Nothing Special   »   [go: up one dir, main page]
Scribd Logo
Upload

Welcome to Scribd!

  • 77 views

    Caloric Test 20031002

    Uploaded by

    Hisham Elkilaney
    This document summarizes the history and procedures of caloric testing. It describes how caloric testing works by inducing nystagmus through convection of the inner ear fluid using irrigation of hot and cold water. It provides details on standard bithermal caloric testing procedures and observations. Key metrics like canal paresis and directional preponderance are defined to analyze caloric test results and identify possible peripheral or central causes of abnormal findings.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Caloric Test 20031002

    Uploaded by

    Hisham Elkilaney
    77 views21 pages
    This document summarizes the history and procedures of caloric testing. It describes how caloric testing works by inducing nystagmus through convection of the inner ear fluid using irrigation of hot and cold water. It provides details on standard bithermal caloric testing procedures and observations. Key metrics like canal paresis and directional preponderance are defined to analyze caloric test results and identify possible peripheral or central causes of abnormal findings.

    Original Description:

    Caloric Test

    Copyright

    © © All Rights Reserved

    Available Formats

    PDF, TXT or read online from Scribd

    Did you find this document useful?

    Is this content inappropriate?

    This document summarizes the history and procedures of caloric testing. It describes how caloric testing works by inducing nystagmus through convection of the inner ear fluid using irrigation of hot and cold water. It provides details on standard bithermal caloric testing procedures and observations. Key metrics like canal paresis and directional preponderance are defined to analyze caloric test results and identify possible peripheral or central causes of abnormal findings.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    77 views21 pages

    Caloric Test 20031002

    Uploaded by

    Hisham Elkilaney
    This document summarizes the history and procedures of caloric testing. It describes how caloric testing works by inducing nystagmus through convection of the inner ear fluid using irrigation of hot and cold water. It provides details on standard bithermal caloric testing procedures and observations. Key metrics like canal paresis and directional preponderance are defined to analyze caloric test results and identify possible peripheral or central causes of abnormal findings.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 21

    CALORIC TEST

    R1 Chang
    2003/10/02
    History
    Robert Barany in 1906,
    1914 Nobel Prize
    Fitzgerald and Hallpike(1942):biaural,
    bithermal caloric test, ocular fixation
    Further modification: eye closure, eye
    open in the dark or behind Frenzel`s
    glasses, ENG recording
    Computerized caloric test
    Variant caloric tests:
    Bithermal test (the standard)
    Monothermal test -- a single large bolus of ice water
    is given rather than two irrigations with hot and cold
    Air caloric -- air is used instead of water.
    Bilateral irrigation -- both sides are irrigated
    simultaneously
    Balloon test -- a water filled balloon is used instead
    of water.
    Ice water caloric -- used to confirm complete loss
    Bithermal Caloric tests (1)
    Bailey 3rd edition
    Supine and head elevated 30 degrees
    The EAC is irrigated directly with
    250ml of water
    7 degrees above and below body
    temperature (30 and 44)
    for 30 secs
    Bithermal Caloric tests (2)
    Observation:
    Ocular movement
    2 minutes, beginning with stimulation
    (duration)
    Frequency
    Fixation suppression
    Slow-phase velocity
    Amplitude
    Closed-loop system
    A small, distensible
    balloon in the ear
    canal
    For tympanic
    membrane
    perforation
    Mechanism
    a test of the lateral semicircular canals
    alone
    By virtue of vestibulo-ocular reflex
    VOR (Vestibulo-ocular reflex)
    Semicircular canal-extraocuar muscle
    connection
    Purpose: stabilize images on the retina
    during head movement
    Horizontal canal VOR
    A simple 3 neuron reflex
    VOR
    A simple 3 neuron
    reflex
    1: Scarpa`s ganglion
    2: Vestibuar nucleus
    3: Oculomotor nucleus
    (C.N. III, IV, VI)
    VOR
    Vestibular nystagmus
    Slow phase: vestibular nuclei
    Fast phase: saccadic system
    (parapontine reticular formation)
    Thermoconvection
    Barany, 1914
    Thermal gradient
    Movement of the
    intra-canicular fluid
    by convection
    Mechanism
    COWS
    The cold stimulus causes nystagmus to
    the opposite direction
    The warm stimulus causes nystagmus
    to the same direction
    Tasking
    Canal Paresis (CP)
    Right-ear left-ear/total
    (R30+R44)-(L30+L44)/(R30,44L30,44)
    100%
    It should be 25% or less
    Directional Preponderance (DP)
    Right-beating - left-beating/total
    (L30+R44)-(L44+R30)/(R30,44L30,44)
    100%
    It should be 35% or less
    Results(suggestive of a central disorder)
    Spontaneous or positional nystagmus
    with normal caloric results
    Direction-changing nystagmus
    independent of stimulus changes
    Failure of fixation suppression
    Results(suggestive of a central disorder)
    Bilateral reduced or absent caloric
    responses without a history of
    labyrinthine or middle ear disease
    Abnormal saccade and pursuit results,
    especially with normal caloric results
    Hyperactive caloric responses (loss of
    cerebellum-generated inhibition)
    Results(suggestive of a peripheral
    disorder)
    Unilateral caloric weakness
    Bilateral caloric weakness with a history
    of labyrinthine disease or administration
    of ototoxic drugs
    Fatiguing positional nystagmus
    Intact fixation suppression response
    Direction-fixed nystagmus
    The End
    Thank you!

    You might also like