Classification of esophageal motility disorders based on the underlying cause:
1) Primary: Achalasia (type I, II, and III); major disorders of esophageal peristalsis including distal esophageal spasm (formerly diffuse esophageal spasm) and hypercontractile (jackhammer) esophagus (previously nutcracker esophagus); other nonspecific abnormal motility patterns.
2) Secondary: In the course of scleroderma, diabetes mellitus, alcohol abuse, psychiatric disorders, Chagas disease, and associated with aging.
The Chicago classification of esophageal motility disorders based on the result of high-resolution manometry:
1) Incomplete relaxation of the lower esophageal sphincter: Achalasia or obstruction within the esophagus-gastric junction.
2) Significant motor disorders: Lack of contractility, contraction of the distal part of the esophagus, excessively contractile esophagus.
3) Mild motor disorders: Ineffective motor activity or segmental peristalsis.
4) Normal esophageal peristalsis.