Oto Primary Care FINALhigh

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Chapter 7

Dizziness

People often come to the otolaryngologist with a complaint of “dizziness,”

including symptoms such as

disequilibrium

syncope

lightheadedness

ataxia

, and

vertigo

. As otolaryngologists, we focus on disease processes

that produce true vertigo (an illusion of motion), which is primarily asso-

ciated with the balance organs of the inner ear. These are referred to as

peripheral

vestibular disorders. When

central

vestibular disorders are

considered, the differential diagnosis for dizziness becomes quite broad.

Therefore, if your patient does not complain of the true illusion of motion,

redirect your questioning to the evaluation of syncope or

episodic

hypotension

. You may also want to consider imaging studies of the brain

to rule out neoplasm, demyelinating disease, or a vascular abnormality.

These patients may also need referral to a neurologist or cardiologist.

Vestibular Testing

Vestibular testing can be performed to help determine whether the prob-

lem exists within the vestibular (balance) portion of the inner ear.

Vestibular testing may include an audiogram, electronystagmography

(ENG), rotational chair test, posturography, and electrocochleography

(ECOG), depending on the clinical situation.

There are four main parts to

ENG testing

: the calibration test, which mea-

sures rapid eye movements; the tracking test, which evaluates the ability of

the eyes to track a moving target; the positional test, which measures

responses due to head movements; and the caloric test, which measures

responses to warm and cold water introduced to the ear canal. ENG is the

“gold standard” for detecting unilateral peripheral vestibular disorders.

Rotatory chair testing

is the “gold standard” for diagnosing bilateral ves-

tibular weakness. The patient is slowly spun in a rotating chair and dizzi-

ness is measured with optokinetic testing and a fixation test. Moving plat-

form

posturography

is a method of quantifying balance, but should not

be used alone to diagnose vestibular disorders. It is most useful in quanti-

fying balance improvement (or worsening) following treatment for a