"Motility" is a term used to describe the contraction of the muscles that mix and propel contents in the gastrointestinal tract. The gastrointestinal tract is divided into four distinct parts that are separated by sphincter muscles; these four regions have distinctly different functions to perform and different patterns of motility (contractions). They are the esophagus (carries food to the stomach), stomach (mixes food with digestive enzymes and grinds it down into a more-or-less liquid form), small intestine (absorbs nutrients), and colon (reabsorbs water and eliminates indigestible food residues). Abnormal motility or abnormal sensitivity in any part of the gastrointestinal tract can cause characteristic symptoms. 
The most frequent symptoms of GERD, heartburn and acid regurgitation, are so common that they may not be associated with a disease. Self-diagnosis can lead to mistreatment. Consultation with a physician is essential to proper diagnosis and treatment of GERD.
Various methods to effectively treat GERD range from lifestyle measures to the use of medication or surgical procedures. It is essential for individuals who suffer persistent heartburn or other chronic and recurrent symptoms of GERD to seek an accurate diagnosis, to work with their physician, and to receive the most effective treatment available.
Intestinal dysmotility, intestinal pseudo-obstruction
Abnormal motility patterns in the small intestine can lead to symptoms of intestinal obstruction. Symptoms of bloating, pain, nausea, and vomiting can result either from weak contractions or from disorganized (unsynchronized) contractions.
Small bowel bacterial overgrowth
Too many bacteria in the upper part of the small intestine may lead to symptoms of bloating, pain, and diarrhea. Symptoms occur immediately after eating because the bacteria in the intestine begin to consume the food in the small intestine before it can be absorbed. Small bowel bacterial overgrowth is a result of abnormal motility in the small intestine.
The symptoms of constipation are infrequent bowel movements [usually less than 3 per week], passage of hard stools, and sometimes difficulty in passing stools. One motility problem that can lead to constipation is a decrease in the number of high amplitude propagating contractions [slow transit] in the large intestine. The test used to detect this is a transit time (Sitzmark) study.
Outlet obstruction type constipation (pelvic floor dyssynergia)
The external anal sphincter, which is part of the pelvic floor normally stays tightly closed to prevent leakage. When you try to have a bowel movement, however, this sphincter has to open to allow the fecal material to come out. Some people have trouble relaxing the sphincter muscle when they are straining to have a bowel movement, or they may actually squeeze the sphincter more tightly shut when straining. This produces symptoms of constipation.
The symptoms of diarrhea are frequent, loose or watery stools, and a subjective sense of urgency. An excessive number of high amplitude propagating contractions [rapid transit] can be a cause of diarrhea; it reduces the amount of time food residues remain in the large intestine for water to be reabsorbed. Changes in the motility of the small intestine may also occur, but there is little information available on this.
Fecal incontinence means involuntary passage of fecal material in someone over the age of 4 years. The most common causes are (a) weakness of the anal sphincter muscles; (b) loss of sensation for rectal fullness; (c) constipation, in which the rectum fills up and overflows; and (d) stiff rectum, in which the fecal material is forced through the rectum so quickly that there is no time to prevent incontinence by squeezing the sphincter muscles. Diarrhea can also lead to fecal incontinence.
There are actually two anal sphincter muscles: an internal anal sphincter that is part of the intestines, and an external anal sphincter that is part of the pelvic floor muscles. The internal anal sphincter normally stays closed to prevent the leakage of gas or liquid from the rectum, but when the rectum fills up with gas or fecal material, a reflex causes it to open to allow the bowel movement to pass through. The nerves that this reflex depends on are sometimes missing at birth, with the result that the internal anal sphincter stays tightly closed and bowel movements cannot occur. This congenital (birth) defect is called Hirschsprung's disease.
Gastroparesis is a disorder in which the stomach takes too long to empty its contents. No obstruction or blockage is evident. In the majority of people diagnosed with gastroparesis, the cause is unknown (idiopathic). Diabetes is the most common known cause of gastroparesis. The condition can also result as a complication from some surgical procedures. Most people with gastroparesis experience nausea and vomiting. Many have abdominal discomfort or pain, which can range from bothersome to debilitating. Other prominent symptoms include bloating, fullness after eating, or early fullness (satiety) – the inability to finish a meal. These symptoms may be mild or severe, depending on the person. In most cases treatment does not cure gastroparesis – it is usually a chronic condition. However, in most people treatment does help manage the condition.
Achalasia is an esophageal motility disorder. It is diagnosed when there is a complete lack of peristalsis within the body of the esophagus. The lower esophageal sphincter does not relax to allow food to enter the stomach. Symptoms are difficulty swallowing both liquids and solids. Many people also have associated regurgitation, vomiting, weight loss, and atypical chest discomfort.
For more information about motility, please visit the IFFGD website at www.aboutgiMotility.org
- Whitehead WE. Gastrointestinal Motility Disorders of the Small Intestine, Large Intestine, Rectum, and Pelvic Floor. IFFGD Fact Sheet No. 162; 2001.