Introduction

Dizziness is a common symptom for seeking consultation in otology clinic. It is a distressing symptom significantly impacting daily functioning and quality of life. The Dizziness Handicap Inventory (DHI) is a widely utilized patient reported outcome measure consisting of 25 items to assess the impact of dizziness on quality of life [1]. With its comprehensive focus on physical, emotional, and functional aspects related to dizziness, the DHI offers valuable insights into the challenges faced by individuals with vestibular disorders. Originally developed in the English language in 1990 [2], the DHI has since been translated and validated in various languages, reflecting its wide acceptability and reliability [3,4,5,6,7,8,9,10].

Translation, cross cultural adaptation and validation of DHI in different languages enables catering to linguistically diverse populations, facilitating clinical comparisons and cross-cultural research. Hindi being the most widely spoken language in the Indian subcontinent, presents a significant opportunity for translation and standardization of the DHI.

The proposal to translate and validate DHI in Hindi stems from recognizing the limitations of solely relying on English-based assessment tools. Language barriers can impede accurate understanding and response to assessment questions, potentially leading to misinterpretation and misdiagnosis. Moreover, the absence of standardized tools may introduce variability due to translation or interpretation by the questionnaire administrator.

This study aims to translate and validate the Dizziness Handicap Inventory in the Hindi language, thereby providing a standardized tool to assess the impact of dizziness in patients, ensuring its acceptance and validity amongst Hindi-speaking individuals. By overcoming language barriers and reducing assessment variability, this standardized tool aids in the diagnosis and management of vestibular disorders. Furthermore, it facilitates comparisons across languages for clinical or research purposes, fostering a more comprehensive understanding of impact of dizziness across linguistically diverse populations.

Methodology

Study Design and Setting

This study employed a cross-sectional design to assess the validity and reliability of the Hindi translated version of Dizziness Handicap Inventory among individuals presenting with dizziness or vertigo in the Out-Patient Department of Otorhinolaryngology in a tertiary health-care centre.

DHI-Hindi Development

The Dizziness Handicap Inventory questionnaire originally comprises of 25-items in English, where responses are scored as 0 points for “no,” 2 points for “sometimes,” and 4 points for “yes.” To develop the Hindi version (DHI-Hindi), we employed a systematic translation process.

Two forward translators proficient in both English and Hindi languages independently translated the DHI questionnaire into Hindi. Discrepancies between these independent translations were resolved by the authors, ensuring consistency, resulting in reconciliation into a single forward translation.

Subsequently, another bilingual individual, not familiar with the original questionnaire, independently back-translated the Hindi version into English. The back-translated version was then reviewed by the authors against the original instrument, and any discrepancies were identified and resolved. The DHI-Hindi underwent further iterative refinement based on feedback obtained from a pilot test involving 20 dizzy patients attending the Out-Patient Department. Incorporating this feedback, the translation was finalized to ensure its suitability and effectiveness in accurately capturing respondents’ experiences. Before validation, the final version of DHI-Hindi underwent a thorough proof-reading process to ensure accuracy and completeness (Table 1).

Table 1 Dizziness Handicap Inventory-Hindi
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Study Participants and Methodology for Validation

Potential participants were adults (age ≥ 18 years) with chief complaint of dizziness or vertigo and possessing the ability to read and comprehend the Hindi language sufficiently to independently respond to the DHI-Hindi. Participants were recruited after obtaining informed written consent.

We excluded individuals with significant cognitive impairments or conditions that might affect their ability to provide reliable responses, thereby impeding questionnaire completion. Also, individuals who presented with dizziness as part of an acute medical emergency requiring immediate intervention were excluded from the study. Participants were asked to complete the DHI-Hindi by themselves during their OPD visit. Responses on the DHI-Hindi were recorded in an Excel sheet for subsequent analysis.

Data Analysis

Data analysis was conducted using SPSS version 23.0. The reliability of the DHI-Hindi questionnaire was assessed using Cronbach’s alpha coefficient and split-half reliability analysis. Construct validity was examined through factor analysis. The Kaiser–Meyer–Olkin (KMO) measure was utilized to assess sampling adequacy. The results of the study are summarized below.

Results

Participant Characteristics and DHI-Hindi Score

A total of 153 participants completed the Hindi version of the Dizziness Handicap Inventory (DHI-Hindi). Of these participants, 78 were female and 75 were male. The mean age of the participants was 51.47 years, with standard deviation of 12.86. The age range of the participants was 24 to 77 years.

The mean total DHI-Hindi score for all participants was 37.28, with a standard deviation of 15.63. The mean score for females was 37.64 (standard deviation = 15.01), while the mean score for males was 36.89 (standard deviation = 16.35). The difference in mean scores between females and males was not statistically significant (p = 0.40). On analysis of variance (one-way ANOVA), the total DHI-Hindi scores among the different age groups did not exhibit significant differences (p = 0.07). (The age groups were categorized as 20–30 years, 31–40 years, 41–50 years, 51–60 years, 61–70 years, and 71–80 years.)

Ceiling and Floor Effect

The Dizziness Handicap Inventory has a potential score range from 0 to 100. In our sample, the lowest score recorded was 12, observed in 1 participant (0.7%), while the highest score was 88, recorded in 2 participants (1.3%). Nine participants (5.88%) scored below 20, and 3 participants (1.96%) scored above 80. The interquartile range (IQR) for the DHI-Hindi total score ranged from 27 to 44, with a median score of 34. Overall, no ceiling or floor effects were observed. The scatter plot and median (IQR) of DHI-Hindi score in our participants are depicted in Figs. 1 and 2.

Fig. 1
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Scatter plot for DHI- Hindi total score in our study participants

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Fig. 2
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Mean and Median (inter-quartile range) for DHI-Hindi total scores

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Reliability Analysis

The Cronbach’s α coefficient for the overall DHI-Hindi scale was 0.785, indicating good internal consistency. Removal of any item did not significantly increase the reliability of the scale, as indicated by the values of Cronbach’s alpha if item deleted (Table 2).

Table 2 Cronbach’s Alpha coefficient for the DHI-Hindi scale if item is delayed
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Additionally, split-half reliability analysis yielded satisfactory results, with a Cronbach’s alpha coefficient of 0.746 for odd items and 0.704 for even items of the DHI-Hindi scale. The Spearman-Brown coefficient for unequal length was 0.813, and Guttman split-half coefficient was 0.811, further supporting the good reliability and internal consistency of the DHI-Hindi questionnaire (Table 3).

Table 3 Split-half reliability analysis for DHI- Hindi
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Validity

Construct validity was assessed using factor analysis. The Kaiser–Meyer–Olkin measure of sampling adequacy was 0.76, and Bartlett’s test of sphericity was significant (χ2 (300) = 1085.72, p < 0.001), indicating suitability for factor analysis. Principal component extraction revealed nine components with Eigen values greater than 1; however, based on the scree plot (Fig. 3), which levelled out at the fourth factor, three components were retained. Item allocation for the three-factor extraction, after suppressing small components (< 0.3), is presented in Table 4. Note that dh2 did not exhibit a factor loading greater than 0.3 onto any of the three components; therefore, the highest factor loading of 0.277 onto component 1 was considered. The component correlation matrix of the three-factor solution for DHI-Hindi is shown in Table 5.

Fig. 3
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Scree plot for factor analysis

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Table 4 Structure matrix for Principal Component Analysis
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Table 5 Component Correlation Matrix
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The consistency of the three-factor solution with both the original instrument (Table 6) and validated versions of the Dizziness Handicap Inventory (DHI) in various other languages further reinforces the construct validity of the translated DHI-Hindi.

Table 6 Component structure of DHI-Hindi
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Overall, these results support the reliability and validity of the translated version of Dizziness Handicap Inventory in Hindi-speaking populations.

Discussion

The translation and validation of assessment tools such as the Dizziness Handicap Inventory (DHI) are crucial for ensuring accurate evaluation and effective management of vestibular disorders across diverse linguistic populations. In this study, we successfully developed the Hindi translated version of DHI (DHI-Hindi) using a systematic process, and subsequently validated the same in Hindi-speaking individuals suffering from dizziness.

The process of translation involved multiple steps to ensure linguistic and cultural equivalence between the original English version and the translated DHI-Hindi. This included forward translation by bilingual individuals, reconciliation of translations, back translation, iterative refinement based on feedback from pilot testing and proof-reading. Such a rigorous approach is essential for crafting a translated version that accurately captures the intended meaning of the original instrument, ensures that the translated instrument is not only understandable and pertinent to individuals proficient in Hindi, but also aligns with recommended practices for translation and cross-cultural adaptation of patient-reported outcomes measures [11].

The reliability analysis of the DHI-Hindi revealed high internal consistency, as evidenced by a Cronbach’s alpha coefficient of 0.785 for the overall scale, exceeding the recommended level of 0.7 for establishing a reliable measure for population studies. Furthermore, delaying any item did not significantly increase the reliability of the scale, indicating that each item contributes meaningfully to the overall reliability of the DHI-Hindi. Additionally, the split-half reliability analysis yielded satisfactory results, with Cronbach’s alpha coefficients of 0.746 for odd items and 0.704 for even items of the DHI-Hindi scale. The high Spearman-Brown coefficient for unequal length (0.813) and Guttman split-half coefficient (0.811) further supports the good reliability and internal consistency of the DHI-Hindi questionnaire.

Furthermore, the factor analysis confirmed the construct validity of the DHI-Hindi.

Factor analysis revealed a three-factor solution in our study, consistent with the original instrument and validated versions in other languages. This indicates that the DHI-Hindi effectively captures the multidimensional aspects of dizziness-related handicap, encompassing physical, emotional, and functional components, similar to the original DHI.

In the original DHI instrument, items were categorized into three content domains representing the physical, functional and emotional aspects of dizziness, although this classification was not based on statistical factor analysis [2]. However, subsequent studies have proposed various factorial solutions, highlighting the multidimensional nature of the DHI.

For instance, some studies suggested a two-factor solution, such as general functional limitations and postural difficulties, while others revealed a three-factor solution [12]. A study conducted for validation of Lithuanian version of Dizziness Handicap Inventory found a two factor solution [4]. The analysis on Polish version of DHI identified three factor solution which was comparable to the original factor structure. However, the component structure was different from the original subscales [7]. In the Spanish version of the DHI, factors were related to vestibular handicap, vestibular disability, and visuo-vestibular disability. Similarly, the Brazilian version identified factors including mental structure, physical limitations, and loss of function [13]. The German version delineated three factor solution encompassing activity and participation limitations, emotional problems, and motion activity in everyday life [5]. Additionally, the Turkish version identified factors related to functional limitations, physical problems, and emotional problems [14]. Five factor solution has been reported in used of DHI for clinical evaluation of dizzy patients with various vestibular pathologies [1]. The Japanese version too found a five-factor solution, indicating further variability in the factorial structure of the Dizziness Handicap Inventory (DHI) [9].

Despite variations in factorial solutions across studies, most converge into two to three factor solutions, indicative of the multidimensional nature of the DHI. Our study’s finding of a three-factor solution for the DHI-Hindi further supports this trend, albeit with slight variations in component structure (Table 6). Nevertheless, this suggests that the DHI-Hindi retains the fundamental conceptual framework of the original DHI, providing a comprehensive assessment of dizziness-related handicap in Hindi-speaking populations.

By providing a standardized tool to assess the impact of dizziness on quality of life, the DHI-Hindi enables healthcare professionals to accurately diagnose vestibular disorders and monitor treatment outcomes in Hindi-speaking patients. Moreover, researchers can conduct cross-cultural studies comparing dizziness-related handicap across different linguistic populations, contributing to a broader understanding of vestibular disorders.

Conclusion

In conclusion, this study successfully translated and validated the Dizziness Handicap Inventory in Hindi, producing the DHI-Hindi. Through a rigorous translation process adhering to established guidelines, the DHI-Hindi maintains conceptual equivalence while capturing the nuances of the Hindi-speaking population. The statistical analysis demonstrates the reliability and validity of the DHI-Hindi, with high internal consistency and a three-factor solution consistent with the original instrument and validated versions in other languages, although with a different component structure.

The DHI-Hindi provides a standardized and reliable tool for assessing the impact of dizziness in Hindi-speaking individuals, aiding in the accurate diagnosis and effective management of vestibular disorders. By overcoming linguistic barriers and facilitating cross-cultural research, the DHI-Hindi contributes to a broader understanding of dizziness-related handicap. DHI-Hindi can be utilized in clinical practice to monitor treatment outcomes and guide interventions for individuals experiencing dizziness, ultimately improving patient care and research outcomes in Hindi-speaking populations.