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TYPICAL EVALUATION
STUDIES
Clinical pathways for the assessment and treatment of chronic dizzy patients
as well as those with unspecified imbalance problems must begin with a
detailed neurotologic history, office vestibular and physical examination and
formal audiometric testing battery. Diagnostic tests can identify specific
pathology, clinical observational tests can confirm the presence of balance
problems. Typical tests fall into several classifications - Extent and
Site-of-Lesion Studies, Functional performance and Indications for status of
Central compensation process.
- Extent and Site of Lesion Studies
- Electronystagmography (electrodes or video)
- Ocular motor testing with saccade, pursuit and gaze provide for
evaluation of cerebellar/brain stem involvement
- Spontaneous & positional nystagmus - non -localizing but
suggestive of peripheral involvement when ocular
motor studies are normal
- Caloric irrigation testing - localization to right or left
peripheral horizontal semicircular canal system
- Dix-Hallpike - part of a direct clinical examination
- Rotational Chair - via step tests or sinusoidal protocols
- expands the review of the peripheral vestibular system,
typically the horizontal canals in routine protocols. Provides
evidence for possible peripheral involvement when the time constant
is abnormally low
- Suggestions for right/left localization can be noted
- Special paradigms may be used to review Cerebellar Nodulus
involvement
- Computerized Dynamic Posturography
- Motor Control Testing - Suggests possible involvement in the
long loop pathways for stimulation of motor response activation in
the lower limbs
- Postural Evoked Responses - (surface EMG recordings of muscle
activity of the lower limbs provides for site specific localization
of lesions within the long loop pathways and a first approximation
differentiation between certain central nervous system disorders
- Otolith function via Vestibular Evoked Myogenic Potentials - Allows
for evaluation of saccular function via the use of auditory click or
tone burst stimuli
- Functional performance/objectify
complaints
- Presence of spontaneous or positional nystagmus during an
interval that the patient reports vertigo is an objective sign
consistent with that complaint
- Dynamic visual acuity testing (DVA) - objectifies and quantifies the
magnitude of oscillopsia and is a functional manifestation of VOR gain
reduction unilaterally or bilaterally
- Sensory Organization Tests (SOT) a functional evaluation of static
and dynamic balance under a variety of specific support surface and
visual conditions and the only quantitative assessment of aphysiologic
performance
- Disability/functionality scales - Dizziness Handicap Inventory
/SF-36 visual analog scales (VAS), all improve ability to assess a
patients overall functional and disability status
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Indications for status of Central Compensation process
- Physiologic status relative to nystagmus - spontaneous and
positional nystagmus/directional preponderance from caloric/asymmetry
form rotary chair sinusoidal or step test protocols
- Functional status - SOT/DVA/VAS all give indications of functional
performance change over time and hence compensation (note that the
function and physiologic indications can vary in an independent manner)
- Indications, prognosis and design for
Vestibular and Balance Rehabilitation programs (VBRT)
- Symptom presentation is the primary indication for use of VBRT
- SOT - can give indication of functional deficits in postural control
not brought out in the history that would indicate the need for VBRT
when system presentation is not strong in that manner. This study
can be used for assistance in design and monitoring performance for VBRT
- DVA - indicates the need for specific type of exercises (adaptation)
and provides a means for monitoring the effectiveness of therapy in
changing the VOR gain on a direct functional basis
- Caloric irrigations, rotational chair time constant and asymmetry
abnormalities- provide indications of BOR gain deficits and if symptom
presentation is appropriate also would support the use of adaptation
type exercises in a VBRT program. These are of minimal use in
monitoring the outcome of the therapy program unless the patient is
worsening.
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