For example, a new subclass of achalasia was defined by HRM. In this classification, achalasia is divided into types 1, 2 and 3. Type 1 corresponds to classic achalasia (complete esophageal motor failure), type 2 is a compression achalasia (simultaneous panesophageal pressurization with aperistalsis), and type 3 is spastic achalasia with aperistalsis (100% spasm). However, it is unclear if this categorization represents a spectrum of disease among patients with achalasia, or it represents distinct subgroups of patients with different symptom presentation and etiology.