CNMC UG

1. ASSESSMENT OF
VESTIBULAR FUNCTION
TEST
DR. SUDESH BARAILY
DLO PGT.
MCH KOLKATA

2. Balance in humans is maintained by the
integration within the central nervous
system (CNS) of information from the
vestibular labyrinths, the eyes and the
proprioceptive systems. Damage to any of
these three systems may lead to
dyscquilibrium.
Assessment of dizziness must include
evaluation of each of these three peripheral
systems and of the ‘central processing unit
it self.

4. ANATOMY OF THE VESTIBULAR
APPARATUS
THE INTERNAL EAR OF THE LABYRINTH
1) Bony labyrinth
A) Vestibule
B) Semicirular Canals  Lateral, Posterior &
Superior
C) Cochlea
2) Membranous Labyrinth

6. MEMBRANOUS LABYRINTH
 Cochlear duct
 Utricle and saccule
 Semicircular ducts
 Endolymphatic duct and sac

8. PERIPHERAL VESTIBULAR
RECEPTORS
1) Cristae Located in ampullated ends of
3 semicircular ducts. Respond to angular
acceleration

9. 2) Maculae Located in otolith organs, utricle and
saccule

10. CENTRALVESTIBULAR CONNECTIONS
Afferents
1. Peripheral vestibular receptors (scc, utricle and
saccule)
2. Cerebellum
3. Reticular formation
4. Spiral Cord
5. Contralateral vestibular nuclei
Efferents
1. Nuclei of CN III IV VI (Vestibulo ocular reflexes)
2. Motor part of spinal cord (vestibulo spinal fibres)
3. Cerebellum (Vestibulo cerebellar fibres)
4. Autonomic nervous system
5. Vestibular nuclei of opposite side.
6. Cerebral Cortex (temporal lobe.)

11. PHYSIOLOGY (VESTIBULAR SYSTEM)
A) Peripheral  SCC, utricle & saccule
B) Central  made up of nuclei and fibre tracts in CNS to
integrate vestibular impulses with other systems to
maintain body balance.
Semi circular Canals :
 Respond to angular acceleration and deceleration
 Three canals lie at right angles to each other
 One which lies at right angles to the axis rotation is
stimulated the most.
 Stimulus to SCC is flow of endolymp which displaces
the cupula.
 The quick component is always opposite to the
direction of flow of endolymph.

13. UTRICLE AND SACCULE
Utricle stimulated by linear acceleration and
deceleration or gravitational pull during head
tilts.
Sensory hair cells of macula in different planes
are stimulated during head tilts.
Function of saccule is similar
Cerebellum  further coordinates muscle
movements in their rate,range,
force duration and thus helps in
maintenance of balance.

14. ASSESSMENT OF VESTIBULAR FUNCTIONS
1) Clinical History A full general medical
history, cardiovascular & neurological. Specific
aspects of the digginess or imbalance should
be sought.
a) Character of Symptoms (vertigo or digginess)
b) Time, course of dysequilibrium
c) Associated Symptoms  hearing loss, tinnitus
palpitation
d) Precipitating factors  Head, body and eye
movements
e) Drug history  Gentamicin, PCM, Diuretics,
Cisplatinum etc.
2) Clinical Test
3) Laboratory Test

15. CLINICAL TEST
1) Spontaneous nystagmus  it is an important sign
Defn  Invountary rhythimical, oscillatroy movement
of eyes.
 Horizontal, vertical, rotatory
 Slow and a fast component
 Direction indicated by direction of fast component
 Intensity indicated by degree
Degree of nystagmus
1st degree  Nystagmus in direction of fast component
2nd degree  When patient looks straight ahead.
3rd degree  In the direction of slow component.
 Vestibular or peripheral, hystagmus  due to lestion
of labyrinth or VIIIth nv.
 Central nystagmus  lesion in central pathways
vestubular nuclei, brainstem, cerebellum.

16. 2) FISTULA TEST 
 Induction of nystagmus by pressure changes in
the external canal.
 Stimulation of labyrinth results in nystagmus
and vertigo.
 Performed by intermittent pressure on tragus
or by siegel’s speculum.
 Normally test is negative.
 Positive test implies labyrinth is functioning
 False negative  cholesteatoma covers site of
fistula.
 False positive  congenital syphilis and
Meniere’s disease (Hennebert’s sign)

17. 3) ROMBERG TEST
 Stands with feet together, arms by side with eyes first
open and then closed.
 Peripheral lesions  sways to side of lesion.
 Central lesions  Shows instability.
Sharpened Rombery test  if patient performs above test
without sway. Inability to perform indicates vestibular
impairment.
4) GAIT
 Asked to walk along a straight line to a fixed point first
with eyes open and then closed.
 Uncomplensated lesion of peripheral vestibular system
with eyes closed, deviates to affected side.
5) Past pointing and falling
 Acute vestibular failure right side.
 Nystagmus to left, past pointing and falling to right
side.

18. 6) HALLPIKE MANEUVRE (POSITIONAL TEST)

19. Peripheral Central
1. Latency 2-20 Seconds No Latency
2. Duration Less than 1 min More than 1 min
3. Direction of
nystamus
Fixed to the
undermost ear
Changing
4. Fatiguability Fatiguable Non- fatiguable
5. Accompanying
Symptoms
Servere vertigo Non or slight

20. TEST OF CEREBELLAR DYSFUCTION
Cerebellar Hemisphere
Asysnergia (Abnormal finger nose test)
Dysmetria (unable to control range of motion)
Adiadokokinesia
Rebound phenomenon (unable to control movement of
extremity when opposing force, suddenly released)
Cerebellar midline disease
I. Wide base gait
II. Falling in any direction
III. Inability to make sudden turns
IV. Truncal ataxia
Nystagmus  gaze evoked, rebound and opto kinetic.

21. LABORATORY TESTS
Caloric test 
 Induction of nystagmus by thermal stimulation of
vestibular system
 Advantage, each labyrinth tested separately
 Ladyrinthine origin of vertigo if qualitatively similar to
the type experienced, during episodes of vertigo
a. Modified kobrak tests
b. Fitzgerald hallpike test (bithermal caloric test)

23. Canal paresis 
L30 +L44 X 100
Response from Left ear =L30+L44 + R30+R44
R30 +R44 X 100
Response from Right ear =L30+L44 + R30+R44
Seen in Meniere’s ds, Acoustic neuroma,
Post Labyrinthectomy or Vestibular nv section

24. Directional Preponderance
Takes into consideration the duration of nystagmus to the
right or left irrespective of whether it is elicited from rt or
left labyrinth
If nystagmus is 25-30% or more on oneside than other it is directional pre
ponderance

25. COLD AIR CALORIC TEST 
 Done if peforated tympanic membrane
 Dundas grant tube used
 Only a rough qualitative test.
ELECTRONYSTAGMOGRAPHY
 Corneo retinal potentials recorded by electrodes
placed around eyes
 Detects nystagmus not seen with naked eye
 Keeps permanent record of nystagmus.

27. OPTOKINETIC TEST
 Normally produes nystamus with slow component in
the direction of moving stripes
 Optokintic abnormality seen in  brain stem and
cerebral hemisphere lesion.
ROTATION TEST
 Barany’s chair, 10 turns in 20 secs.
 Normally there is nystagmus for 25-40 secs.
 Can be done in congenital abnormality of external ear
canal where caloric best not possible
 Disadvantage, both labyrinths are simultaneously
stimulated

28. GALVANIC TEST
 Only test to differentiate end organ lesion from that of
vestibular nv.
 Normally person sways towards the side of anodal
current
POSTUROGRAPHY
 Measures postural stability
 Maintenace of posture depends on 3 sensory inputs 
visual, vestibular and somatosensory
AUDITORY FUNCTION TEST
 Close relationship, both anatomically and
physiologically, between the vestibular and auditory
divisions of VIII the nv.
 Precise site of lesions causing vestibular disturbance.