Praxis Random Chp7 Part 2

What is vestibular neuritis?

infection/inflmmation of vestibular nerve

What branch of the vestibular nerve is most often impacted in cases of vestibular neuritis?

superior branch (seen impacts on tests testing this branch (lat SCC calorics, vHIT, rotary chair, utricle oVEMP)

Vestibular neuritis is suspected with what symptoms?

acute onset vertigo, nausea/vomiting, generalized imbalance

acute phase lasts hours to days, generalized imbalance may linger for weeks

No HL or tinnitus associated with vestibular neuritis

What is labyrinthitis?

infection/inflammation of inner ear labyrinth and/or CN VIII, similar presentation to vestibular neuritis with concurrent HL and tinnitus

What is vestibulotoxicity?

Vestibular hair cell death caused by medication or chemicals

What is the clinical presentation of vestibulotoxicity?

Bilaterally reduced VOR performance (mild to areflexia)

Reduced otolith reflex pathway responses

Reported oscillopsia, imbalance

w/ or w/o HL and tinnitus

What is BPPV?

benign paroxysmal positional vertigo; most common peripheral vestibular pathology

Caused when otoconia in utricle is dislodged and migrates into SCC, causing the SCC to become sensitive to gravity

Which SCCs are most often impacted by BPPV?

Posterior (90%) - ID by Dix-Hallpike

Lateral (10%) - ID by lateral roll

Anterior is very rare, suspected to more due to failed canalith repositioning

What is the clinical presentation of posterior SCC BPPV?

Symptom latency 1-10 seconds after provoking movement

Symptom duration <1 min

Torsional up-beating nystagmus beats towards underneath ear, changes direction when patient sits up

Nystagmust and symptoms fatigue with repeated evaluation or repositioning

What nystagmus would you see with posterior SCC BPPV in the right ear?

Up-beating, right-torsion

What nystagmus would you see with posterior SCC BPPV in the left ear?

up-beating, left-torsion

What nystagmus would you see with anterior SCC BPPV in the right ear?

down-beating, right-torsion

What nystagmus would you see with anterior SCC BPPV in the left ear?

down-beating, left-torsion

What nystagmus would you see with lateral SCC canalithiasis BPPV?

geotropic; nystagmus generally bilateral with side with larger velocity likely being the lesioned ear

What nystagmus would you see with lateral SCC cupulolithiasis BPPV?

ageotropic; nystagmus generally bilateral with side with larger velocity likely being the lesioned ear

What is a vestibular schwannoma?

Slow-growing benign neoplasms arising from Schwann cells of CN VIII

Mostly on vestibular branch

Unilateral - mostly incidental finding

Bilateral - associated with NF2

What is the clinical presentation of vestibular schwannoma cases?

asymmetrical HL and unilateral tinnitus

Dizziness/vertigo not reported often due to slow-growth of tumor allowing vestibular system to compensate for gradual decline in function

Facial weakness or numbness if tumor impinging on CN VII in IAC

What are examples of third window disorders?

perilymph fistula, superior SCC dehiscence (SCD), enlarged vestibular aqueduct (EVA)

What is a perilymph fistula?

leak of perilymph from labyrinth into ME space following tear in round or oval window

Associated with head trauma, barotrauma, straining, can be idiopathic

How can a perilymph fistula present clinically?

sudden unilateral HL, tinnitus, aural fullness, imbalance

Acute episodes of lightheadedness, imbalance, motion intolerance triggered by internal or external pressure changes

What is SSCD?

superior semicircular canal dehiscence

Caused by deterioration of bony labyrinth covering the superior SCC, acts as third window into labyrinth

Altered trasmission of sound and pressure through the IE

Describe the clinical presentation of SCD

Autophony, increased audibility of bone conducted sounds

dizziness, vertigo, disequilibrium

Tullio phenomenon, Hennebert phenomenon

Pulse-synchronized oscillopsia

Hyperacusis

Aural fullness

pulsatile tinnitus

brain fog, fatigue

enhanced VEMPs (lower than expected threshold)

conductive HL with present acoustic reflexes

What is enlarged vestibular aqueduct syndrome?

Genetic condition associated with progressive HL

Can occur alone or with syndromes like Pendred or BOR

Vestibular system involvement in 70% of cases

What are the clinical signs of vestibular dysfunction in EVA cases?

Enhanced cVEMP/oVEMP responses

Asymmetric caloric

Caloric hypofunction

abnormal vHIT possible

What are signs of progressive cerebellar involvement?

ataxia, abnormal oculomotor performance, down-beating nystagmus

Describe the timing, triggers and symptoms of a labyrinthine infarction

Timing: sudden, symptoms lasting hours-days, vertigo common

Trigger: reduced blood flow to all or part of labyrinth

other symptoms: sudden sensorineural HL, headache, disorientation, diagnosed AICA stroke

Describe the timing, triggers and symptoms of a cerebellar infarction

Timing: sudden imbalance, spontaneous nystagmus ≥ 24 hrs, vertigo rare

Trigger: transient ischemic attack (TIA) in cerebellar artery

Other symptoms: lateropulsion, decreased coordination, hiccoughs, ataxia

What is lateropulsion?

a neurological phenomenon where a person experiences a distorted perception of verticality. They actively push their body across the midline toward their weaker (affected) side while resisting attempts to correct their posture, resulting in severe balance issues and a high risk of falling

What degenerative conditions are associated with cerebellar dizziness?

Idiopathic late-onset cerebellar ataxia

Cerebellar ataxia

Downbeat nystagmus syndrome

CANVAS - Cerebellar Ataxia, Neuropathy, and Vestibular Areflexia Syndrome

What genetic/hereditary conditions are associated with cerebellar dizziness?

Spinocerebellar ataxias

Episodic ataxias

What acquired conditions are associated with cerebellar dizziness?

Paraneoplastic syndrome

autoimmune disorders

Toxicities

Vitamin deficiencies

What infections are associated with cerebellar dizziness?

Acute cerebellitis

Postinfection cerebellar syndrome

Chronic cerebellar infection

What recurrent conditions are associated with cerebellar dizziness?

episodic ataxias

Vestibular migraine

What acute, inflammatory conditions are associated with cerebellar dizziness?

Multiple sclerosis

Sarcoidosis

What is CANVAS?

Cerebellar Ataxia with Neuropathy and Vestibular Areflexia Syndrome

Disorder illustrating clinical presentation of cerebellar degeneration

What findings are consistent with CANVAS?

Bilateral vestibulopathy

• decreased VOR performance; caloric hypofunction, reduced SHA gain, present saccades/low gain on vHIT

• impaired VVOR

• poor fixation suppression

Cerebellar involvement

• cerebellar atrophy, specifically vermis

• cerebellar dysarthria

• truncal ataxia

• dysphagia

• oculomotor abnormalities: saccadic smooth pursuit, gaze-evoked, direction-changing nystagmus, dysmetric saccades, rebound nystagmus

Somatosensory impairment - neuronopathy

No significant impacts on cochlear or cochlear branch of CN VIII (but may have HL due to age)

What peripheral vesitbulopathies may be related to traumatic brain injuries?

Direct end-organ injury

BPPV

Labyrinthine concussion

Posttraumatic endolymphatic hydrops

SCD

otolith dysfunction

medication side effects

What central vesitbulopathies may be related to traumatic brain injuries?

concomittant injury

diffuse axonal injury

postconcussion migraine

cervical dizziness

vestibulo-autonomic reflex impairment

How are vestibular migraines diagnosed?

1) at least 5 episodes of vestibular symptoms of moderate or severe intensity lasting between 5 min and 72 hours

2) current or previous history of migraine with or without aura

3) one or more migraine features with at least 50% vestibular episodes

• headaches with at least two of: unilateral location, pulsating, mod or sev intensity, aggravated by routine physical activity

• photophobia, phonophobia

• visual aura

4) not better accounted for by another vestibular or headache diagnosis

What is PPPD?

Persistant postural-perceptual dizziness

Chronic functional vesitbular disorder; not a structure or psychiatric condition

Often develops after acute vestibular episode (like vestibular neuritis); perceived symptoms will persist after resolution of the acute event

How is PPPD diagnosed?

1) one or more symptoms of dizziness, unsteadiness or nonspinning vertigo present on most days for > 3 months

• symptoms last hours but may come and go, do not need to be present during entire day

2) persistant symptoms occur without provocation, exacerbated by

• upright posture

• active/passive motion without regard to direction or position

• exposure to moving or complex visual environments

3) precipitated by conditions that cause vertigo, unsteadiness, problems with balance, acute/episodic/chronic vestibular syndromes, other neurological or medicla issues, psychological distress

4) symptoms cause significan distress or functional impairment

5) not better accounted for by another disease or diagnosis

What are the three main components of vestibular rehabilitation therapy? Describe each

Adaptation - ability to make long-term changes in neural response to head movement

Habituation - repeated exposure to offending stimulus to gradually inhibit patient’s response to that stimulus

Substitution - use of intact sensory sustem to replace lost sensory system function