Acute Vestibular Syndrome

ACUTE VESTIBULAR SYNDROME
A SYNDROME OF SEVERE VERTIGO, NAUSEA, VOMITING, SPONTANEOUS NYSTAGMUS, AND POSTURAL INSTABILITY
MUST DIFFERENTIATE A PERIPHERAL (VESTIBULAR) INSULT FROM A CENTRAL (INF. CEREBALLAR) INSULT
THE DIFFERENTIAL IS BASED ON CHRONOLOGY OF SYMPTOMS,  PT RISK FACTORS FOR STROKE, ABILITY TO SUPPRESS WITH VISUAL FIXATION, CHARACTERISTICS OF NYSTAGMUS (VERTICLE, DIRECTION CHANGING), ASSOC SYMPTOMS (OTOLOGIC), ACCOMPANYING NEUROLOGIC SIGNS (DYSPHASIA, WEAKNESS ECT..).
NEW LITERATURE SHOWING SOME VESTIBULAR TESTS CAN PICK THESE PTS UP AS WELL: TOROK MONOTHERMAL CALORIC TESTING SHOWS VESTIBULAR DECRUITMENT AND HYPERACTIVE CALORIC RESPONSES WERE OF PARTICULAR VALUE
PAST NEUROLOGY DOGMA LEADS ONE TO BELIEVE THAT VERTIGO, DIZZINESS, WOOZINESS AND GIDDINESS ARE NOT INDICATIVE OF CVDz
THIS DOGMA HOWEVER IS CHANGING—THESE PTS OFTEN PROGRESS ON TO A MAJOR STROKE
IT HAS BEEN SAID THAT ANYONE >45 YEARS OF AGE PRESENTING WITH ACUTE VERTIGO WITH NO ASSOC OTOLOGIC SYMPTOMS SHOULD BE IMAGED FO R/O A CVA —-THIS IS OF COURSE CONTROVERSIAL—-BUT AT LEAST THINK OF IT
VERTIGO LASTING A DAY OR LONGER
VESTIBULAR (VIRAL) NEURONITIS OR NEUROLABYRINTHITIS—VS MS VS VBI
MINUTES-HOURS
HYDROPS VS TIA
SECONDS
BPPV VS TIA
VESTIBULAR NEURONITIS OR NEUROLABYRINTHITIS IS ONLY ASSOC WITH PRECEEDING URTI IN ABOUT 30% OF CASES
PERIPHERAL (COCHLEAR)
AUDITORY
DIPLACAUSIS BINAURIS DYSHARMONICA—HIGHER/ROUGHER PITCH
GOOD SDS (40dB SL)-PHONETICALLY BALANCED WORDS
RECRUITMENT
+ABLB (WITH UNILAT HL)–ALTERNATE BINAURAL LOUDNESS BALANCE TEST—MUST HAVE NL HEARING IN 1 EAR AND MILD LOSS IN THE OTHER—PRESENT TONES AND INCREASE INTENSITY IN BOTH EARS AND PT COMPARES INCREASES
+SISI (20 dB SL)-SHORT INCREMENT SENSITIVITY INDEX—TESTING IF PTS CAN DETECT 1 DB INCRESE IN INTENSITY AT 20 DB SL
+EARLY ACOUSTIC REFLEXES = +ACOUSTIC REFLEXES AT 30 dB(ANY THING LESS THAN 70 dB=RECRUITMENT)
TYPE II BEKESY TRACING
(BEKESY AUDIOMETRY–CONTINUOUS VS PULSED TONES)–CAN ALWAYS HEAR THE PULSED TONES BETTER
INCREASED LATENCY OF WAVE 1 AND 2 OF ABR
ECOG (WAVE I ON ABR)–INCREASED SP/AP RATIO (>33-50%)=THE COCHLEAR MICROPHONIC FROM THE TYPE I OUTER HAIR CELLS
+GLYCEROL TEST(REVERSIBILITY)
ABNL OTOACOUSTIC EMMISSIONS
VESTIBULAR—REALLY ONLY TEST LAT SCC!
+FISTULA TEST/HENNEBERT’S SIGN
TULLIOS PHENOM(GREATEST AT 500HZ)
SYMPTOMS
VERY SYMPTOMATIC—N/V
UNIDIRECTIONAL
EPISODIC
ASSOC. OTOLOGIC Sx–SNHL,TINNITUS,FULLNES, PARESIS
NYSTAGMUS
TYPE III NYLEN POSITIONAL NYSTAGMUS
HORIZONTAL/ROTORY—-VERTICO-TORSIONAL
DIRECTION FIXED—-HEAD SHAKE AND ETOH MAY LEAD TO DIRECTION CHANGING NYSTAGMUS
ASSYMETRIC
SUPPRESSED >50% BY VISUAL FIXATION
ENHANCED BY FRENZELS/EYES COLOSED OR DARKNESS
INDUCED/POSITIONAL
LATENCY(DELAYED ONSET—10-15 SECONDS)
TEMPORARY—LASTS LESS THAN 1 MIN
FATIGABLE
OSCILLOPSIA
ALEXANDERS(BOTCHED RHINOPLASTY) LAW—NYSTAGMUS PRESENT WHEN GAZING TOWARD THE FAST COMPONENT
1ST DEGREE GAZE EVOKED NYSTAGMUS(PRESENT WITH GAZE TOWARD FAST COMPONENT)
EWALD’S 1ST LAW—EYE MOVEMENT, HEAD MOVEMENT, AND PAST POINTING OCCUR IN THE SAME PLANE OS THE STIMULATED CANAL
85% PAST POINTING IS PERIPHERAL
HSN(HEAD SHAKE NYSTAGMUS) +—–VELOCITY STORAGE THEN REVERSAL PHASE
EWALD’S 2ND LAW—EXCITATION IS MORE EFFECTIVE THAN INHIBITION IN CHANGING LABYRINTHIAN ACTIVITY
(HORIZONTAL CANAL(1) AMPULOPETAL FLOW CAUSES INCREASED RESPONSE)
VERTICAL CANALS(2) AMPULOFUGAL FLOW CAUSES INCREASED RESPONSE)
UNILAT WEAKNESS (25% JONKEES)=DIRECTIONAL PREPONDERANCE  = SEEMS TO CORRELATE WITH SPONT NYSTAGMUS
INSUFFICIENT GAIN ON ROTARY CHAIR–ESPECIALLY IN THE LOW FREQUENCIES—-PT MUST BE ALERT
ABNL PHASE LAG
ASYMMETRY
POSTUROGRPHY–CLASSIC 5-6 PATTERN OF VESTIBULOPATHY

CENTRAL-RETROCOCHLEAR
AUDITORY/CENTRAL
POOR SDS <50%
+ROLLOVER
+PIPB–PERFORMANCE INTENSITY FUNCTION FOR PHONETICALLY BALANCED WORDS—-(DECREASED SDS AT INCREASEDDB INTENSITY)
POOR BINAURAL FUSION RESULTS(STAGGERED SPONDIAC WORD TESTING)
ABNL TONE DECAY—< 60 SECONDS–SHOULD HAVE > 60 SECONDS AT 20 DB SL(CARHART, OLSON-NOFFINGER,OWENS,ROSENBERG,GREEN, STAT)
ABNL ACOUSTIC REFLEX TESTING—< 10 SECONDS AT 10 DB SL (SHOULD BE ABLE TO HOLD STAPEDIAL CONTRACTION FOR THIS LONG)—ACOUSTIC REFLEX ABSENT WITH ANY HL > 60 DB
TYPE III OR IV BEKESTY TRACING
ABNL LATENCY ON WAVES III – V ON ABR
VESTIBULAR/CENTRAL
(TRACKING/SLOW PURSUIT)
ABNL SACCADES(FAST) AND GLISSADES(SLOW–CORRECTIVE EYE MOVEMENTS)
MULTI-STEP SACCADES=CEREBELLAR
HYPERMETRIC SACADESS=CEREBELLAR
FLUTTER=BRAINSTEM
INTERNUCLEAR OPHTHALMOPLEGIA=MLF(MS)
SLOWING=CNS
SPONTANEOUS—-NOT SUPPRESSED BY VISUAL FIXATION
BRUN’S (BRAINSTEM COMPRESSION) NYSTAGMUS–ON SIDE OF LESION
CONGENITAL NYSTAGMUS–INVERSION OF OKN
SQUARE WAVE JERKS=CEREBELLAR
PERIODIC ALTERNATING NYSTAGMUS=CNS
REBOUND, UP OR DOWN BEATING=CEREBELLAR/BRAINSTEM
SYMPTOMS—
VERTIGO OCCASIONALLY ABSENT
PROLONGED/STEADY
ASSOC. WITH NEURO DEFICIT
NYSTAGMUS
VERTICAL AND IN ANY VARIABLE DIRECTION
NOT POSITIONAL OR RELATED TO HEAD MOVEMENT
NON-FATIGABLE—REPEATABLE
GAZE PARETIC NYSTAGMUS
PERIODIC ALTERNATING NYSTAGMUS
SUPPRESSED BY FRENZELS OR CLOSING EYES
NO LATENCY
LASTS >1 MIN(PROLONGED OR STEADY)
DIRECTION CHANGING
2ND (1ST + STRAIGHT) GAZE EVOKED NYSTAGMUS
TYPE II OR TYPE I NYLEN POSITIONAL NYSTAGMUS
CALORIC INVERSION OR PERVERSION ON ENG
POOR/WEAK UNI OR B RESPONSE ON OKN
OKN INVERSION = CONG NYSTAGMUS
ABNL PHASE LEADS ON ROTARY CHAIR TESTING
CENTRAL PROCESSING ERRORS
CNS—SYNTHETIC SENTENCE IDENIFICATION WITH CONTRALATERAL COMPETING MESSAGE / FILTERED SPEECH
CAVEATES IN TESTING:
POSITIONAL TESTING—–NO MOVEMENT—THE PT IS IN 1 PARTICULAR (OFTEN PECULIAR) STATIC POSITION
!
POSITIONING TESTING—-LIKE HALLPIKE/DIX (BARANY/NYLEN)
ENG—-REALLY THE ONLY IMPORTANT VESTIBULAR TEST—DISTINGUISHES BETWEEN VESTIBULAR AND NONVESTIBULAR—-HOWEVER, REALLY ONLY TESTS AT A VERY LOW FREQUENCY
UTILIZES THE BULBAR DIPOLE
I—CALIBRATES THE EYE MOVEMENTS—10-15 DEGREES
II—SACCADES, LATENCY, VELOCITY, AND ACCURACY—-ABNL POINT TO A CENTRAL DEFECT
III—SMOOTH PURSUIT—SINUSOIDAL/PERPENDICULAR PATTERN)—GAIN, PHASE, ACCELERATION—-ABNL=CENTRAL PROBLEM
IV—-OPTOKINETIC NYSTAGMUS (FORM/SYMMETRY)
V—-GAZE OR FIXATION
VI—POSITIONAL
VII—POSITIONING
VIII—CALORICS
ROTATIONAL TESTING
ACTIVE—HEADSHAKE = HIGHEST FREQUENCY
PASSIVE—-ROTARY CHAIR TEST = SINUSOIDAL OSCILLATION TEST—ABLE TO TEST THE VESTIB SYSTEM AT MULT FREQUENCIES (LIKE AN AUDIO)
“COMPARE THE VELOCITY OF THE SLOW EYE MOVEMENTS TO THE VELOCITY OF THE CHAIR”
GAIN—THE RATIO BETWEEN THE MAX EYE VELOCITY AND THE MAX CHAIR VELOCITY
PHASE = SYMMETRY
NOT EAR SPECIFIC
CAN TEST CHILDREN EASIER
MOST USEFUL FOR BILAT VESTIBULOPATHY (OTOTOXICITY)
MOST SENSITIVE, FREQ SPECIFIC—ENG ONLY TESTS THE VESTIB SYSTEM AT A VERY LOW FREQ

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