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III The 10-minute Examination of the Dizzy Patient The following is a suggested order of examination for eye movement and posture control abnormalities in dizzy patients. SPONTANEOUS NYSTAGMUS Action: Target fixation in neutral gaze Frenzel goggles Normal: No nystagmus or excessive saccades Abnormal: Jerk nystagmus: Direction fixed, increases with Frenzel goggles = PERIPHERAL Direction changing, increases with fixation = CENTRAL (periodic alternating nystagmus, congenital) Pendular = CENTRAL (congenital nystagmus) GAZE NYSTAGMUS Action: Hold eccentric gaze 20–30 degrees for 10 seconds in horizontal and vertical plane Normal: Physiologic end gaze or no nystagmus Abnormal: Jerk nystagmus (exponentially decreasing slow phase) in direction of gaze = CENTRAL (flocculus, drug effect, alcohol) Downbeat nystagmus in lateral gaze = CENTRAL (Arnold Chiari, midline cerebellum) 437 438 Practical Management of the Dizzy Patient SMOOTH PURSUIT Action: Track finger moving, 60 degrees through 60-degree arc horizontal and vertical Normal: Smooth pursuit movements Abnormal: Saccadic pursuit = CENTRAL (cerebellum, brainstem, parietal lobe) Irregular tracking = acuity, age, medications, attention SACCADES Action: Alternate gaze between fingers Normal: Rapid, accurate, conjugate eye movements Abnormal: Overshoots, undershoots = CENTRAL (dorsal vermis, fastigial nuclei) Slow saccades = CENTRAL (brainstem) Late saccades = CENTRAL (frontal lobe, brainstem, Parkinson’s syndrome) Disconjugate = CENTRAL (MLF syndrome) HEAD THRUST TEST Action: Thrust head 20–30 degrees while fixating on target Normal: No loss of fixation Abnormal: Refixation saccade = PERIPHERAL (loss of VOR) HEADSHAKE TEST Action: Shake head for 20 seconds at 2 Hz (horizontal and vertical) eyes closed, then open eyes (Frenzel goggles) and observe for nystagmus Normal: No nystagmus Abnormal: Unidirectional nystagmus in plane of headshake = PERIPHERAL (toward intact side except hydrops) Vertical nystagmus after horizontal headshake = CENTRAL DYNAMIC VISUAL ACUITY TEST Action: Have patient read eye chart with head still then with 0.2 Hz headshake Normal: <3 line drop in acuity with headshaking Abnormal: <3 line drop with headshaking = PERIPHERAL (bilateral VOR loss) The 10-minute Examination of the Dizzy Patient FIXATION SUPPRESSION TEST Action: Have subject fixate on own thumb while rotating body in exam chair Normal: No nystagmus Abnormal: Nystagmus in direction of rotation = CENTRAL (flocculus) POSITION TESTS Action: Place the head in left/right Hall pike, left/right lateral, supine Normal: No nystagmus Abnormal: Torsional (geotropic) nystagmus with upbeat and ageotropic horizontal components = BPPN (downmost posterior SCC) Horizontal (geotropic or ageotropic) paroxysmal nystagmus = BPPN (downmost lateral canal) Horizontal sustained nystagmus = PERIPHERAL/ CENTRAL AURAL PRESSURE/SOUND TESTS Action: Stimulate ear with positive pressure (otoscope), loud sound, mastoid vibration Normal: No nystagmus Abnormal: Upward deviation with ipsilateral eye torsion toward nose or downbeating nystagmus = superior semicircular canal dehiscence Horizontal nystagmus = perilymphatic fistula CEREBELLAR LIMB TESTS Action: Finger-to-nose Heel-shin Rapid alternating motion Normal: Accurate movements Abnormal: Dysmetria, dysdiadochokinesia (lateral lobe cerebellum) = SOMATOSENSATION TESTS Action: 128 Hz tuning fork to lateral malleolus Normal: Vibration sense present Abnormal: Loss of vibration sense Action: Move great toe up/down Normal: Correctly identifies action Abnormal: Incorrectly identifies action CENTRAL 439 440 Practical Management of the Dizzy Patient POSTURE TESTS Action: Romberg test Sharpened Romberg test Eyes closed foam Normal: Minimal sway, no falls Abnormal: Excessive sway, falls on Romberg = VARIABLE/ APHYSIOLOGIC Falls on foam eyes closed = PERIPHERAL/ MIXED/APHYSIOLOGIC GAIT TESTS Action: Observation of gait Fukuda step test Normal: Normal gait <45-degree rotation on Fukuda test Abnormal: Wide based, ataxic, Parkinsonian, musculoskeletal gait >45-degree rotation on Fukuda test