Elizabeth Dannenbaum

Clinical evaluation of dynamic visual acuity in subjects with unilateral vestibular hypofunction.

Objectives: The objectives of this study are threefold: 1) to examine the effect of frequency of head motion on the clinical dynamic visual acuity (DVA) score in subjects with unilateral vestibular hypofunction (UVH); 2) to compare DVA scores between subjects with UVH and subjects with a complete unilateral vestibular deficit; and 3) to establish whether a relationship exists between the extent of the vestibular deficit and the DVA score. Design: Experimental study. Setting: Vestibular outpatient rehabilitation program. Methods: A convenience sample of 10 subjects with UVH. Main Outcome Measures: Dynamic visual acuity scores were recorded using 2 standard acuity charts: Snellen and E-chart. The DVA scores were obtained at slow (0.5 Hz), moderate (1 and 1.5 Hz), and fast (2.0 Hz) frequencies of head motion in the horizontal and the vertical planes. Percentage of caloric weakness was compared with DVA scores in each subject to test whether a relationship exists between the two. Results: As the frequency of head motion increased, the number of UVH subjects with an abnormal DVA score increased. Subjects with an abnormal DVA score at 1 Hz had the same or higher score as the frequency of the head motion was increased. 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). Conclusion: Subjects with UVH manifest impaired DVA. The frequency of head motion has an impact on clinical DVA scores in UVH subjects.

Optimal parameters for the clinical test of dynamic visual acuity in patients with a unilateral vestibular deficit.

OBJECTIVE To determine the influence of frequency and direction of head movement and type of vision chart on the score of a clinical test of dynamic visual acuity (DVA). METHODS The subjects were 31 healthy individuals (22 to 79 years old) and 10 patients (19 to 70 years old) with a unilateral vestibular deficit owing to surgical resection of an acoustic neuroma. They read a Snellen or an E-chart while their head was passively moved +/- 20 degrees back and forth in the horizontal or vertical direction at one of four frequencies (0.5, 1.0, 1.5, and 2.0 Hz). The DVA score was the difference in the number of lines on the vision chart that could be read with the head passively moved versus with the head immobile. RESULTS Four healthy subjects had a low DVA score during horizontal head movements at the fastest frequency (2.0 Hz) with the Snellen chart. In patients, DVA 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 and vertical movements, and with both vision charts (p < .001). The DVA scores of healthy subjects were more consistent across three trials with the E-chart than with the Snellen chart at 1.0 and 0.5 Hz (horizontal movements, p < .01) and at 1.5 and 1.0 Hz (vertical movements, p < .01). CONCLUSIONS This study provides new indications on the optimal parameters for the clinical test of DVA. From the results, it is recommended that DVA be tested during horizontal and vertical head movements at a frequency of 1.5 Hz with the E-chart.

Visual vertigo analogue scale: An assessment questionnaire for visual vertigo

A common symptom for people with vestibulopathy is dizziness induced by dynamic visual input, known as visual vertigo (VV). The goal of this study is to present a novel method to assess VV, using a nine-item analog scale. The subjects rated the intensity of their dizziness on each item of the Visual Vertigo Analogue Scale (VVAS), which represented a daily situation typically inducing VV. The questionnaire was completed by participants with vestibulopathy (n=102) and by subjects receiving out-patient orthopaedic physiotherapy (n=102). The dizziness handicap inventory (DHI) was also completed by the vestibulopathic group. The Cronbachs Alpha index indicated the VVAS is internally consistent and reliable (Cronbachs Alpha=0.94). The study also found that the VVAS severity scores from vestibular and a non-vestibular population were significantly different (Wilcoxon-Mann Whitney test p < 0.0001). Spearman correlation analysis conducted between DHI and VVAS scores for the clients with vestibulopathy showed positive moderate correlations between the VVAS score and the total DHI score (r=0.67, p< 0.0001). This study showed that the VVAS scale may be useful in providing a quantitative evaluation scale of visual vertigo.

Anxiety among individuals with visual vertigo and vestibulopathy

Abstract Purpose: Visual vertigo (VV) is a type of dizziness triggered by visual stimuli. Despite a high incidence, its relationship with anxiety is not well-defined or understood. This study evaluated anxiety levels in subjects with VV compared to vestibulopathic subjects without VV and healthy individuals. Methods: A cross-sectional study to evaluate anxiety among individuals with VV was conducted twice. The first study included 72 participants (66 to 83 years of age) from senior residential centers. The second included 31 participants from a vestibular rehabilitation program (age range 35–82 years). Study 1 also used the Activities-Specific Balance Confidence (ABC) scale and study 2 the Dizziness Handicap Inventory (DHI). Results: Subjects were classified as VV positive (27 in study 1, 10 in study 2) or vestibulopathic without VV (30 in study 1, 11 in study 2) based on Head Impulse or Dynamic Visual Acuity Tests and the Dizziness Questionnaire. The remaining were age-matched healthy controls. The outcome of each study demonstrated significantly higher anxiety levels (p = 0.0001) in the VV group compared to the other groups. The results of the ABC test demonstrated that subjects in the VV group had significantly lower self-confidence (p = 0.001) than those in the Vest and Cont groups and performed fewer balance-related activities of daily life. DHI results showed that VV group expressed higher (p < 0.001) mean scores for self-perceived feelings of dizziness and imbalance (54%), compared to the Vest (9%) and Cont groups (1%). Conclusions: Anxiety related to VV requires special attention when assessing and managing vestibulopathy, regardless of patient age. Implications for Rehabilitation Anxiety is a characteristic of subjects with visual vertigo (VV) and vestibulopathy. Anxiety in subjects with VV is not related to age. VV should be considered when subjects with anxiety complain of imbalance. Anxiety and vestibulopathy are often interrelated and should be considered in diagnostic evaluations.

2-year review of a novel vestibular rehabilitation program in Montreal and Laval, Quebec.

OBJECTIVE To evaluate the benefits of a vestibular rehabilitation program (VRP) in the Montreal-Laval area. DESIGN The VRP was conceptualized by a panel of experts including otolaryngologists, physiotherapists, and researchers from McGill University and its teaching hospitals. From February 1999 to December 2001, 117 patients were seen, and 88 of them completed the VRP. SETTING The VRP has been established at the Jewish Rehabilitation Hospital in Laval, PQ, to provide specialized rehabilitation to clients suffering from vertigo, dizziness, and/or impaired balance owing to lesions or disorders of the vestibular system. MAIN OUTCOME MEASURES Presence or absence of nystagmus or vertigo during the Dix-Hallpike test, Dizziness Handicap Inventory (DHI), and Dynamic Gait Index (DGI). RESULTS Thirty-five patients with benign paroxysmal positional vertigo of the posterior canal were treated with canalith repositioning manoeuvres. All of the patients (100%) had absence of nystagmus or vertigo after one to four treatment sessions. Forty-six patients with vestibular deficits or dizziness-disequilibrium completed the VRP, which consisted mainly of individualized eye-head and balance home exercise programs. At the end of the VRP, there was a significant decrease in DHI score (31 vs 57; p < .01) and a significant increase in DGI score (18.4 vs 22.6; p < .01). CONCLUSIONS A range of modest to major improvements was shown by comparing initial and discharge scores of patients who had completed vestibular rehabilitation. The VRP appears to be beneficial for patients with a variety of vestibular disorders. Further research is needed to continue optimizing vestibular rehabilitation.

Arm-trunk coordination as a measure of vestibulospinal efficiency.

When arm and trunk segments are involved in reaching for objects within arms reach, vestibulospinal pathways compensate for trunk motion influence on arm movement. This compensatory arm-trunk synergy is characterised by a gain coefficient of 0 to 1. Vestibular patients have less efficient arm-trunk synergies and lower gains. To assess the clinical usefulness of the gain measure, we used a portable ultrasound-based device to characterize arm-trunk coordination deficits in vestibular patients. Arm-trunk coordination without vision was measured in a Stationary Hand Task where hand position was maintained during trunk movement, and a Reaching Task with and without trunk motion. Twenty unilateral vestibular patients and 16 controls participated. For the Stationary Hand task, patient gains ranged from g=0.94 (good compensation) to 0.31 (poor compensation) and, on average, were lower than in controls (patients: 0.67 ± 0.19; controls: 0.85 ± 0.07; p< 0.01). Gains were significantly correlated with clinical tests (Sensory Organization; r=0.62, p< 0.01, Foam Romberg Eyes Closed; r=0.65, p< 0.01). For the Reaching Task, blocking trunk movement during reaching modified hand position significantly more in patients (8.2 ± 4.3 cm) compared to controls (4.5 ± 1.7 cm, p< 0.02) and the amount of hand position deviation was correlated with the degree of vestibular loss in a sub-group (n=14) of patients. Measurement of the Stationary Task arm-trunk gain and hand deviations during the Reaching Task can help characterize sensorimotor problems in vestibular-deficient patients and track recovery following therapeutic interventions. The ultrasound-based portable device is suitable for measuring vestibulospinal deficits in arm-trunk coordination in a clinical setting.

The influence of visual vertigo and vestibulopathy on oculomotor responses.

OBJECTIVE Dynamic visual inputs can cause visual vertigo (VV) in patients with vestibulopathy, leading to dizziness and falls. This study investigated the influence of VV on oculomotor responses. METHODS In this cross-sectional, single-blind study, with experimental and control groups, 8 individuals with vestibulopathy and VV, 10 with vestibulopathy and no VV, and 10 healthy controls participated. Oculomotor responses were examined with 2-dimensional video-oculography. Participants were exposed to dynamic visual inputs of vertical stripes sweeping across a screen at 20 deg/sec, while seated or in Romberg stance, with and without a fixed target. Responses were quantified by optokinetic nystagmus frequency (OKNf) and gain (OKNg). RESULTS Seated with no target, VV participants had higher OKNf than controls (37 ± 9 vs. 24 ± 9 peaks/sec; P < 0.05). In Romberg stance with no target, they had higher OKNf than controls (41 ± 9 vs. 28 ± 10 peaks/sec; P < 0.05). With a target, OKNf was higher in VV participants compared to controls (7 ± 7 vs. 1 μ 2 peaks/sec; P < 0.05). In Romberg with no target, OKNg was higher in the VV group (0.8 ± 0.1) compared to controls (0.6 ± 0.2; P=0.024). OKNf and OKNg did not differ according to VV status. CONCLUSIONS VV participants had increased OKNf and OKNg compared to healthy participants. Visual dependency should be considered in vestibular rehabilitation.

Vestibular Assessments in Children With Global Developmental Delay: An Exploratory Study.

Purpose: To compare results of 3 clinical vestibular tests between children with global developmental delay (GDD) and children with typical development (TD) and investigate the test-retest reliability. Methods: Twenty children with GDD (aged 4.1-12.1 years) and 11 age-matched controls with TD participated. Participants with GDD underwent 2 sessions of testing. Each session consisted of the Clinical Test of Sensory Interaction and Balance (CTSIB), Dynamic Visual Acuity (DVA) test, and the modified Emory Clinical Vestibular Chair Test (m-ECVCT). Results: Up to 33% of the children with GDD had abnormal DVA scores. m-ECVCT results of children with GDD demonstrated larger variance than children with TD. The CTSIB score was significantly reduced in the group with GDD. The test-retest reliability varied, with good reliability for the m-ECVCT and CTSIB, and fair reliability for the DVA. Conclusions: Findings suggest vestibular involvement in children in GDD. The clinical tests demonstrated moderate test-retest reliability.