- Functional dyspepsia symptom questionnaire: an 8-item dyspeptic symptom score questionnaire using 4-point (0-3) Likert scale based on recall of the past 7 days for assessment of epigastric pain, epigastric burning, belching, bloating, postprandial fullness, early satiation, nausea and vomiting. Functional dyspepsia will be further classified into epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS) according to the Rome III definitions.