Hearing & Balance/Vestibular therapy Flashcards
Vestibular system made up of 3 components:
- peripheral sensory apparatus
- central processor
- mechanism for motor output
What nerves innervate the vestibular system?
two branches?
CN VIII (vestibulocochlear nerve)
1. Superior division: utricle and anterior and horizontal semicircular canal
2. Inferior division: saccule and posterior semicircular canal
Describe vascular supply to vestibular system:
Basilar artery –> AICA –> Labyrinthine artery –> DIVIDES:
- Anterior vestibular artery: Anterior SCC, Horizontal SCC, Utricle, vestibular nerve
- Common Cochlear Artery –> posterior vestibular artery: posterior SCC, sacule
Canals are responsible for: ______.
three parts:
angular acceleration of the head:
Anterior semicircular canal
Posterior semicircular canal
Horizontal semicircular canal
What are the otolith organs?
Responsible for?
Utricle and Saccule
Linear acceleration of head
What are the motion sensors of the VS?
hair cells
- Semicircular canals are arranged _____ to each other
- ___#__ semicircular canals become __#__ coplanar pairs
perpendicular to each other.
6 semicircular canals become 3 coplanar pairs.
- right and left horizontal
- left anterior and right posterior
- right anterior and left posterior
What are the 3 axes of semicircular canals?
Roll, Pitch, Yaw
Describe the push pull arrangement of coplanar pairing:
when angular head motion occurs within their shared plane, the endolymph of the coplanar pair is displaced in opposite directions with respect to their ampullae and neural firing increases in one vestibular nerve and decreases on the other side.
Sensory redundancy is an advantage of the push-pull system. If damage occurs to the semicirucular canal’s imput from one member of the pair (Ie vestibular neuritis or BPPV), then:
CNS will still receive vestibular information about head velocity within that plan from the contralateral member of the coplanar pair.
____ is a reflex eye movement that stabilizesimages on the retina during head movement. Produces eye movement in the direction opposite to head movment
VOR: vestibulo-ocular reflex
- EOM are arranged in pairs, which are oriented in planes close to those of the canals.
- This arrangement allows a single pair of canals to be connected predominantly to a single pair of extraocular muscles
- this results in conjugate eye movements in the same plane as head motion
The vestibular nerve is unique among the cranial nerves in that:
neurons are constantly firing at 100spikes/sec even with the head still.
With sudden loss of vestibular nerve function on one side, there is:
strong bias into the brainstem from the intact side (a relative excessive excitation), resulting in nystagmus that is present even without head movement.
Name 6 common vestibular disorders
- BPPV - benign paroxysmal positional vertigo
- unilateral hypofunction
- bilateral hypofunction
- Meniere’s disease/migraine
- Central vertigo
- Perilymphatic fistula
- superior canal dehiscence
Typical presentation of vestibular disorders: 6)
- dizziness induced by motion of head/body
- complaints of movement in the environment
- impairment in balance
- nausea/sweating/emesis
- ringing in ears
- decreased concentration/mild memory deficits/decreased focus/anxiety
What is the most important component in correctly diagnosing a patient with complaints of dizziness?
taking a proper history
Name the 8 common medications to treat dizziness
- meclizine (antivert, bonine) - antihistamine
- Lorazepam (ativan)
- Clonazepam (Klonopin)
- Dimenhydrinate (Dramamine) - antihistamine
- Promethazine (Phenergan) - 1st gen antihist - neuroleptic
- Amitriptyline (elavil) - TCA
- Scopolamine (patch) muscarinic antagonist
- diazepam (valium)
4 classes of medications to consider during assessment and treatment:
- ototoxic meds (any history of bad infection requiring strong abx?)
- Amiodarone (cardiac med that can be very toxic)
- Chemotherapy meds (any history of cancer?)
- anticonvulsants
4 most common vestibular function testing
- VNG/ENG (video or electronystagmography)
- VEMP (Vestibular-Evoked Myogenic Potential)
- Rotary chair testing
- CDP (computerized dynamic posturography)
VNG/ENG testing is comprised of (5)
- calibration testing - saccades
- spontaneous nystagmus test
- pursuit testing
- postitional tests (Hallpike)
- Caloric tests
- What is the purpose of VEMP testing?
(Vestibular evoked myogenic potential) - electrodes attached to:
- How performed?
- When considered abnormal?
- to determine if the saccule and the inferior portion fo the vestibular nerve and central connections are intact and working normally
- SCM bilaterally
- Head is lifted when loud clicks are introduced. The response evoked in the neck EMG is recorded for each side.
- abnormal when they are asymmetrical, low in amplitude, or absent.
Purpose of the rotary chair test:
3 parts:
to determine whether or not dizziness is due to a disorder of the brain or inner ear.
(assesses lateral canal)
- chair test
- optokinetic test
- fixation test
Indications for rotary chair test: (5)
- Gold standard test for bilateral vestibular loss
- good for testing special populations (peds, handicapped)
- inconclusive ENG results
- eval of vestibular compensation
- ototoxicity management
_____ test has been validated by controlled research studies to isolate the functional contributions of vestibular inputs, visual inputs, somatosensory inputs, central integrating mechanisms, and neuromuscular system outputs for postural and balance control.
Computerized dynamic posturography (CDP)
Computerized dynamic posturography (CDP) test protocols include (3)
- sensory organization test (SOT)
- Motor control test (MCT)
- Adaptation test (ADT)
____ is the mechanical disorder of the inner ear caused by abnormal stimulation of 1 or more of the 3 semicircular canals within the ear.
Benign paroxysmal positional vertigo
BPPV is the most common cause of _____
vertigo
Benign paroxysmal positional vertigo is characterized by (2)
- vertigo/dizziness (typically 50% of patients)
BPPV onset is usually ____. In the elderly it may mimic _____.
Spontaneous
neuritis crisis
Predisposing factors to BPPV: 8
- head trauma
- labyrinthitis
- ischemia in anterior vestibular artery
- advanced age
- female gender
- meniere’s disease
- migraine
- Osteoporosis, osteopenia
Conditions that require caution with positional testing: 9
- limited cervical ROM
- severe rheumatoid arthritis
- down syndrome
- cervical radiculopathies
- paget’s disease
- low back dysfunction
- spinal cord injuries
- torn/detached retina
- glaucoma
For nausea medications given prior to vertigo examination, _____ does not suppress ocular nystagmus while ____ and ____ do.
Zofran
Diazepam (valium) and meclizine
BPPV mechanism:
caused by movement of calcium carbonate crystals from utricle to semicircular canal – known as otoconia
in BPPV: in canal involvement, treatment is always based on ____
direction of nystagmus
in BPPV, with canal involvement, treatment is always based on direction of nystagmus:
1. upbeating nystagmus
2. downbeating nystagmus
3. right torsion
4. left torsion
- posterior canal
- anterior canal
- right side involvement
- left side involvement
______ is performed with the patient sitting[3] upright on the examination table with the legs extended. The patient’s head is then rotated to one side by approximately 45 degrees. The clinician helps the patient to lie down backwards quickly with the head held in approximately 20 degrees of extension. This extension may either be achieved by having the clinician supporting the head as it hangs off the table or by placing a pillow under their upper back. The patient’s eyes are then observed for about 45 seconds as there is a characteristic 5–10 second period of latency prior to the onset of nystagmus. If rotational nystagmus occurs then the test is considered positive for benign positional vertigo. During a positive test, the fast phase of the rotatory nystagmus is toward the affected ear, which is the ear closest to the ground. The direction of the fast phase is defined by the rotation of the top of the eye, either clockwise or counter-clockwise. Home devices are available to assist in the performance of the Dix–Hallpike Maneuver for patients with a diagnosis of BPPV
Dix-Hallpike
Which test:
The patient begins seated at side of an examination table. The head is turned 45 degrees away from side being tested to align the posterior semicircular canals with the plane of movement; patient is quickly laid onto the table onto the side being tested. The clinician observes the patient’s eyes for one minute.
Sidelying test
Benign paroxysmal positional vertigo of the posterior canal is diagnosed if an upbeating and rotational nystagmus (fast phase towards the ear being tested) is observed with the patient in this test position. The nystagmus should begin after a brief latency (5-10 seconds), last less than one minute, and should correlate with symptoms of vertigo
Practically lateral canal BPPV can almost always be seen on the Dix Hallpike test, especially if the examiner does not attain a substantial head-hanging posture but instead tests the patient supine. Nevertheless, the best position to see the direction changing horizontal nystagmus of lateral canal BPPV is not the Dix-Hallpike maneuver. Rather one starts with the body supine, head inclined forward 30 degrees, and then turns the head to either side. This is called the
“supine roll test)
_____ nystagmus might be a signal that there is lateral canal cupulolithiasis
apogeotropic nystagmus
Treatment of BPPV depends on ____
correctly identifying involved canal and mechanism
describe canalith repositioning maneuver (or epley maneurver)
The following sequence of positions describes the Epley maneuver:
The patient begins in an upright sitting posture, with the legs fully extended and the head rotated 45 degrees towards the affected side.
The patient is then quickly and passively forced down backwards by the clinician performing the treatment into a supine position with the head held approximately in a 30 degree neck extension (Dix-Hallpike position) where the affected ear faces the ground.
The clinician observes the patient’s eyes for “primary stage” nystagmus.
The patient remains in this position for approximately 1–2 minutes.
The patient’s head is then turned 90 degrees to the opposite direction so that the unaffected ear faces the ground, all while maintaining the 30 degree neck extension.
The patient remains in this position for approximately 1–2 minutes.
Keeping the head and neck in a fixed position relative to the body, the individual rolls onto their shoulder, rotating the head another 90 degrees in the direction that they are facing. The patient is now looking downwards at a 45 degree angle.
The eyes should be immediately observed by the clinician for “secondary stage” nystagmus and this secondary stage nystagmus should beat in the same direction as the primary stage nystagmus. The patient remains in this position for approximately 1–2 minutes.
Finally, the patient is slowly brought up to an upright sitting posture, while maintaining the 45 degree rotation of the head.
The patient holds sitting position for up to 30 seconds.
The entire procedure may be repeated two more times, for a total of three times.
During every step of this procedure the patient may experience some dizziness
epley maneuvers are intended for what branches of BPPV?
anterior or posterior canalithiasis
describe the liberatory maneuver (semont)
Step 1: Start with the patient sitting on a table or flat surface with head turned away from the affected side. Step 2: Quickly put the patient into the side-lying position, toward the affected side with the head turned up. Nystagmus will occur shortly after arriving at the side-lying position. Keep the patient here until at least 20 seconds after all nystagmus has ceased. Step 3: Quickly move the patient back up and through the sitting position so that he or she is in the opposite side-lying position with head facing down (head did not turn during the position change). Keep the patient in this position for ~30 seconds (some recommend up to 10 minutes). Step 4: At a normal or slow rate, bring the patient back up to the sitting position.
treats anterior and posterior canal cupulolithiasis
Describe the canalith repositioning maneuvery for horizontal canal BPPV (BBQ roll, log roll, also called Lampert maneuver)
Step 1: Seat the patient on a table positioned so they may be taken back to the head hanging position with the neck in slight extension. Stabilize the head with your hands and move the head 45 degrees toward the side you will test. Move the head, neck and shoulders together to avoid neck strain or forced hyperextension. Step 2: Observe for nystagmus and hold the position for ~10 seconds after it stops. Step 3: Keeping the head tilted back in slight hyperextension, turn the head ~90 degrees toward the opposite side and wait 20 seconds. Step 4: Roll the patient all the way on to his or her side and wait 10 to 15 seconds. Step 5: From this side-lying position, turn the head to face the ground and hold it there 10 to15 seconds. Step 6: Keeping the head somewhat in the same position, have them sit up then straighten the head. Hold on to the patient for a moment because some patients feel a sudden but very brief tilt when sitting up. REPEAT: After waiting 30 seconds or so, repeat the whole maneuver. If there is not paroxysmal nystagmus or symptoms during Dix-Hallpike positioning (Steps 1, 2) then there is a high likelihood of success.
