Saccades. Assess volitional horizontal saccades with special attention to. Dysfunction indicative of central involvement (pons or cerebellum)

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1 Saccades Assess volitional horizontal saccades with special attention to Amplitude? Duration? Synchrony? Dysfunction indicative of central involvement (pons or cerebellum)

2 Dynamic Visual Acuity Compare static vs. dynamic, >1 line degradation considered significant Oscillate head at varying frequencies from 2-7 hz within a 20 degree arc of rotation about the yaw plane Use of metronome to standardize frequency Alter direction of line reading to control for memorization

3 DVA Scores (herdman et al 1998) Subject Normal subjects N=51 Dizzy, nonvestibular n=16 Unilateral vestibular loss n=53 Bilateral vestibular loss N=34 Normal DVA (%) Abnormal DVA (%)

4 Head Impulse Apply a rapid rotation of the head (<20 degrees) in the plane of each canal Sensitivity is maximized by performing the test with: Unpredictable head thrusts Frequency (>2 hz) and velocity >180 deg/sec Movement strictly within the plane of the canal of interest

5 Head Impulse Normal response: Patient s gaze should remain fixated on examiners nose (stable) Abnormal responses: Hypo-active VOR: Eyes travel with the skull during the head thrust, a corrective saccade in a direction opposite to the head thrust is required to place eyes back to the nose, this suggests a diminished ipsilateral vestibular-ocular reflex (VOR) Hyperactive VOR: Eyes over-correct for the head impulse. Corrective saccade needed in direction of head impulse, this suggests central vestibular dysfunction.

6 Head Impulse Tests high frequency VOR Head impulses can be utilized to assess the function of the: Superior vestibular nerve: Head thrusts performed in the plane consistent with anterior or horizontal canal stimulation. Inferior vestibular nerve: Head thrusts performed in the plane consistent with posterior canal stimulation.

7 Head Impulse Test Normal Abnormal

8 Head impulse: Sensitivity / Specificity Data summarized in: Balance Function Assessment and Management Jacobsen / Shepard 2008 Sensitivity and Specificity are 100% for patients with complete unilateral vestibular loss Sensitivity varies with the severity of the unilateral vestibular loss. Pooled data with a variety of patient populations Sensitivity 76% Specificity 94%

9 Head Shaking 2 hz head shaking horizontal or vertical for 15 seconds Fixation removed May be best elicited with the affected ear in a dependent position (Palla 2005) For peripheral dysfunction > than 3 beats of post head shaking nystagmus considered clinically significant for unilateral vestibular dysfunction

10 Head shake: Sensitivity / Specificity Data summarized in: Balance Function Assessment and Management Jacobsen / Shepard 2008 Sensitivity / Specificity varies with the severity of unilateral vestibular loss. Pooled data with a variety of patient populations Sensitivity 56% Specificity 71%

11 Hyperventilation 1 breath/sec for 40 seconds Symptoms within 20 seconds without nystagmus suggestive of possible anxiety etiology Nystagmus induced by hyperventilation may imply Unilateral vestibular hypofunction or Cerebellar Pontine Angle Tumor

12 Hyperventilation Choi et al (Neurology 2007) More commonly evoked in pts with acute vs. (<7 days) vs. chronic vestibular loss (60% vs. 21%) More commonly noted in pts with CPA tumors than unilateral hypofunction (82% vs. 34%) Typically ipsilesional with CPA tumors Tendency for hyperventilation-induced nystagmus to be present with small CPA tumors and smaller caloric asymmetries

13 When to use Frenzel / Infrared Goggles to Block Fixation? Spontaneous nystagmus* Gaze Holding* Head Shake Nystagmus Hyperventilation Valsalva Head Positioning * = also assessed with fixation present

14 Distinguishing Features: Peripheral vs. Central Feature Peripheral Central Effect of Fixation Direction Effect of Gaze Reduces nystagmus Fixed, mixed horizontal and torsional Increases with gaze directed toward fast phases Enhanced or unchanged Pure vertical, torsional or horizontal May change direction

15 Cervicogenic dizziness Neck Torsion Test Trunk and head rotation is manipulated Symptom provocation with head and trunk rotated in tandem implies possible vestibular dysfunction Symptom provocation during trunk rotation with the head fixed may suggest cervicogenic dizziness Traction Test Reduction of dizziness with the application of cervical traction

16 Head Positioning Tests Hallpike See picture Roll Test Sidelying Test

17 Balance Testing Static balance Romberg Single limb stance Altered sensory cues CTSIB Fukuda Step Test Reactive Balance

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19 CTSIB (Clinical Test for Sensory Interaction for Balance) #1: firm surface, eyes open #2: firm surface, eyes closed #3: compliant surface, eyes open #4: compliant surface, eyes closed Comparative use of proprioceptive, vision and vestibular cues. Maintain consistent position during testing Condition #4: Vestibular bias

20 Marching with eyes closed for 50 steps Fukuda Step Test Invalid for patients with lower limb impairment Rotation greater than 45 degrees indicative of uncompensated peripheral vestibular dysfunction Data (Jacobson 2008) Sensitivity: 70% Specificity: 59%

21 Gait Eyes Open Eyes Closed

22 Gait Gait Yaw Gait Pitch

23 Gait Pivot Left Pivot Right

24 Gait Head motion and eyes closed Tandem

25 Dizziness Handicap Inventory (Jacobson 1990) 25 item questionnaire Response options: Yes = 4 pts Sometimes = 2 pts No = 0 pts Composite score is summed to measure perceived disability: (0-100 pts) Subscales include: physical, emotional, and functional Scores >60 are correlated with functional impairment and falling

26 Activities Specific Balance Confidence Scale (Powell 1995) Patient rates level of self-confidence in balance with 16 common tasks Each task is rated from 0 to 100% 0% = no confidence 100% = completely confident Total all 16 items and divide by 16 to obtain a composite score

27 Activities Specific Balance Confidence Scale (Powell 1995) Data (Miller 2003) Positively correlated with the Two Minute Walk Test Negatively correlated with the Timed Up and GO < 67% = older adults at risk for falling; predictive of future fall. (LaJoie 2004) Predictive of physical functioning (Myers 1998) >80% = high level of physical functioning 50-80% = moderate level of physical functioning < 50% = low level of physical functioning