Dizzy battery at a glance

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In this short presentation Audiologist Mohammad S. Asghar recommends Dizzy battery approach to evaluate full vestibular function

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  • Point to remember: Note the Vestibular nerve innervations of Sup and Inf. Vest N.
  • Dizzy battery at a glance

    1. 1. Dizzy battery at a Glance MOHAMMAD S. ASGHAR AU.D (USA) , AUD (C), REG.CASLPO. M.SC AUDIOLOGICAL MEDICINE (UK), M.B,B.S (PB) M.C.P.S (ENT) CERTIFIED BY THE AMERICAN BOARD OF AUDIOLOGY (ABA) DIRECTOR HEARING & BALANCE SERVICES
    2. 2. Anatomy of the vestibular system
    3. 3. Anatomy of Vestibular System
    4. 4. Nerve supply of vestibular system
    5. 5. Blood supply of Inner Ear
    6. 6. Irrigation Parallels Innervation Blood supply Innervation Basilar A VIIIth N AICA Labyrinthine A Common Cochlear Artery Main Cochlear Artery Cochlea Vestibulo Cochlear artery Post Vest A Post SCC Ampulla Majority of Scaula Ant Vestibular A Anterior SCC Ampulla Horizontal SCC Ampulla Utricle Minority of Sacula Auditory Nerve Vestibular N Inferior division Superior Division
    7. 7. Vestibular system: central connections
    8. 8. Anatomic and Basic Medical considerations: Vestibular system consists of two groups of specialized sensory receptors. 1: Three semicircular canals Lateral or horizontal, Posterior or inferior, Superior or vertical SSC, which originate from utricle and also end at utricle at a dilated end called ampulla. 2: Two otolith organs: Utricular macula and saccular macula.
    9. 9. Vestibular testing, (Introduction) In vestibular testing we are always testing output of vestibular system. We do not have any direct clinical measurement for vestibular testing. 1) For ENG, vHIT and Rotary Chair tests we use VOR 2) For Posturography we use VSR. 3) For VEMP we use vestibulocolic response (VCR) &VOR 4) For Meniere's Disease and endolymphatic Hydrops we use Ecoch.G and VEMP.
    10. 10. The Vestibulo-ocular reflex; The VOR normally acts to maintain stable vision during head motion. This reflex has two components. The angular VOR, mediated by the SCCs, compensates for rotation. The linear VOR mediated by the otoliths, compensates for translation. -- Tests based on VOR: ENG, rotary chair test, VAT, Active head rotation test, Dynamic visual acuity test, oVEMP & vHIT
    11. 11. The Vestibulospinal Reflex The purpose of the VSR is to stabilize the body. The activity is induced on the side to which the head is inclined, and flexor activity s induced on the opposite side. -- Tests Based on VSR: Computerized dynamic posturography (CDP, Sensory integration test).
    12. 12. The Vestibulocollic Reflex. The VCR acts on the neck musculature to stabilize the head. -- Tests Based on VCR: cVEMP
    13. 13. Tests involving Sup. and inf. divisions of vestibular Nerve: Sup. Vestibular N: ENG, caloric test, High frequency head shake test, Rotary chair test, VAT, oVEMP & vHIT Inf. Vestibular N: VEMP , This is the only test available to test the integrity of the Inf. Vestibular N of Vestibular nerve & Now vHIT can also test part of Inf Vest N.
    14. 14. What are we testing? Five motion sensors – VOR (i.e. Input/output, ENG /R chair) lateral canal only & now vHIT and oVEMP (Utricle and All SSC). VCR (VEMP test) saccule only  Abnormal gravity sensitivity (positional nystagmus) - BPPV Tracking (pursuit, saccade test, OKN test) , Sensorimotor integration (posturography) Tests only VSR, documents functional aspects of the balance system.
    15. 15. Believe in yourself (your own exam) Quality control on vestibular testing is nonexistent Computer software is crude No method exists of recording torsion (which you need for BPPV) There are many places where corners can be cut or things can go wrong Experienced eyes (with Frenzel's) are sometimes are more reliable than most ENG’s So no substitute for experience and your clinical acumen.
    16. 16. Flow chart PT A Cochlear N VIII N AB R Baseline thresholds Shape of audiogram Retrocochlear pathology/ VEMP may add credibility Ecoch. G MD/EH Drop attacks Ant.SCC Sup. Vest. N Lat.SCC Utricle PTA ABR Ecoch. G VEMP VAT/Positioni ng/vHIT Caloric/ Posiit.Rot Chair/vHIT oVEMP Post.SCC Vestibular N Inf. Vest. N Saccule VAT/Positioni ng/vHIT cVEMP Dizzy battery PTA ABR Ecoch.G ENG Rotary VAT/v Chair HIT VAT ENG oVEMP oVEMP cVEMP vHIT VAT ENG VEM P
    17. 17. Conclusion Assessment of vestibular function has advances from ENG being the only test to a test battery approach where we can actually diagnose the site of lesion to the exact receptor site in the ear. Although we are still struggling to manage the dizzy patients after diagnoses but armed with the diagnoses we can better prepare the patient to deal with the problem and become a part of rehab team.
    18. 18. Conclusion Lat. Canal: ENG, VAT, vHIT, Rotary Chair Post Canal: vHIT, VAT, Positional test Sup Canal: vHIT, VAT Utricle: oVEMP Saccule: cVEMP Ecoch.G: MD/EH
    19. 19. What Next If you are dizzy ask your doctor for vestibular testing as ear is the cause of vertigo in almost 50% of patient.

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