The development of the Malay-ECOHIS involved two phases. The first phase involved the cultural adaptation of the English ECOHIS into Malay . The second phase involved psychometric validations of the newly developed Malay-ECOHIS [26, 27].
In the cross-cultural adaptation phase, the English ECOHIS was first translated into the Malay language by a team of independent translators consisted of a psychologist, a peadodontist, dental public health specialists and experts in quality of life assessment. The experts were also proficient in both Malay and English languages. Next, the experts met together to analyse the content and wordings of the translations. The objective was to ensure that conceptual and item equivalence between the original ECOHIS and its Malay versions were maintained throughout the process . Conceptual equivalence is achieved when answers to the same questions reflect the same concept in the original ECOHIS and its Malay version respectively, and also the concepts are meaningful in both cultures and languages concerned. Item equivalence is achieved when the meaning of the individual item in both sets of questionnaires is contextually similar. Following the meeting, the experts agreed on one consensus translation derived from the translations. The consensus translation was called the draft Malay-ECOHIS.
Next, the draft-Malay ECOHIS was tested for face validity on a non-random sample of 20 mothers of 4-6 year old children in a classroom setting at one of the kindergartens supervised by one of the authors (RE) . The time taken to answer the questionnaire was noted. Afterwards, the author (RE) undertook a detailed discussion with the mothers on their understanding of the purpose, instructions, content, wordings, answering options, and general layout of the questionnaire. Based on the mothers’ feedback, a minor adjustment was made to the draft Malay-ECOHIS. The mode of questionnaire administration was self-administered.
Next, the draft Malay-ECOHIS was back translated into English by a language expert from the Department of Languages, University of Malaya who was proficient in both English and Malay languages. Then, the experts reconvened to compare the back translation with the original ECOHIS. After minor modifications, the experts agreed on the back translation of the Malay-ECOHIS. Small changes to the draft Malay-ECOHIS were made accordingly before it was finalised.
The assessment of the Malay-ECOHIS psychometric properties involved 2 studies. In study 1, the Malay-ECOHIS was distributed by one of the authors (NAH) to a convenient sample of 127 parents of 4-6 year old children from two public and one private kindergarten in Kelana Jaya district in the Selangor state. To assess the test-retest reliability, the scale was redistributed to 20 % of the sample after 10 days . In study 2, in order to assess the relationship between the Malay-ECOHIS and clinical outcomes, the scale was distributed by RE and ZY to 860 parents of 4–6 year old preschool children from 25 kindergartens from 2 districts in Selangor state. Oral examinations were undertaken on the children.
The Malay-ECOHIS comprised 13 items divided into two main parts, i.e. the child impacts section and the family impacts section. The number of items and sections in the Malay-ECOHIS were similar to the original ECOHIS . In the Malay-ECOHIS, the child impacts section contained four domains, i.e. child symptom (1 item), child function (4 items), child psychology (2 items) and child self-image and social interaction (2 items). The family impacts section contained two domains, i.e. parental distress (2 items) and family function (2 items).
The questionnaire has 5 response options: 0 = never, 1 = hardly ever, 2 = occasionally, 3 = often, 4 = very often, and 5 = don’t know. The different score ranges for each domain were as follows: child symptom, range 0–4; child function, range 0–16; child psychology, range 0–8; child self-image/social interaction, range 0–8; parental distress, range 0–8 and family function, range 0–8. Total score was calculated by simply summing up the response codes of the 13 items. Thus, the overall score ranged between 0 and 52 (0–36 for the child section and 0–16 for the family section). In our study, we dealt with ‘don’t know’ (DK) responses by following the method of data scoring proposed in the original version, where DK responses were recoded as missing values . In cases with up to 2 missing responses in the child section or 1 missing response in the parent section, we ascribed the score for the missing value as the average of the rest of the items for that section . Subsequently, we only excluded cases with more than 2 missing responses in the child section or more than 1 in the family section. When answering the Malay-ECOHIS, parents were asked to consider the lifetime experience of the child with regard to oral problems and related impacts. Higher scores indicate greater oral impacts and poorer OHRQoL and vice versa.
In our study, the inclusion criteria were mothers of children aged between 4 and 6 years with no chronic medical conditions, no long-term medication, no physical or learning disabilities, and accompanied by a Malay-speaking parent who lived with the child most of the time.
Ethics, consent and permissions
Ethical approval for the study was granted by the Medical Ethics Committee, Faculty of Dentistry, University of Malaya [Reference: DF CO1403/0042(P)]. Permission to conduct the study was obtained from the State Education Department, State Oral Health Division (Selangor), kindergarten teachers and parents of the children.
Information about the study was given to the parents to read. A written consent from the parent was obtained before they answered the questionnaire.
In this study, psychometric properties of the Malay-ECOHIS were analysed by assessing its internal consistency and test-retest reliability as well as construct, convergent and discriminant validity.
For internal consistency reliability, Cronbach’s alpha coefficient, inter-item correlation and corrected item-total correlation were used to assess the degree of homogeneity of the child and family impacts sections. Cronbach’s alpha values ≥ 0.70 were considered acceptable for comparison between groups . The test-retest reliability test was carried out to ensure the Malay-ECOHIS would yield consistent scores when administered at two different times . This was determined by the weighted kappa value for categories of Malay-ECOHIS scores and Intraclass Correlation Coefficient (ICC) in a one-way random effect parallel model for the child and family impacts sections. The 95 % confidence interval was estimated. The degree of test-retest reliability was assessed based on the ICC values, i.e. ≤0.40 = weak, 0.41 to 0.60 = moderate, 0.61 to 0.80 = good, and 0.81 to 1.00 = excellent . Arbitrary guidelines characterized kappa value over 0.75 as excellent, 0.40 to 0.75 as fair to good, and below 0.40 as poor .
The ability of the Malay-ECOHIS to assess pre-school children’s OHRQoL was assessed by examining the association between Malay ECOHIS scores and a number of subjective variables designed to indicate, both objectively and subjectively, the levels of oral health status and quality of life of the study population.
Convergent validity of the Malay-ECOHIS was tested on its ability to measure what it intended to measure . In this study, the Malay-ECOHIS was intended to measure child’s oral impacts which also mirrored levels of child’s oral health status. Consequently, the convergent validity was tested by comparing its relationship with a suitable global oral health rating item on perceived oral health status of the child, i.e. “How do you describe your child’s oral health status?” The underlying hypothesis was that parents who rated their child’s oral health status as poor would score highly on the Malay-ECOHIS.
Construct validity of the Malay-ECOHIS was assessed by comparing its relationships with other measures that assess related constructs, i.e. perceived satisfaction on child’s oral health, perceived child’s treatment needs, and presence of toothache. The items used were (1) “How satisfied are you with your child’s teeth/mouth?” (2) “In your opinion, would your child require any dental treatment?” and (3) “How often has your child had pain in their teeth, mouth or jaws?” The hypothesis related to the tests was that preschool children whose oral health was rated as less satisfactory and needed dental treatment and those with pain in their teeth and mouth would experience lower levels of OHRQoL and higher Malay-ECOHIS scores. The impacts of child’s oral health on his/her daily life were also closely related to the impacts on family members [8, 9].
Discriminant validity of the Malay-ECOHIS was tested by comparing its relationship with the child’s dental visits due to dental problems and the child’s caries status. The hypothesis behind this was that mothers who often brought their child to the dentist for treatment were more likely to report that their child experienced dental problems. Likewise, children with caries would have significantly higher oral impacts than children with no caries.
In this study, the Malay-ECOHIS scores were skewed. Therefore, non-parametric statistics, i.e. Kruskal-Wallis and Mann Whitney were used to assess relationships between the Malay-ECOHIS and subjective/objective measures . Data distribution was described in terms of mean and median. The SPSS statistical package version 17 was used for data analysis . The level of statistical significance was set at p < 0.05.