Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

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au Not all dizziness is created equally Learning outcomes lecture Understand the key causes and origins of dizziness and associated movement imbalance in a person post stroke Awareness of emerging

1 Your stroke patient is dizzy challenges of assessment and treatment. Katrina Williams Specialist Neurological Physiotherapist FACP 2008 Clinical Academic University of Queensland Senior Neurological Ageing and Balance Clinic UQ Not all dizziness is created equally Learning outcomes lecture Understand the key causes and origins of dizziness and associated movement imbalance in a person post stroke Awareness of emerging evidence for treatment options Learning outcomes practical session Novice therapist Awareness of the oculomotor signs and tests for exploring a person with stroke who reports dizziness and imbalance Therapist with prior vestibular training Awareness of the outcome tools and treatment strategies that can be employed to address the dizziness Role of the vestibular system Sense of self vs world - movement and alignment To provide information about a persons Position in respect to gravity Velocity and direction of movement Control of self movement To provide outputs that control a person postural alignment / uprightness Visual clarity when moving / visual uprightness Resolve sensory conflict For optimal outcome of the vestibular integration one needs Normal functioning of the vestibular apparatus Normal functioning of the central integrative systems Normal functioning of the motor outputs The role of the vestibular system Vestibular disorders association July The peripheral vestibular system Hain, TC. July Quick review of the vestibular apparatus Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

Peripheral apparatus and nerves 5 - Sensory end-organs 5 distinct sensory

orientation 2 Otolith organs Utricle & Saccule Sensory end organs SCCs =

dizziness-and-hearing.com. July 2017 http://www.dizziness-and-balance.

jpg Movement awareness Nerve supply to vestibular apparatus Curthoys 2012

Inferior vestibular nerve supplies posterior canal saccule Neural pathways

pons and medulla located in the medulla and pons superior, lateral, medial &

2 Peripheral apparatus and nerves 5 - Sensory end-organs 5 distinct sensory organs 3 semicircular canals (SCC) Anterior, Horizontal Posterior orientation 2 Otolith organs Utricle & Saccule Sensory end organs SCCs = Crista Ampullaris Otoliths = Macula Hain, TC. July Movement awareness Nerve supply to vestibular apparatus Curthoys 2012 Superior vestibular nerve supplies anterior canal horizontal canal utricle Inferior vestibular nerve supplies posterior canal saccule Neural pathways of the vestibular system Vestibular nuclei 4 major vestibular Nuclei in the pons and medulla located in the medulla and pons superior, lateral, medial & inferior connected to the nuclei of the abducens, trochlear and oculomotor nerves (CN (- eye muscles- 3, 4 & 6) Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

Vestibular area Vestibular area Posterior ventral nucleus Brain Stem = pons/medullar/midbrain /thalamus/hypothalamus Posterior ventral nucleus Brain Stem = pons/medullar/midbrain

Abducens motor nucleus Vestibular ganglion Vestibular nucleus Spinovestibular tract Vestibular-spinal tract Vestibular ganglion Vestibular nucleus Spinovestibular tract Vestibular-spinal tract Pons

3 Vestibular area Vestibular area Posterior ventral nucleus Brain Stem = pons/medullar/midbrain /thalamus/hypothalamus Posterior ventral nucleus Brain Stem = pons/medullar/midbrain /thalamus/hypothalamus Cerebellum Cerebellum Vestibular nerve Occulo-motor nucleus Trochlear motor nucleus Vestibular nerve Occulo-motor nucleus Trochlear motor nucleus Abducens motor nucleus Abducens motor nucleus Vestibular ganglion Vestibular nucleus Spinovestibular tract Vestibular-spinal tract Vestibular ganglion Vestibular nucleus Spinovestibular tract Vestibular-spinal tract Pons Vestibular area Posterior ventral nucleus Brain Stem = pons/medullar/midbrain /thalamus/hypothalamus Cerebellum Vestibular nerve Occulo-motor nucleus Trochlear motor nucleus Vestibular ganglion Vestibular nucleus Spinovestibular tract Abducens motor nucleus Vestibular-spinal tract Mid-brain Medulla Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

Moore, T http://www.vestib.com July 27 2016 http://www.vestib.com/arterial-supply.

Monitors vestibular performance and readjusts central vestibular processing Calibrates vestibular reflexes Cerebellar projections have an inhibitory influence Supply the medial pons & give rise to

centers 24% Superior cerebellar artery From AICA or Basilar 16% Basilar artery Sole supply to inner ear (vestibular apparatus) Supplies the VII and VIII cranial nerve anterior and inferior

net/hearingandbalancecentre/presentation-kitchener-may-2015 Integration of vascular and nerve supply to the vestibular apparatus Seeing straight - seeing clearly Why is my stroke patient saying they

4 Moore, T July Cerebellum Cerebellum = adaptive processor / calibration unit Motor control fine tuner / motor skill acquisition / supervised learning Cognitive functions attention / language Monitors vestibular performance and readjusts central vestibular processing Calibrates vestibular reflexes Cerebellar projections have an inhibitory influence Supply the medial pons & give rise to Superior cerebellar artery Superior cerebellum and peduncles Cerebellar nuclei P Cerebral A Midbrain Quick review of the vascular supply to the Brain Stem Blood supply: 45% AICA Balance and dizzy centers 24% Superior cerebellar artery From AICA or Basilar 16% Basilar artery Sole supply to inner ear (vestibular apparatus) Supplies the VII and VIII cranial nerve anterior and inferior cerebellum Ponto-medulla junction Supply the Pons and medulla houses the vestibular nuclei Entire posterior and inferior cerebellum Integration of vascular and nerve supply to the vestibular apparatus Seeing straight - seeing clearly Why is my stroke patient saying they can t focus? Visual field loss Control of eye movements and eye reflexes Three key centres of control Centres controlling the nuclei Supranuclear (cortex) Pathways connecting the nuclei Internuclear (midbrain) - MLF Nerves supplying the EOM Infranuclear (local to muscle cranial nerves 3, 4 and 6) Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

Other oculomotor systems: Vestibular and visual systems Used to track a moving target Smooth pursuit Vergence Used to position eye to object of interest (target) Saccadic sudden jerky eye movement

Trajectory of object must be predictable Pursuit mechanism not sustainable with velocities > 70 /s; frequencies >1Hz; accelerations >240 /sec Used instead of the VOR to maintain clear visual viewing

to replace a target of interest onto the fovea if has moved off This is the eye movement used if smooth pursuit cannot be used secondary to pathology or outside the normal velocity for pursuit or

5 Other oculomotor systems: Vestibular and visual systems Used to track a moving target Smooth pursuit Vergence Used to position eye to object of interest (target) Saccadic sudden jerky eye movement When head is moving used in combination with saccades and smooth pursuit Vestibular Optokinetic Smooth pursuit tracking Maintains an object of interest on the fovea with and without head movements Trajectory of object must be predictable Pursuit mechanism not sustainable with velocities > 70 /s; frequencies >1Hz; accelerations >240 /sec Used instead of the VOR to maintain clear visual viewing from no movement to head movements up to 5 Hz Smooth pursuit system origins of control Supra-nuclear control center Abnormal Smooth pursuit Other oculomotor systems: Saccadic eye movements Mechanism to replace a target of interest onto the fovea if has moved off This is the eye movement used if smooth pursuit cannot be used secondary to pathology or outside the normal velocity for pursuit or trajectory is unpredictable Saccade system Frontal eye field Frontal and Parietal Cortex Superior colliculus Basal Ganglia Internuclear control Brain Stem Para pontine reticular formation Medial longitudinal fasciculus Saccades can be hyper or hypometric Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

Pathways for saccadic and smooth pursuit circuits Saccades hypometric Role of the Vestibular System in seeing clearly Normal VOR Vestibular Ocular Reflex

Visual target is stationary or in motion Maintain image of interest steady on the fovea of the retina during head movements Has two components: Angular VOR

Subjective Visual Vertical (SVV) perceptual Sense of visual upright Ocular tilt = skew deviation, head tilt and ocular torsion Damage to 8 th nerve

6 Pathways for saccadic and smooth pursuit circuits Saccades hypometric Role of the Vestibular System in seeing clearly Normal VOR Vestibular Ocular Reflex (VOR) The VOR is an important mechanism to maintain stable vision during rapid or non-constant head movements Head must be moving at variable velocity Visual target is stationary or in motion Maintain image of interest steady on the fovea of the retina during head movements Has two components: Angular VOR - compensates for rotation (SCCs) Linear VOR - compensates for translation (otoliths) Role of the Vestibular System in seeing straight Ocular tilt Subjective Visual Vertical (SVV) perceptual Sense of visual upright Ocular tilt = skew deviation, head tilt and ocular torsion Damage to 8 th nerve Vestibular nucleus (ipsilesional) Vestibular pathways (MLF, rimlf, INC); contraversive roll-tilt Baier et al 12 Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

Positive test of skew Optokinetic, vergence and fixation system Optokinetic system Takes over from the vestibular system when head movements are too large.

Pathways in the occipital region (PCA) Other oculomotor systems: Optokinetic system Maintains visual objects on the fovea when in constant motion no acceleration so the VOR is not active (eg

when the ocular nuclei (in the pons and medulla) are damaged With just visual motion can create strong sensation of motion This system backs up the VOR when the head is not accelerating or

7 Positive test of skew Optokinetic, vergence and fixation system Optokinetic system Takes over from the vestibular system when head movements are too large. Neural pathways similar to that of smooth pursuit Vergence system Depth tracking Pathways in the parietal, occipital, and frontal regions Fixation system Utilized to look at stationary object Pathways in the occipital region (PCA) Other oculomotor systems: Optokinetic system Maintains visual objects on the fovea when in constant motion no acceleration so the VOR is not active (eg travelling in car) Is a combination of both pursuit tracking and saccades so tracks the object and then resets to the next object or the same one with the head in a new position Ocular palsy Occurs when the ocular nuclei (in the pons and medulla) are damaged With just visual motion can create strong sensation of motion This system backs up the VOR when the head is not accelerating or decelerating The role of the vestibular system for upright posture - Vestibulospinal reflex (VSR) Purpose of the VSR is to stabilise head on the body and maintain upright posture VSR results from motor output from vestibular nuclei to spinal motor neurones. Uses otolith input to a greater extent than the SCCs - ie related to tilt / gravity rather than rotation e.g. standing on a boat rocking side to side, VSR stabilises head by counteracting trunk sway The role of the vestibular system in maintaining head positions - Vestibulocollic reflex (VCR) Acts on the neck musculature in order to stabilise the head Reflex head movement counters the movement sensed by the otolithic or SCC organs Neural pathways unclear Further reading Dr Hain website: Dizziness and Balance Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

head is moving too fast to utilise visual systems for object focus (VOR loss or VOR cancellation impairment) Stabilisation of the head is critical for good performance (otolith malfunction)

8 Role of the vestibular system in postural control and clear vision.key is integration Depends on the nature of the task & on the environmental conditions Dizziness arises when the vestibular system has imbalanced integration or output Triggers dizziness when: The head is moving too fast to utilise visual systems for object focus (VOR loss or VOR cancellation impairment) Stabilisation of the head is critical for good performance (otolith malfunction) Stabilisation of the body alignment (otolith malfunction) When there is conflict between the somatosensory and visual systems Role of the visual system in causing dizziness Depends on the nature of the task & on the environmental conditions Dizziness arises when the eyes don t move to keep the object of interest in focus on the fovea blurred vision Trigger dizziness when: Tracking objects that are predictable (Smooth pursuit) Tracking objects that are unpredictable (Saccades) Scanning the environment (Saccades / VOR cancellation) Focussing on objects which are stationary with a moving background (optokinetics) Example of symptoms from a stroke Cardinal features of brainstem stroke: 1. An ipsilateral peripheral cranial nerve involvement 2. A contralateral weakness or sensory deficit 3. Cerebellar signs, if present, should be ipsilateral 4. Unusual ocular signs Nystagmus direction changing or unilateral in gaze PICA (lateral medullary) is the most common brainstem stroke Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

9 Moore, T July vascular supply Supply the medulla houses the vestibular nuclei entire posterior and inferior cerebellum Vascular lesions: PICA Structure supplied: Vestibular nuclei, posteroinferior cerebellum Lateral spino-cerebellar tract, posterior inferior cerebellum Vagal nuclei & Nerve Symptoms: Reported vertigo, reported / observed nystagmus horizontal direction changing, skew eye deviation ocular tilt, visual tilt, not reduced with fixation. Down beating. Observed unsteady gait, reduced postural control, ipsilateral propulsion, limb ataxia Dysphagia, decreased gag reflex Vascular lesions: PICA Structure supplied: Vestibular nuclei, postero-inferior cerebellum Lateral spino-cerebellar tract, posterior inferior cerebellum Vagal nuclei & Nerve Trigeminal Nerve (CN V) & nucleus Oculomotor nerve (CN VI) Facial nerve (CN VII) Spino-thalamic tract Descending hypothalamic reticular fibres (sympathetic) Symptoms: Reported vertigo, reported / observed nystagmus horizontal direction changing, skew eye deviation, not reduced with fixation. Down beating Observed unsteady gait, reduced postural control, ipsilateral propulsion, limb ataxia Dysphagia, decreased gag reflex Ipsilateral Facial hemi-anaesthesia Reported double vision, observed decreased lateral eye movement Ipsilateral Facial paralysis Contralateral hemi-sensory loss -Horner s syndrome (ptosis - drooping upper eyelid, constricted pupil, decreased sweating) Direct vestibular impairments Reduced function of the vestibular ocular reflex from Integration Velocity storage unit malfunction delay in start and cessation of vestibular inputs and influences Damage to nuclei reception and transmission Reduced integration of primary vestibular impulses due to Cerebellum damage Reduced capacity to suppress reflexes (eg VOR) Integration and output Reduced capacity to utilise other sensory systems for postural control and alignment Direct visual impairments Reduced function of the visual system from Output Reduced capacity to move eyes synchronously and with accuracy to target dysmetria / (Hypo or Hyper) and lateral gaze palsy (unilateral) Smooth pursuit and saccades affected from modulation / transmission perspective Integration and output Reduced capacity to utilise other sensory systems for postural control and alignment Summary of signs and symptoms of vestibular and visual integration malfunction in strokes Impaired postural alignment Impaired sense of upright visual and heptic Impaired control of eye movement Impaired control of transitioning between mechanisms for visual, vestibular control Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

Assessment options - impairments Clinical assessment of vestibular and visual function Oculomotor bed side examination +/-

assessment *Emerging evidence suggest that patient with poor sitting alignment abilities (eg pusher) increases the

Clinical assessment of vestibular function Vestibular function bed side examination +/- vestibular test (best done with

App Line/Dome test *Dynamic Visual acuity (DVA) Clinical assessment of vestibular function Vestibular balance tests ovemps* /

Nystagmus / Gaze evoked nystagmus 2. Smooth pursuit 3. Saccades 4. Head shaking nystagmus 5.

Head impulse test Likely to see on oculomotor assessment Nystagmus direction changing or unilateral Smooth pursuit jumpy /

10 Assessment options - impairments Clinical assessment of vestibular and visual function Oculomotor bed side examination +/- VNG Smooth pursuit /Saccades /Skew eye deviation / VOR Cancellation Limited evidence to consider optimal position for assessment *Emerging evidence suggest that patient with poor sitting alignment abilities (eg pusher) increases the variability of measures. (Piscicelli et al 16) Therapeutic consideration stabilise trunk during testing. Clinical assessment of vestibular function Vestibular function bed side examination +/- vestibular test (best done with infra-red goggles) Head shaking nystagmus VOR reflex Video Head Impulse Test *Subjective Visual Vertical bucket test Currator App Line/Dome test *Dynamic Visual acuity (DVA) Clinical assessment of vestibular function Vestibular balance tests ovemps* / cvemps Calorics Rotational chair Video Head Impulse Test* Demonstration of oculomotor key assessments for a stroke patient 1. Nystagmus / Gaze evoked nystagmus 2. Smooth pursuit 3. Saccades 4. Head shaking nystagmus 5. Vestibular ocular reflex cancellation 6. Vestibular ocular reflex 7. Head impulse test Likely to see on oculomotor assessment Nystagmus direction changing or unilateral Smooth pursuit jumpy / saccadic intrusion with possible reduced range with one eye in one direction Saccades slower, reduced range with multiple adjustments slower, increased range with multiple oscillation Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

Likely to see on oculomotor assessment Evidence (emerging) impaired vestibular dysfunction Head shaking nystagmus VOR cancelation positive VOR loss: positive; difficulty with head rotation and focus

11 Likely to see on oculomotor assessment Evidence (emerging) impaired vestibular dysfunction Head shaking nystagmus VOR cancelation positive VOR loss: positive; difficulty with head rotation and focus at higher speeds / positive Dynamic Visual Acuity Functional outcome) Evidence (emerging) impaired vestibular dysfunction Clinical Implications from expected signs assessment Look beyond the obvious movement to capture the other signs of cerebellar or brainstem dysfunction - assess. Assess in ways that challenge or isolate vestibular and visual impairments in relation to function. Functional assessment for the dizzy stroke Functional assessment Choose assessment outcome that incorporate vestibular or visual integration Functional Gait Assessment Dynamic Gait Index BESTest or minim BESTest Dynamic Visual acuity 10mwt + head turns (H and V) Romberg / Sharpened Romberg Equitest Balance Master King Devick Test Others???? Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

12 Role of vestibular and visual orientated stroke rehabilitation Treatment To improve the integration of the vestibular information centrally To improve the motor outputs of the ocular motor system Usual therapy for balance and function already addresses some of the motor outputs for posture and balance, we need to do more. Emerging treatment options with therapy Working with dizzy or imbalanced patients combine treatment strategies when necessary to improve a patients capacity to use the vestibular inputs and hone the motor outputs including eye control Goal is to manipulate the systems affected by the stroke (eg visual output and vestibular integration) so the body can integrate all systems to spatial co-ordinates which are then transformed and integrated into an egocentric, bodycentered reference frame. Evidence (emerging) impaired vestibular dysfunction Verticality will be altered - training with vision then without - seems logical to activate this part of the vestibular system Stimulate the optokinetic system to activate one side of the vestibular system via visual stimulation of the ocular tilt Vestibular stimulation via galvanic stimulation Train in the vertical and translational planes for otolith activation Emerging treatment options and additions to standard therapy Manipulation of the vestibular inputs / outputs Use of virtual reality rotational coherent dots. (Reinhart et al 16) Normalisation of spatial disorientation of SVV Use of correct visual or hepatic vertical to improve standing balance (Hong et al 13) Improved balance symmetry and reduced sway greater with visual vertical corrections Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

13 Emerging treatment options and additions to standard therapy Manipulation of the vestibular inputs / outputs Galvanic vestibular stimulation mixed findings depending on outcome used Reduced spatial neglect and normalised verticality perception (Volkening et al 16) Reduced postural asymmetry (Bonan et al 16) Combining visual stimulus with movement Ideas?? Planes of movement for otolith activation Addition of visual activation Type Direction Ideas for future therapy VR Clinical Implications from expected signs training from emerging evidence Train the oculomotor systems, combine with the vestibular for output calibration and motor control for function Train the VOR if suboptimal in testing Train the smooth pursuit / saccades / convergence / divergence Emerging treatment options and additions to standard therapy what about the eyes???? Manipulation of the eye movements Here we explore the evidence more from mild TBI s and concussions as there is yet nothing directly linked to stroke Eye tracking Smooth pursuit Saccadic training Tracking Convergence divergence Horizontal vertical torsional tracking Tracking smooth pursuit Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

14 Saccades VOR Cancellation Convergence / Divergence Exploring the assessment tools and treatment Time to get dirty and get giddy! Visual vertical Bucket / Curator App Visual optical stimulation +/- balance assessment Video Head Impulse Test Vision therapy ideas Katrina Williams 2017 Specialist Neurological Physiotherapist FACP

Extraocular Muscles and Ocular Motor Control of Eye Movements

Extraocular Muscles and Ocular Motor Control of Eye Movements Linda K. McLoon PhD mcloo001@umn.edu Department of Ophthalmology and Visual Neurosciences Your Eyes Are Constantly Moving. Yarbus, 1967 Eye