Dynamic Visual Acuity Test - Non-Instrumented

Loss of <3 lines of visual acuity during dynamic testing conditions is considered “within normal limits”. Loss of 3 or more lines is suggestive of potential vestibular dysfunction. (Herdman, 2007)

Loss of > 2 lines during dynamic visual acuity using Illegible E-test is considered abnormal (Longridge and Mallinson, 1984 and 1987)

Children with Bilateral Vestibular Hypofunction (BVH) (Rine et al, 2003; n = 76 typically developing children; mean age = 7 years; n = 26 adults; mean age = 32 years; n = 11 children with BVH).

Passive Yaw Head movements (hDVA): n = 30 (reliability sub-analysis), mean age = 25 years for reliability component of study.

• Excellent test—retest reliability ICC(2,2) r = 0.94

Passive Pitch Head movements (vDVA): n = 11, mean age 25 years (reliability sub-analysis). Note: Vertical DVA was “poorly tolerated” by participants.

• Excellent test-retest reliability r = 0.88

Children with Bilateral Vestibular Hypofunnction (Rine et al, 2003)

• Excellent inter-tester reliability ICC(3,2) = 0.84

Predictive Validity, Yaw Passive

Children with BVH vs. Adults and Typically Developing Children (Rine et al 2003);

• Excellent Sensitivity: 100%
• Excellent Specificity: 100%
• Excellent Positive Predictive Value: 100%
• Excellent Negative Predictive Values: 100%
  Predictive Validity, Pitch Passive

Though statistical differences have been found between known groups (TD vs. BVH), observed differences were not clinically significant (all achieved DVA scores < 2 lines). The vertical dynamic acuity test was not tolerated by most children, precluding its usefulness (Rine et al, 2003).

Longridge and Mallinson, 1984 (n normals = 80)

·  All control subjects demonstrated normal calorics and < 1 row of deterioration during illegible E-test.

·   82.5% demonstrated no deterioration in reading ability during head motions; 17.5% demonstrated 1 row deterioration.

Longridge and Mallinson, 1987 (n normal= 30)

·     All control subjects demonstrated normal calorics and < 1 row of deterioration during illegible E-test.

94% demonstrated no deterioration in reading ability during head motions; 6% demonstrated 1 row deterioration.

Unilateral Vestibular Hypofunction (Dannenbaum et al 2005, n = 41, 10 with UVH mean age = 49.4(15.5); range 19-70 years.

·      The frequency of head motion has an impact on clinical DVA scores in subjects with UVH. DVAT- NI scores significantly decreased as head movement frequency increased from 0.5 to 1.0 Hz and from 1.0 to 1.5 Hz, during horizontal (yaw) and vertical (pitch) movements, and with both vision charts (p < .001).

·      Study results suggest that DVAT-NI be administered with horizontal and vertical rotational head movements of at least 1.5 Hz with the E-chart.

Unilateral Vestibular Hypofunction (Dannenbaum 2009, n = 10, mean age 58.8 (16.3) range = 40-83, patients with UVH s/p acoustic neuroma resection.

DVAT-NI had week correlation with degree of vestibular deficit established by bithermal calorics. Spearman correlation analyses revealed low-correlation coefficients between percentage of vestibular paresis at the caloric test and DVA scores (horizontal direction: r = 0.31, p = 0.38 for Snellen chart and r = -0.33, p = 0.35 for the E-chart; vertical: r = 0.05, p = 0.91 for the Snellen chart and r = -0.28, p = 0.50 for the E-chart).