World Journal Of Pediatrics-articles

AL Hasniah, AR Jamalludin, AW Norrashidah, MZ Norzila, K Asiah, A Rus Anida, A Ahmad Fadzil, Z Ramli, H Samsinah

Author Affiliations: Pediatric Department, Universiti Kebangsaan Malaysia Medical Centre, Malaysia (Hasniah AL); Department of Community Health, International Islamic University Malaysia (Jamalludin AR); Pediatric Department, Serdang Hospital, Malaysia (Norrashidah AW); Pediatric Institute, Kuala Lumpur Hospital, Malaysia (Norzila MZ, Asiah K); Pediatric Department, Penang Hospital, Malaysia (Rus Anida A); Pediatric Department, Tengku Ampuan Afzan Hospital, Malaysia (Ahmad Fadzil A); Institute for Health Systems Research, Malaysia (Ramli Z); University of Malaya, Kuala Lumpur, Malaysia (Samsinah H)

Corresponding Author: Assoc. Prof. Dr Abdul Latif Hasniah, Pediatric Department, Universiti Kebangsaan Malaysia Medical Centre, Jln Yaacob Latif, 56000 Cheras, Kuala Lumpur, Malaysia (Tel: +6 03 91455395/91455380; Fax: +603-91456637; Email: hasniah@ppukm.ukm.my)

Background: Sleep-disordered breathing (SDB) is common but often underdiagnosed in children. The Pediatric Sleep Questionnaire developed by University of Michigan, USA (English UM PSQ) has high sensitivity and specificity in identifying children with sleep-disordered breathing. This study aimed to translate and adapt the English UM PSQ into Malay language as a screening tool to assess SDB among the Malay speaking population. The second objective was to determine the psychometric measurements of the translated UM PSQ (Malay UM PSQ).

Methods: The Malay UM PSQ was translated through forward-backward translation techniques by two independent accredited bodies and reviewed by a panel of experts. The questionnaire was tested in two phases. The respondents were from hospital staffs with children and parents of primary school children aged 6-10 years. The reliability of questionnaires was measured by Cronbach's α and Kappa (κ) statistics.

Results: The overall scale of internal consistency of the Malay UM PSQ was good, i.e., Cronbach's α = 0.760 (α = 0.457, 0.608 and 0.688 for snoring, sleepiness and behavioral domains respectively). The English UM PSQ also had good internal consistency at α = 0.753 (α = 0.589, 0.524, to 0.793 for snoring, sleepiness and behavioral domains respectively). Test-retest reliability for most items was good with correctness of >85.0% in all items. Only one item was seen in the Malay UM PSQ with κ=0.348, while the remaining ranged from κ=0.489 to 0.811. For the English UM PSQ, κ ranged from 0.660 to 0.945.

Conclusion: Both English and Malay UM PSQ have acceptable psychometric measurement properties as screening tools to assess SDB in the Malay speaking population.

Key words: pediatric; questionnaire; reliability; sleep-disordered breathing

Sleep-disordered breathing (SDB) is a common condition in children. This disorder has a wide spectrum of presentations in children ranging from primary snoring, upper airway resistance syndrome (UARS), obstructive hypoventilation and obstructive sleep apnoea syndrome (OSAS) based upon the severity of airway collapsibility and/or airway resistance. The condition is increasingly recognized and the reported prevalence was between 1.0% and 3.0% among school-aged children.^[1,2]

SDB in children cannot be readily diagnosed from symptoms and clinical findings alone.^[3] Full polysomnography (PSG) is the gold standard procedure in the diagnosis of spectrum of SDB; however, it requires trained personnel in the pediatric sleep medicine and is labor intensive, time-consuming and very costly.^[4-6]

A validated Pediatric Sleep Questionnaire (PSQ) can be used as a screening tool to identify SDB when PSG is not feasible.^[3,4,7] Several validated PSQs have been designed and published to assess SDB in children.^[8-12] We chose the PSQ developed by the University of Michigan, USA (English UM PSQ) due to its simplicity, high sensitivity and specificity in identifying children with SDB.^[8]

Malay or Bahasa Melayu is the ninth most spoken language in the world.^[13] At present, the estimated Malay-speaking population has reached more than 200 millions, living in regions including Malaysia, Singapore, Brunei, Indonesia, Southern Philippines and Southern Thailand.^[14] The English UM PSQ has to be translated and validated before being adapted cross-culturally among the Malay speaking population.

The objectives of this study were to 1) translate the English UM PSQ into Malay language and to adapt the original English version as a screening tool to assess SDB, and to 2) determine the reliability of the translated Malay UM PSQ.

The PSQ consists of 22-item questions divided into three domains, i.e., snoring (9 items), sleepiness (7 items), and behavioral (6 items). This validated questionnaire has a sensitivity and specificity of 0.81 and 0.87, respectively.[8] It classifies 85% of patients correctly in controls and children with polysomnographically defined SDB. Instrument performance is not varied with participant's age (2-18 years). Responses are 'Yes=1', 'No=0' and 'Don't know=Missing'. The cumulative score is calculated from responses of 'Yes' and 'No' only. The optimal SDB scale cut-off indicating the presence of SDB is a score of at least 0.33 (i.e., 33% of the all question-items answered positively). This SDB scale also shows good internal consistency (Cronbach's α of 0.86, 0.66 and 0.84 for snoring, sleepiness and behavioral domains, respectively) and test-retest reliability (Spearman's correlation coefficient, ρ of 0.92, 0.66 and 0.83 for snoring, sleepiness and behavioral domains, respectively).

This was part of the national epidemiological study of the prevalence of sleep-disordered breathing in Malaysian school children.

The English UM PSQ was translated into Malay language by Institut Terjemahan Negara Malaysia (ITNM) and backward translation was performed by another independent company. Both independent accredited bodies were blinded from the reason and rationale of the study.

A Review Panel of Experts was constituted to determine the face validity and cross-cultural equivalence of the Malay UM PSQ. The panel was chaired by the principal investigator and comprised six pediatric respiratory physicians and two other non-clinical members. The process of translating and adapting the English PSQ is summarized in the Fig.

Both of the English and Malay UM PSQ were tested in two phases. Phase 1 study was conducted in August 2009. The questionnaires were distributed among hospital staffs with children aged 6-10 years who were conveniently selected from five different local hospitals to determine the psychometric measurements of the questionnaire. The respondents answered the questionnaire twice after at least an interval of 14 days.

Based on the findings of the phase 1 study, further modifications of the Malay UM PSQ were made. Phase 2 study was performed in December 2009, involving parents of school children aged 6-10 years from a randomly selected primary school.

The study was approved by the Medical Research Ethics Committee, Ministry of Health Malaysia (NMRR code: 08-860-2015) and Ethics Committee UKM (code: FF-043-2009). Copyright permission for the use of the UM PSQ was obtained from the original author and University of Michigan, USA.^[8]

Content validity was verified by qualified pediatric respiratory physicians. Internal consistency was assessed by Cronbach's α where a value ≥0.7 indicated a high reliability, 0.5 to 0.7 = moderate, 0.2 to 0.4 = fair, and ≤0.2 = low reliability.^[15]Long-term stability of the translated questionnaire was tested using Kappa test, κ (test-retest reliability) for both the English and Malay UM PSQ in the phase 1 study. Magnitude of κ value was set according to Landis and Koch as follows: ≤0 = poor, 0.01 to 0.20 = slight, 0.21 to 0.40 = fair, 0.41 to 0.60 = moderate, 0.6 to 0.80 = substantial, and 0.81 to 1 = almost perfect agreement.^[16]

The minimum sample size required to test the internal consistency was calculated to detect the difference of Cronbach's α of 0.70 from 0.60. Based on the formula by Feldt et al^[17] and Bonett,^[18] a minimum of 194 samples were required to test all 22 items in the questionnaire at 80% power and 0.05 significant level (two-tailed).

For Kappa statistics, based on a formula by Flack et al,^[19] a minimum of 133 samples were required to detect the difference of 0.8 from 0.6 of degree of agreement at the 80% power and the 0.05 significant level. Anticipating some non-responses, at least 250 respondents were sampled for each version of the questionnaire. Correlations of score between domains were tested using Pearson's correlation coefficient test. ρ more than 0.3 is considered moderate and anything 0.8 and above is strong.

Diagnostic properties, i.e., the sensitivity, specificity and predictive values of the questionnaires, will be tested using PSG on randomly selected respondents with SDB and non-SDB symptoms in the next phase of the study. Data were put into a custom made database using PHP and MySQL, and analyses were made using SPSS 19 (SPSS Inc, Chicago, Illinois).

In the phase 1 study, the panel strived for conceptual and not literal equivalence translation. Changes were made in Behavioral Scale of the English UM PSQ. We reconstructed the phrase 'fidgets with hands or feet or squirms in seat' (item C10) which became anomalous and poorly understood by respondents, when it was literally translated. The phrase 'on the go' or often acts as if 'driven by a motor' (item C14) was also changed to suit the local context.

Two-hundred and seventy respondents had consented to answer the PSQ. The mean (SD) age of the respondents for the Malay UM PSQ and English UM PSQ were 34 (9) years and 35 (7) years respectively. The majority of respondents who answered the Malay UM PSQ and English UM PSQ were Malay females with tertiary education. However, more respondents with tertiary education chose to answer the English rather than Malay UM PSQ (Table 1).

Although the overall internal consistency was acceptable for the Malay UM PSQ (Cronbach's α = 0.659), there was poor internal consistency in the snoring and sleepiness domains (Table 2). Modifications were made for items A5, A7, B6, B7 and B9 but no changes were made in the Behavioral domain. In the English UM PSQ, acronyms A, B, C were used to separate question items of the 3 domains. We retained acronym A and removed acronym B and C in the questionnaire distributed to respondents to prevent confusion. The numbering was also changed accordingly, i.e., A1 to A22. The final Malay UM PSQ was accepted after all the changes were made and used in the phase 2 study.

The questionnaire showed better and good overall internal consistency at Cronbach's α=0.753 ranging from 0.524 to 0.793 between the domains (Table 2).

Five hundred and fifty-four parents of students from a primary school answered the Malay questionnaire. Their demographic data are shown in Table 1.

We found loud snoring in 4.9% of the students, trouble breathing during sleep in 2.3% and mouth-breathing in 2.5%. Higher percentage of respondents reported sleepiness during the day and behavioral problems, i.e., 18.2% and 25.8% respectively. There was a weak correlation between loud snoring and both sleepiness and behavioral domains (ρ=0.221 and 0.098 respectively). Eighty-three (15.0%) of 554 students had positive SDB symptoms.

The overall scale of internal consistency of the Malay UM PSQ improved from α = 0.659 to 0.760 with a major improvement of the snoring domain from α = 0.163 to 0.457 and the sleepiness domain from α = 0.299 to 0.608. The behavioral domain remained good at α = 0.688 (Table 2).

Percentages of correct answer in all items were >85.0%. The result showed a good test-retest reliability for most items except A4 item (κ value <0.4) (Table 3).

Our study showed that the Malay UM PSQ demonstrated a good reliability for the Malay speaking population. In phase 1 study, the socio-demographic characteristics for respondents who answered the Malay and English PSQ were almost similar. The test-retest reliability was good and comparable with that of the English UM PSQ. The Malay UM PSQ used in the phase 1 study had a lower internal consistency compared to that reported by Chervin et al^[8] because of different sample population. The sample in our study was from the general population compared to the sleep clinic-based population in their study. Generally, parents with SDB children had better awareness of SDB symptoms leading to more valid and reliable responses. In addition, a few items had ambiguous phrases that may lead to poor understanding of respondents. The internal consistency for the English UM PSQ was comparable with that reported by Chervin et al.^[8]

Cross-cultural adaptation of a questionnaire is much more than simple translation; the novel version must reflect in depth and the true significance of questions in another language.^[20,21] We experienced a long process of translating and adapting the English UM PSQ into Malay language which took us about six months to produce the final version. We found that many English words in this questionnaire required elaboration using lengthy Malay words, or otherwise conceptual equivalents were used in the translation.

Interestingly, we found a high percentage of parents reported symptoms of sleepiness and behavioral problems compared to the snoring domain. These symptoms may relate to SDB or signify other problems such as poor sleep hygiene, late sleeper, habit disorders or parenting style. We are currently doing the phase 2 study where randomly selected children with SDB and non-SDB symptoms are tested with PSG, a diagnostic test to discriminate children with and without SDB.

In conclusion, the Malay UM PSQ has been successfully translated and adapted for the Malay speaking population. Both the English and Malay UM PSQ have acceptable measurement properties as a screening tool for SDB in children.

We would like to thank all medical staff, teachers and students of SK Bukit Naga for their participation and co-operation. We would also like to thank the Director-General of Health Malaysia for his permission to publish this work.

Funding: This study was supported by the National Institutes of Health Malaysia Research Grant, Ministry of Health, Malaysia. This study is a project under the 9th Malaysia Plan Research Priority Area, sub-area "Letter of Intent for Respiratory Illness".

Ethical approval: This study was approved by Medical Research Ethics Committee, Ministry of Health Malaysia (NMRR code: 08-860-2015) and Ethics Committee UKM (code: FF-043-2009). Copyright permission for the use of UM PSQ was obtained from the original author and University of Michigan

USA

Contributors: All authors contributed to the concept of the study, analysis and interpretation of data, drafting and revision of the article, and final approval of the version for publication.

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