Transcript Balance and Equilibrium

頭暈
新光醫院 神經科
許維志 醫師
Balance and Equilibrium
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Equilibrium
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The ability to maintain orientation of the
body and its parts in relation to external
space.
Interaction between self and environment.
Sensory input from visual, vestibular, and
proprioceptive information.
Integration in the brain stem and
cerebellum.
Disorders of Equilibrium
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Diseases affect
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Central or peripheral vestibular pathways
Cerebellum
Proprioceptive sensation
Mismatch of input signals and
disintegration
Symptoms
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Vertigo
Ataxia
Vertigo and Dizziness
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Vertigo 眩暈
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Illusion of movement of the body or the
environment.
Impulsion, oscillopsia, nausea, vomiting, cold
sweating, or unsteadiness
Dizziness 頭昏
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No association of illusion of movement
Light-headedness, faintness, giddiness,
swimming
Vestibular System
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Semicircular canal
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Sense angular acceleration
Head rotation
Otolith organs
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Sense linear acceleration
Head translation and uprightness
The Vestibules
The Vestibule
The Ampulla
Functions of Semicircular Canals, Saccule and Utricle
Vertigo
Cerebellar System
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Archicerebellum
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Flocculonodular lobe
vestibulocerebellum
Paleocerebellum
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Posterior lobe
Pontocerebellum
The oldest cerebellum
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Anterior lobe
Spinocerebellum
Neocerebellum
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The next oldest
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Caudal part
Eye/head movement
Midline
Neck/trunk movement
The newest cerebellum
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Hemsiphere
Limb movement
Origin and Classification of Vertigo
The Saccades, Pursuit, and Vestibular Control of Eye Movements
Dizziness
History
Near-faint
Disequilibrium
without vertigo
Central origin
Vertigo
Psychological
dizziness
Peripheral origin
Physiological
dizziness
Distinguishing Vestibular From
Nonvestibular Dizziness
Vestibular
Nonvestibular
Description
Spinning, falling,
drunkenness, motion
sickness, tilting
Floating, near-fainting,
fatigue, head fullness,
out-of body sensation
Precipitating factors
Head movements,
position changes
Standing after sitting or
lying, cardiac disease,
agoraphobia
Associated features
Nausea, vomiting,
Palpitation, diaphoresis,
unilateral tinnitus or
syncope, loss of
hearing loss, imbalance, concentration, dyspnea
oscillopsia
Physiological Vertigo
Type
Provocative stimulus Mechanism
Motion sickness
Prolonged passive head
Vestibular-visual
movement or movement of conflict
the environment
Visual vertigo
Excessive visual
stimulation
Vestibular-visual
conflict
Mal de debarquement Long voyage on ship or
plane
Maladaptation to
chronic vestibular
stimulation
Height vertigo
Standing in a high place
looking out
Lack of nearby
stationary objects in
peripheral vision
Space sickness
Zero gravity
Canal-otolith conflict
Causes of Pathological Vertigo
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Peripheral vertigo
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Vestibular end organs: inner ear,
labyrithine apparatus
Vestibular nerve
Central vertigo
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Brainstem: vestibular nucleus
Archicerebellum (flocculonodular lobe)
Peripheral Causes of Vertigo
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Benign paroxysmal positional vertigo
Meniere’s disease
Acute peripheral vestibulopathy
(vestibular neuritis)
Head trauma
Cerebellopontine angle tumor
Toxic vestibulopathies
Disorders of the
Disorders of the
Semicircular Canal Otolith Organs
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Vertigo (spinning of the
environment or the self)
Nystagmus
Past-pointing of the
limbs
Ataxia
Positive Romberg sign
Turning during steppage
test
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Tilt, a false sense of
linear motion
Vertical diplopia
Skew deviation
Ataxia
Positive Romberg sign
Translation on the
steppage test
Central Causes of Vertigo
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Vertebrobasilar ischemia & infarction
Cerebellar hemorrhage
Alcoholic cerebellar degeneration
Multiple sclerosis
Posterior fossa tumors
Paraneoplastic cerebellar degeneration
Spinocerebellar degneration
Differentiating Peripheral From Central Vertigo
Peripheral
Central
Nausea/vomiting
Severe
Variable, mild
Imbalance
Mild-moderate
Severe
Hearing loss
Common
Rare
Neurological
symptoms
Rare
Common
Nystagmus
Unidirectional in all
gaze; inhibit with
fixation
Direction-changing in
different gaze; not
inhibited with fixation
Compensation
Rapid
Slow
Systemic Causes of Vertigo
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Drugs: anticonvulsants, sedatives, antihypertensives
Hypotension, presyncope: heart diseases,
postural hypotension
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Infectious diseases: syphilis, meningitis
Endocrine diseases: DM, hypothyroidism
Vasculitis: collagen vascular disease, giant-cell
arteritis
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Others: anemia, polycythemia, systemic toxins
Causes of Dysequilibrium without Vertigo
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Disorders of afferent senses
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Bilateral vestibular loss
Sensory ataxia
Multisensory disequilibrium
Disorders of central processing and motor
responses
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Cerebellar degeneration
Frontal lobe syndrome
Extrapyramidal syndrome
Approach to Vertigo and Dizziness
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General examination
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BP in the lying and standing
Look for cardiac arrhythmia
Examination of extracranial and peripheral
vasculature
Approach to Vertigo and Dizziness
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Neurological examination (1)
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Consciousness and mental status
Visual acuity and visual field
Fundus
Screening for hearing impairment
Ocular motor examination
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Nystagmus
Ocular motor palsy
Slow or ataxic ocular movement
assessing current history
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Ask the patient to describe the symptoms without using the word
dizzy. Have the patient differentiate vertigo from presyncope or
near-syncope.
Determine if the patient has a sense of being pushed down or
pushed to one side (pulsion). A peculiar sense of movement of
objects viewed when the patient moves is termed oscillopsia.
Ascertain whether the symptoms are related to an anxiety attack;
patients with agoraphobia may describe their symptoms as
dizziness.
Determine if the sensation is continuous or episodic (ie, attacks);
if episodic, find out if the sensation is fleeting or prolonged.
Ascertain whether the onset and progression of symptoms were
slow and insidious or acute.
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Ask the patient about head trauma and other illnesses to determine the setting
of the initial symptoms. Trauma resulting in damage to an ear often manifests
as unilateral hearing loss, which may be the cause of episodic vertigo even years
later (posttraumatic hydrops).
Determine if the attacks are associated with turning the head, lying supine, or
sitting upright.
Determine if symptoms of an upper respiratory infection or flu-like illness
preceded the onset of vertigo.
Inquire about associated symptoms such as hearing loss or tinnitus (ringing in
the ears), aural fullness, diaphoresis, nausea, or emesis.
Determine if the patient has an aura or warning before the symptoms start.
If hearing loss is evident, find out if hearing fluctuates.
Determine if the patient has a headache or visual symptoms such as
scintillating scotoma.
Ask the patient about brainstem symptoms such as diplopia, dysarthria, facial
paresthesia, or extremity numbness or weakness.
Ascertain the degree of impairment during an attack
Examination of Vestibulo-ocular Reflexes
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Spontaneous nystagmus
Elicit slow phases with slow head rotation, in
yaw (horizontal), pitch (vertical), and roll
(torsion), and with high accelerations in yaw
and pitch (head thrust)
Caloric test
Head-shaking nystagmus
Vestibulospinal Testing
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Past-pointing with arms, with eyes closed
Romberg: feet apposed, in tandem, in tandem
on toes, on one foot at a time, standing on
compliant foam rubber
Fukuda stepping test or walking around a circle
Tandem gait, forward and backward
Approach to Vertigo and Dizziness
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Neurological examination (2)
 Motor system examination
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Focal or diffuse weakness
Reflex changes
Sensory examination
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Stock-and-gloving sensation loss:
polyneuropathy
Loss of vibratory and proprioceptive sensation:
Vit B12 deficiency or tabes dorsalis
Romberg’s sign
Approach to Vertigo and Dizziness
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Neurological examination (3)
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Cerebellar examination
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Observation of sitting and standing and walking
Bending backward
Tandem gait
Walking around a chair
Finger-nose-finger
Heel-knee-shin
Approach to Vertigo and Dizziness
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Neurological examination (3)
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Cerebellar examination
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Pronation-supination
Knee-patting
Rapid touching of each finger to the thumb
Arm deviation
Arm tapping
Rebound test
The Most Common Causes of Vertigo
Syndromes Seen in a Neurological Clinic
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Benign paroxysmal positioning vertigo
Phobic postural vertigo
Basilar migraine
Meninere’s disease
Vestibular neuritis
(T. Brandt, “Vertigo, its multisensory syndrome”)
Benign Paroxysmal Positioning Vertigo
The Vertical Vestibulo-ocular Projections
Excitatory afferents
Inhibitory afferents
Characteristic Nystagmus of BPPV
Benign Paroxysmal Positional Vertigo
(BPPV) – Symptoms & Signs
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Brief attacks of rotational vertigo and
concomitant rotatory nystagmus precipitated
by rapid head tilt, turning or extension.
The symptoms can be induced by Hallpike
maneuver.
Typical peripheral vestibular nystagmus, short
latency, limited duration, reversal on
returning to the upright position, and
fatigability on repeated provocation.
Benign Paroxysmal Positional Vertigo
(BPPV) – Pathogenesis & Treatment
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Otolith debris floats freely within the
endolymph of the semicircular canal:
canalolithiasis.
Heavy debris settles on the cupula
transforming it as a transducer of angular
acceleration into a transducer of linear
acceleration: cupulolithiasis.
Treatment by canal repositioning or libratory
maneuvers.
Brandt-Daroff vestibular exercise
Meriere’s Disease
Meriere’s Disease
Meniere’s Syndrome
– Symptoms & Signs
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Fluctuating hearing loss, tinnitus, episodic
vertigo and a sensation of fullness or
pressure in the ear.
Attacks lasted for hours but dizziness and
unsteadiness remain for a few days.
Repeated attacks lead to progressive tinnitus,
hearing loss, and impaired vestibular function.
Usual in the fourth to sixth decades.
Meniere’s Syndrome
– Pathogenesis & Treatment
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Endolymphatic hydrops: increase of volume of
endolymph associated with distension of entire
endolymph system.
The attacks are caused by rupture of membranous
labyrinth leading to paralysis of the surrounding
vestibular or cochlear hair cells and neural structures.
Symptomatic treatment of acute spells.
Salt restriction and diuretics.
Intratympnic treatment with ototoxic antibiotics.
Labyrinthectomy or vestibular neurectomy.
Basilar Migraine
– Symptoms & Signs
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Vertigo may occur in about one-fourth of migraine
patients, and can occur without headache.
Other symptoms of basilar migraine include ataxia,
dysarthria, diplopia, visual symptoms, tinnitus,
decreased hearing, bilateral pareses or paresthesia
and decreased level of consciousness.
Benign paroxysmal vertigo of childhood.
Benign recurrent vertigo of adulthood.
Motion sensitivity with frequent bouts of motion
sickness occurs in at least one-half of patients with
migraine.
Basilar Migraine
– Pathogenesis & Treatment
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Vasoconstriction (?). Neuronal depression (?).
Genetic.
Channelopathy.
Symptomatic treatment of acute attack
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Antivertiginous medications.
Antiemetics.
Sumatriptans and ergotamines often are ineffective and
even aggravate vertigo.
Prophylactic treatment of attacks
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Beta-blockers.
Calcium channel blockers.
Valproic acid.
Tricyclics.
Vestibular Neuritis
Vestibular Neuritis
– Symptoms & Signs
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Vertigo, nausea, and vomiting developed over several
hours, reach a peak within 24 h, and resolve
gradually over several weeks.
Generally without hearing symptoms.
Diagnosis is based on acute unilateral peripheral
vestibular loss and exclusion of other inner ear
diseases.
Ramsay Hunt syndrome by varicella-zoster infection
may causes facial paresis, tinnitus, hearing loss, and
a vestibular defect.
Vestibular Neuritis
– Pathogenesis & Treatment
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Presumed of viral origin.
Similar to Bell’s palsy caused by reactivation of
dormant herpes infection in the Scarpa’s ganglion
within the vestibular nerve.
Treatment is symptomatic. Antivertiginous medication
should not be given as long as nausea and vomiting
subsides. These drugs suppress central compensation.
Corticosteroid may shorten the clinical course.
Vestibular rehabilitation exercise.
Drugs That Can Cause Dizziness or Be Harmful to the Dizzy Patient
Drug
Drugs that causes
dizziness
Drug that interfere with
vestibular compensation
Anti-arrythmics
amiodarone, quinine
+
Anticonvulsants
barbiturates, CBZ, PHT
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Antidpressant
amitiptyline, imipramine
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Antihypertensives
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Diuretics
hydrochlorothiazide, furosemid
Antiinflammatory Drugs
ibuprofen, indomethacin, ASA
Ototoxic
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Antibiotics
aminoglycosides
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Chemotherapeutics
cisplatin
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Hypnotics
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Muscle relaxants
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Tranquilizers
BZD
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Vestibular suppressants
meclizine, scapolamine
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+
The End
Thank You.
The Supranuclear Control of Eye Movements
The Optokinetic nystagmus (OKN)
The Internuclear Ophthalmoplegia (INO)