Diagnosis is reached with esophageal manometry and barium swallow radiographic studies. The acoustic stapedius reflex can also be recorded by means of extratympanic manometry (ETM). The diagnosis is generally confirmed by esophageal manometry. The gold standard investigation is a 24 hours manometry of oesophagus. Some have advocated the use of anorectal physiology testing (anorectal manometry). The oxygen uptake is detected by manometry. Specific tests for achalasia are barium swallow and esophageal manometry. Diagnostic techniques involve anorectal manometry, barium enema, and rectal biopsy. Other tests rarely ordered include anorectal manometry, anal sphincter electromyography, and defecography. Antroduodenal manometry may also be used to evaluate motility. The temperature is taken via a thermometer and pressure is calculated using manometry. Anorectal manometry may help to differentiate acquired from congenital forms. Rhinomanometry is a form of manometry used in evaluation of the nasal cavity. Anorectal manometry is a technique used to measure contractility in the anus and rectum. DES and nutcracker esophagus present similarly and can may require esophageal manometry for differentiation.