10/20/2015 House Rules: • If your pager or cell phone goes off during this presentation, you must stand and sing a BPPV: Understanding Eye Barry Manilow song (Loudly!) Movements & Treatment Approaches David A. Zapala, Ph.D. & Janet Shelfer, Au.D. Ringing cell phones & Otolaryngology / Head and Neck Surgery / Audiology AQUIRING knowledge Mayo Clinic - Jacksonville don’t mix! Benign Paroxysmal Positional Dix-Hallpike or Nylen Maneuver Vertigo (BPPV) • Intense but transient vertigo provoked by moving into specific head positions – Most common cause of vertigo – Accompanied by a characteristic nystagmus – Thought to be caused by debris in the semicircular canals Furman and Cass “Benign Paroxysmal Positional Vertigo.” NJM 1999. Our aim is to help sharpen your Characteristic Response abilities to: – Torsional nystagmus (rolling eye movement) & vertiginous sensation • Onset latency (5-45 sec) – Recognize and understand common subtypes of • Crescendo then fatigues (typically within 30 sec) BPPV presentations and how to treat them • Symptoms extinguish (adapt) over repeated trials – Recognize when “Benign” is not benign – Appreciate current limits of our understanding of this condition – Can be treated by a simple in office procedure 1 10/20/2015 Development of Theories of BPPV • Adler (1897): First formal description Theories of BPPV • Barany (1921): Case report • Proposed degeneration of the utricle as cause of condition • BPPV formally defined by Dix and Hallpike (1952) • Described BPPV in 100 cases • Demonstrated utricular degeneration in one temporal bone Cupulolithiasis Theory Cupulolithiasis Theory • Schuknecht (1969, 1972): “Heavy Cupula” explanation – Debris (otoconia?) adheres to cupula of the posterior semicircular canal – Weight of otoconia causes cupula to deflect, making it gravity-sensitive. – Nystagmus eventually subsides due to due to central vestibular adaptation Schuknecht (1969, 1972) Cupulolithiasis Theory Canalithiasis Theory Schuknecht (1969, 1972) 2 10/20/2015 Schuknecht 1974 Canalithiasis Theory • Lim, 1973: – Loosened otoconia dissolves in vivo • (we now think this may explain the long term remission of symptoms) • Hall et al., 1979 – Loose debris don’t necessarily adhere to cupula • Brandt & Daroff, 1980 – Exercises for central habituation limit duration of BPPV Development of Canalithiasis Canalithiasis Theory (cont.) Theory • Pagnini et al., 1989: • Semont, Fereyss and Vitte, 1988 – Horizontal canal conversion of BPPV – Liberatory Maneuver • Parnes & McClure, 1990 • Dislodges and repositions debris into utricle – 84% success rate with one maneuver, 93% success rate – Observation of free-floating particles in PSSC with two maneuvers and a recurrence rate of 4.2% during canal plug surgery Curing BPPV with the Liberatory maneuver. Adv Oto Rhinol Laryngol 42; 290-293 Development of Canalithiasis Evidence for “Canaliths” Theory • Epley JM. 1992 – Canalithiasis • Canalith Repositioning Maneuvers to move loose debris into utricle The canalith repositioning procedure: for treatment of benign paroxysmal positional vertigo. Otolaryngol Head Neck Surg. 1992, Parnes, Agrawal & Atlas. Diagnosis and Management of Benign Sept;107(3):399-404. Paroxysmal Positional Vertigo (BPPV). CMAJ, Sept 30, 2003; 167 (7), 681-693. 3 10/20/2015 Canalithiasis Theory Pros of Canalithiasis Theory • Theory explains: • “Canaliths,” which have a heavy specific – Why there is adaptation: gravity relative to endolymph, drift to • Nystagmus persists only so long as canaliths are lowest position in membranous labyrinth. moving toward the pull of gravity. – Produces movement of endolymph – Why there is fatigue: • Debris spreads out in the canal with repeated – Endolymph movement deflects the cupula, movement and loosing effectiveness as a “plunger” stimulating hair cells and inducing vertigo & – Why there is spontaneous remission: nystagmus • Debris leaves the canal Theory Offers Treatment • Canaliths may be repositioned using Neuronal Degeneration Theory gravity to “drift” debris away from sensory epithelium From: Baloh, R. W. (1998) “Dizzy Patients: The Varieties of Vertigo” in: Hospital Practice, http://www.hosppract.com/issues/1998/06/dmmbal.htm Neuronal Degeneration Theory Neuronal Degeneration Theory • Gacek, (2003) • Ganglionitis disrupts otolith / semicircular – Loose basophilic debris not found in temporal canal output bones of patients with BPPV symptoms – Loss of inhibitory effect of utricle or saccule on • Severe neuronal degeneration of the inferior SSC output vestibular nerve in these temporal bones. • Cupulolithiasis and Canalithiasis cannot account for – Produces aberrant nerve activity posterior canal symptoms • Adaptation on Dix-Hallpike testing due to central suppression and adaptation. 4 10/20/2015 Summary • All of these theories have something to offer. BPPV: Brief Anatomy and – Mechanical “Lithiasis” theories offer rational Functional Review approach to non-surgical treatments – Neural theory may explain cases of more persistent positional nystagmus • Never get too attached to your theories... BPPV: Background Anatomy Ocular Motor Nerves & Muscles • Ocular Motor System • CN III: Oculomotor – Medial Rectus • Vestibular End Organ Anatomy – Superior Rectus • Vestibulo-Ocular Reflex (VOR) – Inferior Rectus – Inferior Oblique – Interpretation of Eye Movements • CN IV: Trochlear – Superior Oblique • CN VI: Abducens – Lateral Rectus Complementary Muscle Pairs Peripheral Vestibular System • “Cardinal” Eye Positions • Five sensory receptors – Isolate muscle pairs – Three Cristea – Failure of one eye to match • Horizontal its complement may betray • Anterior/superior ocular motor deficit. • Posterior /inferior – Maculae • Saccule • Utricle Barber & Stockwell, 1980 The Ampulla of the horizontal canal is toward the front - Remember this! 5 10/20/2015 Ampulla Semicircular Canals • Quasi-orthogonal canals on same side • Coplanar canals between sides • Law of reciprocal innervation From: Jay W. McLaren, Ph.D., Mayo Clinic Parnes et.al, 2003 Vestibular Macula Vestibular Macula • Saccule • Utricle – Action: – Action: • Translational movements • Lateral translations – Vertical • Acceleration and static head tilt – Anterior / Posterior (A/P) – How to remember • Linear Acceleration • “The Utricle is On the floor - – How to remember: YoU step over the Utricle” • “The Saccule is Stuck to Wall” From: Jay W. McLaren, Ph.D., Mayo Clinic From: Jay W. McLaren, Ph.D., Mayo Clinic Central Vestibular System Peripheral Vestibular System • Five sensory receptors • Four Primary Vestibular – Three Cristea Nuclei • Horizontal – As many others… • Anterior/superior • Interact with Ocular • Posterior /inferior Motor System – Maculae • Saccule • Utricle The Ampulla of the horizontal canal is toward the front - Remember this! 6 10/20/2015 Three Ways to Understand the Vestibulo-Ocular Reflex Vestibulo-Ocular Reflex • Goal: Maintain “gaze stability” regardless of head / trunk movement • Method #1: Neuroanatomy... • Gaze stability means: – Keep the object of attention on fovea – Maintain horizontal meridian orientated to horizon Three Ways to Understand the Easy!?! Vestibulo-Ocular Reflex • Method #1: Neuroanatomy… • Method #2: Ewald’s Laws of Semicircular Canal Dynamics Ewald’s First Law Ewald’s Second Law • Vestibular evoked eye movements occur in • Vestibular nerve can encode fast (high the plane of the canal being stimulated. acceleration) excitatory movements better – If you stimulate the horizontal canal, you get a than inhibitory movements. horizontal eye movement. – The resting discharge rate of the vestibular nerve is just under 100 spikes/sec – Excitatory acceleration can drive nerve firing rate to +300 spikes/sec – Inhibitory acceleration, no matter how fast, can never drive nerve output below 0 spikes/sec 7 10/20/2015 Ewald’s Third Law Vertical Canal Excitation • Horizontal Canal Excitation – Ampullopetal endolymphatic flow stimulates crista • Vertical Canal Excitation – Ampullofugal endolymphatic flow Note:stimulates “Petal” means crista toward, Tellian and Shepard’s Graphic “Fugal” means “away from” Parnes et.al, 2003 Three Ways to Understand the Ecological Approach to Vestibular Vestibulo-Ocular Reflex Evoked Eye Movements • Method #1: Neuroanatomy… • Vestibular evoked eye movements are designed to: – Maintain gaze stability during unexpected head / body movements • Method #2: Ewalds Laws of Semicircular – Maintain eye orientation so that the horizon lines up Canal Dynamics with the horizontal meridian of the retina • Method #3: Ecological Approach A Model... The View “Under the Hood” P P Right Left Right H H Left A A 8 10/20/2015 SSC Planes Law of Reciprocal Innervation LARP RALP • Six SSCs are matched in LARP RALP • Head movements that complement pairs -three stimulate the nerve of one planes... canal, inhibit output in the – Two Horizontal complementary canal – Right Anterior and Left Right Left Right Left • Leading Ear Excites Posterior (RALP) • Lagging Ear Inhibits – Left Anterior and Right Posterior (LARP) Relating Horizontal SSC Output Horizontal Canal Dynamics to VOR • Q: Which way does the cupulla of the • So with Left Head Turn: – The Left Horizontal SCC horizontal canal bend to excite the Excites Left Vestibular vestibular nerve? Nerve – Right Horizontal SCC • A: It “swings away from” the leading ear. Inhibits Right Vestibular Right Left – A.K.A.: “ampullopetal flow” - endolymph Nerve flows towards the utricle – The Eyes Drift to the Right side of the Orbit to maintain Gaze stability (VOR) Relating Horizontal SSC Output Relating Horizontal