Gastrointestinal (GI) motility refers to the movement of food and waste through the digestive tract. When this process is disrupted, it can lead to a range of uncomfortable and sometimes serious symptoms, such as bloating, nausea, constipation, diarrhea, abdominal pain, or difficulty swallowing. To diagnose the root of these symptoms, healthcare providers often turn to specialized tests that measure how well different parts of the GI tract are functioning.
Here’s a breakdown of the most used motility tests, what they evaluate, and what patients can expect.
Esophageal Manometry
Purpose: Evaluates the function of the esophagus and the lower esophageal sphincter (LES).
What It Involves: A thin, flexible catheter with pressure sensors is passed through the nose and into the esophagus. The patient swallows small amounts of water while the sensors measure muscle contractions along the esophagus.
Used to Diagnose:
- Achalasia
- Esophageal spasm
- Ineffective esophageal motility
- GERD-related motility issues
Duration: About 30–60 minutes.
24-Hour pH Monitoring (with or without impedance)
Purpose: Measures acid (and sometimes non-acid) reflux from the stomach into the esophagus.
What It Involves: A catheter is placed in the esophagus (or a wireless capsule may be attached during endoscopy) to record pH levels over 24 hours. Impedance testing can also detect the movement of non-acidic substances.
Used to Diagnose:
- Gastroesophageal reflux disease (GERD)
- Non-acid reflux
Duration: 24 hours of monitoring, with data downloaded and reviewed afterward.
Gastric Emptying Study (Scintigraphy)
Purpose: Measures how quickly food leaves the stomach.
What It Involves: The patient eats a standardized meal containing a small amount of radioactive material. A scanner tracks how quickly the stomach empties over several hours.
Used to Diagnose:
- Gastroparesis
- Functional dyspepsia
- Rapid gastric emptying (dumping syndrome)
Duration: 2–4 hours, sometimes up to 6.
SmartPill (Wireless Motility Capsule)
Purpose: Provides a comprehensive evaluation of transit times throughout the GI tract (stomach, small intestine, and colon).
What It Involves: The patient swallows a capsule that transmits data about pH, temperature, and pressure as it travels through the digestive system. No radiation is involved.
Used to Diagnose:
- Gastroparesis
- Slow-transit constipation
- Generalized motility disorders
Duration: The capsule typically passes within 1–5 days.
Colonic Transit Study
Purpose: Measures how long it takes stool to move through the colon.
What It Involves: Several types exist:
- Radiopaque marker test: The patient swallows a capsule containing markers visible on X-rays, which are taken over several days.
- Scintigraphy or SmartPill may also be used.
Used to Diagnose:
- Chronic constipation
- Colonic inertia
Duration: Usually completed over 5–7 days.
Anorectal Manometry
Purpose: Assesses the strength and coordination of the muscles used in bowel movements.
What It Involves: A small catheter with a balloon is inserted into the rectum. It measures pressure, sensation, and reflexes while the patient performs squeezing or pushing maneuvers.
Used to Diagnose:
- Dyssynergic defecation
- Fecal incontinence
- Pelvic floor dysfunction
Duration: About 30–45 minutes.
Defecography (Conventional or MRI)
Purpose: Provides visual imaging of the rectum and pelvic floor during simulated defecation.
What It Involves: A contrast material (or gel for MRI) is inserted into the rectum. The patient sits on a specialized toilet in front of an X-ray or MRI machine and is asked to bear down as if having a bowel movement.
Used to Diagnose:
- Rectocele
- Enterocele
- Anismus
- Rectal prolapse
Duration: 30–60 minutes.
GI motility tests play a crucial role in diagnosing functional gastrointestinal disorders, which often do not show up on standard imaging or blood tests. While some of these procedures may seem intimidating, they are usually low-risk and provide valuable insights that can guide effective treatment.
If you’re experiencing persistent digestive symptoms that have not been explained by routine exams, ask your gastroenterologist whether motility testing might be appropriate for you. Understanding how your gut moves could be the key to feeling better and getting back to living the life you want.
Citations.
CDC
National Institutes of Health and Human Services
UCLA Health
Motility Society