Sialorrhea or drooling is considered normal in children up to 2 years of age,1 and generally improves after 18 months of age as sensorial function and oral-motor maturity develops. Drooling may cause serious clinical, functional and social problems, such as aspiration, asphyxia, feeding problems, skin tears, isolation, stigmatization and rejection.2

Quality of life (QOL) is usually described as a multidimensional item attempting to point out the characteristics of human experience from the perspective of the individual himself regarding his subjective perception, considering physical, psychological, social, economic and also emotional aspects and with the sensation of well-being as central factor.3,4 Validated questionnaires are one of the means to quantify QOL and to check the potential impact of an injury or illness on it. These questionnaires can be universal or specific to any affliction. The Drooling Impact Scale (DIS) evaluates the impact of sialorrhea on the QOL of the caregiver and of the child.

Since the reality of our country is different than that of developed countries regarding both economic aspects and the access to health services, it is necessary to study how and in what ways sialorrhea is affecting the lives of family members and patients.

However, no specific instrument for this target population was found in Brazilian Portuguese, making such an assessment impossible. As such, this study carried out the translation of the DIS into Brazilian Portuguese as well as its validation for our population.

There were no conceptual differences in the back-translation compared to the original version. The final Portuguese version of the DIS was then approved in format and content.

A total sample of 40 subjects (and respective respondent parents) was enrolled for this validation protocol, as recommended by Terwee et al.7 Population characteristics are shown in Table 1.

The mean DIS value for the whole population was 51.77 (SD = 16.13). The internal consistency obtained with Cronbach’s alpha indicated a value of 0.72 for the entire sample. Table 2 presents DIS individual item mean scores, SD, corrected item-total correlation coefficients and Cronbach’s alphas if the item is deleted. Mean individual item scores ranged from 1.48 (Item 7. “Quão envergonhada a criança parecia estar por causa da baba?”) to 8.08 (Item 2. “Qual era a quantidade da baba?”). Items showing the lowest corrected item-total correlation coefficient were 7 (“Quão envergonhada a criança parecia estar por causa da baba?”) and 9 (“Em que medida a baba afetou a vida de seu filho?”), standing below acceptance criterion value of 0.30. The exclusion of those items 7 and 9 from the questionnaire would result in a Cronbach’s alpha value of 0.74 and 0.76, respectively.

The Bartlett’s test of sphericity was significant (p < 0.0001), confirming correlation among variables tested. Kaiser-Meyer-Olkin (MO) measure of sampling adequacy revealed a value of 0.72, indicating that the correlation matrix was reasonably suitable for factor analysis. Initial Eigenvalues and the Scree plot suggested a three-factor structure, but Parallel analysis suggested a two-factor solution. As this last approach is considered less prone to overestimate the number of latent factors, we have proceeded with a two-factor confirmatory factor analysis. Factor loadings and communalities for this solution are shown in Table 3. The first factor was responsible for 33.78% of the variance with an Eigenvalue of 3.38. The second factor explained 16.1% of the variance with an Eigenvalue of 1.61. The first factor apparently encompassed items relating to an objective frequency of drooling events and consequences, while the second factor seemed to embrace a more subjective experience on how drooling affected the patient and respective caretakers. Cronbach’s alpha for the first and second factor was 0.74 and 0.61, respectively.

Final fit indices for the two DIS factor models (Model 1 = 1 factor, Model 2 = 2 factors) tested according to confirmatory factor analysis are described in Table 4. The Chi-Square (x2) p-value for models 1 and 2 are 0.073 and 0.577, respectively. Although both models did not reject the null hypothesis that the model fits the true covariance structure from the population, evaluated indices showed systematically better fit results for model 2 (2 factors) compared to model 1.

There are quantitative and qualitative methods to assess the QOL of patient and caretaker concerning the impact of salivation. Qualitative scales, such as DSFS, The Visual Analogue Scale (VAS)12 and DIS are scales that rate scores and give a subjective impression.

The DSFS is based on the Thomas-Stonell and Greenberg scale1 and assesses the severity of sialorrhea compromise. VAS measures the salivation reference rate where “0” indicates normal salivation and “100”, extremely high salivation rate.12 The DIS assesses the impact of sialorrhea on the quality of life of the caretaker and the patient. None of these or any other instrument was found with a validated translation into Brazilian Portuguese.

After completing the steps described in the methods section and according to the definition of the measurement properties proposed by the Mokkink et al. in 2010,13 the final Portuguese version was tested to verify its equivalence with the original questionnaire. The ideal population is in the range of 3 to 5 respondents for each question in a translated questionnaire. The DIS has 10 questions, therefore an adequate population for this study would be between 30 and 50 participants,7 justifying our final enrollment of 40 respondents.

The Brazilian Portuguese language version of the DIS questionnaire showed an acceptable internal consistency, with a Cronbach’s alpha above 0.7. Regarding individual analysis of the items in the scale, it was found that mainly Item 7 (“Quão envergonhada a criança parecia estar por causa da baba?”) and Item 9 (“Em que medida a baba afetou a vida de seu filho?”) showed poor correlation with the remaining items, and their exclusion would potentially result in a higher global Cronbach’s alpha. Item 7 also showed the lowest communality value (0.1) contributing poorly to the scale variance. Both questions are directed to a subjective experience of how much drooling affects interaction between patient and caretakers. A hypothesis is that attributing higher scores at those items would elicit a perception of directing negative feelings towards the patient, and consequently could have discouraged caretakers in doing so.

Upon exploratory factorial analysis, a two-factor structure was identified: “objective” × “subjective” experience on drooling. This solution seemed reasonable when considering the DIS questions. Confirmatory factorial analysis confirmed superiority of a two-factor model base on different fit indices.

As a validated and globally utilized scale, there is no intention in changing its original structure. The purpose is solely a better understanding on how this scale performs not only in our language, but also in our culture. Exploratory factorial analysis also allowed for a deeper appreciation of latent factors existing within the scale framework.

Validation of this instrument allows physicians and other personnel involved in the care of these patients to perform a better management of patients experiencing drooling. With this tool, we are now able to guide routines and provide guidelines both before and after the different kinds of treatments in order to improve the general well-being of the patient and his family.

DIS has been successfully translated to Brazilian Portuguese language. Although some items have shown poorer correlation results, whole consistency was considered acceptable.

The authors declare no conflicts of interest.