Prospective study involving the translation and cross-cultural adaptation of the Visual Vertigo Analogue Scale (VVAS) into the European Portuguese language and culture, based in the recommendations of Beaton et al.10 STROBE statement checklist was used. Prior consent was requested and obtained from the original author of the VVAS for the development of this instrument.

The steps of this process were as follows: first, the English to Portuguese translation was performed by one ENT physician expert in vestibular diseases and a naïve translator, who both have Portuguese as their first language. The translators carefully followed the design principles of the original version. Second, this translation was consolidated. Third, a “back translation” from Portuguese into English was performed by one native English individual that was unaware of the original wording. This step was necessary in order to bring out unclear wording or cultural peculiarities in the symptom’s description, and to assure a consistent translation of the content of each item. Fourth, the back translation was checked against the original wording to ensure that each translated item captured the nuances of the original English wording. If there had been differences in nuance between the original version and the back translated version, the translation would have been modified to improve the correspondence between the two versions, but this final procedure was not necessary. Prior to these versions conference, Elizabeth Dannenbaum (author of the original VVAS) compared the original VVAS with both back translations. Finally, the complete translation included not only the items but also the instructions and the overall format of the questionnaire. All of these were carefully reproduced from the English original to produce an accurate translation (Fig. 1).

Figure 1.

Visual vertigo analog scale Portuguese translation.

(0.32MB).

Two groups were recruited. The vestibulopathy group consisted of 198 subjects who were sequentially enrolled at our tertiary outpatient Equilibrium Clinic from December 2017 to December 2019. Each subject was diagnosed by one experienced Otolaryngologist based in a structured interview, physical examination, and complementary exams as necessary according to the International Classification of Vestibular Disorders from the Barany’s Society.11 The control group consisted of 63 healthy escorts consecutively extracted from the same population without history of vestibulopathy symptoms or any other otological disease that also volunteered to answer the questionnaire. Both groups volunteered to answer the 9-item scales and the DHI before the appointment. The participants in the study did not have any help from the assistant and the answers were reviewed for completeness.

Portuguese VVAS consists of nine visual analog scales which subjects were asked to rate. Each scale pertained to a specific visual vertigo provoking situation. The subjects should mark a vertical line on a 10-cm line to indicate the amount of dizziness provoked by each situation, between two anchors, with zero (0) representing no dizziness and ten (10) representing an extreme dizziness or activity avoided due to dizziness. The distance from the zero anchor to the subject’s marking was measured to the nearest next whole number in centimeters. Items that were not applicable to the participant’s daily life (e.g., going to movies) were not completed. If the subject answered with a whole number, that was the one that was considered. To summarize the nine items, two final scores were calculated: Visual Vertigo Analogue Scale (VVAS) positive and Visual Vertigo (VV) severity.8

The subjects were classified as VVAS positive if two or more items were rated above zero on the analogue scale. A parameter of interest was the VV severity score that was calculated as an average based on the mean scores of non-missing items: VV Severity = (rated analogue scale items/number of answered items) × 10. Thus, a VV severity score of 0 indicated that the subject did not experience Visual Vertigo, whereas a score of 90–100 will indicate severe visual vertigo.8

The DHI is a 25-item questionnaire that asks the patients to rate their self-perception of disability from dizziness. DHI consists of a 7-item physical subscale, a 9-item emotional subscale, and a 9-item functional subscale. A score of 4-points is assigned to a “yes” response, 2-points to “sometimes”, and 0-points to “no” response. Thus, the total score ranges from 0 (no perceived disability) to 100 (maximum perceived disability). Scores can fluctuate from normal (less than 15 points), mild handicap (16–34 points), moderate handicap (36–52 points) or severe (>53 points).12

Data collected were analyzed using SATA 15®. The sample was described in terms of the distribution of the descriptive variables by means of summary measures.

To compare the proportion of positive VVAS in control and vestibular groups, Chi-Square statistics was applied. A Mann–Whitney test for independent samples was carried out to compare VV severity scores between control and vestibular groups. Test-retest reliability of the positive VVAS was assessed with the Wilcoxon test. The internal consistency of the VVAS was examined by the Cronbach’s alpha statistical index.

The VV severity score was compared between the controls and vestibular subgroups resorting to a Kruskal Wallis test. Post-hoc comparisons were performed using Bonferroni correction. A Spearman correlation analysis was carried out to explore relationship between VV Severity and DHI total scores. The statistical significance was set at 0.05.

The VVAS was tested in 198 participants with vertigo and 63 healthy subjects. The mean age of the vestibulopathy group was 58.0 ± 13.3 years old with 65.7% (130/198) being females. The control group consisted of 63 subjects with 43.4 ± 13.3 years old, where 44.4% (23/63) were females. Table 1 resumes characteristics of participants.

The VVAS was positive in 170 patients (85.9%) and in 10 (15.9%) subjects in the control group. A statistically significant association between VVAS positive and vestibulopathy group patients was found (p < 0.001) (Table 2). Visual vertigo scores were significantly different between control and vestibulopathy groups, respectively (2.3 ± 0.9 vs. 35.3 ± 1.8, p < 0.001).

The Cronbach’s Alpha analysis of 0.95 indicated that the VVAS was internally consistent and reliable. Moreover, item-to-total correlation coefficients revealed moderate-to high associations between VVAS individual items and total score, further evidencing homogeneity and strong internal consistency of the VVAS.

For test-retest reliability estimations, 45 patients repeated the VVAS (7–658, 291) days. No statistically significant differences between the results of the initial positive VVAS and the final positive were found (p > 0.05).

VV severity scores were significantly different between patients and controls (p < 0.001). Post hoc tests reveal the existence of statistically significant differences between control subjects and patients with Persistent Postural Perceptual Dizziness (PPPD), Ménière Disease (MD), Vestibular Migraine (VM), Chronic Unilateral Vestibulopathy and Acute Unilateral Vestibulopathy and Benign Paroxysmal Positional Vertigo (BPPV) (p < 0.001), as well as with Central Vestibulopathy, Bilateral vestibulopathy and Semicircular Dehiscent Syndrome (p < 0.05).

No statistically significant differences were found between controls and subjects of the other groups (p = 1.000), nor comparing the subgroups between themselves (p > 0.05).

Non-parametric Spearman correlation analysis carried out between total DHI and VV severity scores for the vestibulopathy patients revealed positive strong correlation (r = 0.82, p < 0.001).