evaluation of balance

Question 1

what makes up balance?

Answer 1

• proprioception
• ocular cues
• vestibular

Question 2

what does balance do

Answer 2

• tells us where we are in the world

- allows for gaze stabilization

Question 3

clinical testing

Answer 3

• HISTORY
• ear examination
• eye movements
• head thrust
• fukuda stepping test
• fistula test
• dix hallpike
• lab testing

Question 4

what to ask from a history

Answer 4

• true vertigo or not (e.g. not dizziness)
• episodic nature
• duration e.g. 2 minutes, hours, days
• precipitating factors e.g. head movements, loud noise
• associated factors e.g. migraines, tinnitus, hearing loss

Question 5

role of the utricle and saccules and their location

Answer 5

detect acceleration and gravity (from crystals)

utricle is in the horizontal plane
saccule is in the vertical plane

Question 6

describe the basilar firing rate and what happens when you turn your head

Answer 6

basilar firing rate is constant at rest for each side of the vestibular system
when you turn your head one side fires a little bit less and the opposite side a little more. Depending on inhibition or activation from fluid in cupula

Question 7

what happens when your head is turned right

Answer 7

left lateral circular canal is stimulated and that in turn moves eyes to the left, rapidly

(eye movement are equal and opposite to head movement)

Question 8

describe the main function of the vestibular-ocular reflex

Answer 8

to stabilize the image on the retina

Question 9

consequences of a sudden reduction of right ear function

Answer 9

eye thinks the head is turning and therefore fast phase to the left and slowly back right to the midline

nystagmus to the left

the patient will have symptoms of vertigo

Question 10

define nystagmus

Answer 10

rhythmic oscillation of the eye with a fast and slow phase

also described in the direction of the fast phase e.g. left nystagmus if the eye moves in fast phase to the left (hypofunction in the right)

Question 11

define head thrust

Answer 11

uses the principle of gaze stabilization and the idea that eye movement are equal and opposite to head movement

get patient to look at your nose (bring the head down 30 degrees) and move their head quickly to the right and patient should keep eyes on you
abnormal will be a delayed eye catch up to your nose

Question 12

define cold calorics test

Answer 12

1. patients lies down with their LSCC up
2. cold water causes endolymph to become dense and fall
3. deflection cupula away (inhibit right side)
4. causes nystagmus fast phase to beat away to left

Question 13

describe warm calorics

Answer 13

• endolymph becomes less dense, rises and causes deflection cupula towards (excitation)
• increases firing in right ear, so nystagmus which beats towards the stimulation

Question 14

COWS

Answer 14

cold opposite

warm same

Question 15

fistula test

Answer 15

press the ear to see if nystagmus occurs

Question 16

fukuda stepping test

Answer 16

get the person to hold hands out and step up and down, someone affected will not be able to move straight instead will move to the side affected.

Question 17

BPPV (benign paroxysmal positional vertigo)

Answer 17

• vertigo that lasts 1 minute
• associated with positions: rolling over, looking up, bending over etc
• not associated with hearing loss or tinnitus

Question 18

Dix-hallpike

Answer 18

test for BPPV

• the patient lies down and you suddenly dropped and turned their head, holding it down for 1 minute (better with a pillow under back) testing posterior SCC

Question 19

how will vestibular hypofunction test

Answer 19

• will produce positive head thrust

- fukuda to the side of the lesion