Vestib Evaluation

Case History: Onset What was the patient doing the first time it occurred? What brings the dizziness episode on? How long does the episode last? How frequent are the episodes? Did the patient have a cold/virus or ear infection when this first occurred? Does it get worse when they move their body in a particular direction? Have patient describe the sensation without using the word ‘dizzy’. • Patient may describe vertigo- the sensation of movement- is the patient spinning? Is the room spinning? Does patient complain that the “dizziness” worsens when they turn in a particular direction (the direction of the fast phase) • Patient may describe presyncope- feeling faint or light-headed (consider orthostatic hypotension- is it worse when they move from a sitting to a standing position?) • Patient may describe disequilibrium- feeling unsteady and unbalanced • Does the patient describe a feeling of being pushed or pulled from side to side (indicative of utricular dysfunction); or a feeling of being pushed or pulled back and forth (indicative of both utricle and saccule dysfunction) • Other- Patient may describe a floating sensation What makes it worse? What makes it better? Does the patient have hearing loss? Unilateral or bilateral? If a hearing loss is present, does the patient have fluctuating hearing? Does the patient complain of aural fullness? Does the patient describe tinnitus? Unilateral or bilateral? Does patient have a history of ear infections? Does patient have a history of migraines, depression, and anxiety? Does the patient have a history of head and/or neck trauma?....Is it recent ie within the last year? Verify that the patient did not take any vestibular suppressants within the last 48 hours.

 Ototscopy, Tympanometry, (Audiometry where applicable): •Tympanometry is useful not only in ruling out middle ear anomalies, but is also useful in cases of suspected perilymph fistula. Use the ‘special function’ on the tympanometer. A positive Hennebert’s sign (nystagmus due to pressure change in the ear canal) is a positive indication for perilymph fistula.

Behavioral Tests prior to VNG/ENG:
 * Voluntary pursuit tracking:  "follow my finger with your eyes only, and keeping your head still"  take eyes through "H" pattern of movements, looking for any anomalous eye movements (e.g., saccadic pursuit, disconjugate pursuit, any spontaneous or gaze-evoked nystagmus).
 * Saccade Test:
 * Vertebrobasilar screening:
 * VNG/ENG Test Battery: Assesses the integrity of the vestibular system by measuring eye movements, as the oculomotor system is stimulated by the vestibular system during head turn.

VNG: DEPENDS ON THE REFLECTIVE PROPERTIES OF CORNEA AND PUPIL LOCALIZATION Advantage- can be used in patients with retinal pathologies. ENG: DEPENDS ON THE CORNEO-RETINAL POTENTIAL (the voltage difference between the anterior and posterior poles of the eye). ENG cannot be used in patients with retinal pathologies.

Seat the patient on the bench. “This test is going to measure your eye movements. Your eyes are connected to the inner ear and they tell us what’s going on in the portion of the inner ear that deals with balance.” VNG- have patient look left to right to determine artifact (not necessary for ENG) ENG:-scrub patient and place electrodes RANGE:  4 FT+/- 1 inch - adjust patient- move bench as needed CALIBRATION 1) Beam is in the horizontal position. “You will see the red dot move from left to right, like a pendulum. Follow it with your eyes only without moving your head”. 2) Position beam vertically. “You will see the dot move up and down. Follow it with your eyes only without moving your head.” 3) Accept, Stop, Save

IMPORTANT to engage the patient in some conversation or task anytime the goggles are closed (VNG) or the eyes are closed (ENG).

SPONTANEOUS (30s) (nystagmus indicative of central or peripheral pathology) 1) Position Beam horizontally. Sitting without vision “Pretend you are looking at the dot, (VNG-I will close the goggles, keep your open, and pretend to stare at it) (ENG- Just close your eyes and pretend to stare at it) GAZE NYSTAGMUS (30s) (nystagmus indicative of central or peripheral pathology) R- the red dot is going to be all the way to the right, just keep looking in the right direction without moving your head L- the red dot is going to be all the way to the left, just keep looking in the left direction without moving your head ADJUST BEAM VERTICALLY U- the red dot is going to be in the upward position, just keep looking up without moving your head D- the red dot is going to be in the downward direction, just keep looking down without moving your head

ADJUST BEAM HORIZONTALLY

SACCADE (1 min) (looking for normal saccadic speed, latency and accuracy)

“the red dot is going to randomly jump across the bar, just follow It with your eyes wherever it goes without moving your head” REVIEW, ANALYZE, SAVE

TRACKING (1min) (to establish normal nystagmus) “the dot is going to move back and forth. Follow the dot from one end to the other. Keep following it even when it picks up speed. REVIEW, ANALYZE, SAVE

OPTOKINETIC (15s) (to establish normal nystagmus) “You will see a series of red dots move across this bar, like a parade going by. I want you to count as many dots as you can that come through the center. They move very fast, so count as many as you can.

HEAD SHAKE (nystagmus indicates peripheral dysfunction) “I’m going to shake your head from left to right as if you are saying “no”, for 20s .Keep your eyes open the entire time, even after I shake your head: (VNG- keep your eyes open while I close the goggles) (ENG-close your eyes)

DIX HALLPIKE (Have patient scoot back a little if necessary) (to diagnose BPPV) “I’m going to take you from a sitting to a laying position, while your head is turned to the right. Your head will hang over the table but just rest your head against the headrest. Keep your eyes open even if you feel dizzy. “I’m going to bring you up back to a sitting position. Once I sit you back up, face forward” “I’m going to take you from a sitting to a laying position, while your head is turned to the left. Your head will hang over the table but just rest your head against the headrest. Keep your eyes open even if you feel dizzy “I’m going to bring you up back to a sitting position. Once I sit you back up, face forward”

POSITION (30s each) (to determine peripheral dysfunction) Sitting with vision “Keep your eyes on the dot for about 30s, (VNG- dot disappears once we start the test, just pretend it’s still there) <p data-parsoid="{"dsr":[8219,10588,0,0]}">Supine with vision “Lay down on your back and stare up at a point above you for 30s” Supine without vision VNG-“I’m going to close your goggles. Keep staring at that spot and we’ll play a game to keep your mind busy” ENG- “Pretend you are still staring at that spot but just close your eyes. We’ll play a game to keep your mind busy” Right with vision “Turn your head to the right so that your ear is touching the pillow. Stare at a point in front of you for 30s Right without vision VNG: “Let’s keep staring at that same spot while I close your goggles and you keep your eyes open (game) ENG- “Pretend you are still staring at that spot but just close your eyes. We’ll play a game to keep your mind busy” Left with vision “Move your head to the left so that your ear is touching the pillow. Stare at a point in front of you for 30s Left without vision VNG: “Let’s keep staring at that same spot while I close your goggles and you keep your eyes open (game) ENG- “Pretend you are still staring at that spot but just close your eyes. We’ll play a game to keep your mind busy” OTHER: Place head in caloric position (elevate head rest to 30 degrees) (vision denied) VNG: “Look straight ahead and don’t close your eyes while I keep your goggles shut” ENG: “Look straight up at that spot again; close your eyes while pretending to stare at that spot CALORICS (to stimulate the lateral semicircular canals using a temperature gradient) “I am going to put cool air into your right ear for about one minute. During and after that minute, you may get a sensation of movement but all I want you to do is to keep your eyes open the entire time and for you to focus on my category games. (Explain the category games. Ensure patient that process should not cause any pain but to have them inform you if it does) (After about 1min 40s open goggle covers and instruct patient to focus on finger, all while game is being played. After about 10 s, close the goggle covers but have patient continue to keep his/her eyes open and continue with alerting) “Ok, we’ll be doing the same thing in your left ear; keep your eyes open (play game with patient) (After about 1min 40s open goggle covers and instruct patient to focus on finger, all while game is being played. After about 10 s, close the goggle covers but have patient continue to keep his/her eyes open and continue with alerting) “Now, we’ll be putting warm air starting with your right ear; keep your eyes open (play game with patient) <p data-parsoid="{"dsr":[10697,10932,0,0]}">(After about 1min 40s open goggle covers and instruct patient to focus on finger, all while game is being played. After about 10 s, close the goggle covers but have patient continue to keep his/her eyes open and continue with alerting) “Ok, we’ll be doing the same thing in your left ear; keep your eyes open (play game with patient) <p data-parsoid="{"dsr":[11033,11655,0,0]}">Important Points To Remember: - In vestibular testing, alert patients in order to avoid suppression of nystagmus in the vision denied condition. Mental alerting will  increase the amplitude of the nystagmus. - Fixation- in central disorders nystagmus is not suppressed by fixation; in peripheral disorders nystagmus is suppressed by fixation. - Factors Affecting Caloric Testing: Middle ear anomalies such as a perforated eardrum, cerumen impaction, presence of a mastoid cavity; Other factors- medications such as meclizine, improper irrigation, inadequate mental alerting and insufficient break time between irrigations.