Assessment of quality of life, functional capacity, and disability in patients with vestibular disorders: A cross-sectional study

Sarah Alshehri

doi:10.4103/KKUJHS.KKUJHS_16_20

ORIGINAL ARTICLE

Year : 2020 | Volume : 5 | Issue : 2 | Page : 67-70

Assessment of quality of life, functional capacity, and disability in patients with vestibular disorders: A cross-sectional study

Sarah Alshehri
Department of Surgery, College of Medicine, King Khalid University, Abha, Saudi Arabia

Date of Submission	30-Sep-2020
Date of Acceptance	18-Nov-2020
Date of Web Publication	25-Feb-2021

Correspondence Address:
Dr. Sarah Alshehri
Department of Surgery, College of Medicine, King Khalid University, Abha
Saudi Arabia

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/KKUJHS.KKUJHS_16_20

Abstract

Background: The Vestibular Disorders Activities of Daily Living Scale (VADL) is a valid and reliable scale designed to assess the activity component in people with vestibular disorders. It is a self-evaluation scale and has been adapted into French, Brazilian Portuguese, Arabic, and Persian. Objectives: In this study, we assessed the internal consistency, intrarater reliability, and concurrent validity of the Arabic version of the VADL scale (VADL-A) in patients with vestibular disorders. Methodology: A total of 50 patients with vestibular disorders completed the VADL-A, the Dizziness Handicap Inventory (DHI), and the Activities-Specific Balance Confidence (ABC) scales during a visit to their health-care provider. On the following day, they filled out the VADL-A scale again. The obtained data were used to assess the psychometric properties of the scale. Results: The internal consistency of the scale was excellent, with a Cronbach's alpha of 0.977. The intrarater reliability was also compelling, with an intraclass correlation coefficient of 0.94. The concurrent validity was obtained by comparing the VADL-A with the DHI and ABC scales and was found to be moderate, with r values of 0.52 (P = 0.003) and -0.65 (P < 0.001), respectively. Conclusion: The results of our study proved the VADL-A to be a reliable and valid scale for assessing activity-related problems in patients with vestibular disorders.

Keywords: Arabic, reliability, validity, vestibular activity daily living scale

How to cite this article:
Alshehri S. Assessment of quality of life, functional capacity, and disability in patients with vestibular disorders: A cross-sectional study. King Khalid Univ J Health Sci 2020;5:67-70

How to cite this URL:
Alshehri S. Assessment of quality of life, functional capacity, and disability in patients with vestibular disorders: A cross-sectional study. King Khalid Univ J Health Sci [serial online] 2020 [cited 2021 Jun 12];5:67-70. Available from: https://www.kkujhs.org/text.asp?2020/5/2/67/309604

Introduction

Individuals with vestibular disorders often experience vertigo, dizziness, visual blurring, and imbalance. These symptoms can be exacerbated by activities that require head or body movements and can lead to functional limitations that interfere with routine daily activities.^[1],[2] The severity of vestibular disorders varies among patients and often becomes more prominent with age. It is related to a decreased functional capacity and can lead to dependence on self-care and mobility activities and can reduce one's quality of life.^[3],[4],[5]

Several subjective self-report measures are used to evaluate patients who suffer from vestibular dysfunction. These measures include the Dizziness Handicap Inventory (DHI),^[6] the Activities-Specific Balance Confidence (ABC) Scale,^[7] the Vertigo Handicap Questionnaire,^[8] and the Vestibular Disorders Activities of Daily Living Scale (VADL). These measures gauge the impact of vestibular disorders on patients' quality of life.^[9] The VADL, in particular, is used to estimate the effect of vestibular disorders on patients' daily living activities and functional capacity.^[9],[10] It is composed of three subscales evaluating functional, ambulation, and instrumental tasks that measure the patient's self-perceived independence while performing activities.^[9] The VADL has been translated and validated in several languages, including Spanish, Korean, and Brazilian Portuguese.^[11],[12]

In our previous work, we translated the VADL into Arabic (VADL-A). However, assessment tools must be valid, consistent, and reproducible. The current study aims to apply the Arabic version of VADL to vestibular disorder patients and assess its psychometric properties, including its internal consistency, intrarater reliability, and concurrent validity.

Methodology

Permission for this cross-sectional study was obtained from the institutional ethical committee of the university (ECM #2019-59-HAPO-06-B-001). The sample size was calculated by using MedCalc statistical software. Based on previous study sample sizes and our expected outcome, we acquired a sample size of 50. The study was conducted in a university hospital setting. Patients who arrived at the hospital to meet with ear, nose, and throat (ENT) surgeons, neurologists, general medicine consultants, or vestibular specialists were asked to participate. A total of 72 people were screened for inclusion in the study; 19 did not meet the inclusion criteria, and 3 did not wish to participate. To fulfill the inclusion criteria for this study, participants had to be diagnosed as having a vestibular disorder by an ENT surgeon and be at least 18 years old. Patients were excluded if they suffered from any other neurological disorder in addition to a vestibular disorder, had undergone surgical procedures, or were not capable of reading and answering the three questionnaires and answering the one questionnaire two times for any reason.

The included patients were informed of the study's procedures and signed a written informed consent form. The investigator also guaranteed that the information collected from the patients would remain confidential. The investigator then conducted an initial detailed vestibular assessment and asked the participants to complete the three assessment measures: the VADL-A, DHI, and ABC scales. A sufficient period of rest was provided between the questionnaires, and the order in which the questionnaires were filled out was randomized with a digitally generated random number table. The patients were asked to return the following day to begin treatment and were asked to complete the VADL form within a 24-h period. Completing the three questionnaires on the 1^st day allowed us to compare the results of the VADL-A to the DHI and ABC scales, as well as provided data for computing the concurrent validity. Repeating the VADL-A on the 2^nd day allowed us to assess intrarater reliability and internal consistency.

Data analysis

The result analysis was conducted using SPSS statistics 22.0 (IBM Corp., Armonk, N.Y., USA). The mean and standard deviations for age, VADL-A subsection, and total score were calculated with univariate analysis using descriptive statistics. The normality of variables was measured using the Shapiro–Wilk test. The concurrent validity of the scale was measured using the Pearson correlation coefficient. The intra reliability for the VADL-A scale scores was determined using the intraclass correlation coefficient. The internal consistency of the total scale and its components was measured using Cronbach's alpha. Significance was indicated by P < 0.05 at the 95% confidence interval.

Results

In this observational study, VADL-A was applied to 50 subjects with vestibular disorders. Of the 50 subjects, 32 had peripheral vestibular disorders and 18 had central vestibular disorders; 27 were men and 23 were women. Details of the mean and standard deviations for the age, VADL-A functional, ambulation, instrumental subsection, and total scores for the two testing periods are presented in [Table 1].

Table 1: Mean and standard deviations for the age and vestibular activity daily living scale-A scores

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The VADL-A concurrent validity was assessed using the Pearson correlation coefficient. The concurrent validity for the total VADL-A score and its subcomponents ranged between moderate and good. The VADL-A was rated twice by the 50 subjects with vestibular dysfunctions in a period of 24 h to assess intrarater reliability, which was excellent. Details of the validity and reliability are presented in [Table 2]. The Bland–Altman graph was plotted to determine the intrarater reliability and is depicted in [Figure 1]. The patients' scores were used to measure the internal consistency. The internal consistency was measured for each component and subsection, and the total scores were assessed using Cronbach's alpha. The detailed alpha scores of internal consistency are presented in [Table 3].

Table 2: Content validity and intrarater reliability scores for the Arabic version of the vestibular activity daily living scale total scores and their subcomponents

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Table 3: Internal consistency for individual components, subsections, and total scores of the Arabic version of the vestibular activity daily living scale

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Figure 1: Bland–Altman graph showing intrarater reliability

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Discussion

In this cross-sectional study, we assessed the psychometric properties of the Arabic version of the VADL scale in patients with vestibular disorders. Following the cross-cultural adaptation of the VADL to the Arabic population, this is the first study to assess the psychometric properties of the VADL-A in patients. In this study, the VADL-A was proven to be a valid and reliable scale for assessing daily living activities in patients with vestibular disorders.

Ricci et al. conducted a similar study of the elderly population to evaluate the properties of the Brazilian-Portuguese version of the VADL. The participants included in this study were at least 65 years old and suffered from dizziness due to vestibular disease. The mean and standard deviation of the VADL-Brazilian scores was 4.1 ± 1.6 points. The validity of the VADL-Brazilian was determined by comparing it with the ABC scale. It was inverse in nature with r = -0.63, and its DHI showed a positive but weak correlation, with r = 0.47.^[13] In our study, we found that the mean and standard deviation of the VADL-A scores was 3.55 ± 1.49 points. To verify the validity of the VADL-A, the scale score was compared with the ABC and DHI. This process revealed r values that were similar to those of the VADL-Brazilian validation. The ABC yielded an inverse score with r = -0.65 (P < 0.001), and the DHI comparison yielded a positive but moderate correlation, with r = 0.52 (P = 0.003).

Çiçek Çinar et al. conducted a similar study, which was designed to verify the psychometric properties of the Turkish version of the VADL in 175 subjects with peripheral vestibular disorders. This study indicated significant internal consistency, with Cronbach's alpha values of 0.96 for the total test score and 0.92, 0.93, and 0.89 for the functional, ambulation, and instrumental subsections, respectively. The Turkish version of the VADL was compared with the Turkish DHI to test concurrent validity, a process that yielded a moderate correlation indicated by r = 0.518 and statistical significance at P < 0.05.^[14] Our study produced similar results. The internal consistency of the VADL-A had a Cronbach's alpha value of 0.97 for the total test score and values of 0.94, 0.96, and 0.98 for the functional, ambulation, and instrumental subsections, respectively. We tested the concurrent validity by comparing it with the Arabic DHI and found a similar r value (0.52, P = 0.003).

The internal consistency indicates the level of correlation between individual items on a scale. Here, we found a similar value of internal consistency (0.97) to that of the original English version of the VADL.^[15] Thus, we assume that the Arabic translation was suitable and the questions were consistent. Moreover, the intrarater reliability was strong, indicating that there was little variation in how the participants answered the questions. The concurrent validity was moderate and thus adequate. This moderate concurrent validity was due to the uniqueness of the VADL scale. The VADL scale does not assess emotional components, whereas the DHI includes 9 questions that pertain to emotions of 25 total questions.^[6] Perhaps, for this reason, we did not see a complete correlation between the two scales. To address this issue, we included a further scale frequently used to study vestibular disorders: the ABC scale. With the ABC, our validity rating was better than with the DHI. This is because of similarities between the ABC scale and the VADL scale regarding questions related to balance and to walk.

Overall, we obtained information about the reliability and validity of the VADL-A scale; however, a broad scope remains for studying other psychometric properties, such as sensitivity, specificity, minimal detectable change, and minimal clinically important differences. We encourage future researchers to apply the scale to a variety of vestibular disorders and to examine additional psychometric properties.

Conclusion

The VADL-A is a reliable and valid scale for assessing activity-related issues in patients with vestibular disorders. A high intrarater reliability was found, with an intraclass correlation coefficient of 0.94. Internal consistency was also impressive, with a Cronbach's alpha of 0.97. The concurrent validity was moderate when compared with the DHI and ABC scales, with r = 0.52 and -0.65, respectively.

Acknowledgment

We sincerely thank the Deanship of Scientific Research, King Khalid University, Abha, Kingdom of Saudi Arabia, for funding this research project with number R. G. P1/167/41.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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