MATERIALS AND METHODS: This cross-sectional study is conducted at the Otorhinolaryngology-Head and Neck Surgery (ORL-HNS) clinic of Hospital Universiti Sains Malaysia. The forward and backward translation of the OSA- 18 questionnaire into the Malay language (Malay OSA-18) was performed and tested for content and face validity. The questionnaire's internal validity and reliability were tested using Pearson's correlation, Cronbach α and inter-reliability coefficient tests. The psychometric properties (validity, reliability and reproducibility) were assessed.

RESULTS: We observed 84 patients ranging from six months up to 12 years of age. The mean age was 8 years old, and 63.1% were male patients. Among the samples, 96.4% presented with palatine tonsillar enlargement, and 84.5% presented with adenoid tonsillar enlargement. Based on the questionnaire the patient's caregiver answered, Pearson's correlation demonstrated that all the symptom scales correlate and measure the same things. The Cronbach's α coefficient value for each symptom scale was acceptable, within 0.6-0.8. The total Cronbach's α coefficient value was 0.89. The test-retest evaluation was excellent, with the value of intraclass correlation (ICC) more than 0.90.