['Ineffective esophageal motility (IEM) has been defined by the presence of > or = 30% liquid swallows with contraction amplitude < 30 mmHg (ineffective swallows) in the distal esophagus ("old" IEM). A recent study with combined multichannel intraluminal impedance and manometry (MII-EM) raised the question whether the manometric diagnosis of IEM should be based on a new definition: > or = 50% ineffective liquid swallows ("new" IEM). The aim of this study was to evaluate the association between the number of ineffective liquid swallows and symptoms and bolus transit in patients with "new" or "old" IEM who underwent MII-EM studies using 10 liquid and 10 viscous swallows.', 'There were 150 patients with "old" IEM included in the study. The patients diagnosed with "old" IEM (N = 150) (group A) were compared with those who retained a manometric diagnosis of IEM by the new definition (N = 101) (group B). The patients who did not retain their manometric diagnosis of IEM by the new definition (N = 49) (group C) were compared with group B. IEM was characterized as mild (normal bolus transit for both liquid and viscous swallows), moderate (abnormal bolus transit either for liquid or viscous swallows), or severe (abnormal bolus transit for both liquid and viscous swallows).', 'There was no statistical difference in frequency of mild, moderate, or severe IEM and frequency of symptoms between group A and B. Group C had a significantly higher frequency of mild IEM and significantly lower frequency of severe IEM than group B. Heartburn (25.7%vs 10.2%, P= 0.03) and dysphagia (24.8%vs 12.3%, P= 0.08) showed a trend towards a greater frequency in group B than in group C.'] Is revised criterion for diagnosis of ineffective esophageal motility associated with more frequent dysphagia and greater bolus transit abnormalities?