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REVIEW ARTICLE

Central Vertigo and Dizziness

Epidemiology, Differential Diagnosis, and Common Causes

Mehmet Karatas, MD

Background: Dizziness is a common complaint among patients

seen by primary care physicians, neurologists, and otolaryngolo-

gists. The most common causes of dizziness are peripheral vestib-

ular disorders, but central nervous system disorders must be ex-

cluded. This article provides an overview of the epidemiology of

dizziness, differentiating between central and peripheral vertigo, and

central causes of dizziness.

Review Summary: Dizziness is among the most common com-

plaints in medicine, affecting approximately 20% to 30% of persons

in the general population. Dizziness is a general term for a sense of

disequilibrium. Vertigo is a subtype of dizziness, defined as an

illusion of movement caused by asymmetric involvement of the

vestibular system. Central vestibular lesions affecting the pons,

medulla, or cerebellum cause vertigo, nausea, vomiting, severe

ataxia, multidirectional nystagmus that is not suppressed by optic

fixation, and other neurologic signs. The other types of dizziness are

dysequilibrium without vertigo, presyncope, and psychophysiologic

dizziness, which is often associated with anxiety, depression, and

panic disorder.

Conclusions:Epidemiologic studies indicate that central causes are

responsible for almost one-fourth of the dizziness experience bypatients. The patients history, neurologic examination, and imaging

studies are usually the key to differentiation of peripheral and central

causes of vertigo. The most common central causes of dizziness and

vertigo are cerebrovascular disorders related to the vertebrobasilar

circulation, migraine, multiple sclerosis, tumors of the posterior

fossa, neurodegenerative disorders, some drugs, and psychiatric

disorders.

Key Words: dizziness, central vertigo, epidemiology, differential

diagnosis, central causes

(The Neurologist2008;14: 355364)

Dizziness is a common complaint among patients visitingtheir physicians. Patients use the term dizziness to de-scribe many different sensations. Dizziness can be classifiedinto 4 groups: (1) vertigo, which is an illusion of movement,

either of the person or the visual surround, (2) dysequilibriumwithout vertigo, (3) presyncope (near-faint), and (4) psycho-physiologic dizziness, which is often associated with anxietyand panic.14

Vertigo is a subtype of dizziness, defined as an illusorysensation of movement, and may occur in peripheral and/orcentral vestibular disorders. Asymmetric involvement of the

vestibular system leads to vertigo.5 When the vertiginoussensation is one of horizontal environmental spin or of clearself-rotation, the lesion is peripheral, mostly in the vestibularend-organ.3

Dysequilibrium, which is dysfunction in vestibular,somatosensory, visual systems, and frontal lobes, cerebellum,and basal ganglia, refers to imbalance or unsteadiness asdizziness without vertigo.2

Presyncope refers to the lightheaded sensation thatoccurs just before fainting. The absence of an illusion ofmotion distinguishes it from vertigo. Giddiness, generalizedweakness, and pallor may accompany it. The mechanism isalmost always a reduction in blood flow to entire brain.2,6,7

Psychophysiological dizziness refers to a combinationof symptoms reported as floating, rocking, or swimmingsensations, giddiness, internal spinning, or a feeling of beingremoved from ones body. Symptoms may worsen withstress, fatigue, and some daily activities. It may also developafter labyrinthine disorders.2,8,9

In this review, the epidemiology of central vertigo anddizziness, distinguishing central from peripheral vertigo, andsome central causes of dizziness and vertigo are discussed.

EPIDEMIOLOGYDizziness and vertigo rank among the most common

complaints in medicine, affecting approximately 20% to 30%of patients in the general population.3 Although dizziness andvertigo are present in patients of all ages, they are rareprimary complaints in children. Almost 20% of patients olderthan 60 years have experienced dizziness severe enough to

From the Department of Neurology, Baskent University, Medical School,Adana Research Center, Adana, Turkey.

Reprints: Mehmet Karatas, MD, Stadyum Cad, 39/1, 01120 Adana, Turkey.E-mail: [email protected].

Copyright 2008 by Lippincott Williams & WilkinsISSN: 1074-7931/08/1406-0355DOI: 10.1097/NRL.0b013e31817533a3

Central causes are responsible for nearly 25%of the dizziness experienced in patients.

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affect their daily activities.3,4,10 An estimated 7.5 millionpatients with dizziness are examined each year in ambulatorycare setting in the United States, and it is one of the mostcommon principle complaints in the emergency depart-ment.11 On the other hand, in Europe, dizziness and vertigoare also frequent causes of presentation at the emergency

room, with an incidence that approximates 3.5% in Italy.12

Neuhauser et al13 reported that the lifetime prevalence ofvestibular vertigo was 7.8%, the 1-year prevalence was 5.2%,and the incidence was 1.5% in Germany. Kanashiro et al14

also reported that the most common syndromes in 515 adultswith dizziness were benign paroxysmal positional vertigo(28.5%), phobic postural vertigo (11.5%), central vertigo(10.1%), vestibular neuritis (9.7%), Meniere disease (8.5%),and migraine (6.4%) (Table 1). On the other hand, benignparoxysmal vertigo of childhood, migraine-associated dizzi-ness, vestibular neuronitis, and otitis media-related dizzinessalso accounted for vertigo in children.10 According to Sekineet al,15 the most common peripheral vestibular disorder was

benign paroxysmal positional vertigo (32%), followed byMeniere disease (12%), all peripheral vestibular disordersaccounted for 65%, and central vestibular disorders ac-counted for 7%. Kroenke et al16 also published the results thatdizziness was attributed to a peripheral vestibulopathy in44%, a central vestibulopathy in 11%, psychiatric causes in16%, other conditions in 26%, and unknown causes in 13% ofthe patients in their series. Thus, it seems that these epide-miologic studies indicate that central causes (certain centralvestibular disorders, migraine, and phobic) are responsiblefor nearly 25% of the dizziness experienced in patients.1518

In addition, certain serious causes for central vertigo arerelatively uncommon, including cerebrovascular disease(6%7%), cardio-circulatory diseases (1.5%3.6%), and pos-

terior fossa tumors (1%).15,19 The prevalence of variouscauses of central vertigo has not been well delineated inepidemiologic studies so far.

DIFFERENTIATING BETWEEN PERIPHERAL ANDCENTRAL VERTIGO

The vestibular system consists of peripheral and centralpart. The semicircular canals, the otoliths (utricle and sac-cule), and the vestibular nerve are peripheral parts of the

vestibular system. The vestibular nuclear complex, vestibu-locerebellum, brainstem, spinal cord, and vestibular cortexare also central parts of the vestibular system.20,21 Vertigooccurs in acute unilateral loss of vestibular function. Auto-nomic symptoms such as sweating, pallor, nausea, and vom-iting are also commonly associated with vertigo, but are rare

with other types of dizziness.5

The physician first must determine whether the vertigois of peripheral or central origin, because the presence ofcentral disorders such as cerebellar infarction or hemorrhage,basilar artery occlusion, vertebral artery dissection, or atumor of the posterior fossa may require emergency manage-ment. Central vertigo is generally associated with severeimbalance, additional neurologic signs, less prominent move-ment illusion and nausea, and central nystagmus (which ispure vertical/torsional, multidirectional, and no suppressionwith optic fixation).2,5,21 The history usually provides thebasic information for distinguishing between peripheral andcentral vertigo.5 Nausea and vomiting are typically morepronounced in peripheral vertigo than in central vertigo.Imbalance is always associated with vertigo; more severe

imbalance is especially associated with central causes. Pa-tients with peripheral vestibular lesions also have imbalance,but they are able to walk. By contrast, many patients withcentral vestibular lesions are unable to stand or walk. Audi-tory symptoms such as hearing loss, tinnitus, fullness, or painin the ear are commonly seen in peripheral lesions such asthose affecting the labyrinth or eighth nerve. Besides hearingloss and tinnitus, lesions of the internal auditory canal may beassociated with ipsilateral facial weakness. Lesions in thecerebellopontine angle may cause ipsilateral facial numbness,weakness, and limb ataxia. Vertigo also can be seen as part ofan aura of temporal epilepsy, and during the seizure, thepatient is amnestic. Owing to a rapid compensation process,

acute vertigo due to peripheral lesion tends to improve indays to weeks, whereas central vertigo may not improve ormay do so more slowly.5,2226 Table 2 outlines guidelineshelpful in the differential diagnosis of vertigo.

TABLE 1. Frequency of Various Causes of Dizziness inDifferent Countries (%)

Japan(Sekine 2005)

Brazil(Kanashiro 2005)

USA(Kroenke 2000)

BPPV 32 28.5

Meniere disease 12 8.5

(Other) peripheralvestibular

21 9.7 44

Central vestibular 7 10.1 11

Psychiatric 11.5 16

Migraine 6.4

Unknown 13

Other 26

BPPV indicates benign paroxysmal positional vertigo.

Central vertigo is generally associated with

severe imbalance, additional neurologic signs,

less prominent movement illusion and nausea,

and central nystagmus.

Spontaneous nystagmus of peripheral origin

increases in amplitude with gaze in the

direction of the fast phase.

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Nystagmus, which is an involuntary rhythmic oscilla-tion of the eyes, is helpful for localizing vertigo. The direc-tion of the fast phase defines the direction of nystagmus.Spontaneous nystagmus occurs in patients seated, eyes in

primary position, and without movement of the head. Gaze-evoked nystagmus is elicited by changes in gaze position.Positional nystagmus is present in particular head positions,not in the sitting position.2125 Typical nystagmus producedby labyrinth dysfunction is a jerky nystagmus. Spontaneousnystagmus of peripheral origin increases in amplitude withgaze in the direction of the fast phase and decreases with gazeaway from the fast phase (Alexander law). Peripheral spon-taneous nystagmus is also inhibited with optic fixation, andthat nystagmus usually is prominent for only the first 12 to 24hours.5,22,25,26 Within a few days, peripheral spontaneousnystagmus may be inhibited completely, even with gaze inthe direction of the fast phase. Spontaneous nystagmus ofcentral origin typically changes direction when the patientlooks away from the direction of fast phase. It often persists forweeks or months. Vertical or pure rotatory nystagmus is alwaysproduced by a central vestibular lesion.5 Neurologic signs suchas diplopia, disconjugate gaze, Horner syndrome, severe gaitataxia, dysarthria, dysphagia, facial weakness and numbness,long tractus findings, and limb incoordination also indicate acentral lesion. On the other hand, diplopia can occasionally beseen in an acute peripheral vestibular lesion for a few days or sobecause of deafferentation of otolith inputs.21,22,27

The head-shaking nystagmus, which is elicited in re-sponse to a vigorous rotation of the head in the horizontalplane, is also a useful finding to identify patients havingunilateral vestibular hypofunction. On the other hand, thehead-thrust maneuver is used to assess the vestibulo-ocularreflex, and it is only positive for peripheral vestibular disor-

ders. During the maneuver, the patient fixates a visual target,and eye position is observed immediately after a small thrust

of the head to the left and right. A refixation saccade after thehead thrust indicates a decreased vestibulo-ocular reflex onthe side of head thrust. If the defect is on both sides, the headthrust test will be positive in both directions.23,28 Posturaltesting is important, particularly when evaluating paroxysmalpositional vertigo. In peripheral vestibular disorders, calorictesting produces an impaired response in one ear often calledcanal paresis. Directional preponderance occurs with bothperipheral and central vestibular lesions. Central vestibulardisorders also lead to deficits in the conjugation of eyemovements, saccadic pursuit and horizontal optokinetic ab-normalities, central spontaneous or positional nystagmus,failure of fixation suppression, slowing of the nystagmus fastphases, a slowing down of the nystagmus slow phases,

perverted nystagmus, vertical optokinetic abnormalities, andretraction nystagmus.2428 Table 3 differentiates betweenspontaneous peripheral and central nystagmus.

With undiagnosed vertigo, after careful history taking,general, neurologic, and neuro-otologic examinations, as wellas screening tests for blood count, electrolyte and glucoselevels, and thyroid function are required; neuroradiologicimaging is indicated when a central lesion is suspected.5,2023

SELECTED CENTRAL CAUSES OF DIZZINESSTable 4 outlines common central causes of dizziness. The

selected most common disorders related to dizziness are dis-cussed below.

Cerebrovascular DisordersThe blood supply to the inner ear, brainstem, and

cerebellum arises from the vertebrobasilar system. Vertigocan occur from occlusion of this system, which includes thevertebral arteries, the basilar artery, the posterior inferiorcerebellar artery, the anterior inferior cerebellar artery, andthe superior cerebellar artery. Because circulation to the innerear arises from the vertebrobasilar system, usually from theanterior inferior cerebellar artery, vertigo due to cerebrovas-cular disease can be of peripheral or central origin.2,29 Vas-cular syndromes related to vertigo or dysequilibrium aregiven below.2

TABLE 3. Differentiation Between Spontaneous Nystagmusof Central and Peripheral Origin

Central Peripheral

Appearance Pure vertical/torsional,pan, multidirectional,disconjugate, ordissociated, maychange direction withchanges in gaze

Torsional-horizontal,unidirectional in allgazes, conjugated

Suppression with OF No or minimal Yes

Alexander law No Yes

Direction-fixed No Yes

Localization Medulla, pontinetegmentum, cerebellum

Labyrinth, vestibularnerve

PAN indicates periodic alternating nystagmus; OF, optic fixation.

TABLE 2. Differential Diagnosis of Central andPeripheral Vertigo

Central Peripheral

Nausea None/mild Severe

Movement illusion Less prominent More prominent

Worse with head movement No YesNeurologic signs Common Rare

Imbalance Severe Mild to moderate

Hearing loss Rare Common

Oscillopsia Severe Mild

Caloric test Hyperexcitability Canal paresis

Recovery Months or longer Days to weeks

A refixation saccade after the head thrustindicates a decreased vestibulo-ocular reflex on

the side of head thrust.

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a. Vertebrobasilar transient ischemic attacksb. Posterior inferior cerebellar artery syndromec. Anterior inferior cerebellar artery syndromed. Superior cerebellar artery syndromee. Insular infarctionf. Cerebellar and brainstem hemorrhage

Vertebrobasilar transient ischemic attacks of the cere-bellum or brainstem are characterized by episodic vertigo ordysequilibrium, usually of 1 to 15 minutes duration, withconcurrent diplopia, dysarthria, ataxia, drop attack, and clum-siness of the extremities. Vertebrobasilar transient ischemicattacks presenting as isolated vertigo are usually related tovascular occlusion in the distal segment of the vertebral

arteries between the posterior inferior cerebellar artery andthe anterior inferior cerebellar artery, and the subclavian stealsyndrome.5,3033 Rarely, insular infarction with the middlecerebral artery territory can cause contraversive tilts, bodylateropulsion, nausea, unsteady gait, and rarely, rotationalvertigo.34,35 Hemorrhage into the brainstem or cerebellummay produce sudden vertigo. Headache and neck stiffnesssuggest hemorrhage rather than infarction.31,36

When evaluating the patient with acute vertigo, thephysician should seek risk factors for stroke, such as hyper-tension, hyperlipidemia, diabetes, smoking, heart disease. Onthe other hand, headache and neck pain followed by vertigoor unilateral facial paresthesias is an important sign of ver-

tebral artery dissection, and may precede onset of stroke byseveral days.29,35,37

MigraineMigraine is estimated to occur in 18% to 29% of

women, 6% to 20% of men, and 4% of children.2 Vertigomay occur in up to 25% of patients with migraine.5 Headacheand dizziness are 2 of the most frequent symptoms occurringin the general population. Conversely, migraine and vertigo

are 2 clinical features that tend to occur together.38 Migrainemay be associated with many vestibular symptoms, includingepisodic vertigo, chronic motion sensitivity, and nonspecificdizziness. On the other hand, patients with migraine maypresent with benign paroxysmal positional vertigo, Menieredisease, and motion sickness more often than patients withoutmigraine. However, persistent cerebellar syndrome may de-velop in the course of familial hemiplegic migraine.39,40

Dizziness also may be due to orthostatic hypotension, anxietydisorders, or major depression, all of which have an increasedprevalence in migraineurs.39

It has been believed that vertigo in migraine may arisefrom disorders such as spreading depression, regional

changes in brain perfusion, release of neurotransmitters, andparoxysmal dysfunction of ion channels anywhere along theperipheral or central vestibular structures.40,41 The principleclinical vestibular syndromes related to migraine can beclassified into 3 groups39,42:

a. Basilar-type migraineb. Benign paroxysmal vertigo of childhoodc. Migrainous vertigo (or vestibular migraine)

Basilar-type migraine, as a subtype of migraine withaura, is characterized by recurrent headaches, usually occip-ital, associated with aura symptoms localizing to the vascularterritory of the basilar artery.2 The International Headache

Society criteria for basilar-type migraine require the presenceof 1 or more preceding aura symptoms. The aura generallylasts less than 1 hour and is usually followed by a headachethat may be occipital. The visual aura is usually followed byvertigo, tinnitus, decreased hearing, diplopia, ataxia, dysar-thria, bilateral paresthesia, and paresis and impaired cogni-tion. The headache can be associated with nausea and pro-jectile vomiting.43 Triptans are contraindicated in basilar-typemigraine because of risks of vasospasm and stroke.2

Benign paroxysmal vertigo of childhood, as a subtypeof childhood periodic syndromes in migraine, is characterizedby onset between 1 and 4 years, abrupt randomly occurringattacks of vertigo and imbalance often with nausea and

vomiting that lasts for 30 seconds to 20 minutes, usuallyunaccompanied by headache. These children are healthybetween attacks. This syndrome often subsides by adoles-cence or evolves into migraine headaches.21 Migraine pro-phylaxis can be effective at decreasing the frequency andseverity of attacks.43

Migrainous vertigo is a vestibular disorder caused bymigraine, which presents with attacks of spontaneous orpositional vertigo lasting seconds to days and migrainoussymptoms during attack. The prevalence of migrainous ver-tigo is 7% in the dizziness clinic and 9% in the migraineclinic.44,45 Although migrainous vertigo is the most commoncause of spontaneous recurrent vertigo, it is not presently

Migraine may be associated with many

vestibular symptoms, including episodic vertigo,

chronic motion sensitivity, and

nonspecific dizziness.

TABLE 4. Central Causes of Dizziness

1. Cerebrovascular disorders

2. Migraine

3. Multiple sclerosis

4. Central positional vertigo/nystagmus

5. Epilepsy6. Craniocervical junction disorders

7. Neoplastic: primary, metastatic or paraneoplastic

8. Inherited ataxias

9. Psychophysiologic

10. Global cerebral hypoperfusion and hypometabolism

11. Neurodegenerative disorders: parkinsonism, normal pressurehydrocephalus

12. Posttraumatic dizziness

13. Toxic: alcohol, Cu, Hg, talium, lead, organic solvents, drugs(diphenylhydantoin, barbiturates, primidone, carbamazepine,5-fluorourasil, methotrexate, piperazine nitrofurantoin, lithium)



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included in the International Headache Society classificationof migraine.39 Migrainous vertigo can be diagnosed accord-ing to the following criteria: (1) recurrent vestibular symp-toms, (2) migraine according to criteria of InternationalHeadache Society, (3) at least 1 of the following migrainoussymptoms during at least 2 vertiginous attacks: headache,

phonophobia, photophobia, scintillating scotoma, or other auras,and (4) exclusion of other causes.40,44 Vertigo is occasionallycoincident with headache but more often occurs as an isolatedsymptom. Migraine-related vertigo is characterized by varyingmotion illusions and motion sensitivity, often with nausea.Vestibular symptoms associated with migraine are often de-scribed as spinning, slow or fast rotation, rocking, tilting, sway-ing, swimming, to and fro oscillation, or floating. Attack dura-tion often varies from seconds to days. Spell frequencies alsovary from 1 per month to 40 per month. Migraine also mayoccur with other causes of vertigo including benign paroxysmalpositional vertigo, psychogenic dizziness, Meniere disease, andother vestibular disturbances.21,44,46

Treatment of migrainous vertigo currently parallels thatof migraine headache.42 Mild symptoms or brief or infrequentspells may be left untreated. The long lasting (at least 30minutes) and frequent symptoms need vestibular suppressantssuch as meclizine, diazepam, or promethazine during vertigoattacks, and a migraine prophylactic drug.21,47

Multiple SclerosisVertigo is the initial symptom in about 5% of patients

with multiple sclerosis and occurs some time during thedisease in 50% of patients. Vestibular symptoms in multiplesclerosis may be sustained over days to weeks, and may beparoxysmal or positional. Prolonged spontaneous attacks ofvertigo occur if a demyelinative plaque is located in the root

entry zone of the vestibular nerve or nucleus. These findingsresemble acute peripheral vestibulopathy such as vestibularneuritis. Vertigo may last for hours to days and be associatedwith imbalance, vomiting, direction-fixed horizontal-tor-sional nystagmus with quick phase beating toward the unaf-fected side, and suppressed by visual fixation, and unilateralcanal paresis on caloric testing. Sudden hearing loss mayaccompany the vertigo when the auditory nerve is alsoinvolved. On the other hand, if central vestibular structuressuch as the vestibular nuclei, cerebellar peduncles, or thecerebellum are affected by demyelinating plaques, then ver-tigo, severe ataxia, other cranial nerve abnormalities, direction-changing nystagmus, pure vertical nystagmus, intentional

tremor, or pyramidal tract dysfunction may occur. Selectiveinvolvement of the vestibular nuclei may produce a syndromeindistinguishable from that of a peripheral lesion, except thenystagmus may not be suppressed by optic fixation, indicating acentral origin.2,48 Pendular nystagmus and internuclear ophthal-moplegia are common findings in multiple sclerosis. Such signscause distressing oscillopsia, dizziness, diminished vision, anddiplopia rather than vertigo. Frohman et al49 reported that themost common cause of vertigo in patients with multiple sclerosisis benign paroxysmal positional vertigo related to complicationof treatments. Central positional vertigo also can be seen inmultiple sclerosis with lesions located in the region of the fourthventricle.5 Conversely, most patients with multiple sclerosis

frequently have short-lasting paroxysmal vertigo and dizzinessnot related to benign paroxysmal positional vertigo.49

Central Positional Vertigo/NystagmusPositional vertigo results from a transient excitation

within the vestibular system triggered by a change in posi-

tion. Positional vertigo has been attributed to lesions of thesemicircular canals and their connections in the vestibularnuclei and cerebellum. Structural and metabolic factors in thesemicircular canals can alter the specific gravity of the cupulaand trigger positional vertigo during a particular head posi-tion. The peripheral and central origins of positional vertigohave long been known. The most common form of positionalvertigo is benign paroxysmal positional vertigo, and is nearlyalways benign and treatable; however, in rare cases, posi-tional vertigo can be a symptom of central nervous systemdisorder. Bertholon et al50 reported that benign paroxysmalpositional vertigo was found in 80% of patients with posi-tional vertigo, and central positional vertigo/nystagmus wasdiagnosed in 12% of patients with positional vertigo. Patients

with benign paroxysmal positional vertigo have brief epi-sodes of vertigo with position change, typically when turningover in the bed and getting in and out of bed. The diagnosisis easily made by Dix-Hallpike test.5

Central positional vertigo/nystagmus can be caused byvarious central nervous system lesions located in the regionof the fourth ventricle, dorsal vermis, and vestibular nu-clei.23,51 The most probable explanation for the central posi-tional vertigo/nystagmus is a vestibular tone imbalancecaused by disinhibition of the vestibular reflexes.51 There are3 forms of central positional vertigo/nystagmus: (1) posi-tional downbeat nystagmus, (2) positional nystagmus withoutconcurrent vertigo, and (3) positional vertigo with nystag-mus. The most common associated disorders due to central

positional vertigo/nystagmus are cerebrovascular disorders,spinocerebellar atrophy, multiple sclerosis, Arnold-Chiaritype-1 malformations, tumors of the brainstem and cerebel-lum, and some drugs.51,52 Differentiation between benignparoxysmal positional vertigo and central positional vertigo/nystagmus based on features such as latency, courses andduration of nystagmus during attack, fatigability, vertigo,vomiting, and time period during which nystagmus occursmay be impossible. Only central positional vertigo/nystag-mus is typically associated with pure vertical positionalnystagmus that does not remit with repeated positioning.Other neurologic signs of brainstem and cerebellum can beseen. Magnetic resonance imaging is the diagnostic tool of

Central positional vertigo/nystagmus can be

caused by various central nervous system

lesions located in the region of the fourth

ventricle, dorsal vermis, and vestibular nuclei.



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choice for identifying the posterior fossa lesion related tocentral positional vertigo/nystagmus.5,23 Table 4 provides thefeatures differentiating benign paroxysmal positional vertigofrom central positional vertigo/nystagmus (Table 5).

EpilepsyEpilepsy is a rare cause of vertigo. Vertigo associated

with epilepsy can be classified as vertiginous epilepsy, rota-tory seizures, vestibulogenic seizures, and dizziness and ver-tigo due to anticonvulsants.53

Recurrent vertigo attacks, and imbalance or dizzinesswith nausea, vomiting, or unilateral tinnitus during simplepartial seizures may occur without other symptoms of epi-lepsy.2 Such attacks also can be an epileptic aura for otherseizures. Such seizures can be triggered by stimulation of thevestibular cortex in fronto-temporo-parietal region.5355

Rotatory seizures (gyratory seizures) are defined as

circling behavior characterized by a rotation around the bodyaxis during a seizure for at least 180 degree, speech arrest,and secondarily generalized seizures. These seizures are rel-atively uncommon and may occur more frequently in frontallobe epilepsy than in temporal lobe epilepsy. Thalamic stim-ulation also has been shown experimentally to induce circlingmovements.56,57

Seizures evoked by vestibular stimulation (during ca-loric testing) are called vestibulogenic seizures and are com-plex partial or secondarily generalized seizures. Vertigo cannot be always seen during such evoked seizures.58,59

Anticonvulsants such as diphenylhydantoin, carbamaz-epine, barbiturates, diazepam, primidone, and others can

frequently cause dizziness, vertigo, imbalance, and doublevision as an adverse effect.2

Craniocervical Junction DisordersSpontaneous and positional vertigo, tinnitus, hearing

loss, dysarthria, dysphonia, ataxia, shortness of the neck,

lower neck hair line, limited range of motion in the neck,lower cranial nerve signs, and sometimes hydrocephalus aretypically seen in craniocervical junction anomalies. Symp-toms worsen with neck extension and cough.6062 The anom-alies associated with vertigo/dizziness are listed below:

a. Congenital fusion of the atlas and foramen magnum: Thisis the most common anomaly at the craniocervical junc-tion. The anteroposterior diameter of the canal behind theodontoid process is less than 19 mm. There are signs ofupper cervical spinal cord compression.61,62

b. Atlantoaxial dislocation: This indicates instability of C1(atlas) on C2 (axis) of more than 3mm from the C1 arc andodontoid process. It may be congenital; however, it is

frequently associated with rheumatoid arthritis and Downsyndrome.21

c. Platybasia and basilar invagination: Platybasia refers to aflattening of the base of the skull and the angle formed byintersection of the plane of the clivus; the plane of theanterior fossa is greater than 135 degrees. Basilar invagi-nation is an upward bulging of the occipital condyles.These anomalies give rise to a characteristic shortness ofthe neck and a combination of cerebellar and spinal signs.A normal-pressure hydrocephalus also may be seen.61,62

d. Chiari type-1 malformation: It is defined as more than 5mm of cerebellar tonsillar herniation below the foramenmagnum, most easily visualized on a midline sagittal

T1-weigthed magnetic resonance image. Patients maypresent with constant or slowly progressive dizziness orgait instability that may worsen with neck extension. AChiari type-1 malformation is frequently associated withspontaneous or positional vertigo, tinnitus, hearing loss,and lower cranial nerve signs. Downbeat nystagmus mayoccur spontaneously or may be induced with head hang-ing. Spontaneous vestibular nystagmus also can occur ona central basis as a result of compression of medullaryvestibular structures. The severity of symptoms of a Chiaritype-1 malformation may progress over time owing toaging, trauma, and degenerative effects on thejunction.21,6365

Tumors of the Cerebellopontine Angle andPosterior Fossa

Vestibular schwannoma or acoustic neuroma is a be-nign tumor arising from Schwann cells of the vestibular nerveinto internal auditory canal. This tumor accounts for 5% to10% of all intracranial tumors and is the most commonlyoccurring tumor of the cerebellopontine angle. The vestibularschwannoma grows slowly into the internal auditory canaland cerebellopontine angle, displacing the adjacent cerebel-lum, pons, or fifth and seventh cranial nerves. Progressiveunilateral hearing loss, tinnitus, and ataxia are common.Patients sometimes note true vertigo. Bruns nystagmus,

TABLE 5. Features Distinguishing BPPV From CPVN

Features BPPV CPVN

Latency 330 s None

Duration ofnystagmus

530 s 30 s

Direction ofnystagmus Torsional/vertical (P,A canals),horizontal (H canal)

Pure vertical/torsionalinappropriate withcanal

Persistent downbeatnystagmus in any

positionNo ()

Fatigability Yes No

Vertigo Always Can not be seen

Severe nausea () ()

Vomiting in firstmaneuver

Rare Common

Worse withnonspecific headmovement

No ()

Evoked by Dix-

Hallpike

() ()

Resolves aftermaneuvers

() No

Other neurologicsign

No May be

BPPV indicates benign paroxysmal positional vertigo; CPVN, central positionalvertigo/nystagmus; P, posterior; A, anterior; H, horizontal.



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which is a combination of peripheral vestibular nystagmusand gaze-paretic nystagmus, also may be seen. Less often,facial numbness and weakness, loss of taste and otalgia,trigeminal neuralgia, and symptoms of increased intracranialpressure may be seen. These symptoms also may occur withany mass in the cerebellopontine angle including meningi-

oma, trigeminal neuroma, cholesteatoma, epidermoid cysts,and metastatic tumors. Gadolinium-enhanced magnetic reso-nance imaging is the best technique for diagnosing a vestib-ular schwannoma. Neurofibromatosis type-2 is also an auto-somal-dominant disorder characterized by bilateral vestibularschwannoma, meningioma, or glioma.6668

Cerebellopontine angle meningiomas cause hearingloss and facial pain or numbness, dizziness and ataxia, andare the second most common tumor of the posterior fossa,after vestibular schwannoma. Magnetic resonance imag-ing usually differentiates a meningioma from a vestibularschwannoma because the latter originates from the internalauditory canal.66

Cerebellar tumors are astrocytomas, ependymomas,medulloblastomas, hemangioblastomas, and metastases. Me-dulloblastomas are the most common cerebellar tumors inchildren, and metastases are the most common in adults. Thetypical history for a posterior fossa tumor is the accumulationand progression of neurologic symptoms over weeks tomonths. Ataxia, nystagmus, and other ocular motor disordersare common and also depend on the specifically affected partof cerebellum. Positional vertigo and nystagmus, usuallydownbeat, also may occur. Occipital headache, radiatingforward, is the most common symptoms manifesting withcerebellar tumors. Cyclic vomiting, or vomiting upon lyingdown, and lower cranial nerve palsies may occur late in the

course. Compression of the fourth ventricle may cause ob-structive hydrocephalus that leads to papilledema.2,66

Paraneoplastic Cerebellar DegenerationParaneoplastic neurologic syndromes are nervous

system disorders caused by cancer but not metastaticdisease, vascular or metabolic deficits, infections, or nu-tritive deficiency. Immunologic factors probably play thecrucial role in the pathogenesis of paraneoplastic neuro-logic syndromes. Paraneoplastic cerebellar degeneration isa rare complication of cancer and is most frequentlyassociated with ovary, breast, and lung cancer as well as

Hodgkin lymphoma. Several paraneoplastic antineuronalantibodies such as anti-Yo and anti-Ri (breast and gyne-cologic cancer), anti-Hu (lung cancer), anti-Tr, and anti-mGluR1 (Hodgkin lymphoma) have been identified inpatients with paraneoplastic cerebellar degeneration. Para-neoplastic cerebellar degeneration typically begins fairlyabruptly and progress rapidly through several months witha subacute cerebellar syndrome. Patients with paraneoplas-tic cerebellar degeneration present with dizziness, nausea,and vomiting followed by gait instability, diplopia, nys-tagmus, gait and appendicular ataxia, dysarthria, and dys-phagia. Opsoclonus/myoclonus also may be seen in chil-dren with neuroblastoma.2,6973

Hereditary AtaxiasThe hereditary ataxias are a heterogeneous group of

genetic disorders that can be seen as an autosomal-dominant,recessive, X-linked, mitochondrial inheritance. The adult-onset autosomal dominant ataxias are now classified bysequential numbers assigned when a new genetic locus is

discovered, currently SCA1 through SCA28. The most com-mon autosomal recessive ataxia is Friedreich ataxia, which isusually caused by a GAA repeat expansion in the frataxingene. Symptoms of Friedreich ataxia begin before 20 yearsbut may manifest as late as the sixth decade. An axonalsensory neuropathy with areflexia, positive Babinski sign,dysarthria, proprioceptive and vibratory sensory loss, opticatrophy, scoliosis, diabetes, and cardiomyopathy besides typ-ical cerebellar ataxia are characteristic. Other rare causes ofautosomal recessive ataxias include ataxia-telangiectasia,abetalipoproteinemia, and Refsum syndrome.29,74,75

The familial episodic ataxias are rare, distinct, anddominantly inherited diseases of early onset characterized by

episodes of ataxia. Most patients recover fully between at-tacks, but some may develop progressive ataxia with cere-bellar atrophy. There are 2 subtypes of episodic ataxia:episodic ataxia type 1 (EA1), which manifests with interictalmyokymia without vertigo; and episodic ataxia type 2 (EA2),which often manifests with ataxia, vertigo, nausea, vomiting,dysarthria, and interictal mainly downbeat and gaze-evokednystagmus. Some EA2s develop progressive ataxia later inlife. Ataxic spells lasting minutes to hours are provoked bystress, exercise, or alcohol, and may respond to acetazol-amide. Familial episodic ataxias indeed are channelopathies.EA1 is caused by mutations in a potassium channel-encodinggene on chromosome 12p13, whereas EA2 is caused bymutations in a calcium channel-encoding gene localized onchromosome 19p, which is highly expressed in the cerebel-lum, which is also the disease-causing gene in spinocerebellarataxia type 6 and several kindreds with familial hemiplegicmigraine.29,7680

Psychiatric Dizziness

a. Psychogenic dizziness: Panic disorder with agoraphobia,generalize anxiety and personality disorders, and depres-sion are frequently seen in dizzy patients. Patients withpsychogenic dizziness have certain stimuli or social eventsas main causes, and a clear dissociation between objectiveand subjective dysequilibrium, inappropriately excessive

anxiety or fear, and no spontaneous nystagmus detected.On the other hand, primary vestibular disorders also caninduce secondary psychiatric symptoms.2,81,82

b. Phobic postural vertigo: Phobic postural vertigo is com-paratively the most frequent form of dizziness and ischaracterized by a combination of nonrotational dizzinessand subjective disturbance in the upright stance and gaitdespite normal results of clinical balance tests. Patientswith phobic postural vertigo often report a particularlyincreased unsteadiness when looking at moving visualscenes. It may be accompanied by anxiety and panicsymptoms. It is almost invariably associated with partic-ular constellations of perceptual stimuli or social situa-



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tions. There is a tendency for rapid conditioning, gener-alization, and avoidance behavior to develop. Thesubjective postural imbalance without falls is typical forphobic postural vertigo. Frequently, onset of the conditionfollows periods of particular psychosocial stress.8284

Phobic postural vertigo should be distinguished from

panic disorder or agoraphobia. Behavioral therapy andregular physical activity are effective in phobic posturalvertigo. When left untreated, phobic postural vertigo be-comes chronic in most cases and leads to considerableimpairments also at work.8,9,25,83,85

Presyncopal DizzinessPresyncope refers to light-headedness without an illu-

sion of movement that occurs just before fainting or losingconsciousness. Presyncopal signs and symptoms includinggeneralized weakness, giddiness, headache, blurred vision,diaphoresis, paresthesia, pallor, nausea, and vomiting areusually present for seconds or minutes before loss of con-sciousness. Presyncopal symptoms may be spontaneous, po-

sitional, or have specific triggers depending on the cause. Themechanism is almost always a reduction in blood flow to theentire brain.

Causes of presyncope have been categorized as cardio-vascular, neurologic, neurocardiogenic (vasovagal), meta-bolic, and psychiatric. Cardiovascular causes can be struc-tural heart disease, coronary heart disease, and arrhythmia.The most common neurologic causes are orthostatic hypo-tension and postural orthostatic tachycardia syndrome. Or-thostatic hypotension, which is one of the most commoncauses of syncope, can be attributed to impaired peripheralvasoconstriction or to a reduction of intravascular volume.On the other hand, postural orthostatic tachycardia syndrome

is a type of orthostatic intolerance characterized by excessivetachycardia and decreased cerebral blood flow in the uprightposition. Neurocardiogenic presyncope or vasovagal presyn-cope as an unexplained cause can be associated with painfulor emotionally stressful situations such as anxiety or fear,with prolonged standing or specific trigger situations. It isoften noted in individuals receiving sympathetic blockingagents and vasodilator drugs for hypertension, elderly pa-tients receiving tranquilizers, and patients with anemia. Hy-povolemia and hypoglycemia may lead to faintness andweakness. Hyperventilation is also a common cause of diz-ziness in anxious patients.7,86,87

Medical history and physical examination including

pulse and blood pressure monitoring both supine andstanding, cardiac auscultation, electrocardiogram, Holtermonitoring, tilt-table test, and blood glucose and hemato-crit analyses are the most important parts of the evaluationfor suspected presyncope.6,7,86

CONCLUSIONSDizziness and vertigo are among the most common

complaints in medicine, affecting approximately 20% to 30%of persons in the general population. Dizziness is a generalterm for a sense of disequilibrium. Vertigo is a subtype ofdizziness, defined as an illusion of movement caused byasymmetric involvement of vestibular system. Central ves-

tibular lesions affecting the pons, the medulla, or the cere-bellum cause vertigo, nausea, vomiting, severe ataxia, mul-tidirectional nystagmus (which is not suppressed by opticfixation), and other neurologic signs. Epidemiologic studiesindicate that central causes are responsible for almost one-fourth of the dizziness experienced by patients. The most

common central causes of dizziness and vertigo are cere-brovascular disor ders related to vertebrobasilar circulation,migraine, multiple sclerosis, tumors of posterior fossa, neurode-generative disorders, some drugs, and psychiatric disorders. Theother types of dizziness are dysequilibrium without vertigo,presyncope, and psychophysiologic dizziness, which is oftenassociated with anxiety, depression, and panic disorder.

ACKNOWLEDGMENTThe author is grateful to Prof. Dr. Tulay Kansu for

editorial assistance with the article.

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