Functional luminal imaging probe (FLIP) is being increasingly used in the diagnosis of functional gastrointestinal (GI) disorders and has advantages of detection of distensibility in GI tract.1,2 The previously used technique, manometry, could measure the inner active contractility of GI tract.3 However, without active swallowing of bolus, manometry cannot generate a significant signal. To overcome this, the measurement of bolus transit from high-resolution impedance manometry has been attempted, especially in patients with
functional dysphagia without major motor esophageal dysmotility.