Transcript CasePresentation _Year Three

Case Presentation
Beth Burlage
History
• 75-year-old male
• Reports constant dizziness and imbalance
• Problems initially began after a serious
auto accident in 1998
• Immediately after the accident, the
dizziness was present and over time
became progressively worse
• Had a CT scan (imaging) and is
scheduled for his first MRI following VNG
Audiogram
VNG testing
•
VNG - video nystagmography
•
Records eye movements such as nystagmus - a type of eye movement
characterized by alternating slow phase movements in one direction
quick phases in the other direction.
There are two types of nystagmus:
•
Physiologic nystagmus- normal - slow phases are vestibulo-ocular reflex
movements that stabilize vision during head movement, whereas the fast
phases are re-setting movements.
•
Pathologic nystagmus - abnormal-the slow phases may be due to a
vestibular imbalance or due to failure in the eye position-holding
mechanisms of the oculomotor system.
•
“nystagmus production is a complex phenomenon that involves many
neuronal centers and the changes in nystagmus characteristics are often
of diagnostic value” Jacobsen, et. al. 2000
Pertinent Findings
• All eye-movement systems depend on the same cranial
nerves and ocular muscles to effect the specific type of
eye motion desired. The brain stem cranial nerve nuclei,
cranial nerves, and extra-ocular muscles are the final
common pathway for all eye movements
• Ocular motor tests include:
• Gaze, Saccades, tracking, OKN
• Gaze testing - this portion of the test is one of various test
conditions that assesses the vestibulo-ocular function. The
patient is asked to focus on a light (without moving his/her
head). The light remains stable in either a horizontal or
vertical position and then rebounds to a center position.
Gaze Tracings
• Right directed gaze shows right beating
nystagmus, upon rebounding, the
nystagmus is direction changing
• In the left directed condition, nystagmus
is left beating and direction changing
upon rebounding
• Bilateral horizontal gaze nystagmus
Pertinent Findings, cont.
• Saccade - vestibulo-ocular
assessment. The patient is asked to
follow the light with their eyes
without moving their head as it
randomly moves across a vertical
plane
Saccadic tracing
• The saccades display direction
changing nystagmus beating in the
direction of the light’s movement
(ex. When the light bounces towards
the left, nystagmus is left-beating)
Pertinent findings, cont.
• Caloric stimulation- using air
irrigation, the horizontal semi-circular
canal is stimulated by temperature
changes in the ear.
• Even those with normal vestibular
function will present with nystagmus
and sensations of dizziness during
caloric testing
• Normal findings show that upon
fixating their eyes on an object (in
this case, a small light inside of the
video goggles), the patient will be
able to suppress the nystagmus.
Caloric tracings
• Upon fixation, the patient not only
was unable to suppress, the
nystagmus actually became
stronger
• It is noted that failure to fixate
bilaterally is an implication of
brainstem or cerebellar disease
Interpretation
• Results indicate a Central Nervous
System (CNS) lesion
• CNS lesions can often be the result
of drug intoxication, abnormal
growths, or likely in this case,
traumatic brain injury
Management
• Refer to Neurology for MRI
• After neurologic assessment and
possible treatment, reassess central
vestibular function
• Hearing loss - hearing aids?
– VAMC policy is to provide hearing aid
to those who express interest/need