Balance Final

2 lateral (horizontal0 canals both lie in a plane 30* above horizontal

Posterior canal on one side is in parallel plane to the anterior canal on opposite side

Left posterior & Right anterior

Right posterior & Left anterior

The otoliths are calcium carbonate or calcite cryastals which rests above the otolithic membrane ontop of the stereocilia . They are found on the macula in the utricle and saccule. They produce a shearing movement which displaces the stereocilia during head movements and in turn an Action potential is generated.

sense linear motion, motion due to gravity

Vision and somatasensory

Superior Rectus
Inferior Rectus
Medial Rectus
Lateral Rectus
Inferior Oblique
Superior Oblique

Medial and Lateral Rectus

Conjugate: exact duplication of eye position

rapid eye movements made to bring a point of regard onto the fovea

begins abruptly and have extremely high initial acceleration

end as abruptly as they begin

pursuit system allows one to move the eye at the same speed as the target so the target reamins stable on the retina

-a tracking response closely related to smooth pursuit
-eye movement is elicited by tracking of a field rather than a discrete target
-purpose of OKN is to stablize an entire visual field, not a single target like pursuit

suppression of unintended eye movements.
-the brain suppresses internally generated eye movements

Vestibular Ocular REflex
-primary purpose is to elicit a rapid compensatory eye movement that maintain stability of images on the fovea during head motion
-as the head moves in one direction, the eyes move in another direction

-maintains posture and center of mass over the base of support
-acceleration of the head causes an upper and lower limb response, limbs ipsilateral to the direction of acceleration are extended where those contralateral to the acceleration are contracted

reflexive and protective averting and aducting movement of the eyes that occurs during eye closure

Occular dysmetria: cebellar lesion, overshoots/undershoots

Saccadic Slowing: basal ganglia lesion

Internuclear Ophthalmoplegia: MLF lesion: rounded tracings, adducting eye lags, smoothing curve, separate eye recordings to confirm

Gain- the distance the eye moves while tracking the target

an inability to fixate visual targets while the head is moving

A sensation of spinning when one is still

double vision, seeing 2 images of a single object

-Alexander's Law: strongest on gaze in direction of beating
-never vertical
-declines quickly (days to weeks)

-bilateral beating
-can have vertical beating
-can have curvilinear slow phase
-declines slowly if at all

-central gaze nystagmus
-large cerebello-pontine angle tumors
-gaze ipsi to leasion generates large slow nystagmus with exp decay in slow phase
-gaze contra to lesion generates small fast nystag in opposite direction of ipsi gaze response

-cerebellar disease
-movement generated
-decays rapidly
-beats in direction of movement

-medullary disease
-cyclic, 90 sec in 1 direction, 10 sec nothing or vertical, then 90 sec in other direction

-brainstem, cerebellar or inferior olivary disease
-can be generated by alcohol, drugs

-from fixed brain defect either genetic or developmental origin
-pendular and or jerk-type
-disorder of slow eye movement sub-system
-null points or periods
-convergence inhibition

Positional: nystagmus that is produced by being in a given position
-don't normally expect to see nystagmus in positional testing
-if nystagmus present with fixation: centrally generated
-if nystagmus is visually suppressed, then peripheral
-direction fixed does not indicate a side
-direction changing=central

Dix-Hallpike: traditional method, for PSCC

Canalithiasis: presence of free-floating otoliths in the PSCC

-rotary/torsional movement
-latency of about 10 sec
-fatigues within 30-45 sec
-usually beating to lower ear
-accompanied by vertigo
-R,L, or in both positions

-this position puts the patients horizontal canal in a roughly vertical plane

Tympanic membrane perforation or patient with a mastoidectomy. (obvious precautions with water around electricity and care to prevent bacteria and algae growth, yearly evaluation of water temperature and mineral deposit cleaning) (p202)

warm stimuli creates cupulopetal flow

cold stimuli creates cupulofugal flow

Cold Opposite
-creates an inhibitory response and the eye beats toward the opposite ear

Inversion is when the response beats in the wrong direction

Due to: tester error or brainstem lesion

best index of peripheral lesion

(RC+RW)-(LC+LW)/ (sum of all 4)

Greater than 25% is significant

of little diagnostic value

(RW+LC)-(RC+LW)/(sum of all 4)

Ask questions such as listing favorite movies, counting, naming foods that start with "Q"

-the ratio of the eye speed (slow phase velocity) of the nystagmus with the eyes open and the patient fixating, divided by the eye speed with the eyes closed = fixation index -- the extent to which visual fixation can suppress the calorically induced vestibular signal.

gain is generally higher at higher frequencies

It uses frequencies that are higher than those produced by caloric stimuli, closer to normal operating range.

It measures sways energy under various visual and support conditions. It distorts the cues and teases out the contributions of each of the sensory systems.

An inconsistent patter is abnormal on conditions 1,2,3,4 or any combination and normal on 5 & 6.

it provides a relative measure of the patient's ability to use the sensory input cues of vision, vestibular, and proprioceptive to maintain quiet upright stance.

CDP are useful in fall prevention programs, "assessing patients for postural control abilities in static and dynamic situations". (Jacobson, p 339) For patients w/ bilateral hypofunction, "CDP can assist in the determination of the extent of the functional impact". (p 340)

Adaptation
-used to induce recovery in UVD
-vestibular system can be modified during the acute stage after UVD
-vestibular stimuli produces an erro signal between the head and visual input
-OKN stimuli may do this as well
-may occur with as little as 1-2 minutes of stimulus
-brain is trying to reduce the error signal
-symptoms will increase
-Adaptation of VOR is context specific
-the VRT protocols must stress the system in different ways
-need to adapt to a range of frequencies
-need to push the envelope at each stage

Semont Liberatory maneuver
Epley (Canalith repositioning maneuver)
Gans
Appiani (HC BPPV)
Casani (HC BPPV)

traditional canalith repositioning maneuver
-begins with modified Hallpike positioning, which should provoke symptoms
-head is rotated from 45* toward the affected side to 45* toward the unaffected side
-patient is rolled onto the unaffected side with head in 45* toward unaffected side
-returned upright

-patient is seated on the exam table in the side lying position with head turned away from ear to be treated
-patient is moved from involved side to uninvolved side (should provoke nystagmus)
-liberatory head-shake is performed
-returned to upright seated position
-head brought downward briefly and then brought upright

-patient side lying on unaffected ear- held for 1 minute after the burst of geotropic nystagmus ends
-head is turned downward 45* to move otoconia out of the SCC - held for 2 minutes
-returned to upright position

Stable- acute stage of vestibular attack is over, no active disease

Uncompensated- brain has not adjusted to a stable lesion

Non-stableized: greater difficulty for VRT, on-going vest difficulties that come and go

-chronic vestibular disorders that don't respond to other treatments
-has useful hearing

-for patients with BPPV that does not respond to repositioning treatments

following surgery, it is important that there is adjunctive medical and vestibular rehab therapy
-vestibular rehab will help the brain accommodate to the fixed deficit

-reduce sodium, caffeine, nicotine
-thiazide diuretics
-little support for steroids (oral or intratympanic)
-use of antihistamine
-meniett device (pressure)

2nd most common cause of recurrent vertigo
-modification of diet and lifestyle
-avoid caffeine, chocolate, cheese, processed meat, red wine
-medications
-refer to neurologist, serotonin reuptake inhibitors
-physical therapy
-accupunture

-steroid

-sound or pressure induced vertigo due to dehiscence of bone overlying the superior SCC
-chronic disequilibrium
-oscillopsia
-conductive hyperacusis
-low-threshold, high-amplitude VEMP
-audiometric air-bone gap with preserved acoustic reflexes

-an abnormal communication between the perilymphatic spaces and middle ear space
-can produce tinnitus, hearing loss, nausea, and balance complaints
-pressure test with impedance bridge - look for symptoms
-exploratory surgery and repair
-bed rest, can heal spontaneously

-unilateral impairment of the vestibular nerve or labyrinthine organ

-test of the saccular/inverior vestibular nerve function
-short latency electormyograms evoked by high-level acoustic stimuli recorded from surface electrodes on the SCM

-cervical vertigo
-dysequilibrium
-light headedness
-ataxia
-unsteadiness

- it allows you to determine which sensory system may be compromised or may be depended on more
-compare across conditions and come up with ratios

Hip dominant
-high frequency
-greater effect in horizontal shearing force

Spontaneous Nystagmus
Head Impulse test (Head Thrust)
Head Shake
Dynamic Visual Acuity
Valsalva Induced Nystagmus
Romberg
Fukuda Stepping

-if observed, note the direction of fast phase
-if peripheral; nystamus should increase in velocity when gase in direction of fast phase
-w/o fixation suppression then it is a central sign

-Uses oculocephalic response to identify uni and bilateral periph weakness
-move head to right, eyes move to left
-abnormal, catch-up saccades

-shake the head 10-30 cycles
-normal, no visible nystagmus
-abnormal post-head-shake nystagmus - sign of imbalance in the vetibular inputs
-typically peripheral cause with fast phase directed toward the contrlesional ear

-looking for oscillopsia due to defect in VOR
-read vision chart before and after an oscillation in the head
-normal: no more than drop of 1 line
-drop in best corrected vision of 2 or more lines

-normal- no sensation of dizziness or vertigo
-conjugate movement of the eyes toward the CONTRAlesional ear if lateral and anterior canal involved with a corrective saccade toward the IPSI ear
-horizontal nystagmus=lateral canal and beats toward the affected ear
-torsional and downbeating vertical nystagmus=anterior canal
-vertical upbeating nystagmus=posterior

-normal: maintain standing position with eyes closed for 30 sec without falling
-abnormal: marked sway or fall, loss of proprioceptive input from lower limbs

-identify a peripheral vestibular system impairment manifested as an asymmetry in lower extremity vestibulospinal reflex (tome)

Impaired eye shows difficulty in adduction- damage to connections in the brainstem

Gain = OUTPUT/INPUT, in this case the output is the eye speed -- during the slow phase because that is the portion of the movement that is vestibularly driven -- and the input is the speed of the rotation. (If the VOR worked perfectly, the eyes would move exactly as fast as the head, but in exactly the opposite direction. Thus the ratio of eye speed to head (or chair) speed would be 1.00.) (Copied from Dr. G’s
response)