?
Neurofibromatosis type 2
47
Name 3 features of Sticker Syndrome:
- Hearing loss (mixed)
- short sighted (myopia), -retinal detachment, -cataracts
- mid-facial hypoplasia, -bifid uvula
- premature arthritis
48
3 Features of Osteogenesis Imperfecta (AD) defect in collagen :
- fractures, skeletal deformity
- blue sclera
- poor dentition
- progressive hearing loss (ossicles in middle ear affected)
- ligament laxity
49
A white forelock is associated with which Syndrome? Due to failure of proper what? What type of HL? Eye appearance? Management?
Waardenburg
- failure of proper melanocyte differentiation
- mod-profound SNHL
- pale blue eyes/heterochromia, down sloping eyes
- manage with hearing aid/cochlear implant and skin/eye photo-protection
50
Alport syndrome is due to a mutation in type __ ____ genes which affects the ____ ____ of the kidney and is mostly ____ inheritance
Fts: heamaturia, proteinuria and HT, and ~50% have ___ deafness by 25yrs
- type IV collagen
- basement membrane
- X-linked
- sensorineural
51
How may pts describe being dizzy? What about true vertigo definition?
- dizzy: lightheaded, giddy, faint, spinning, floaty
- vertigo: self motion (internal spinning) or world motion (room spinning) can also feel like being pulled sideways orlike a room is tilting
52
Name 4 otological causes of dizziness/vertigo:
- trauma, -infection
- vascular, -Meniere's
- autoimmune disease
- ototoxicity, -metabolic bone
- vestibular structural abnormalities
53
Name 4 neurological causes of dizziness/vertigo:
- CNVIII nerve disorders
- brainstem, cerebellar, basal galglia disease
- cerebrovascular
- migraine
- MS
- trauma, infection
- epilepsy
54
What in the ear is responsible for spatial rotation movements? How many do we have?
- semicircular canals
| - we have 3 on each side
55
What is the function of the utricle and saccule?
Otolith organs: tells where your body is in respect to gravity
- utricle: horizontal acceleration
- saccule: vertical acceleration
56
what happens in BPPV ? (benign paroxysmal positional vertigo)
The otoconia displace especially if looking up/down/side, causing severe short lasting vertigo
57
Name 3 functions of the vestibular system and parts responsible:
Motion sensors of the head for..
- rotation (semicircular canals)
- linear acceleration (otolith organs)
- gravity (otolith organs)
58
Explain the vestibulo-Ocular Reflex (VOR): (responsible for maintaining gaze/stabilising vision on a certain point) e.g. if you turn your head to left..
- if you move head to left, left inner ear is stimulated, this sends signals to the vestibular nucleus in brainstem, sends signals to CNIII and CNVI nuclei so
- medial rectus causing inward eye movement
- lateral rectus causing outward eye movement
59
What reflex co-ordinates head and trunk movements to maintain head how?
- vestibular-spinal reflexes
| - maintains head in an upright position
60
What is vestibular nystagmus? Which phase is the direction?
- involuntary to and fro movement of eyes (will have diplopia or vertigo)
- has a fast phase and a slow phase
- direction of the fast phase is the direction of nystagmus
- slow phase is produced by the vestibular system
61
Suggest q's for a vertigo history:
- duration (seconds/hours?), -positional
- associated neuro sx (!) e.g. dysarthria, numbness, weakness
- new headache
- auditory/cochlear (hearing loss/tinnitus), -recent viral infection
- previous vertigo, -vascular RFs, -Family hx
62
What examination should you do w a pt presenting with vertigo?
- otoscopy (infection, vesicles - R. Hunt s.)
- eye movement (CN III, IV, VI)
- HINTS Plus (head impulse test, NT-nystagmus type, test of skew deviation) and Hall pike positional test for diagnosis of BPPV.
- cerebellar function
- CNs V, VII
- Gait: Romberg, Unterberger's and Tandem gait (heel-toe)
63
What is a catch up saccade in the context of the Head Impulse Test? What will pt experience?
An abnormal result where by the eyes lag and catch up to focus on the target as the VO reflex is not working
- everything moves up and down or side to side, so can't stabilise gaze, worse on walking, feel unsteady, off balance
- known as oscillopsia
64
HINTS criteria (head impulse, nystagmus, test of skew deviation) generally if head thrust is abnormal, and nystagmus is unilateral and there is no skew deviation, it indicates what? What is the 1 exception?
A peripheral problem (e.g. inner ear)
| -AICA infarct (anterior inferior cerebellar artery infarct - supplies labyrinth can --> hearing loss)
65
BPPV key fts:
- most common cause of vertigo
- posterior semicircular canal (where ca2+ crystals end up) is most affected
- can be spontaneous or 2ndry to head injury, whiplash, post vestibular neuritis
- typical nystagmus,
- Hallpike test to diagnose
- particle repositioning manoeuvres - Epley to treat
- recurrence
66
What is acute vestibular neuritis's features? onset? sx? in head thrust how to know which ear is the abnormal one?
- sudden onset
- acute vestibular sx (nausea, vomiting, unsteady walk)
- +/-prodromal viral URTI
- symptomatic recovery by central compensation
- recovery influenced by: age, vision, proprioception, mental health, usually recover ~1week
- whichever side you move the head to that causes the eye abnormality (catch up saccade) is the side of the affected ear
67
What is meniere's aka endolymphatic hydrops?Triad of what? Fts? what may precede it?
- fluctuating low frequency hearing loss, severe vertigo and roaring tinnitus
- recurrent episodes with initial episodes usually worse
- preceding aural pressure common
- treat w diet, medication or surgery
68
What is the management for meniere's aka endolymphatic hydrops?
- lifestyle:
- acute attack relief:
- prophylaxis:
- surgical: if severe/rx refractory
- lifestyle: reduce salt and caffeine
- acute attack relief: cinnarizine, prochlorperazine, cyclizine
- prophylaxis: betahistine, diuretics e.g. bendroflumethiazide
- surgical: trans-tympanic gentamicin or steroids, endolymphatic sac surgery, vestibular neurectomy, labyrinthectomy
69
Migraine related vertigo can mimic/co-exist w Meniere's, fts? What should be avoided in these pts?
NB: this is common and is often under-diagnosed, consider in anyone w Migraine + spontaneous episodic vertigo
- classical migraine and family hx
- episodic with symptom free periods
- usually has other fts of migraine, -can be present with or without headache. -Treat as for classical migraines
- often have motion sensitivity
- AVOID OPIATES
70
Post-traumatic Vertigo after a head injury is v common, what is often the cause that could be treated? rx depending on primary contributor e.g..
- lots are due to BPPV or due to vestibular migraine (most are central vestibular gait apraxia related)
- e.g. treat w Epley/semont manoeuvre, treat w vestibular rehabilitation or with migraine prophylaxis
71
What is PPPD? Persistent postural-perceptual dizziness? rx?
- common chronic dysfunction of vestibular system and brain often w anxiety, avoidance, disability..
- persistent dizziness, non-spinning vertigo +/-unsteadiness
- treat w CBT, SSRIs, vestibular rehab and physiotherapy
72
Name 2 syndromes that cause vertigo:
- Usher's Syndrome
- CHARGE
- BOR
- Multisensory dizziness syndrome
73
What is -Multisensory dizziness syndrome ? suggest areas affected and how to treat this?
- reduces inputs from >1 sensory system
- seen in elderly and those w systemic disease e.g DM
- typical combo e.g. reduced visual acuity (glaucoma/cataract), peripheral neuropathy, impaired hearing, vestibular hypofunction
- unable to adapt to unfamiliar surroundings
- rx by improving sensory input e.g. surgery for cataract, good DM control, hearing aids, use cane/walker and avoid sedatives!
