Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4433_Библиотеки_им_академика_М_И_Перельмана
.pdf
464 BALANCE FUNCTION ASSESSMENT AND MANAGEMENT
https://t.me/medicina_free
information but is an indicator of overall vestibular
responsiveness across a range of frequencies (0.01 to
0.64 Hz); therefore, rotary chair cannot be used to localize unilateral peripheral vestibular system involvement
but is an excellent assessment for diagnosing bilateral
vestibular loss. The two main rotary chair paradigms
utilized with children are the sinusoidal harmonic
acceleration (SHA) test and the step test (refer to Chapter 13 for additional information on these paradigms).
One advantage of the rotary chair is that unlike caloric
testing, middle-ear abnormalities (i.e., pressure equalizing tubes, atresia, etc.) do not preclude testing.
Rotary chair testing is tolerated by most children.
Children can sit in the chair independently or can be
seated on a parent’s lap. For children younger than
5 years, SHA testing is preferred because of its gentle
nature. Electrodes are used for eye movement recording and a chair-mounted camera is used to monitor
the child during rotation. The chair-mounted camera
is used to ensure that the child is awake and alert. On
occasion, children will not tolerate the use of electrodes
on the face, in which case the chair-mounted camera
can be used to subjectively observe nystagmus during rotation (Figure 18–3). Infants being tested are
seated on the parent’s lap and the parent is asked to
place a hand over the child’s head, attempting to keep
the head still. For children greater than 5 years, either
step or SHA can be completed and eye movements are
recorded with video goggles. Similar to adults, some
degree of mental tasking is recommended during rotation as rotary chair gain can decrease with decreased
alertness. Older children are generally engaged in conversation or simple cognitive tasks such as counting or
spelling, and younger children are kept alert by singing children’s songs. Difficulty lies in alerting children
with significant hearing loss. In this instance, children
are encouraged to wear their hearing aids. If the child is
seated on the parent’s lap, the parents are encouraged
to talk or sing to the child to maintain alertness.
Rotary chair outcome parameters are gain, phase
(time constant), and symmetry. Similar to adults, gain
less than 0.01 with phase greater than 68 degrees in
response to 0.01 Hz during SHA testing suggests
bilateral vestibular loss (Strupp et al., 2017); therefore,
inclusion of 0.01 Hz is recommended. A typical order of
testing would be 0.04, 0.01, 0.16 Hz for a mid, low, and
high frequency assessment. If the child is still cooperative, 0.02 and 0.08 Hz would be completed.
Figure 18–4 demonstrates abnormal rotary chair
SHA gain in a 12-year-old with history of meningitis. In
children with normal vestibular function, high rotary
chair gains have consistently been reported compared
with adults (Charpiot et al., 2010; Maes, De Kegel, Van,
figure 18–3. Example of a child seated on a parent’s
lap during rotary chair.
tively observed on an external monitor via an infrared
chair mounted camera (inset ).
The child’s eyes can be subjec-
& Dhooge, 2014; Valente, 2007), with the exception of
Casselbrant et al. (2010) who found a linear increase in
rotary chair gain in children ages 3 to 9 years. Because
of these findings, high gain in young children is not
considered a pathologic finding unless coupled with
other indications for central pathology. Some data suggest significant differences in phase between adults and
normal children. In infants, phase has been found to be
more variable and have a tendency to exhibit a phase
lag. This variability and lag both improve with age. The
variability in phase is attributed to lack of steady head
position during testing (Staller, Goin, & Hildebrandt,
1986). In older children, larger phase values have been
found compared with adults (Valente, 2007). Because
larger phase values (i.e., phase leads) can be indicative of peripheral vestibular system involvement, ageappropriate normative data are needed to determine
18. PEDIATRIC VESTIBULAR TESTING 465
https://t.me/medicina_free
figure 18–4. Example of abnormal rotary chair gain in a 12-year-old child with history of meningitis. Left panel
shows low gain for all frequencies assessed (0.02, 0.08, 0.16, and 0.32 Hz), middle panel shows asymmetry, and
right panel shows phase.
This child also had low vHIT gains, as shown in Figure 18–5.
appropriate clinical cutoffs. Collectively, these findings suggest that the VOR undergoes maturation from
childhood to adulthood and that age-appropriate normative data are needed when assessing children.
Rotary chair can be completed on children of any
age; however, it is typically completed on children
older than 4 months due to development of the VOR
(Staller et al., 1986). Additionally, higher amplitude
nystagmus is associated with heavier babies (Eviatar
& Eviatar, 1979). Staller et al. (1986) report 10% of
infants less than 60 days old do not generate measurable nystagmus in response to rotation. It has been recommended that if children less than 6 months of age
do not elicit nystagmus to rotation, testing should be
repeated once they are older than 6 months to rule out
maturational effects (Eviatar & Eviatar, 1979).
Postural Control Assessment
The Sensory Organization Test (SOT) is a routine
assessment of balance function for both adults and children. The SOT evaluates use of visual, vestibular, and
proprioceptive sensory inputs in the maintenance of
balance. During SOT, postural sway is measured over
three trials for each of the following six conditions:
(1) eyes open, stable platform; (2) eyes closed, stable
platform; (3) eyes open, sway surround; (4) eyes open,
sway platform; (5) eyes closed, sway platform; and
eyes open, sway surround, sway platform. In each
(6)
of these conditions, some facet of the visual, vestibular,
and/or proprioceptive system is disrupted, providing
a functional assessment of overall balance. For example, condition 5 primarily assesses how well the subject utilizes vestibular inputs for maintaining balance;
in this condition, the subject has his or her eyes closed,
eliminating use of the visual system, and the platform
sways, eliminating effective use of proprioception.
Outcome parameters for the SOT include an equilibrium score for each trial and an overall composite
score. The equilibrium score is a percentage of degree
of sway, from 0 to 100, and assumes an anterior posterior postural sway envelope of 12.5°, so a score of 0
means the child swayed maximally 12.5° (or more),
and a score of 100 means the child was perfectly still.
Children must weigh at least 30 lbs to put enough
weight on the platform to record postural sway. Normative data for the SOT exist in children down to age 3
(Hirabayashi & Iwasaki, 1995; Rine et al., 1998). Overall composite scores improve with age, meaning that
younger children demonstrate greater degrees of sway
than older children and adults (Casselbrant et al., 2010;
Peterson et al., 2006; Rine et al., 1998; Valente, 2007).
As reviewed above, children make appropriate use of
somatosensory information by age 6; however, use of
visual and vestibular information is still undergoing
maturation. Thus age-appropriate normative data are
necessary for SOT. In younger children, where use of
somatosensory information is mature, performance
on conditions 1 to 3 can be expected to mimic that of
adults; however, in the remaining conditions, where
visual and vestibular information are predominantly
utilized, greater degrees of sway can be expected for
younger children. By age 12 to 15 years, children can
be expected to perform adult-like under all SOT conditions (Peterka & Black, 1990; Peterson et al., 2006).
The purpose of the SOT in children is to detect
balance dysfunction, but it can also be used to monitor various disorders known to affect the postural control pathway (Hirabayashi & Iwasaki, 1995). Children
often require extensive coaching, reinforcement, and
466 BAlAnCE FunCtion AssEssmEnt And mAnAgEmEnt
https://t.me/medicina_free
encouragement. Some children have fear of closing
their eyes during testing. In this instance, fun glasses
can be used to eliminate clear vision, or the room lights
can be dimmed or turned off for brief periods in order
to eliminate visual cues.
Pursuit Tracking
Pursuit tracking, or smooth pursuit, is the ability to
visually track a moving visual target. The purpose of
evaluating pursuit tracking is to assess the vestibulocerebellum and, more generally, the brainstem and
cerebellum. During pursuit tracking, patients view a
computer-generated visual target, which oscillates back
and forth at frequencies ranging from 0.2 to 1 Hz. The
main outcome parameter is gain, which is calculated by
dividing eye velocity by target velocity. In adults, it has
been well described that the ability to perform pursuit
tracking declines with age.
Children have the ability to perform smooth pursuit eye movements as young as 2 months of age (Jacobs
et al., 1997); however, smooth pursuit gains are significantly lower and more variable in children compared
with adults and continue to mature with age (Accardo,
Pensiero, Da, & Perissutti, 1995). Children should be
able to achieve normal smooth pursuit by age 5 (Levens,
1988). Pursuit tracking is significantly affected by level
of attentiveness; therefore, children should be coached
throughout testing. For all ocular motor testing, use of
fun, colorful targets can be helpful in the assessment of
children. Some manufacturers allow the programming
of cartoon characters as visual targets.
Random Saccade
A saccade is a rapid eye movement from one point of
fixation to another. There are a variety of paradigms to
assess saccade performance; however, the most widely
used is the random saccade test. With the random saccade test, the main outcome parameters are latency,
velocity, and accuracy. Saccade latency is calculated
as the time from target onset to the initiation of eye
movement; velocity is the speed of the eye movement
as it moves to the target; and accuracy is the precision
with which the eyes meet the target. These outcome
parameters are all analyzed via commercial systems.
In general, saccade accuracy is thought to arise from
the posterior vermis region with velocity and latency
originating by the parapontine reticular formation.
Because these outcome parameters are engendered by
different substrates, abnormalities of saccade latency,
velocity, and accuracy can help to further determine
site of lesion. In children, saccade latency decreases
with age, while saccade velocity is stable during childhood. Maturation of saccades is thought to be complete
by age 12 (Bucci & Seassau, 2012).
OKN Up to Age 7
OKN nystagmus is a reflexive eye movement in
response to moving objects in the visual field. When
visual targets are moving to the right, left-beat OKN
occurs and vice versa for visual targets moving to the
left. A true test of the OKN system requires that at minimum, the target (stripes, dots, etc.) take up 90% of the
visual field. OKN is thought to reach maturation by
age 7 (D’Agostino, Melagrana, Pasquale, & Taborelli,
1997). For children less than 7 years of age, gain values
decrease with the decreased age and thus require agespecific normative ranges. As with the adult, OKN is
dominated with smooth pursuit tracking even though
saccades are also involved. As in the discussion in the
introduction, this can be taken advantage of to get an
estimate of smooth pursuit by using OKN (Mezzalira
et al., 2005; Valmaggia et al., 2004). Like other tests of
ocular motor function, cartoon characters can be substituted for standard visual targets. Children generally
do not require any special instructions, as OKN is a
reflexive eye movement; however, they can be asked
to simply watch or attempt to count the visual stimuli.
Hallpike and Roll Tests
The Dix–Hallpike and roll tests are bedside assessments for the presence of benign paroxysmal positional
vertigo (BPPV) in the vertical and horizontal canals,
respectively. BPPV is rare in children; however, it
should not be disregarded in the pediatric population,
particularly in the event of head trauma or if the child
complains of positional dizziness. There are no specific modifications in the way the Dix–Hallpike or roll
maneuvers are completed in children. BPPV has been
reported in children as young as 3 years (Saka et al.,
2013). Treatment of BPPV in the pediatric population
utilizing canalith repositioning maneuvers is the same
as with adults. However, issues with both assessment
and treatment of BPPV in children are fear of being
dizzy and keeping their eyes open during these provoking maneuvers. Reassurance and use of fun visual
targets, stickers, or finger puppets can be helpful.
Gaze Testing and Positional Testing
The purpose of gaze testing is to assess for the presence
of spontaneous and/or gaze-evoked nystagmus. During gaze testing, the presence of nystagmus is evalu-
18. PEdiAtriC vEstiBulAr tEsting 467
https://t.me/medicina_free
ated while patients view a visual target directly in front
of them (center position), eccentrically 30° to 40° to the
right, left, up, and down and then in these same eye
positions with fixation removed. Gaze-evoked nystagmus can originate from either the peripheral or
the central vestibular system, with differences in clinical presentation between the two (see Chapter 10 for
details). Nystagmus that is peripheral in origin will
generally have a linear slow component, be direction fixed, and enhance with fixation removed. Nystagmus is considered to be of central origin if it has
a rounded (versus linear) slow component velocity,
rebounds (where the fast component of the nystagmus
changes with the direction of the last eye movement),
or enhances or does not change in intensity with fixation. In children, at minimum a subjective assessment
of spontaneous nystagmus should be completed. Like
adults, children’s gaze testing can uncover evidence of
an acute peripheral vestibular disorder or provide evidence for central vestibular system involvement.
The purpose of static positional testing is to examine the effect of gravity on positional changes of the
head. During static positional testing, eye movements
are recorded with fixation removed in the sitting,
supine, body-right, body-left, and pre-caloric positions.
Additionally, positional testing can be completed with
the head turned right and left in the sitting, supine,
and head-hanging positions to examine the influence
of cervical head movement. The interpretation of positional nystagmus in children is similar to that of adults.
Positional nystagmus is classified as either direction
fixed (e.g., right-beating in all positions) or direction
changing (e.g., right-beating in some positions and leftbeating in others). Direction-changing nystagmus may
be further categorized as geotropic (nystagmus beating toward the earth) or ageotropic (nystagmus beating
away from the earth).
The clinical significance of positional nystagmus is
determined by its intensity, frequency, and direction. In
terms of intensity, positional nystagmus is considered
clinically significant if it meets the following criteria:
(1) the slow phase velocity is greater than 5 degrees
per second in any given position and (2) the slow phase
velocity is less than 6 degrees per second but is present in more than 50% of positions (minimum two out
of four positions). Significant positional nystagmus is
localized as peripheral, central, or non-localizing based
on the direction and pattern of nystagmus. Directionfixed positional nystagmus is typically localized to the
peripheral vestibular system, specifically when there
are no other indications of central vestibular system
involvement on either direct exam or case history.
Direction-changing nystagmus, within any given posi-
tion, is localized to the central vestibular system, while
direction-changing nystagmus between positions can
localize to either the periphery or central system or be
considered non-localizing.
VEMPs: Cervical and Ocular
VEMPs are used to assess otolith function by measuring muscle potential changes in response to acoustic
stimulation. There are two types of VEMP responses:
cervical and ocular. Cervical VEMPs measure muscle
potential changes in the sternocleidomastoid muscle
and provide information regarding saccule and inferior vestibular nerve function (Colebatch, Halmagyi,
& Skuse, 1994), while ocular VEMPs measure muscle
potential changes in the inferior oblique eye muscle and
are speculated to provide information regarding utricle and superior vestibular nerve function (Rosengren,
McAngus, & Colebatch, 2005). Both the cervical and
ocular VEMPs are recorded in response to acoustic
stimulation, either air or bone conduction. The cVEMP
is an ipsilateral, inhibiting response, meaning that
acoustic sound delivered to the ear causes the ipsilateral contracted sternocleidomastoid muscle to relax.
The oVEMP is a contralateral, excitatory response,
meaning that acoustic sound delivered to the ear
causes the contralateral inferior oblique muscle to contract. VEMPs have been shown to be purely vestibular
in nature as they are preserved in patients with sensorineural hearing loss (Colebatch et al., 1994).
Outcome parameters in cVEMP are the p13 and
n23 latencies and the p13/n23 peak-to-peak amplitude. Cervical VEMPs have been measured in children
as young as 1 to 4 weeks in response to 95 to 100 dB
nHL, 500 Hz tone bursts (Erbek et al., 2007; Sheykholeslami, Megerian, Arnold, & Kaga, 2005). Cervical
VEMP responses in children are similar in morphology
to those of adults, with the exception that both the p13
and n23 latencies are shorter in children and prolong
with age; there is also greater variability in the p13/
n23 peak-to-peak amplitude in children (Chang, Yang,
Wang, & Young, 2007; Kelsch, Schaefer, & Esquivel,
2006; Sheykholeslami et al., 2005; Valente, 2007). Prolongation of the p13 latencies with age has been attributed to neck length in children (Chang et al., 2007).
The presence of cVEMP responses at birth provides
evidence for their early development.
The outcome parameters in oVEMPs are the
n10 and p16 latencies and the n10/p16 peak-to-peak
amplitude. Wang, Hsieh, and Young (2013) report that
oVEMPs are not present in children until 12 months and
do not report reliable response rates in children until
4 years. These responses are difficult to obtain in infants
468 BAlAnCE FunCtion AssEssmEnt And mAnAgEmEnt
https://t.me/medicina_free
as sustained up-gaze is necessary for measuring ocular VEMP. However, oVEMPs have also been recorded
when children gently close their eyes, taking advantage of Bell’s phenomenon, which can be attempted in
young children (Huang, Yang, & Young, 2012; Wang et
al., 2013). No significant differences in oVEMP latency
or amplitude have been reported compared with adults.
VEMPs are fairly quick to administer and are especially helpful in the pediatric population as they provide ear-specific information about vestibular function
without inducing symptoms of dizziness. Difficulties
in obtaining these responses in the pediatric population are that children must sustain contraction of the
sternocleidomastoid muscle (background tonic electromyography [EMG]) for cVEMPs and sustain up-gaze
for oVEMPs. Kelsch et al. (2006) report less sternocleidomastoid fatigue when children are allowed to prop
up on their elbows. We have found toys and computer
animations as well as continued verbal reinforcement
to be helpful for maintaining head turn and contraction with cVEMPs. For oVEMPs, stickers placed on the
ceiling or video playing on a tablet has been helpful for
maintaining 30 degree up-gaze.
For either type of VEMP, one final concern is the
high stimulus level required to record these responses
(Portnuff, Kleindienst, & Bogle, 2017). In adults, a 125 dB
SPL, 500 Hz tone burst is typically used. Although this
stimulus level is considered safe in adult-sized ears,
stimuli are approximately 3 dB higher in children’s
ears (Rodriguez, Thomas, Fitzpatrick, & Janky, 2018;
Thomas, Fitzpatrick, McCreery, & Janky, 2017). Therefore, prior to VEMP, tympanometry is recommended to
rule out any conductive component that might attenuate the stimuli. In children whose ear canal volumes
are less than 0.9 mL, a 120 Hz tone burst would be recommended for safe exposure (Rodriguez et al., 2018).
Additionally using a 750 Hz tone burst is considered
safe due to its shorter duration compared with 500 Hz
(Rodriguez et al., 2018).
Caloric Irrigations
Bithermal caloric testing is currently regarded as the
gold standard in assessment of the horizontal canal
and, subsequently, the superior branch of the vestibular nerve. The main benefit of caloric testing is that it
yields ear-specific information. Caloric testing can be
completed with either air or water stimuli. With either
method, a cool (inhibitory) or a warm (excitatory) stimulus is delivered to each ear. While air is a more convenient stimulus type, water has been shown to result in
higher slow phase velocities, specifically in response to
warm water (Maes et al., 2007; Zangemeister & Bock,
1980; Zapala, Olsholt, & Lundy, 2008). Water calorics
have been deemed the stimulus of choice, with air stimulation recommended when water is contraindicated.
Interpretation of caloric responses in children is
identical to that of adults. Interpretation is completed
in two ways: (1) the magnitudes of slow component
velocities are first identified as being reduced, normal,
or hypermetric, and (2) comparisons between right and
left irrigations are made using the peak of the response
in Jongkees formula (Jongkees, Maas, & Philipszoon,
1962). Comparisons between right and left ears are
not routinely completed when caloric responses are
reduced bilaterally. A wide range of accepted normal
caloric responses have been reported. Caloric responses
are considered hypermetric when slow phase velocities exceed 60 to 70°/s and are considered bilaterally
reduced when either the sum of all responses is less
than 20°/s or the peak response is less than 10°/s for
warm irrigations and less than 15°/s for ice water irrigations. When comparing right and left responses,
individual labs should determine their own cutoff
criteria; however, caloric asymmetries and directional
preponderances greater than 25% to 30% are traditionally considered significant. Sensitivity and specificity
of the caloric test in response to air has been reported as
0.82 and 0.82, respectively, and in response to water
as 0.84 and 0.84, respectively (Zapala et al., 2008).
Caloric responses have been reported in children
as young as 2 months of age with complete maturation
by 6 to 12 months (Eviatar & Eviatar, 1979); however,
appropriate calibration is a concern in these small children. The slow phase velocity of nystagmus in response
to caloric stimulation has been found to decrease with
age, similar to that noted during rotary chair testing (Andrieu-Guitrancourt, Peron, & Aubet, 1981).
Children may be fearful of completing caloric testing
because it causes symptoms of dizziness, fixation is
removed during testing, and they temporarily cannot
hear out of the ear receiving the irrigation. If reinforcement and reassurance are not enough, the duration of
the stimulus can be decreased to lessen the effect, or two
irrigations can be performed instead of four.
Video Head Impulse Test
During the vHIT, patients wear lightweight goggles,
which simultaneously measure both eye and head
velocity. During vHIT, patients are asked to fixate on a
visual target approximately 1 m in front of them while
head impulses are delivered in the plane of each semicircular canal. Head velocities greater than 150°/s are
recommended for the horizontal canals and greater
than 100°/s for the vertical canals.
18. PEDIATRIC VESTIBULAR TESTING 469
https://t.me/medicina_free
The main outcome parameter in vHIT is gain,
which is a ratio of eye and head velocity. Generally,
gains above about 0.8 are consistent with normal VOR
function, indicating that the eye and head are moving in an equal and opposite direction during the
head impulse. An additional outcome is the presence
of refixation saccades, either overt (occurring after
the head thrust) or covert (occurring during the head
impulse). Video HIT is a reliable test of semicircular
canal function and can be completed in children age
3 and up (Ross & Helminski, 2016; Hamilton, Zhou,
& Brodsky, 2015; Hulse, Hormann, Servais, Hulse, &
Wenzel, 2015). For infants down to 3 months of age,
a non-traditional remote camera system can be used
(Wiener-Vacher & Wiener, 2017) or an alternative calibration technique with traditional goggles (Wenzel
et al., 2017). Most investigations have agreed there is no
significant difference in vHIT gains between children
and young adults (Janky & Givens, 2015; Janky, Patterson et al., 2018; Hamilton et al., 2015); however, vHIT
gains have been reported to increase from infancy to
age 6, being fully adult-like by age 16 (Wiener-Vacher
& Wiener, 2017). Figure 18–5 demonstrates abnormal
vHIT gain in a 12-year-old child with history of meningitis. Both overt saccades, i.e., refixation saccades that
occur after the head impulse, and covert saccades, i.e.,
refixation saccades that occur during the head impulse,
can be seen in response to head impulses to the right
and left.
The advantage of vHIT is that it provides canalspecific information without inducing symptoms of
dizziness. Difficulties in obtaining these responses in
the pediatric population are that children must sustain
gaze on a visual target while delivering head impulses.
Child-appropriate stickers and/or short videos on a
video player are engaging for young children, yet small
enough to serve as a fixation point. Sustained gaze on
this fixed target is reinforced by asking the child questions about the character on the sticker or video. Video
HIT has been found to take longer to complete in children compared with adults (Hulse et al., 2015).
Regardless of whether the focus is for determination of pathophysiology of symptoms, etiology of
hearing loss, or to determine the underlying cause
of gross motor developmental delay, we have found
that all children are able to complete an assessment of
canal function and an assessment of otolith function.
For children greater than 5 years of age, both o- and
cVEMP are feasible as well as any assessment of canal
function (rotary chair, calorics, or vHIT). For children
younger than 5, the first tier assessment is rotary chair
and cervical VEMP with an attempt at bedside head
impulse and questions regarding the child’s attainment of gross motor milestones. With regard to other
assessments, the SOT can be completed on children
greater than 3 years who weigh at least 30 pounds,
while ocular motor testing can be attempted on children of any age.
DISORDERS THAT CAUSE VESTIBULAR
BALANCE PROBLEMS
AND
Vestibular loss can occur in varying degrees (unilateral, mild bilateral, or severe bilateral), can differentially affect the sensory structures (semicircular canal
versus otolith), and can affect different nerve branches
Figure 18–5. Example of abnormal vHIT gain in a 12-year-old child with history of meningitis. Left panel shows
mean (large X) gain for left and right horizontal (lateral) canals. Right-side panels show raw head velocity in the
smooth trace for the left and right lateral canals, with the eye velocities in the nonsmooth trace overlaying of the
head velocities in each of the graphs labeled left and right lateral canals. This finding was confirmed by low rotary
chair gains, as shown in Figure 18–4.
470 BAlAnCE FunCtion AssEssmEnt And mAnAgEmEnt
https://t.me/medicina_free
(superior versus inferior nerve). The time course of
vestibular loss can also vary, occurring either in utero
or acquired after birth. The presence of vestibular loss
is highly associated with the presence of hearing loss
(Li et al., 2016; O’Reilly et al., 2010). In fact, the likelihood of vestibular loss has been shown to increase with
greater degrees of hearing loss (Brookhouser et al.,
1982; Tribukait, Brantberg, & Bergenius, 2004; Janky,
Thomas, et al., 2018). Hearing loss worse than 90 dB
(Tribukait et al., 2004) or bilateral pure-tone averages
greater than 65 dB are associated with vestibular loss
(Janky, Thomas, et al., 2018). Due to this trend, it’s not
surprising that 50% of children who are candidates for
a cochlear implant have some degree of vestibular loss
(Cushing, Gordon, Rutka, James, & Papsin, 2013; Janky
& Givens, 2015). In a recent systematic review and
meta-analysis of possible changes in vestibular function after cochlear implantation, a significant decrease
in VEMP responses post-operatively was found (Yong
et al., 2019). However, the same findings were not seen
in the caloric results and there were insufficient data
for analysis of HIT or posturography. The implication of this work would support that in the majority of
patients post cochlear implantation, vestibular deficits
did not occur secondary to the implantation surgery
but were pre-existing.
All of the disorders that can cause dizziness and
balance disorders in adults have been reported in
children; however, the frequency of the occurrence in
children differs from that of the adult. In a systematic
review, Davitt et al., 2017, provides the frequency of the
diagnoses used in 2726 children. The complete list of
disorders is given below, from most to least prevalent
(% of the 2726 children with this diagnosis).
1. Vestibular migraine (23.8%)
2. Benign paroxysmal vertigo of childhood (13.7%)
3. Idiopathic (11.7%)
4. Labyrinthitis/vestibular neuronitis (8.47%)
5. Posttraumatic vertigo (8.36%)
6. Syncope/orthostatic hypotension (6.79%)
7. Psychogenic (6.27%)
8. Ménière’s disease (3.01%)
9. Seizure (2.82%)
10. Benign paroxysmal peripheral vertigo (2.64%)
11. Otitis media with effusion (2.09%)
12. Bilateral vestibulopathy (2.09%)
13. CNS tumor (1.21%)
14. Airway infection (1.14%)
A selected grouping of these will now be considered in
more detail.
in utero
Cytomegalovirus
Congenital cytomegalovirus (CMV) infection is the
leading cause of hearing loss in children, resulting
in progressive and fluctuating sensorineural hearing loss. CMV is estimated to occur in approximately
40,000 children each year in the United States (Cannon
& Davis, 2005). Vestibular loss is commonly associated
with CMV, with severity ranging from unilateral to
bilateral and affecting both the saccule and horizontal
semicircular canals. Bernard, Wiener-Vacher, Van Den
Abbeele, and Teissier (2017) report greater than 90%
of children with CMV have vestibular loss; of those,
33.3% have complete bilateral vestibular loss, 43.7%
have partial bilateral vestibular loss, and 22.9% have
unilateral vestibular loss, with declining function in
50%. In infants with congenital CMV abnormalities
on rotary chair, the caloric test and cVEMP have been
reported (Bernard et al., 2017; Inoue et al., 2013; Zagolski, 2008b) with subsequent delays in gross motor function (Maes et al., 2017). Inoue et al. (2013) report 60%
of children with CMV have abnormal caloric responses
and 33% have absent cVEMP responses.
Rubella
The rubella virus (commonly known as the German
measles) is seen less frequently due to vaccination. Degree of vestibular loss is variable. While the degree of
vestibular loss has been documented to be higher as the
degree of hearing loss increases (Zagolski, 2009), this relationship has not been found by all (Nishida, Ueda, &
Fung, 1983). Both canal and saccule loss have been documented, with canal loss (via calorics) present in 30 to
43% of cases and saccule loss (via cVEMP) in approximately 43% of ears (Nishida et al., 1983; Zagolski, 2009).
Usher Syndrome
Usher syndrome is an autosomal recessive genetic condition. Usher syndrome is characterized by sensorineural hearing loss and retinitis pigmentosa (RP). There
are three classifications of Usher syndrome. Type I is
characterized by congenital, profound sensorineural
hearing loss, RP, and bilateral vestibular loss. In children with type I Usher syndrome, vestibular function
is generally absent. Children acquire motor milestones
later. The average age for independent walking in children with Usher is 21.9 months (range, 12 to 30 months)
(Jatana et al., 2013). Type II has moderate-to-severe sensorineural hearing loss, progressive RP beginning in
18. PEdiAtriC vEstiBulAr tEsting 471
https://t.me/medicina_free
the second decade of life, and normal vestibular function. Lastly, type III has progressive RP and progressive
hearing and vestibular loss.
Waardenburg
Waardenburg syndrome is a genetic condition that is
associated with congenital hearing loss, heterochromia iridium (different-colored eyes), and a white forelock, among other features. It is estimated to affect 1
in 40,000 (Genetics Home Reference, 2012). The presentation of Waardenburg syndrome can be variable
and similarly the occurrence of vestibular loss can be
variable. As many as 77% have some abnormality on
vestibular function testing (Black, Pesznecker, Allen, &
Gianna, 2001).
Auditory Neuropathy
Auditory neuropathy, or dyssynchrony, occurs when
hearing in the inner ear is normal but there is a breakdown in transmitting that information to the brain. In
addition to the auditory nerve, the vestibular nerve
can be affected. In cases of auditory neuropathy, vestibular testing shows variable abnormality of the superior and inferior vestibular nerves. Few studies have
documented vestibular function in a large group with
auditory neuropathy. While cervical VEMP responses
have been shown to be absent in the majority of cases
(Akdogan, Selcuk, Ozcan, & Dere, 2008; Sazgar, Yazdani, Rezazadeh, & Yazdi, 2010), cVEMP abnormalities
are more likely to occur if neuropathy occurs post-lingually compared with pre-lingually (El-Badry, Gamal,
& Fawzy, 2018). Similarly, abnormal caloric responses
have also been noted (Fujikawa & Starr, 2000; Sheykholeslami, Kaga, Murofushi, & Hughes, 2000). Vestibular function reportedly declines with age (Fujikawa &
Starr, 2000; Masuda & Kaga, 2011), which helps explain
the variability in vestibular findings. For example, in
one cohort of children (n = 3), caloric responses were
normal in all cases (Akdogan et al., 2008). Some individuals with auditory neuropathy affecting the vestibular nerve are asymptomatic in spite of documented
vestibular involvement (Sinha, Barman, Singh, Rajeshwari, & Sharanya, 2013). An estimated one out of five
individuals with auditory neuropathy reports vestibular symptoms (Prabhu & Jamuar, 2017).
GJB2 (Connexin 26 Mutations)
GJB2 (connexin 26 mutations) is the most common
cause of nonsyndromic deafness. In children with
GJB2, vestibular function can vary, ranging from nor-
mal to unilateral to bilateral vestibular loss. Likewise, a
range in incidence of vestibular involvement has been
reported. In 25 children diagnosed with homozygous
connexin 26 mutations, 10 children exhibited a unilateral weakness in response to caloric stimulation and
1 child exhibited bilateral vestibular loss (Cushing et al.,
2013). Cervical VEMP was completed in 24 of those
children, and VEMP responses were absent bilaterally
in 6 and unilaterally in 10 (Cushing et al., 2013). In other
reports, 5/7 children with GJB2 had at least one abnormality on vestibular function tests (VEMP and caloric)
(Kasai et al., 2010). However, others have reported normal canal function in all cases (n = 13) with isolated
absent VEMP responses in 1 child (Inoue et al., 2013).
Large Vestibular Aqueduct Syndrome
Within the vestibular aqueduct is the endolymphatic
duct and sac. The criterion used to determine whether
the vestibular aqueduct is considered enlarged can
vary, but commonly large vestibular aqueduct syndrome (LVAS) is diagnosed when the diameter of the
vestibular aqueduct is greater than 1.5 mm or when its
diameter is twice the size of the posterior canal, as seen
on computed tomography (CT) (Valvassori & Clemis,
1978; Wilson, Hodgson, & Talbot, 1997). LVAS is considered one type of third-window disorder (similar
to superior canal dehiscence syndrome) and therefore
demonstrates the same pattern of findings on audiometric and VEMP testing, that is, conductive hearing
loss not of middle-ear origin and large ocular and cervical VEMP amplitudes with significantly lower thresholds (Merchant et al., 2007; Merchant & Rosowski,
2008; Sheykholeslami, Schmerber, Habiby, & Kaga,
2004; Taylor et al., 2012; Zhou & Gopen, 2011; Zhou,
Gopen, & Kenna, 2008; Zhou et al., 2017). Individuals
with LVAS can also have complaints of dizziness and
imbalance and, in addition to showing an enhancement
on VEMP testing, evidence vestibular loss on caloric
testing (Yetiser, Kertmen, & Ozkaptan, 1999; Zhou et
al., 2017). Approximately 30 to 60% of individuals with
LVAS report vestibular-related symptoms (Jackler &
De La Cruz, 1989; Yetiser et al., 1999; Song et al., 2018).
relationship between LVAS and BPPV in patients
A
(children and adults) has also been reported (Manzari,
2008; Song, Hong, Kim, & Koo, 2012).
LVAS can be associated with both syndromic and
nonsyndromic hearing loss. LVAS is a characteristic feature in branchio-oto-renal (BOR), Pendred syndrome,
and Mondini malformation. BOR is characterized by
malformations in the outer, middle, and inner ear
(LVAS among other malformations) and the kidneys.
472 BAlAnCE FunCtion AssEssmEnt And mAnAgEmEnt
https://t.me/medicina_free
Pendred syndrome, a type of syndromic hearing loss,
consists of hearing loss, LVAS, and goiter (enlargement
of the thyroid). Last, while Mondini malformation can
occur in isolation, coupled with LVAS, it can also be
found in the constellation of Pendred syndrome. In
unselected children with inner-ear malformation, dysfunction on at least one vestibular test (rotary chair,
calorics, or VEMP) has been noted in greater than 50%
of cases (Cushing et al., 2013; Inoue et al., 2013).
Neurofibromatosis Type 2
Neurofibromatosis type 2 (NF2) is a genetic condition
that facilitates the growth of noncancerous tumors. The
most common tumor growth associated with NF2 is
vestibular schwannoma. The incidence of NF2 is 1 in
33,000 (Genetics Home Reference, 2013). Symptoms
associated with NF2 usually present during adolescence; however, isolated cases have been reported of
NF2 in the first year of life (Ruggieri et al., 2013). NF2 is
presumed to affect the superior branch of the vestibular nerve more often than the inferior branch as caloric
abnormalities are more common than absent or reduced
cVEMP responses (Wang, Hsu, & Young, 2005).
Semicircular Canal Dehiscence
While this condition is found most often in the adult
population, it can be seen in children (Jackson et al.,
2014). There is suggestion from the literature that this
may well be a developmental condition that is present
in utero (Carey, Minor, & Nager, 2000; Nadgir, Ozonoff,
Devaiah, Halderman, & Sakai, 2011; Ward, Carey, &
Minor, 2017). The major problem with identification
of this condition is the lack of typical complaints from
adults being reported in children, especially the very
young. In this recent retrospective study (Dasgupta &
Ratnayake, 2019), 580 children underwent comprehensive vestibular function assessment. Thirteen children
(2.2%) were found to have radiographic evidence of
semicircular canal dehiscence (of the 26 ears, 2 were
posterior canal and the remainder were superior canal).
While this condition appears rare, it should not be
overlooked in the child with complaints of dizziness.
Vestibular loss has also been reported variably in
fetal alcohol syndrome and other inner-ear congenital malformations, such as CHARGE syndrome and
Scheibe dysplasia.
acquired
ited, either complete loss of function or reduced function; however, a subset can have normal function or
preserved otolith function (Arnvig, 1955; Cushing et
al., 2013; Wiener-Vacher, Obeid, & Abou-Elew, 2012).
Cushing et al. (2013) report bilateral areflexia in 9/10
and bilateral loss in 1/10 children with meningitis
and preserved saccule function (via cervical VEMP)
in 14/22 ears. Meningitis has been shown to delay
the acquisition of motor milestones (Wiener-Vacher
et al., 2012) and in some cases can cause a regression in
gross motor function. Balance has also been found to
be poorer in older children with history of meningitis
(Cushing et al., 2009).
Ototoxic Drug Use
Medications proven to be vestibulotoxic include aminoglycosides such as gentamicin and streptomycin,
among others. Not all individuals with exposure to
aminoglycosides will experience vestibular loss; however, when vestibular loss does occur, it can be widespread throughout the vestibular periphery, affecting
both the otolith organs and the semicircular canals
(Zagolski, 2008a). Toxicity has been reported to be dose
dependent in some medications, with greater dosage
over a longer course of days increasing susceptibility
(Chen, Bach, Shoup, & Winick, 2013). However, gentamicin is the exception, as it can be vestibulotoxic
regardless of the dose or duration (Ahmed, Hannigan,
MacDougall, Chan, & Halmagyi, 2012). When assessing residual otolith function in patients with known
bilateral canal loss, individuals with history of ototoxicity were noted to have the least amount of residual
vestibular function (Agrawal, Bremova, Kremmyda, &
Strupp, 2013).
Measles and Mumps
Vestibular loss has also been reported variably in
measles (a respiratory virus resulting in fever, runny
nose, coughing, and rash) and mumps (a virus resulting in fever, headache, malaise, and swollen glands);
however, both measles and mumps are not frequently
encountered due to vaccination. Mumps has its association with a prior common cause of unilateral hearing
loss that as an adult has been indicated as a cause for
delayed endolymphatic hydrops, a condition that can
present like Ménière’s disease but without the auditory
symptoms, since the person already has the severe hearing loss (Schuknecht, Suzuka, & Zimmerman, 1990).
Meningitis
In the majority of children with meningitis, some
degree of semicircular canal involvement is exhib-
Ménière’s Disease
Children accounted for 2.3% of Ménière’s disease cases
seen in a recent report by Wang, Wu, Cheng, and Young
18. PEdiAtriC vEstiBulAr tEsting 473
https://t.me/medicina_free
(2018). Using audiometry, oVEMP, and cVEMP along
with caloric tests to investigate the status of the vestibular system in these children, they found a similar
decline in function that mimicked what they had documented in the adult Ménière’s patients. Of interest, a
third of these children had a positive family history of
Ménière’s disease.
Benign Paroxysmal Positional Vertigo
Over a study interval of August 2012 to August 2017,
six hundred and five children from 5 to 19 years of age
were seen for dizziness complaints. Of this group, 19.8%
(120 patients) were diagnosed with BPPV by history
and positive Dix–Hallpike or supine roll tests (Brodsky, Lipson, Wilber, & Zhou, 2017). Of 120 patients with
the diagnosis of BPPV, 22 were under age 11, with the
remainder at or above 11. Those patients with vestibular migraine or with diagnosis of benign paroxysmal
vertigo of childhood demonstrated five times higher
odds of recurrence of BPPV. Most of the cases resolved
with one or two repositioning treatments (71.8%).
Cerebellar Stroke
In the adult, cerebellar infarction (posterior circulation) accounts for only about 2% of all ischemic strokes,
whereas in children the posterior circulation is affected
in about 30 to 40% of stroke (Sarikaya & Steinlin, 2018).
The presenting symptoms of cerebellar stroke in the
adult are vertigo and unsteadiness, whereas this is less
specific in the child, with 40% with limb weakness and
30% with ataxia or speech abnormalities. The overall incidence of stroke in children is reported at 5 in
100,000 (0.005%; Krishnamurthi et al., 2015). Therefore,
while rare, it is important not to miss a stroke event in a
child, and the risk factors for stroke in children are different from those in adults (Sarikary & Steinlin, 2018).
While none of the above-mentioned diseases/syndromes show an exclusive relationship with vestibular
loss, vestibular testing in children should be considered
when hearing loss or any of the above etiologies has
been diagnosed. Techniques for determining the etiology of hearing loss are improving; however, in many
instances the etiology of hearing loss is unknown. Vestibular loss in these cases should be suspected with
greater degrees of hearing loss, gross motor delay, or
balance complaints (O’Reilly et al., 2010; Li et al., 2016;
Wiener-Vacher, Quarez, & Priol, 2018), although again,
this relationship is not mutually exclusive.
Benign Paroxysmal Vertigo of Childhood
The disorder of benign paroxysmal vertigo of childhood is considered a migraine precursor and is listed in
the International Classification of Headache Disorders,
3rd edition (IHS, 2018) and listed in the first and second
editions as well as an episodic disorder associated with
migraine headaches. Therefore, by far the most common disorder to cause dizziness in children would be
developed or developing migraine headaches.
referenCes
Abadie, V., Wiener-Vacher, S., Morisseau-Durand, M. P.,
Poree, C., Amiel, J., Amanou, L., . . . Manac’h, Y. (2000).
Vestibular anomalies in CHARGE syndrome: Investigations on and consequences for postural development.
European Journal of Pediatrics, 159, 569–574.
Accardo, A. P., Pensiero, S., Da, P. S., & Perissutti, P. (1995).
Characteristics of horizontal smooth pursuit eye movements to sinusoidal stimulation in children of primary
school age. Vision Research, 35, 539–548.
Agrawal, Y., Bremova, T., Kremmyda, O., & Strupp, M.
(2013). Semicircular canal, saccular and utricular function
in patients with bilateral vestibulopathy: Analysis based
on etiology. Journal of Neurology, 260, 876–883.
Agrawal, Y., Carey, J. P., Della Santina, C. C., Schubert, M. C.,
& Minor, L. B. (2009). Disorder of balance and vestibular
function in the US adults: Data from the National Health
and Nutrition Examination Survey, 2001–2004. Archives of
Internal Medicine, 169(10), 938–944.
Ahmed, R. M., Hannigan, I. P., MacDougall, H. G., Chan,
R. C., & Halmagyi, G. M. (2012). Gentamicin ototoxicity:
23-year selected case series of 103 patients. Medical Jour-
A
nal of Australia, 196, 701–704.
Akdogan, O., Selcuk, A., Ozcan, I., & Dere, H. (2008). Vestibu-
lar nerve functions in children with auditory neuropathy.
International Journal of Pediatric Otorhinolaryngology, 72,
415–419.
Andrieu-Guitrancourt, J., Peron, J. M. D. D., & Aubet, J. C. P.
(1981). Normal vestibular responses to air caloric tests in
children. International Journal of Pediatric Otorhinolaryngol-
ogy, 3(3), 245–250.
Arnvig, J. (1955). Vestibular function in deafness and severe
hardness of hearing. Acta Oto-Laryngologica, 45, 283–288.
Bernard, S., Wiener-Vacher, S., Van Den Abbeele, T., & Teissier,
N. (2017). Vestibular disorders in children with congenital
cytomegalovirus infection. Pediatrics, 136 (4), 887–895.
Black, F. O., Pesznecker, S. C., Allen, K., & Gianna, C. (2001).
A vestibular phenotype for Waardenburg syndrome? Otol-
ogy & Neurotology, 22, 188–194.
Brodsky, J. R., Lipson, S., Wilber, J., & Zhou, G. (2017). Benign
paroxysmal positional vertigo (BPPV) in children and
adolescents: Clinical features and response to therapy in
110 pediatric patients. Otology & Neurotology, 39, 344–350.
Brookhouser, P. E., Cyr, D. G., & Beauchaine, K. A. (1982).
Vestibular findings in the deaf and hard of hearing. Oto-
laryngology–Head and Neck Surgery, 90, 773–777.
Bucci, M. P., & Seassau, M. (2012). Saccadic eye movements
in children: A developmental study. Experimental Brain
Research, 222, 21–30.
Соседние файлы в папке Библиотека им академика М.И. Перельмана