REVIEW ARTICLE Weak and absent peristalsis ANDRE ´ SMOUT* & MARK FOX  *Academic Medical Centre, Amsterdam, The Netherlands  NIHR Biomedical Research Unit, Nottingham Digestive Diseases Centre, QueenÕs Medical Centre, Nottingham, UK Abstract Background Weak and absent esophageal peristalsis are frequently encountered esophageal motility disorders, which may be associated with dysphagia and which may contribute to gastroesophageal reflux disease. Recently, rapid developments in the diagnostic armamentarium have taken place, in particular, in high-resolution manometry with or with- out concurrent intraluminal impedance monitoring. Purpose This article aims to review the current in- sights in the terminology, pathology, pathophysiology, clinical manifestations, diagnostic work-up,and management of weak and absent peristalsis. Keywords absent peristalsis, high-resolution mano- metry, impedance monitoring, ineffective esophageal motility, weak peristalsis. Motor abnormalities of the esophagus that fit the category Ôweak and absent peristalsisÕ are probably the least studied manifestations of esophageal dysfunction, likely because of the apparent lack of therapeutic options. It is important to recognize that the mano- metric diagnosis of esophageal hypomotility does not necessarily imply abnormal esophageal transit or pres- ence of symptoms, including dysphagia. DEFINITIONS AND TERMS Until 1997, the term Ônonspecific esophageal motor abnormalitiesÕ was generally used by physiologists to denote any dysmotility pattern that was not achalasia, spasm, nutcracker or LES dysfunction. Then, Leite and coworkers published their finding that Ôineffective esophageal motilityÕ (IEM) was the primary finding in patients with nonspecific esophageal motility disor- der. 1 In 2001, this was incorporated into Spechler and CastellÕs 2 classification of esophageal motor disorders, based on conventional manometry. In their classifi- cation, IEM was defined as distal-esophageal hypo- contractility in at least 30% of wet swallows, characterized either as low-amplitude peristaltic waves (<30 mmHg), low-amplitude simultaneous waves (<30 mmHg) or peristaltic waves that are not propagated to the distal-esophagus, or absent peristal- sis. The 30-mmHg criterion was derived from the observation that amplitudes <30 mmHg were fre- quently associated with bolus escape and incomplete bolus clearance. 3 High-resolution manometry (HRM), with or without concurrent intraluminal impedance monitoring, allows a more complete definition of peristalsis. In the recently developed Chicago classification, frequent failed peristalsis (>30% of wet swallows) is separated from weak peristalsis (defined as breaks in the 20- mmHg isobaric contour). Weak peristalsis with large defects is judged to be present when breaks >5 cm are present in >20% of swallows (Fig. 1). Weak peristalsis with small defects is present when breaks of 2–5 cm in length are present in >30% of swallows. 4 This classi- fication of manometric abnormalities as abnormal is also based on the likelihood that such defects are associated with esophageal dysfunction (i.e. bolus escape); however, the clinical relevance of such obser- vations remains uncertain. Indeed, it is likely that Address for Correspondence Andre ´ Smout MD, PhD, Department of Gastroenterology and Hepatology, Academic Medical Center, PO Box 22700, 1100 DE, Amsterdam, The Netherlands. Tel: +31 20 5669111; fax: +31 20 6917033; e-mail: a.j.smout@amc.uva.nl Received: 27 August 2011 Accepted for publication: 25 October 2011 Neurogastroenterol Motil (2012) 24 (Suppl. 1), 40–47 40 Ó 2012 Blackwell Publishing Ltd Neurogastroenterology & Motility