Differential Diagnosis and Management of Brainstem and Cerebellar Infarctions Combined Sections Meeting, February 7, 2015 Indianapolis, IN

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1 3 Differential Diagnosis and Management of Brainstem and Cerebellar Infarctions Combined Sections Meeting, February 7, 2015 Indianapolis, IN Janet O. Helminski, PT, PhD Professor, Midwestern University Janet Callahan, PT, DPT, MS, NCS Clinical Assistant Professor, MGH Institute of Health Professions Clinical Specialist, Massachusetts General Hospital (I) (II) Objectives: Upon completion of this educational session, the participant will be able to: (A) Apply the process of differential diagnosis in the examination and management of brainstem and cerebellar infarctions versus acute vestibular pathology. (B) Identify the constellation of functional impairments associated with specific brainstem, cerebellar and vestibular syndromes. (C) Utilize the oculomotor examination to identify lesion locations associated with brainstem, cerebellar and vestibular structures. (D) Determine the long-term outcomes of the brainstem and cerebellar lesions. Incidence of vertigo and dizziness to Emergency Department. Using data from the National Hospital Ambulatory Medical Care Survey (NHAMCS), vertigo and dizziness accounts for 2.6 million visits annually to US emergency departments. 5 Of all cases of dizziness, 32.9% were due to oto-vestibular causes. 5 Of all oto-vestibular cases, 5.6% were due to acute vestibular syndrome. 5 (III) Acute vestibular syndrome (AVS) may be peripheral or central in origin. (A) Symptoms include rapid onset of: (1) Severe, continuous vertigo or dizziness (2) Nausea with retching or vomiting (3) Gait instability (4) Head motion intolerance (5) Nystagmus (B) Duration of symptoms days to weeks. (C) Cause: Most cases of acute vestibular syndrome are of benign cause (vestibular neuritis or nonbacterial labyrithitis), but approximately 25% are caused by brain stem or cerebellar strokes. 6 Half of stroke patients have no focal neurological signs. 6,7 (D) Imaging not sensitive acutely. (1) CT scans identify 16% of posterior fossa infarctions acutely. 8,9 (2) MRI with diffusion-weighted imaging of the brain identifies only 80% of posterior fossa infarctions in the first day. 6 (E) Clinical Examination important in identifying patients with acute central vestibulopathologies. (IV) History: (A) Medical History Cardiac Risk Factors. Of patients who sustained a brainstem/cerebellar stroke, 30% 1 cardiac risk factor and the others had at least 2 risk factors. 10 (1) Arterial hypertension 1

(2) Diabetes mellitus (3) Hyperlipidemia (4) Cigarette smoking (5) Atrial fibrillation (6) Hypercoagulable state (7) Eclampsia (8) Recent cervical trauma (9) Prior myocardial infarction (10) Prior

11 Determine if medial or lateral brainstem based on medial or lateral structures involved. Determine level of lesion based on cranial nerves involved (figure 1). Figure 1.

2 (2) Diabetes mellitus (3) Hyperlipidemia (4) Cigarette smoking (5) Atrial fibrillation (6) Hypercoagulable state (7) Eclampsia (8) Recent cervical trauma (9) Prior myocardial infarction (10) Prior stroke (B) History of current symptoms of dizziness/vertigo rapid onset. (V) Brainstem anatomy The rule of 4 of the brainstem. 11 Determine if medial or lateral brainstem based on medial or lateral structures involved. Determine level of lesion based on cranial nerves involved (figure 1). Figure 1. Medial and lateral structures of the brainstem. Figure 2. Principle arteries of the brainstem. ( (A) The 4 medial structures and the associated deficit: (1) The Motor pathway (corticospinal tract): contralateral weakness of the arm and leg. (2) The Medial Lemniscus: contra lateral loss of vibration and proprioception in the arm and leg. (3) The Medial longitudinal fasciculus: ipsilateral internuclear opthalmoplegia (failure of adduction of the ipsilateral eye towards the nose and nystagmus in the opposite eye as it looks laterally). (4) The Motor nucleus and neve: ipsilateral loss of the cranial nerve that is affected (III, IV, VI, XII) 2

3 Figure 3. Blood supply to the brainstem. Paramedian and long circumferential branches. 1 (B) The 4 lateral structures and the associated deficit: (1) The Spinocerebellar pathways: ipsilateral ataxia of the arm and leg. (2) The Spinothalamic pathway: contra lateral alteration of pain and temperature affecting the arm, leg and rarely the trunk. (3) The Sensory nucleus of the V: ipsilateral alteration of pain and temperature on the face in the distribution of the Vth cranial nerve (this nucleus is a long vertical structure that extends in the lateral aspect of the pons down into the medulla). (4) The Sympathetic pathway: ipsilateral Horner s syndrome, partial ptosis and a small pupil (miosis). (C) There are 4 cranial nerves in the medulla, 4 in the pons, and 4 above the pons (2 in the midbrain). (D) There are 4 motor nuclei in the medial brainstem (cranial nerve III, IV, VI, and XII) and 4 nuclei in the lateral brainstem (V, VII, IX, and XI) (VI) Brainstem vascular syndromes. 11 (A) The blood supply to the brainstem vertebral basilar system (Figure 2). (1) Paramedian branches (Figure 3) occlusion of the paramedian branches results in medial (or paramedian) brainstem syndromes (CST involved - motor) 3

(2) Long circumferential branches (Figure 3 and 4) occlusion of the long circumferential branches results in lateral brainstem syndromes

(a) Posterior inferior cerebellar artery (b) Anterior inferior cerebellar artery (c) Superior cerebellar artery Figure 4.

Three planes of motion pitch (frontal plane), roll (sagittal plane), and yaw (transverse plane).

4 (2) Long circumferential branches (Figure 3 and 4) occlusion of the long circumferential branches results in lateral brainstem syndromes (spinothalamic tract sensation) and cerebellar syndromes (ataxia). (a) Posterior inferior cerebellar artery (b) Anterior inferior cerebellar artery (c) Superior cerebellar artery Figure 4. Circulation to brainstem and cerebellum - long circumferential branches ( 2013). Figure 5. Three planes of motion pitch (frontal plane), roll (sagittal plane), and yaw (transverse plane). (VII) Other Etiologies causing Brainstem Lesions mimicking vestibular lesions (A) Multiple Sclerosis (B) Paraneoplastic Syndromes (VIII) Vestibular Anatomy. (A) Three Planes of Motion (Figure 5) (1) Pitch (sagittal plane) (2) Roll (frontal plane) (3) Yaw (transverse plane) (B) Vestibular Ocular Reflex Pathway (Figure 6) (1) Peripheral vestibular system (a) Sensory transducer hair cells located within sensory epithelium. (1) Crista ampullaris of ampulla of semicircular canal. Hair cells consist of 1 kinocillium and multiple stereocillia. Hairs cells located within cupula gelatinous diaphragm. 4

5 Figure 6. Schematic illustrating differences in the semicircular canal-ocular and short-latency utriculo-ocular connectivity. Blue lines afferent projections, red lines 2 nd order connections, and green lines for abducens neuron projections. 4 Schematic illustrating differences in the short-latency utriculo-ocular and semicircular canal-ocular (2) Maculae of utricle and sacculus. Weighted sensory epithelium consisting of hair cells embedded within the otolithic membrane with calcium carbonate crystals (otoconia) embedded on top. (1) detect linear acceleration. (2) Generate translational VOR (b) CN VIII vestibular nerve (Figure 7). Innervates hair cells and project to vestibular nuclear complex. (1) Two branches of the vestibular nerve. (a) Superior vestibular nerve fibers originate from lateral Figure 7 Origin (macula and crista ampullaris) and termination (vestibular nuclear complex) of vestibular nerve projections. 2 5

canal, anterior canal, and utricle. (b) Inferior vestibular nerve fibers originate from posterior canal and saccule. (2) Discharge firing rate of vestibular nerve.

6 canal, anterior canal, and utricle. (b) Inferior vestibular nerve fibers originate from posterior canal and saccule. (2) Discharge firing rate of vestibular nerve. (a) At rest, tonic discharge 90 spikes/s, equal on both sides, signally the brain that the head is not moving. (b) With movement, asymmetry in discharge firing rate. The canal towards which the head is turning increases and the opposite side is inhibited. Firing rate spikes/s depending on side. (2) Central vestibular system (a) Vestibular nuclear complex (figure 7) - axon projects through medial longitudinal fasciculus. (1) Superior vestibular nucleus projects to oculomotor and trochlear nuclei and integrates vertical VOR. (2) Medial vestibular nucleus projects to abducens nuclei, oculomotor nuclei and bilaterally to cervical/thoracic spinal cord to integrate horizontal VOR and vestibular colic reflex. (3) Lateral vestibular nucleus projects ipsilaterally to spinal cord to integrate lateral vestibular spinal tract (protective extension). (4).Descending vestibular nucleus integrates both sides. (b) Vestibular commissural system (c) Cerebellum (1) Flocculus adjusts and maintains gain of VOR (2) Paraflocculus adjusts gain of smooth pursuit (3) Nodulus adjusts duration of VOR. Processes otolithic input. (C) Extrinsic Muscles of Eye and innervation(figure 8). (1) Superior oblique CN IV (2) Superior rectus CN III (3) Inferior oblique- CN III (4) Inferior rectus- CN III (5) Medial rectus CN III (6) Lateral rectus CN VI (D) Direct Vestibulo-Ocular Projections: (1) Anterior Canal (a) Excitation: ipsilateral superior rectus and contralateral inferior oblique (b) Inhibition: ipsilateral inferior rectus and contralateral superior oblique (2) Posterior Canal (c) Excitation: ipsilateral superior oblique and contralateral inferior rectus (d) Inhibition: ipsilateral inferior oblique and contralateral superior rectus (3) Lateral Canal Figure 8. Extrinsic muscles of the eye. ( 6

7 (e) Excitation: ipsilateral medial rectus and contralateral Lateral rectus (f) Inhibition: ipsilateral lateral rectus and contralateral medial rectus (IX) Lesions to the vestibular system Mechanisms of Compensation. (A) Inter-relationship of vestibular neurons. (B) Signs and symptoms of unilateral vestibular deficit. (1) Static At rest, asymmetry tonic firing rate results in:. (a) Spontaneous nystagmus- lesion AVOR pathway fast phase away from side of lesion. Peripheral lesion spontaneous ny observed with fixation first 5 days and without fixation from 5 days 8 years. Central lesion spontaneous ny observed with/without fixation. (b) Decreased tone of extensor muscles side of lesion lesion graviceptive pathway. (2) Dynamic reduced gain of the central vestibular system. Gain = output/input. (a) Oscillopsia an illusion that everything in the environment is moving lesion VOR pathway. (b) Postural responses inadequate on side of lesion due to lesion graviceptive pathway. (X) Plane specific classification of central vestibular syndromes based on oculomotor, postural and perceptual signs. (A) Planes of motion pitch, roll, and yaw. (B) Lesion to graviceptive pathways results in vestibular tone imbalance (asymmetrical resting firing rate), with the head is at rest, resulting in a syndrome consisting of a perceptual tilt, head and body tilt, vertical misalignment of the visual axes (skew deviation) and ocular torsion. (C) Localizing nystagmus in brainstem disorders. 12,13 Table 1. Localizing nystagmus in brainstem disorders. 12,13 Plane Direction of Nystagmus (Fast Phase) Roll (Frontal) Contraversive ocular torsion Contraversive ocular torsion Ipsiversive ocular torsion Ipsiversive ocular torsion Location of Lesion Duration Side of Lesion Pontomedullary Transient Unilateral Interstitial nucleus of Cajal Permanent Unilateral Pontomesencephallic Transient Unilateral Rostral interstitiaul nucleus of the medial longitudinal fasciculus Permanent Unilateral Pitch (Sagittal) Upbeat only Paramedian Bilateral pontomesencephalis (ventral tegmental tract, brachium conjunctivum) Medulla (perihypoglossal nuclei) Downbeat only Flocculus Bilateral 7

8 Yaw (horizontal) Combined syndromes (roll and yaw) Upbeat or downbeat or transitions Contraversive Horizontal Torsion and horizontal Paramedian pontomedullary Root entry zone of the vestibuar nerve, medial and superior vestibular nuclei, and paramedian pontine reticular formation pontomedullary syndromes, vestibular neuritis (D) Signs of plane specific vestibular syndromes. 12 Bilateral Unilateral Unilateral Table 2. Signs of Plane Specific Vestibular Syndromes. 12 Plane Vertical Misalignment Ocular Torsion Head Tilt Body Tilt Falls Perceptual Tilt Past Pointing of Visual Axes (Skew Deviation) Roll x x x x Vertical Pitch Forward/ Forward/ Forward/ Horizontal backward backward backward Yaw Rotation/ lateral Straight ahead x (E) Graviceptive pathway for roll. 12 Pathway crosses at level of pons. Subjective visual vertical is most sensitive sign in roll plane Table 3. Graviceptive pathway for roll. 12 Location of Lesion Arterial Ocular Tilt Reaction Subjective Visual Vertical Supply Ipsiversive Contraversive Ipsiversive Contraversive Peripheral (superior Vertebral X x vestibular nerve) Pontomedullary Junction (medial and superior vestibular nuclei) Vertebral X X Pontomesencephalic Paramedian from Basilar X X Thalamus Paramedian None None X X Thalamic Vestibular Cortex Thalamogeniculate, temporal branches of CMA, deep perforators None None X 8

9 (F) Frequency subjective visual vertical (SVV) tilt, skew deviation, ocular torsion, and ocular tilt reaction (OTR) in acute unilateral brainstem and thalamic infarctions. 3 Table 3. Frequency subjective visual vertical, skew deviation ocular torsion, and ocular tilt reaction in acute unilateral brainstem and thalamic infarctions. 3 Ocular Torsion (%) Lesion Brainstem Medullary (Wallenbeg s syndrome) Patients (no.) SVV Tilt (%) Monocular Binocular Skew (%) OTR (%) Pontomedullary Pontine Pontomesencephalitc Mesencephalic Mesodiencephalic Anterior polar thalamic Posterlateral thalamic Paramedian thalamic Total (G) HINTS to Diagnose Stroke in the Acute Vestibular Syndrome Three step bedside examination. 10 (1) Examination. (a) Head Impulse Test (b) Direction-changing nystagmus in eccentric gaze (c) Skew deviation (vertical ocular misalignment (XI) Clinical Examination: (A) Neurological screen to identify focal neurological signs. (1) Motor screen (2) Sensory screen (3) Cranial nerves (other than III, IV, and VI) (4) Oculomotor examination (a) Fixation/alignment (b) Extra-ocular movements (c) Saccades (d) Pursuit (e) Gaze holding (f) VOR (g) Vergence (B) Disorders of Fixation (Spontaneous nystagmus) (1) Downbeating nystagmus: 9

10 a. Most common form of acquired spontaneous nystagmus. b. Associated with lesions in the pontomedullary tegmentum and flocculus/araflocculus of the cerebellulm. c. Possibly associated with brainstem connects from Anterior Semicircular canal. (2) Upbeating nystagmus. a. Caudal Medulla b. Ventral tegmental tract (3) Torsional nystagmus (C) Disorders of Alignment: Skew deviation (vertical ocular misalignment). (1) Symptom: a. Vertical diplopia b. Subjective visual vertical (2) Differential diagnosis a. Graviceptive pathway b. CN IV lesion (3) Tests: Monocular v binocular a. Bucket Test 14 i. Ipsiversive v contraversive tilt b. Maddox Rods c. Upright v Supine Position Test 15 (D) Disorders of gaze holding (1) Peripheral Vestibuar Dysfunction a. Non-direction changing due to vestibular tone imbalance b. Alexanders Law (2) Central Vestibular Dysfucntion a. Direction changing b. Neural Integrators i. Horizontal ii. Vertical (E) Disorders of the VOR (Head Impulse Test) (1) Test of peripheral vestibular function (2) Positive in isolated medial vestibular nucleus lesions (3) References 1. Greenberg D, MJ A, RP S. Clinical Neurology. 8 ed. New York: McGraw-Hill Companies; Goldberg M. The Vestibular System. In: Kandel E, Schwartz J, Jessell T, Siegelbaum S, Hudspeth A, eds. Principles of Neural Science. 5th ed. New York: McGraw Hill Medical; 2012: Brandt T, Dieterich M. Vestibular syndromes in the roll plane: topographic diagnosis from brainstem to cortex. Annals of neurology. Sep 1994;36(3): Angelaki DE. Eyes on target: what neurons must do for the vestibuloocular reflex during linear motion. Journal of neurophysiology. Jul 2004;92(1): Newman-Toker DE, Hsieh YH, Camargo CA, Jr., Pelletier AJ, Butchy GT, Edlow JA. Spectrum of dizziness visits to US emergency departments: cross-sectional analysis 10

11 from a nationally representative sample. Mayo Clinic proceedings. Jul 2008;83(7): Tarnutzer AA, Berkowitz AL, Robinson KA, Hsieh YH, Newman-Toker DE. Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome. CMAJ : Canadian Medical Association journal = journal de l'association medicale canadienne. Jun ;183(9):E Newman-Toker DE, Kattah JC, Alvernia JE, Wang DZ. Normal head impulse test differentiates acute cerebellar strokes from vestibular neuritis. Neurology. Jun ;70(24 Pt 2): Chalela JA, Kidwell CS, Nentwich LM, et al. Magnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison. Lancet. Jan ;369(9558): Edlow JA, Newman-Toker DE, Savitz SI. Diagnosis and initial management of cerebellar infarction. The Lancet. Neurology. Oct 2008;7(10): Kattah JC, Talkad AV, Wang DZ, Hsieh YH, Newman-Toker DE. HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke; a journal of cerebral circulation. Nov 2009;40(11): Gates P. The rule of 4 of the brainstem: a simplified method for understanding brainstem anatomy and brainstem vascular syndromes for the non-neurologist. Internal medicine journal. Apr 2005;35(4): Brandt T, Dieterich M. Central vestibular syndromes in the roll, pitch, and yaw planes. Neuro-opthalmology. 1995;15(6): Buttner U, Helmichen C, Buttner-Ennever JA. The localizing value of nyetsgmus in brainstem disorders. Neuro-opthalmology. 1995;15(6): Zwergal A, Rettinger N, Frenzel C, Dieterich M, Brandt T, Strupp M. A bucket of static vestibular function. Neurology. May ;72(19): Wong AM. Understanding skew deviation and a new clinical test to differentiate it from trochlear nerve palsy. Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus / American Association for Pediatric Ophthalmology and Strabismus. Feb 2010;14(1):

Ocular Tilt Reaction: Vestibular Disorder in Roll Plane

대한안신경의학회지 : 제 8 권 Supplement 1 ISSN: 2234-0971 Ocular Tilt Reaction: Vestibular Disorder in Roll Plane Ji-Yun Park Department of Neurology, Ulsan University Hospital, Ulsan, Korea Ocular tilt reaction