Heart Rate Variability in Children With a Functional Gastrointestinal Disorder

Chronic or recurrent abdominal pain in children is a very common complaint in children and
adolescents, and is most often associated with the presence of a functional gastrointestinal
disorder (FGID). It is likely that the clinical symptoms in FGIDs are the result of an
interaction between biologic, psychologic, and social factors. The psychologic factor most
implicated is chronic stress or anxiety. Stress may influence gastrointestinal function and
symptoms through altering the balance of the autonomic nervous system (ANS). Imbalance in
the ANS has potential effects on gastrointestinal mechanosensitivity, motor function (e.g.
stomach emptying and accommodation), and electrical rhythms. All of these can be associated
with abdominal pain. Theory and early evidence from studies done with healthy adult
populations suggest that ANS imbalance can reduce the body's ability to respond electrically
to food/water consumption. However, the relationships between chronic stress/anxiety, ANS
balance/imbalance, and electrical activity in the stomach before and after eating/drinking
remain to be fully explored in children with FGIDs. The current study is a two-part pilot
study designed to assess these relationships. Part I involves assessment of anxiety/stress
(i.e., BASC parent- and self-reports) along with ANS balance (i.e., heart rate variability)
and electrical activity in the stomach (i.e., electrogastrography) measured in the fasting
state and following a test meal. Part II involves the same assessments with rapid water
loading replacing the test meal. Results will be analyzed by specific FGID, as well as for
the group as a whole. We expect to enroll 75 children ages 8-17 in each part, including 30
healthy controls and 45 children with an FGID. Elucidating these relationships is a
necessary first step in developing more effective treatments for children with recurrent
abdominal pain and, ultimately, reducing the personal and societal costs of this common pain
entity.