An Overview of Vestibular Dysfunction and Rehabilitation ... conference/annual... · Brain Injury...
Transcript of An Overview of Vestibular Dysfunction and Rehabilitation ... conference/annual... · Brain Injury...
An Overview of Vestibular Dysfunction and Rehabilitation in
Individuals with Brain Injury
Janet Callahan PT, DPT, MS, NCS
The Numbers
TBI Rates
htt
ps:
//w
ww
.cd
c.go
v/tr
aum
atic
bra
inin
jury
/dat
a/ra
tes.
htm
l
Brain Injury and Vestibular Dysfunction
BPPV CENTRAL PERIPHERAL
% R
ange
of
Pat
ien
ts
0
80
40
20
60
30
10
50
70
Maskell F et al, 2009
9 – 71% of patients experienced dizziness
Faaq C 2007, Smith PF 2013, Besnard S 2015, Yardley L 1998, Black O 2004, Bigelow RT 2015
• Impaired gaze stability • Impaired postural control • Impaired eye-hand coordination • Impaired executive function • Impaired spatial orientation • Impaired motion perception • Impaired attention • Impaired memory • Impaired cognition • Fatigue
Implications of Vestibular Dysfunction
Role of the Vestibular System
• Stabilize visual images on the fovea of the retina during head movements to allow clear vision
• Maintain postural stability during head movements
• Provide information used for spatial orientation – ability to maintain our body orientation and/or
posture in relation to the surrounding environment at rest and during motion
Zee D, Leigh J, Neurology of Eye Movements
Components of the Vestibular System
Hain TC, et al. Anatomy and Physiology of the Vestibular System. In Herdman SJ (ed): Vestibular Rehabilitation. FA Davis, Philadelphia, PA, 2000, p4.
Motor Neurons
Vestibular
Primary processor (Vestibular nuclear
complex)
Adaptive processor
(Cerebellum)
Eye Movements (VOR)
Postural Movements
(VSR) Proprioception
Visual
other CNS
processing
Herdman S . (2007) Vestibular Rehabilitation (3rd ed.)
Peripheral Vestibular Apparatus
• 3 Semicircular Canals – Angular acceleration
• Anterior
• Posterior
• Lateral
• 2 Otolith organs – Linear acceleration/gravity
• Utricle
• Saccule
• Work in complimentary pairs
• One side is excited while other side is inhibited
Bony Labyrinth
Membranous
Labyrinth
Perilymph
Endolymph
Semicircular Canal Receptors
CUPULA
OTOLITHS
VESTIBULAR SYSTEM
Hain TC, et al. Anatomy and Physiology of the Vestibular System. In Herdman SJ (ed): Vestibular Rehabilitation. FA Davis, Philadelphia, PA, 2000, p4.
Motor Neurons
Vestibular Primary processor (Vestibular nuclear
complex)
Adaptive processor
(Cerebellum)
Eye Movements (VOR)
Postural Movements
(VSR) Proprioception
Visual
other CNS
processing
Landing pad/relay station for all sensory inputs
Central Vestibular Projections
Vestibular Nuclear Complex Vestibulo-Cerebellum
Monitors vestibular receptor activity Calibrates the Vestibular Ocular Reflex
Fine tunes eye movements
Central Vestibular Projections
• Thalamus – Discriminates between self movement vs. that of the
environment – Multisensory integration for
postural control
• Vestibular Cortex – Junction of parietal and
insular lobe – Multisensory integration of
vestibular information with somatosensory and visual input
http://www.sciencedirect.com/science/article/pii/S1053
811911014340
VESTIBULAR SYSTEM
Hain TC, et al. Anatomy and Physiology of the Vestibular System. In Herdman SJ (ed): Vestibular Rehabilitation. FA Davis, Philadelphia, PA, 2000, p4.
Motor Neurons
Vestibular Primary processor (Vestibular nuclear
complex)
Adaptive processor
(Cerebellum)
Eye Movements (VOR)
Postural Movements
(VSR) Proprioception
Visual
other CNS
processing
Vestibular Motor Projections
Gaze stabilization
Vestibulo-Ocular Reflex
(VOR)
Postural Control
Vestibulo-Spinal Reflex
(VSR)
Via Cranial Nerve VIII to vestibular nuclear complex
At Rest
0
80-100
RIGHT LEFT
Spik
es/S
ec
What happens with head movement? S
pik
es/S
ec
0
200
RIGHT LEFT
Assymetrical input indicates to CNS that the head is moving
Right side excited Left side inhibited
Head Turn Right
What if receptor(s) or CN VIII is not functioning?
0
80-100
RIGHT LEFT
Head Turn Right
Spik
es/S
ec
CNS receives inadequate information about head movement Compensatory eye movement is absent or inadequate
Impaired gaze stability (VOR) and postural control (VSR)
Left side inhibited
What happens when the head rotates continuously? (Real or Perceived)
Nystagmus
Nystagmus
•Involuntary rhythmic conjugate eye movement •May be spontaneous, gaze-evoked or positional •Named for fast phase
PERIPHERAL •Engaged when head
rotation exceeds the limits of eye rotation to produce a slow phase eye movement
(VOR) in one direction and a fast phase saccadic “reset”
back towards primary position
•Damage to vestibular receptor or nerve
CENTRAL Occurs as a result of a
number of different brain conditions or damage to
certain brain (stem) structures
Nystagmus
VOR maintains fixation on
target
Saccadic reset to reposition eye in center of socket
Slow Phase Fast Phase
See repetitive cycles of VOR to stabilize gaze
followed by saccadic re-set
In the event of continuous head rotation…………..
Clinical Finding Central Peripheral
Complaints of Vertigo Vertigo less common. More often disequilibrium, dizziness, unsteadiness
More Common
Nystagmus: •Spontaneous •Positional •Gaze-evoked
Single Plane: (upbeating, downbeating, torsional)
Direction Changing: gaze-evoked nystagmus greater towards side of lesion
Mixed Plane: (vertical-torsional, horizontal-torsional) Non-direction changing Increases with gaze to more neurally active side Increases in direction of quick phase
Suppression of Nystagmus with Visual Fixation (no Frenzels)
NO- nystagmus remains the same or increases
YES- nystagmus decreases
Lesion Location
PERIPHERAL STRUCTURES
• Vestibular end organ
• Vestibular nerve
CENTRAL STRUCTURES • Brainstem • Cerebellum • Thalamus • Insular Cortex
Peripheral Vestibular System
Damage to Peripheral Receptor Labyrinthine Concussion
https://www2.aofoundation.org/wps/portal/surgerymobile?contentUrl=/srg/93/01
Damage to Peripheral Receptor Benign Paroxysmal Positional Vertigo
Damage to Peripheral Receptor Perilymphatic Fistula
• Damage to Round or oval window
• Sound or pressure induced vertigo and or nystagmus
• Symptoms increase with activity
• Often associated with head trauma
• Surgical repair if doesn’t seal over with bedrest
Round Window
Oval Window
Damage to Vestibular Nerve Unilateral Vestibular Hypofunction
Vestibular Nerve
Examination
Examination
• History
• Oculomotor Examination
• Vestibular System Function
• Postural Control
DIZZINESS Symptoms
• Vertigo
– Illusion of movement; Spinning
• Lightheadedness
– Feeling in head; feeling faint
• Dysequilibrium
– Off balance; unsteadiness; stagger
• Oscillopsia
– Visual blurring with head motion
Dizziness What do patients call it?
• Spinning
• Balance problems
• Fogginess
• Spaciness
• Lightheadedness
• Like being on a boat
• Rocking
• Feeling “off”
Pattern of Symptom Occurrence
• Circumstances
– Spontaneous
– Position change
– Eye, head or body movement
– Environment
– Activities
– Coughing or sneezing
• Intensity
• Duration – Intermittent
• Minutes
• Hours
– Constant
• Timing – Acute vs. Chronic
– Onset • Sudden
• Gradual
Peripheral Vestibular Dysfunction Pattern of Symptoms
Disorder Tempo Symptoms Circumstances
Vestibular Nerve Injury
Sudden onset; Acute Dizziness
(May not be noticed due to LOC)
Vertigo, disequilibrium, N/V,
oscillopsia
Spontaneous, exacerbated by head
movement
Unilateral Vestibular Hypofunction
Chronic Dizziness
Dizziness, disequilibrium
Induced by head movement, complex
environments, altered sensory
inputs
Bilateral Vestibular Hypofunction
Chronic Dizziness Lightheadedness, Dizziness,
disequilibrium
Induced by head movement, complex
environments, altered sensory
inputs
BPPV Sudden onset; Spells of dizziness lasting
seconds
Vertigo, lightheaded, N/V
Induced by positional change: lying down, sitting
up, rolling over
Eye Movements
Examination of Oculomotor Control
What is so important about the oculomotor system?
• Vestibulo-Ocular Reflex involves eye movements and is fully integrated with other oculomotor control systems
• VOR occurs in combination with pursuit, saccades and vergence eye movements
• Impairments in these oculomotor control systems = central vestibular dysfunction
Symptoms of Oculomotor Disturbances
• Blurred vision
• Double vision
• Oscillopsia
• Dysequilibrium/Falls
• Frontal headache
• Fatigue
• Difficulty reading
• Difficulty attending
• Difficulty in school
• Difficulty using computers
• Difficulty with target accuracy
• Difficulty with depth perception
Eye Movement Examination
• Alignment/Fixation
• Extraocular Movements
• Gaze Holding – End range
– 30 degrees
• Pursuit
• Saccades
• Vergence
• VOR
Ocular misalignments result in impaired eye-head coordination
HYPOTROPIA
EXOTROPIA ESOTROPIA HYPERTROPIA
Ocular Misalignments
Six Extra-ocular Muscles Controlled by Three Cranial Nerves
http://www.cs.txstate.edu/~uj1001/pictures/eye_muscles.gif
CN VI CN IV
CN III
CN III
CN III
CN III
http://quizlet.com/9891924/week-03-jack-and-his-spots-flash-cards/
Extraocular Movements
Oculomotor Nuclei within the Brainstem
Blumenfeld, 2002
Trochlear (CN IV) nucleus
PO
NS
M
IDB
RA
IN
Extra-ocular Movements
• Determine if ROM of eyes is full and gaze is conjugate (eyes move together)
• Abnormality indicates potential cranial nerve abnormality
• Effects coordination of eyes with one another
• Results in Diplopia
Cranial Nerve Palsies
CN III Oculomotor • Lesion:
– Monocular deviation in primary gaze “down and out”
– No adduction or upward vertical eye movements
– Eyelid ptosis
– Impaired pupillary light reflex
– Diplopia worse looking away from side of lesion
• Innervates all eye muscles except lateral rectus and superior oblique
Cranial Nerve Palsies
CN IV Trochlear • Innervates Superior
Oblique • Lesion: – Monocular deviation up
and extorted
– Cannot look down and out in primary position
– Adopts head tilt to accommodate elevation and rotation
Cranial Nerve Palsies
CN VI Abducens
• Innervates lateral rectus
• Lesion:
– Esotropia in primary gaze (inward)
– Cannot Abduct
– Diplopia worse looking towards side of lesion
Right Gaze Primary Gaze Left gaze
Gaze-Evoked Nystagmus
• Peripheral
– Resting tone imbalance
– Unidirectional
– Beats in same direction no matter the eye location in socket
• Central
– Neural integrator dysfunction
– Direction changing
– Beats in direction of eye movement
Gaze-Evoked Nystagmus (Peripheral)
Gaze-Evoked Nystagmus (Central)
Impaired Pursuit
Hypermetric Saccades
Hypermetric Saccades
Vergence
• Moves eyes in opposite directions to keep images at different distances stable on the fovea
– Convergence
• visual axes comes together
– Divergence
• visual axis separate
• Impairment results in diplopia, blurring and eye strain
https://www.en.eyebrainpedia.com/vergence
Vestibular Function
Vestibulo-Ocular Reflex (VOR)
• Holds image steady on retina during head movements – Head turns left – Left lateral SCC hair cells are
excited, while right are inhibited – Vestibular nerve to vestibular
nuclei to oculomotor nuclei – Stimulates ipsilateral (left) CN III:
medial rectus and contralateral CN VI: lateral rectus
– Eyes turn right
• Impairments result in reduced gaze stability, visual blurring, impaired postural control
Head Thrust Videos
Head Thrust
Positional Provocational Testing BPPV
Herdman, SJ & Tusa, RJ. Chapter 17; Vestibular Rehabilitation (3rd edition)
Roll Test for Lateral Canals
http://www.webmd.com/hw/health_guide_atoz/zm2447.asp
Dix-Hallpike Test for Vertical Canals
Central vs. Peripheral
Clinical Finding
Central Peripheral
Saccades impaired YES NO
Smooth pursuit impaired YES (may also be impaired with advanced age)
NO
Convergence impaired YES NO
VOR impaired YES YES
Head Thrust impaired Possible (e.g vestib. nuclei) YES to side of hypofunction
VOR Cancellation impaired YES NO
Head Shaking Nystagmus + Vertical nystagmus >2-3 beats horizontal nystagmus beating suggests peripheral. Beats towards the more neurally active side.
Interpretation What does it all mean? Peripheral Dysfunction Central
Dysfunction Mixed Dysfunction
Cause BPPV Damaged Receptor
Damage to CNS
structures
Combination
Treatment Re-positioning maneuvers
Adaptation, Substitution
exercises; Postural control
training
Adaptation, Substitution
exercises; Postural control training
Adaptation, Substitution exercises;
Postural control training
Goal Eliminate Dizziness
Optimize gaze and postural
stability
Optimize gaze and postural stability
Optimize gaze and postural stability
Prognosis Very good good fair fair
Interventions and
Outcomes
Purpose of Vestibular Rehabilitation
• Exercise approach to remediate dizziness and disequilibrium symptoms associated with peripheral and/or central vestibular dysfunction
• Based on the premise that the CNS can adapt/change in response to peripheral and central vestibular dysfunction
• In cases where the CNS cannot adapt/change, vestibular rehabilitation may be directed at substituting for vestibular dysfunction
Vestibular Compensation
• Robust, multi-faceted process of re-establishing postural control, gaze stability and spatial orientation.
• Occurs as a result of neuroplasticity
• Typifies the principles of motor learning
– Appropriate stimulus
– Work at maximal level of performance
– Allow adequate success/minimize error
– Follows principles of task specificity
Vestibular Interventions
• Adaptation:
– Improve gaze stability by increasing the gain of the VOR
• Substitution:
– Use of other strategies to replace lost or compromised function
• Postural Control Retraining
• Habituation:
– Reduce sensitivity through repeated exposure
Adaptation Exercises: Gaze Stability Exercises
X1 viewing exercises:
Head moving 20 – 300 side to side/up and down while visually fixating on a stationary target
X2 viewing exercises:
Head moving 20 – 300 side to side/up and down while visually fixating on a target moving opposite head movement
Refer to Adaptation Handout
Adaptation Exercises: X1 Viewing Exercises
Adaptation Exercises: X2 Viewing Exercises
Substitution Exercises
• Purpose: To foster the use of alternative strategies to replace the lost or compromised vestibular function
• Goals: – Improve gaze stabilization
– Maximize postural stability
– Central preprogramming
– Use of other strategies:
Corrective eye saccades
Slowed head movements
Increase use of smooth pursuit
Substitution Exercises
• Visual Fixation on Stationary Object – X1 viewing at slow speed to increase use of cervico-ocular
reflex and central pre-programming
• Active Eye Movements Between 2 Targets – Facilitates use of saccadic or smooth pursuit strategies and
central pre-programming
• Remembered/Imaginary Targets – Improve voluntary control and central pre-programming
Active Eye-Head Movement Between Two Targets
• Hold 2 targets at eye level 10-12 inches apart, head in midline
• Move eyes to one target
• Maintain eyes on target and turn head to same target
• Shift eyes to 2nd target
• Move head to 2nd target
• Repeat in opposite direction
Active Eye-Head Movement Between Two Targets
Remembered Targets
• Place target directly in front of you
• While looking at the target, close eyes
• Slowly turn head away while imagining the target
• Open eyes and verify still focused on the target adjust gaze if necessary
• Repeat in multiple directions and at variable speeds
Remembered Targets
Progression of Gaze Stability Exercises
VARIABLE PROGRESSION
Duration 1 2 minutes per exercise
Frequency 2 5 times per day
Velocity Increase head speed while keeping target in focus
Target Size Large Small
Target Distance Near Far
Background Simple Complex
Position of Patient Supported sitting Walking
Support Surface Firm Compliant Wide Narrow BOS
X1 Viewing Complex Background Example
X1 Walking
©2016 Neurology Section, APTA
Clinical Practice Guideline 2016
A. Action Statement 1: EFFECTIVENESS OF VESTIBULAR REHABILITATION IN PERSONS WITH ACUTE AND SUBACUTE UNILATERAL VESTIBULAR HYPOFUNCTION. Clinicians should offer vestibular rehabilitation to patients with acute or subacute unilateral vestibular hypofunction. (Evidence quality: I; recommendation strength: Strong
A. Action Statement 2: EFFECTIVENESS OF VESTIBULAR REHABILITATION IN PERSONS WITH CHRONIC UNILATERAL VESTIBULAR HYPOFUNCTION. Clinicians should offer vestibular rehabilitation to patients with chronic unilateral vestibular hypofunction. (Evidence quality: I; recommendation strength: Strong
A. Action Statement 3: EFFECTIVENESS OF VESTIBULAR REHABILITATION IN PERSONS WITH BILATERAL VESTIBULAR HYPOFUNCTION. Clinicians should offer vestibular rehabilitation to patients with bilateral vestibular hypofunction. (Evidence quality: I; Recommendation strength: Strong)
Effectiveness of Vestibular Rehabilitation Exercises – Central Dysfunction
Brown KE et al., 2006 Retrospective Case Series: “Physical Therapy for Central Vestibular Dysfunction”
• 48 patients with central vestibular dysfunction
– Central vestibulopathy, cerebellar dysfunction, stroke, mixed central and peripheral and post-traunmatic central disorders
• Significant differences were found pre and post vestibular rehabilitation on ABC, DHI, DGI, TUG and FTSTS
• Cerebellar patients improved the least
BPPV Interventions
CRM for Posterior Canal BPPV Log Roll for Lateral Canal BPPV
Straight Head Hang for Anterior Canal
BPPV
Compliments JO Helminski
Summary
• Vestibular dysfunction can influence learning
• Oculomotor examination impairments indicate central vestibular dysfunction
• Improvements in vestibular function can lead to improved gaze stability, postural control, concentration, attention, memory etc.
I have a question
Me first
No, me first
Questions?