Vestibular Function and Vestibular Function and AnatomyAnatomy

Prof. Hamad Al-MuhaimeedProf. Hamad Al-MuhaimeedProfessor/ConsultantProfessor/Consultant

Department of OtorhinolaryngologyKing Abdulaziz University Hospital

System of balanceSystem of balance Membranous and bony labyrinth embedded in Membranous and bony labyrinth embedded in

petrous bonepetrous bone 5 distinct end organs5 distinct end organs

– 3 semicircular canals: superior, lateral, 3 semicircular canals: superior, lateral, posteriorposterior

– 2 otolith organs: utricle and saccule2 otolith organs: utricle and saccule

Semicircular canals sense angular accelerationSemicircular canals sense angular acceleration Otolithic organs (utricle and saccule) sense Otolithic organs (utricle and saccule) sense

linear accelerationlinear acceleration

EmbryologyEmbryology

3rd week of 3rd week of embryonic embryonic developmentdevelopment

Otic placode formed Otic placode formed from neuroectoderm from neuroectoderm and ectodermand ectoderm

Otocyst or otic vesicle Otocyst or otic vesicle 4th week4th week

Semicircular canals Semicircular canals are orthogonal to each are orthogonal to each otherother

Lateral canal inclined Lateral canal inclined to 30 degreesto 30 degrees

Superior/postereor Superior/postereor canals 45 degrees off canals 45 degrees off of sagittal planeof sagittal plane

Utricle is in horizontal Utricle is in horizontal planeplane

Saccule is in vertical Saccule is in vertical planeplane

AnatomyAnatomy

There are five There are five openings into area of openings into area of utricleutricle

Saccule in spherical Saccule in spherical recessrecess

Utricle in elliptical Utricle in elliptical recessrecess

45% from AICA45% from AICA 24% superior 24% superior

cerebellar arterycerebellar artery 16% basilar16% basilar Two divisions: Two divisions:

anterior vestibular and anterior vestibular and common cochlear common cochlear arteryartery

Superior vestibular Superior vestibular nerve: superior canal, nerve: superior canal, lateral canal, utriclelateral canal, utricle

Inferior vestibular Inferior vestibular nerve: posterior canal nerve: posterior canal and sacculeand saccule

Membranous labyrinth is surrounded by Membranous labyrinth is surrounded by perilymphperilymph

Endolymph fills the vestibular end organs along Endolymph fills the vestibular end organs along with the cochleawith the cochlea

PerilymphPerilymph

– Similar to extracellular fluidSimilar to extracellular fluid

– K+=10mEQ, Na+=140mEq/LK+=10mEQ, Na+=140mEq/L

– Unclear whether this is ultrafiltrate of CSF or Unclear whether this is ultrafiltrate of CSF or bloodblood

– Drains via venules and middle ear mucosaDrains via venules and middle ear mucosa

EndolymphEndolymph

– Similar to intracellular fluidSimilar to intracellular fluid

– K+=144mEq/L, Na+=5mEq/LK+=144mEq/L, Na+=5mEq/L

– Produced by marginal cells in stria vascularis Produced by marginal cells in stria vascularis from perilymph at the cochlea and from dark from perilymph at the cochlea and from dark cells in the cristae and maculaecells in the cristae and maculae

– Absorbed in endolymphatic sac which Absorbed in endolymphatic sac which connected by endolymphatic, utricular and connected by endolymphatic, utricular and saccular ductssaccular ducts

Sensory structuresSensory structures

Ampulla of the semicircular canalsAmpulla of the semicircular canals Dilated end of canalDilated end of canal Contains sensory neuroepithelium, cupula, Contains sensory neuroepithelium, cupula,

supporting cellssupporting cells

Cupula is gelatinous Cupula is gelatinous mass extending across mass extending across at right angleat right angle

Extends completely Extends completely across, not responsive across, not responsive to gravityto gravity

Crista ampullaris is Crista ampullaris is made up of sensory made up of sensory hair cells and hair cells and supporting cellssupporting cells

Sensory cells are either Sensory cells are either Type I or Type IIType I or Type II

Type I cells are flask Type I cells are flask shaped and have chalice shaped and have chalice shaped calyx ending shaped calyx ending

One chalice may synapse One chalice may synapse with 2-4 Type I cellswith 2-4 Type I cells

Type II cells – cylinder Type II cells – cylinder shaped, multiple efferent shaped, multiple efferent and afferent boutonsand afferent boutons

Hair cells have 50-100 stereocilia and a single kinocilium.

stereocilia are not true cilia, they are graded in height with tallest nearest the kinocilium.

Otolithic organsOtolithic organs

Utricle and saccule sense linear accelerationUtricle and saccule sense linear acceleration Cilia from hair cells are embedded in gelatinous Cilia from hair cells are embedded in gelatinous

layer layer Otoliths or otoconia are on upper surfaceOtoliths or otoconia are on upper surface

Calcium carbonate or Calcium carbonate or calcitecalcite

0.5-30um0.5-30um Specific gravity of Specific gravity of

otolithic membrane is otolithic membrane is 2.71-2.942.71-2.94

Central region of Central region of otolithic membrane is otolithic membrane is called the striolacalled the striola

Saccule has hair cells Saccule has hair cells oriented oriented awayaway from the from the striolastriola

Utricle has hair cells Utricle has hair cells oriented oriented towardstowards the the striolastriola

Striola is curved so Striola is curved so otolithic organs are otolithic organs are sensitive to linear sensitive to linear motion in multiple motion in multiple trajectoriestrajectories

Senses and controls Senses and controls motionmotion

Information is Information is combined with that combined with that from visual system and from visual system and proprioceptive systemproprioceptive system

Maintains balance and Maintains balance and compensates for compensates for effects of head motioneffects of head motion

DEFINITION & DEFINITION & TERMINOLOGIESTERMINOLOGIES

DEFINITION & DEFINITION & TERMINOLOGIESTERMINOLOGIES

VERTIGO (illusion of rotational, linear or VERTIGO (illusion of rotational, linear or

tilting movement such as “spinning”, tilting movement such as “spinning”, “whirling” or “turning” of the patient or the “whirling” or “turning” of the patient or the surrounding . DISEQUILBRIUM sensation surrounding . DISEQUILBRIUM sensation of instability of the body positions, walking of instability of the body positions, walking or standing described as “off balanced” or or standing described as “off balanced” or “imbalanced”.“imbalanced”.

DEFINITION & DEFINITION & TERMINOLOGIESTERMINOLOGIES

OSCILLOPSIA (inability to focus on OSCILLOPSIA (inability to focus on

objects with motion, such as reading a sign objects with motion, such as reading a sign while walking , seen with bilateral or central while walking , seen with bilateral or central vestibular loss). vestibular loss).

DEFINITION & DEFINITION & TERMINOLOGIESTERMINOLOGIES

LIGHTHEADEDNESS (sense of impending LIGHTHEADEDNESS (sense of impending

faint, presyncope).faint, presyncope). PHYSIOLOGIC DIZZINESS (motion PHYSIOLOGIC DIZZINESS (motion

sickness, height vertigo),sickness, height vertigo),

EVALUATION OF THE DIZZY EVALUATION OF THE DIZZY PATIENTPATIENT

HistoryHistory Dizziness is a term used to describe any of a Dizziness is a term used to describe any of a

variety of sensation that produce spatial variety of sensation that produce spatial disorientation.disorientation.

Onset and Duration of Symptoms:Onset and Duration of Symptoms:

EVALUATION OF THE DIZZY EVALUATION OF THE DIZZY PATIENTPATIENT

HistoryHistory

Character of Dizziness:Character of Dizziness: Contributing Factors:Contributing Factors: Associated Symptoms:Associated Symptoms:

PHYSICAL EXAMINATIONPHYSICAL EXAMINATION

H & N and General Physical Exam:H & N and General Physical Exam: Otoscopy:Otoscopy: Vestibular Testing:Vestibular Testing: Neurological Exam:Neurological Exam:

General Characteristics of General Characteristics of Peripheral and Central Causes of Peripheral and Central Causes of

VertigoVertigo

CharacteristicCharacteristic PeripheralPeripheral Central Central

IntensityIntensity severesevere mildmild

FatigabilityFatigability fatigues,fatigues, does notdoes notAssociatedAssociated adaptationadaptation fatiguefatigue

General Characteristics of General Characteristics of Peripheral and Central Causes of Peripheral and Central Causes of

VertigoVertigoCharacteristicCharacteristic PeripheralPeripheral Central Central

SymptomsSymptoms nausea,nausea, weakness,weakness,hearing loss,hearing loss, numbnessnumbnesssweatingsweating falls morefalls more

likelylikely

Eye closed symptom, symptomsEye closed symptom, symptomsworse withworse with better with better witheyes closedeyes closed eyes closed eyes closed

General Characteristics of General Characteristics of Peripheral and Central Causes of Peripheral and Central Causes of

VertigoVertigo

CharacteristicCharacteristic PeripheralPeripheral Central Central

NystagmusNystagmus horizontal, may horizontal, may vertical verticalbe unilateralbe unilateral bilateralbilateralrotaryrotary

Ocular Ocular suppressessuppresses no effect no effectFixationFixation nystagmus (maynystagmus (may or enhances or enhances

not suppressnot suppress nystagmusnystagmusduring acuteduring acutephase )phase )

CAUSES OF VERTIGOCAUSES OF VERTIGO

PERIPHERAL VERTIGOPERIPHERAL VERTIGO:: Benign Paroxysmal Positional VertigoBenign Paroxysmal Positional Vertigo Meniere DiseaseMeniere Disease Vestibular NeuronitisVestibular Neuronitis Perilymphatic FistulasPerilymphatic Fistulas

CAUSES OF VERTIGOCAUSES OF VERTIGO

CENTRL CAUSESCENTRL CAUSES Cerebellospontine Angle TumuorsCerebellospontine Angle Tumuors Traumatic Vestibular DysfunctionTraumatic Vestibular Dysfunction

CENTRAL AND SYSTEMIC CENTRAL AND SYSTEMIC CAUSES OF VERTIGOCAUSES OF VERTIGO

Multiple SclerosisMultiple Sclerosis Other Neurological Disorder (stroke, Other Neurological Disorder (stroke,

seizures, middle cerebellar lesions, seizures, middle cerebellar lesions, parkinsonism, psudobulbar palsy)parkinsonism, psudobulbar palsy)

Metabolic Disorders (hypo/hyper-Metabolic Disorders (hypo/hyper-

thyroidism, diabetes)thyroidism, diabetes)

CENTRAL AND SYSTEMIC CENTRAL AND SYSTEMIC CAUSES OF VERTIGOCAUSES OF VERTIGO

Medications and Intoxicants (psychotropic Medications and Intoxicants (psychotropic drugs, alcohol, analgesics,drugs, alcohol, analgesics, anesthetics, anesthetics, antihypertensives, anti-arrhythmics, antihypertensives, anti-arrhythmics, chemotherapeutics)chemotherapeutics)

VascularVascular Causes (vertebrobasilar Causes (vertebrobasilar insufficiency, basilar migraine syndrome, insufficiency, basilar migraine syndrome, vascular loop compression syndrome)vascular loop compression syndrome)

VESTIBULAR TESTINGVESTIBULAR TESTING

HALLPIKE TESTHALLPIKE TEST ELECTRONYSTAGMOGRAPHY ELECTRONYSTAGMOGRAPHY

ROTATION TESTROTATION TESTOCULOMOTOR TESTINGOCULOMOTOR TESTING

POSTUGRAPHYPOSTUGRAPHY

CALORIC TESTINGCALORIC TESTING

Only test that evaluates vestibular function Only test that evaluates vestibular function

in each ear independently, determines in each ear independently, determines unilateral versus bilateral weaknessunilateral versus bilateral weakness

Technique:Technique: Theoretical Normal Response:Theoretical Normal Response:

CALORIC TESTINGCALORIC TESTING

Directional Preponderance:Directional Preponderance: Unilateral Caloric Weakness:Unilateral Caloric Weakness: Bilateral Weakness:Bilateral Weakness:

DIAGNOSISDIAGNOSIS

Based on clinical history, physical Based on clinical history, physical

examination and audiological findings examination and audiological findings (initial low-frequency SNHL) with exclusion (initial low-frequency SNHL) with exclusion of other causes of hearing loss and vertigo is of other causes of hearing loss and vertigo is adequate for diagnosis and initiating adequate for diagnosis and initiating empirical therapy.empirical therapy.

Meniere’s Disease Meniere’s Disease (Endolymphatic (Endolymphatic

Hydrops Hydrops))Signs and SymptomsSigns and Symptoms Episodic Vertigo lasting minutes to hoursEpisodic Vertigo lasting minutes to hours Episodic fluctuating SNHL (usually unilateral), Episodic fluctuating SNHL (usually unilateral),

recovery between episodes may be incomplete recovery between episodes may be incomplete resulting in a progressive SNHL (initially at resulting in a progressive SNHL (initially at lower frequencies)lower frequencies)

Tinnitus and episodic fullness associated with or Tinnitus and episodic fullness associated with or without the hearing losswithout the hearing loss

Meniere’s Disease Meniere’s Disease (Endolymphatic (Endolymphatic

Hydrops) Hydrops)

Signs and SymptomsSigns and Symptoms Classic Menieres Disease presents with all of the Classic Menieres Disease presents with all of the

above symptoms (vertigo, hearing loss, tinnitus, above symptoms (vertigo, hearing loss, tinnitus, and aural fullness), however Meniere Disease and aural fullness), however Meniere Disease may also present as any combination of the above may also present as any combination of the above symptomssymptoms

Meniere’s Disease Meniere’s Disease (Endolymphatic (Endolymphatic

Hydrops) Hydrops) DIAGNOSISDIAGNOSIS Vestibular testing may reveal unilateral Vestibular testing may reveal unilateral

weakness on affected side.weakness on affected side. Electrocochleography:Electrocochleography:

MEDICAL MANAGEMENT MEDICAL MANAGEMENT OF MENIERE DISEASEOF MENIERE DISEASE

Dietary Restrictions:Dietary Restrictions: Diuretics:Diuretics: Vestibular Suppressants:Vestibular Suppressants: Corticosteroids:Corticosteroids: Allergy Management:Allergy Management: Stress ReductionStress Reduction

BENIGN PAROXYSMAL BENIGN PAROXYSMAL POSITIONAL VERTIGO POSITIONAL VERTIGO (BPPV, Cupulolithiasis)(BPPV, Cupulolithiasis)

BPPVBPPV Frequency- 50% of peripheral vertigo, 20% of pts over 80 have Frequency- 50% of peripheral vertigo, 20% of pts over 80 have

BPPVBPPV

Clinical history: sudden onset, brief vertigo, brought on by Clinical history: sudden onset, brief vertigo, brought on by changes in head position, particularly turning in bed, or tilting changes in head position, particularly turning in bed, or tilting head back, may have prior history of vestibular neuritis or head head back, may have prior history of vestibular neuritis or head traumatrauma

Exam: + Dix-Hallpike (don’t forget 5-10% have horizontal Exam: + Dix-Hallpike (don’t forget 5-10% have horizontal variant)variant)

Pathophysiology: loose calcium crystals in posterior Pathophysiology: loose calcium crystals in posterior semicircular canalsemicircular canal

Treatment: Epley manueverTreatment: Epley manuever

MANAGEMENTMANAGEMENT

Education, reassurance and observationEducation, reassurance and observation Particle Repositioning Maneuver (Epley’s Particle Repositioning Maneuver (Epley’s

Maneuver): Maneuver): Home vestibular positional exercisesHome vestibular positional exercises Antivertiginous medicationsAntivertiginous medications Singular Neurectomy:Singular Neurectomy:

Vestibular NeuritisVestibular Neuritis Frequency: 15% of peripheral vertigoFrequency: 15% of peripheral vertigo

Clinical history: sudden onset severe vertigo c N/V, sx’s improve Clinical history: sudden onset severe vertigo c N/V, sx’s improve in days to weeks secondary to central compensation, can have in days to weeks secondary to central compensation, can have chronic effects for months to years.chronic effects for months to years.

Exam: unilateral nystagmus c fast phase away from affected ear, Exam: unilateral nystagmus c fast phase away from affected ear, amplitude of nystagmus decreases when looking towards affected amplitude of nystagmus decreases when looking towards affected ear, +/- hearing loss or tinnitusear, +/- hearing loss or tinnitus

Pathophysiology: probably secondary to viral infection & Pathophysiology: probably secondary to viral infection & inflammation of vestibular nerve or labyrinthinflammation of vestibular nerve or labyrinth

Treatment: steroids- 3 week tapering course, starting at 100 mg.Treatment: steroids- 3 week tapering course, starting at 100 mg.– Strupp et al. (2004). Methylprednisolone, Valacyclovir, or the Strupp et al. (2004). Methylprednisolone, Valacyclovir, or the

Combination for Vestibular Neuritis. NEJM 351, pp. 354-361. Combination for Vestibular Neuritis. NEJM 351, pp. 354-361.

PERILYMPH FISTULAPERILYMPH FISTULA

Pathophysiology:Pathophysiology: Causes:Causes: SSx:SSx: Diagnosis:Diagnosis: Treatment:Treatment:

VERTEBRONBASILAR VERTEBRONBASILAR INSUFFICIENCY (VBI)INSUFFICIENCY (VBI)

Pathophysiology:Pathophysiology: SSx: SSx: Diagnosis:Diagnosis: TreatmentTreatment

OTHER VESTIBULAR OTHER VESTIBULAR DISORDERSDISORDERS

Basilar Migraine Syndrome:Basilar Migraine Syndrome: Vestibular Epilepsy:Vestibular Epilepsy: Multiple Sclerosis (MS):Multiple Sclerosis (MS): Labyrinthine Apoplexy:Labyrinthine Apoplexy: Subclavian Steal Syndrome:Subclavian Steal Syndrome: Hyperrinsulinemia/Diabetes:Hyperrinsulinemia/Diabetes:

Etiology Recur Onset Duration Associated features

BPPV + sudden <1 min elderly, induced by position change

Meniere’s + gradual hours ear fullness, tinnitus, low freq hearing lossVestibular - gradual days-weeks 50% c preceding viral neuritis or sudden illness, +/- hearing lossMigraine + gradual sec-days young F, HA, positive

visual phenomenonVB TIA + sudden mins CN, long-tract sx’s/

signs Labryinth - sudden days-months hearing stroke loss +/- tinnitus

Brainstem - sudden days-months CN, long-tract stroke sx’s/ signs Cerebellar - sudden days-months unil dysmetria, stroke “central” nystagmus

MANAGEMENT CONCEPTMANAGEMENT CONCEPT

Safety: Safety: Acute Vestibular Suppression:Acute Vestibular Suppression: Vestibular Rehabilitation:Vestibular Rehabilitation: Surgical Management:Surgical Management:

SURGICAL MANAGEMENT SURGICAL MANAGEMENT OF VERTIGOOF VERTIGO

SURGICAL MANAGEMENT SURGICAL MANAGEMENT OF VERTIGOOF VERTIGO

Endolymphatic Sac Surgery:Endolymphatic Sac Surgery: Vestibular Nerve Section:Vestibular Nerve Section: Transtympanic Or Intratympanic Transtympanic Or Intratympanic

Aminoglycoside Injections:Aminoglycoside Injections: LabyrinthectomyLabyrinthectomy

Conclusion

1. Is this vertigo?

2. Is this central or peripheral?

3. History- focus on age, PMH, duration

4. Exam- focus on CN and coordination,focal neurological findings, Dix-Hallpike