Signs and Symptoms of Central Vestibular Disorders
Over the years, one of the principal uses of vestibular
function evaluations, both direct examination and laboratory
studies, has been to differentiate between peripheral and central
vestibular system disorders. In most cases well-defined
abnormalities on pursuit tracking or with saccade testing are
indicators of central vestibular system involvement. However,
just as a significant caloric asymmetry would be taken as an
indication of peripheral dysfunction, the abnormal central
findings on vestibular laboratory testing need to fit with the
symptom presentation to suggest that those findings relate to the
patient's presenting complaints. It is the purpose of this
article to review the signs and symptoms associated with
dizziness that would more likely be of central vestibular
The symptoms being reported by the patient can be very useful
as a first filter to narrow etiologic possibilities and serve as
a framework for interpretation of the findings from the formal
laboratory or by means of direct office examinations. To make use
of the presenting symptoms, the examining audiologist needs
details of the symptoms. Recognize that the most common term used
by a patient is that of
dizziness. The term
is a general term that can encompass imbalance, lightheadedness,
objective vertigo (objects in the room appear to move) and
subjective vertigo (the sensation of spinning is within the
patient's head, objects in the environment are stationary),
or combinations of the above. Therefore, in extracting the
history of the presenting and past symptoms there are four areas
of information that play a major role in helping to provide a
first-pass judgment as to whether the symptoms would be most
likely of peripheral or central origin. These four are as
- Temporal course of the symptoms: If the symptoms are
paroxysmal, would the typical duration be measured in seconds,
minutes, hours, or days, and what is the range from the
shortest to longest? If continuous, are there exacerbations in
the intensity of the symptoms, and what is the duration of
- Circumstances surrounding the onset of the symptoms: Are
the symptoms occurring in a spontaneous manner or are the
symptoms provoked by head or visual movement, visual
complexity, or visual patterns?
- The characteristics of the symptoms: Specifically, what
does the patient mean when he or she uses the term
dizziness? Is the patient experiencing true objective vertigo,
subjective vertigo, imbalance, lightheadedness, unexplained
falls, or combinations of these symptoms? Also, are the
symptoms accompanied by any of the following: nausea and
vomiting, headaches, heart palpitations, feelings of panic,
drop attacks, or any of the "Ds" (diplopia,
dysphagia, dysarthria, dysmetria [or asymmetric muscle
weakness])? The importance of the "Ds" is that any of
these symptoms on a consistent, unexplained basis is an
indicator of involvement of the posterior fossa. The other
associated symptoms can occur with either peripheral or central
- Status of their hearing by their perception: Do they have
unilateral or bilateral perceived hearing loss? Is this slowly
progressive and is one ear worse than the other? Do they have
sudden changes in hearing or fluctuations in hearing? Are they
experiencing tinnitus and/or aural fullness?
Before looking in more detail at the symptom characteristics,
which are more typical for central versus peripheral, a brief
discussion of the pathophysiology behind true vertigo will be
useful. Vertigo, independent of its anatomical lesion site,
results from sudden, asymmetrical neural activity. The asymmetry
in neural activity could be anywhere from the labyrinths to the
posterior cerebellum with the inclusion of the Pons area of the
brainstem. The distinction between labyrinthine involvement and
other structures within the posterior fossa would be by the
presence of brainstem/cerebellar symptoms of the "Ds."
It is highly unlikely that lesions in the midbrain or above will
produce true vertigo even with right-left asymmetries in neural
activity. For the centers above the posterior fossa, the most
common complaints would be lightheadedness and imbalance without
any vertigo. This implies that with vertigo as a complaint,
especially objective vertigo, the lesion is far more likely to be
confined to the posterior central circulation system involving
the vertebral arteries, basilar artery, and the Circle of Willis.
In contrast, the area of the brain fed primarily by the anterior
circulation involving the carotid arteries is much less likely to
be involved if the complaint is vertigo.
One can make a broad generalization regarding the symptoms
that are more likely to be of peripheral origin compared to those
of central origin. Table 1 shows this generalized separation. As
shown in Table 1, when a peripheral lesion is involved, onset is
more often than not sudden and usually memorable as the patient
will be able to tell you a specific date and in some cases a
specific time. True vertigo, where a patient reports seeing
objects moving in the room, would be the most common initial
symptom. If the peripheral condition is provoking paroxysmal,
spontaneous events of true vertigo such as that seen in
Meniere's syndrome, it would be highly unusual to have the
true vertigo last longer than 24 hours continuously. However, a
single spontaneous onset of a vestibular crisis event (e.g.,
vestibular neuronitis or labyrinthitis) can have vertigo that
will persist for 24-72 hours on a continuous basis, then
resolving into head motion provoked symptoms. Vestibular crisis
events do not create paroxysmal, spontaneous symptoms. If the
presentation were of head movement provoked symptoms, it would be
typical to have the dizziness last for only seconds to 2 minutes
after a provocative movement if the patient stops his or her
activity. Lastly, it would be much more common to have auditory
symptoms accompany a peripheral (labyrinthine or VIIIth nerve)
In contrast, lesions of central origin are usually slow in
development, with the patient unable to give you a time of onset.
This can also be true for symptoms from nonvestibular involvement
(e.g., peripheral neuropathy). If symptoms are of sudden onset
with vertigo or imbalance and they do not involve the
labyrinthine or VIIIth nerve, then usually you have accompanying
symptoms suggesting posterior fossa involvement ("Ds").
The principal symptom is more likely to be that of imbalance and
lightheadedness with vertigo absent. In cases where psychological
conditions such as anxiety are a major portion of the disorder,
the symptoms may be very vague, with the patient struggling to
articulate his or her experiences. The psychological group is
also more likely to present with subjective vertigo that is a
slow spinning within the head that is present on a constant basis
and exacerbated by visual motion and/or complex visual
It would be very comforting if all patients fell clearly into
the group of peripheral or central symptoms; however, this is not
the case. While patients will have a dominant group of symptoms
that will be more closely tied to peripheral or central origin,
there will be those who have a full mix of the two groups.
Therefore, the above discussion is provided as an initial guide
but it is certainly not the final answer. Just as we have done
with symptoms, the signs (either direct office examination or
formal vestibular and balance laboratory findings) that are
presented, when mixed with the symptoms, begin in most patients
to present a clearer picture of the origin of the dizziness.
Table 2 presents a generalization of signs divided as was done
for symptoms into peripheral and central origin.
As presented in Table 2 the lesion of peripheral origin is
likely to present with direction-fixed, dominantly horizontal
nystagmus. The nystagmus, especially in the subacute and chronic
states may likely only be seen with visual fixation removed and
when visualization will be direction fixed, independent of the
direction of gaze. These patients will typically follow
Alexander's law with increasing intensity of the nystagmus as
they gaze in the direction of the beat of their nystagmus. In
contrast, the lesion of central origin is more likely to present
with pure vertical or torsional nystagmus and if horizontal it is
more likely to change direction based on the direction of the
patient's gaze. Other contrasting features would be the
absence of abnormalities on pursuit tracking and saccade testing
in the peripheral lesion and the likelihood of seeing
abnormalities on these tests in the patient with a central
lesion. Headshake testing in the horizontal or vertical
direction, if nystagmus is produced, should be horizontal from
either direction of shaking for the peripheral lesion and may
well be vertical for the central lesion. Although most persons
with sudden onset of severe peripheral origin vertigo with
nystagmus say they could not walk at the beginning, they actually
are able to coordinate their lower limbs in a walking pattern
even though they may well need assistance secondary to the severe
imbalance. However, central vestibular lesions may well produce a
situation where at the onset of symptoms, if they are sudden, the
patient cannot coordinate the lower limbs in a walking pattern
and cannot walk even with assistance.
When considering the signs that represent possible central
system involvement, abnormalities in pursuit tracking and in
random saccade testing are such that they are specific to central
system deficits. There are no peripheral lesions that are known
to produce abnormalities in either of these two tests, with the
exception of the spontaneous nystagmus that can exist from an
acute peripheral lesion of any etiology. To further discuss in
detail the interpretation of pursuit tracking and that of random
saccade testing is beyond the limited scope of this article and
the interested reader is referred to the suggested resources
listed at the end of the article for further detailed information
in this regard. The two other principal indicators of central
involvement, the type of nystagmus (pure vertical and pure
torsional) and nystagmus provoked by eccentric gaze, require
further explanation as these are the most likely to be confused
with possible peripheral system involvement.
Is pure vertical down- or upbeating nystagmus to be considered
peripheral or central in origin? In answering this question it is
useful to consider the specific eye movements that are provoked
in a normal individual when each of the semicircular canals is
individually stimulated. The movements considered below are the
compensatory eye movement (slow component of nystagmus), the
vestibulo-ocular reflex (VOR), when the canal in question is
stimulated, not the beat or fast component.
- Horizontal (lateral) canals right and left: VOR response
would be to the left and right, respectively.
- Anterior (superior) canals right and left: VOR response
would be up for both with a torsional movement to the left for
the right canal and to the right for the left canal.
- Inferior (posterior) canals right and left: VOR response
would be down for both with a torsional movement to the left
for the right canal and to the right for the left canal.
Using the above descriptions of the VOR responses for each of
the canals, the only way to produce a down-beating nystagmus from
the periphery would be with simultaneous stimulation of both
anterior canals. The VOR response would be pure up with the
torsional components canceling and the beat would be down. To
have this happen via a pathological insult would require that
both anterior canals have simultaneous irritative lesions or have
simultaneous paretic lesions of both posterior and horizontal
canals. Currently, there is only one condition that has been
reported that is a peripheral disorder known to produce at least
transient pure down-beat nystagmus: bilateral superior canal
dehiscence. Otherwise, the likelihood of a peripheral disorder
capable of causing pure vertical up- or down-beating nystagmus is
so remote that pure vertical nystagmus should be considered of
central origin until proven otherwise. This same rationale may be
applied with the use of the specific individual canal eye
signatures to pure torsional and pure up-beating nystagmus.
Of the principal signs for central involvement, gaze stability
during eccentric gaze is the only one in which abnormalities of
either the peripheral or central vestibular and ocular motor
systems can produce abnormalities. Therefore, it is best to lay
out distinguishing and contrasting features that will allow for
this peripheral versus central nervous system differentiation.
The principal abnormality noted in gaze stability testing would
be the development of nystagmus in place of steady gaze, referred
to as gaze-evoked nystagmus. The general characterizations of
gaze-evoked nystagmus of peripheral origin are given in Table 3,
and those characterizations associated with gaze-evoked nystagmus
of central origin are given in Table 4. While all of the
characteristics listed can be observed, the dominant one for
determining that the gaze-evoked nystagmus is of peripheral
origin is the enhancement in the nystagmus with fixation removed.
For gaze-evoked nystagmus of central origin, the dominant
characteristic is that of direction-changing nystagmus or pure
vertical or pure torsional nystagmus.
Another aspect of gaze-evoked nystagmus of central origin is a
feature referred to as rebound nystagmus. In this situation,
nystagmus is produced beating in the last direction the eye moved
as the eye is returned to primary position from eccentric gaze.
Even for a normal individual, if the eccentric gaze is held for
an extended period of time, one to two beats of nystagmus may be
visualized. What is being tested for is a burst of nystagmus
lasting several seconds, with the fast component in the last
direction of movement of the eye. For example, if persistent
gaze-evoked, right-beating nystagmus is noted on right gaze, then
on return to center (a leftward eye movement) a brief event of
left-beating nystagmus is seen that does not persist.
A caveat to the above discussion is the realization that the
signs and some of the symptoms that we would associate with
central nervous system involvement can be produced by migraine
headaches. Virtually all of the abnormal findings we have
discussed for both central and peripheral lesions, as well as
abnormal caloric and rotational chair findings, have been
reported in patients where migraine headaches were the principal
cause of their dizziness. It is beyond the scope of this article
to present a full discussion of migraine-related dizziness and
the reader is referred to the suggested resources, but it is
worth noting that this can be a factor of confusion.
While a brief discussion, hopefully this article has provided
the essentials on the use of presenting symptoms and signs to
assist in the identification of dizziness of central origin.
Those desiring further details on the above issues are referred
to the resources that provide the basis behind the information
presented herein and are the suggested readings for continued
study in this area.
Neil T. Shepard, PhD, CCC-A
Mayo Clinic, Rochester, MN
Deutschlander, A., Strupp, M., Jahn, K., Quiring, F., &
Brandt, T. (2004). Verticaloscillopsia in bilateral superior
canal dehiscence syndrome.
Neurology, 62, 784-787.
Furman, J. M., & Cass, S. P. (2007).
Balance disorders: A case-study approach. Philadelphia: F. A. Davis.
Furman, J. M., Marcus D. A., & Balaban, C. D. (2003).
Migrainous vertigo: Development of a pathogenetic model and
structured diagnostic interview.
Current Opinion in Neurology, 16, 5-13.
Jacobson, G. P., & Shepard, N. T. (2008).
Balance function assessment and management. San Diego, CA: Plural Publishing.
Leigh, J. R., & Zee, D. S. (2006).
The neurology of eye movements
(4th ed.). New York: Oxford University Press.
Staab, J. P., & Ruckenstein, M. J. (2007). Expanding the
differential diagnosis of chronic dizziness.
Archives of Otolaryngology-Head & Neck Surgery, 133, 170-176.
Resources on Central Vestibular Disorders
Table 1: Generalized symptoms of peripheral and central
- Labyrinthine/VIIIth nerve
- Sudden, memorable onset
- Typically true vertigo at onset
- Paroxysmal spontaneous events <24 hours
- Head movement provoked symptoms <2 minutes
- Vestibular crisis: sudden onset vertigo slowly improving
from continuous to head movement provoked symptoms in
- More likely to have auditory involvement
- Central vestibular or nonvestibular symptoms
- Sudden onset of vertigo, lightheadedness/imbalance with
one of the Ds
- Slow-onset imbalance standing and walking
- Vague symptoms of any character
- Slow subjective vertigo (spinning within the
patient's head) lasting 24/7
Table 2: Generalized signs for peripheral and central vestibular
- Labyrinthine/VIIIth nerve
- Direction-fixed, dominantly horizontal nystagmus
- Abnormal vestibulo-ocular reflex, via head thrust or
- Nystagmus more likely to be seen with fixation
- Nystagmus more likely to be exacerbated when gazing in
the direction of the fast component of the jerk nystagmus
- Nystagmus more likely to be exacerbated post horizontal
headshake - horizontal nystagmus
- Pursuit tracking and saccade performance normal (or age
- If sudden onset, can stand and walk with assistance
- Central vestibular or nonvestibular signs
- Direction-changing nystagmus
- Nystagmus more likely enhanced with fixation present
- Nystagmus more likely to be pure vertical or pure
- Nystagmus post-headshake vertical
- Likely to have abnormal performance on pursuit and/or
- If sudden onset, likely not to be able to stand and walk
even with assistance
Table 3: Characteristics of gaze-evoked nystagmus of peripheral
- Acute lesion: In a peripheral lesion, nystagmus is usually
only visible with fixation present when the lesion is acute in
- Direction fixed: Nystagmus with fixation present or absent
should be direction fixed in nature. It may have both
horizontal and vertical components, but it must have a
horizontal component to be considered of peripheral origin
(i.e., pure vertical nystagmus is taken as central until proven
otherwise; see text for explanation).
- Alexander's law: The horizontal nystagmus should follow
Alexander's law (i.e., the nystagmus increases in its
intensity as the patient gazes further in the direction of the
fast component of the nystagmus); this applies to horizontal
nystagmus component only.
- Enhanced with fixation removed: This is the primary
determiner of the periphery being the source of the nystagmus.
When fixation is removed, nystagmus is brought forth when
absent with fixation, or nystagmus intensity increases if seen
with fixation present.
- Nystagmus enhanced with headshake test: If ongoing,
direction-fixed nystagmus of peripheral origin is present it
can usually be enhanced with headshake testing.
- Linear slow component: On the tracing of the nystagmus, the
slow component is a linear trace (straight line).
Table 4: Characteristics of gaze-evoked nystagmus of central
- Acute or chronic: When nystagmus is seen with fixation, it
can be from an acute or chronic (beyond 12 weeks) lesion. The
nystagmus persists following the lesion onset without any
significant diminution in intensity with time.
- Direction fixed or changing: While the nystagmus could be
direction fixed in nature, such as pure up or down beat, it is
likely to be direction changing based on the direction of gaze
(i.e., right beat with right gaze, left beat with left gaze,
etc.). This also applies to a form of nystagmus called
"rebound" nystagmus. With rebound nystagmus, the
direction of the beat is always in the last direction that the
eye moved. Also, pure vertical or pure torsional nystagmus even
though direction fixed is taken as indicative of central
involvement until proven otherwise.
- Rarely in primary: It is rare to have horizontal nystagmus
persist in the primary (straight ahead) gaze position (it can
be there for a brief interval when rebound is present and
returning from eccentric gaze). Pure vertical or pure torsional
nystagmus can persist in the primary gaze position with central
- Enhanced with fixation present: Typically, nystagmus is
increased in its intensity with fixation present and no change
or a reduction in the nystagmus is seen when fixation is
- Vertical nystagmus post headshake test: It would be unusual
to see horizontal nystagmus enhanced with horizontal headshake
when the nystagmus is of central origin only. It is possible
that following either a horizontal or vertical headshake test
the nystagmus produced is that of pure vertical when a central
lesion is the source of the nystagmus.
- Decreasing speed of slow component: The horizontal
nystagmus trace many times will show a slow component that is
nonlinear, implying a slowing in the speed of the eye as it
moves from the lateral toward the primary gaze position.
About the Author
Dr. Shepard is the director of the Dizziness and Balance
Disorders Program at the Mayo Clinic, Rochester, Minnesota, and
is a professor of audiology in the Mayo Clinical School of
Medicine. He received his undergraduate and master's
training in Electrical and Biomedical Engineering from the
University of Kentucky and the Massachusetts Institute of
Technology. He completed his PhD in auditory electrophysiology
and clinical audiology from the University of Iowa in 1979. He
has specialized in clinical electrophysiology for both the
auditory and vestibular systems. His work over the past 28
years has been focused on clinical assessment and
rehabilitation of patients with balance disorders and on
clinical research endeavors related to both assessment and
This article first appeared in the Vol. 8, No. 1,
January/February 2009 issue of