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Vestibular Disease: (Mohammad, 2011; n = 28 (16 peripheral vestibular disorders, 9 central vestibular disorders, 3 mixed central and peripheral); Age range 16-78 years. Standard error of the measurement (SEM), SEM% and minimal detectable change (MDC) values for the gaze stabilization test (GST, deg/sec)

Response Stability (Standard Error of the Measure)

Vestibular Loss: Unilateral or Bilateral vestibular hypofunction (Whitney 2009; n = 12 patients with UVH or BVH; mean age 70.1 (6.6) years; n = 20 controls mean age = 70 (5.3) years). Identification of persons with unstable gait using the timed up and go and DGI performance concurrent with GST head movements. GST results in response to yaw and pitch plane head movements identified subjects with TUG and DGI performance deficits (*p < 0.05). See table below. 

Pritcher et al 2008, (n = 20 young controls, n = 21 elderly controls, n = 16 patients with vestibular disease (n = 12 UVH, 1 BPPV, 2 BVH, 1 multisensory dysequilibrium) Cut-point for of velocity < 61 d/s and downward; GST velocity was 44% Sn and 90% Sp for identification of patients with vestibular disease with ROC identified maximum LR of 4.5 (95% CI 1.5-13.3) (AUC, 0.73; 95% CI, 0.59-0.88 p < 0.01) (¡°Adequate¡± validity)

Patients with vestibular disease: Poor

Mohammad et al 2011 n = 29 patients with vestibular disease (16¨C78 years) participated (n = 16 peripheral vestibular disorders, n = 9 central vestibular disorders, and n = 3 mixed central /peripheral vestibular disorders. Intraclass correlation coefficient (ICC) for GST performed on the same day (within session) after a 30 minute rest break and after 7-10 days (between sessions). 

Intraclass correlation coefficient (95% confidence intervals) 

Predictive Validity

Goebel 2006, N = 28 (14 patients with vestibular loss of > 50%, 14 healthy controls) GST demonstrated 93% specificity, 64% sensitivity, and a reliability index of 0.91 for the detection of unilateral dysfunction with ipsilesional movement.

Pritcher 2008, N = 57, (20 young controls 20-40 yrs, 21 elderly controls (60- 80 yrs), and 16 patients with vestibular disease (20-80 yrs). Identification of subjects with vestibular disease was maximized at an average downward velocity of less than 61 degrees per second and a likelihood ratio of 4.4 (sensitivity, 44%; specificity, 90%)

Convergent Validity -

Whitney et al 2009, (n = 12 persons with unilateral or bilateral vestibular loss, n = 20 control subjects).  Spearman non-parametric correlation coefficients (and significance Levels) for associations between average GST results (degrees/sec) for yaw and pitch and measures of dynamic gait performance in patients with vestibular disorders and control subjects.

NeuroCom Clinical Integration Seminar Lab Manual- Manufacturer Norms

Normal Response: Average abilities range from 75-105 deg/sec. High performance individuals (i.e. athletes) can achieve velocities up to 160 deg/sec). 

Abnormal Response: Basic functional performance can become limited at 

< 70 deg/ sec

Older Controls: Adequate

Ward et al 2010, n = 40 subjects, (n = 20 older adults 76.3 + 5.3 years, n = 20 young controls 25.2 + 3.2 years). Intraclass correlation coefficient (ICC) for GST performed on the same day was 0.75 for in the yaw plane (¡°Excellent¡±) and 0.69 in the pitch plane (¡°Adequate¡±).  ICC at 7-10 days in N = 20 subjects was 0.59 in yaw (¡°Adequate¡±) and 0.54 in pitch (¡°Adequate¡±).

Concurrent Validity

Ward et al 2010,  N = 40, (N = 20 older adults 76.3 + 5.3 years, N = 20 young controls 25.2 + 3.2 years) between GST and Dynamic Visual Acuity Test (DVAT) loss determined by Spearman¡¯s correlation coefficient revealed -0.62 in yaw and -0.38 in pitch (p < 0.02). Not established in patients with vestibular dysfunction.

Convergent Validity-

Healthy Older Adults: (Ward et al 2009; n = 86 GST > 90 d/s was significantly correlated with ¡°excellent¡± self-report of balance (p < 0.05)