Electrogastrograms Can Quantify Chronic Nausea

Electrogastrograms Can Quantify Chronic Nausea
Novel technology measures stomach neuromuscular activity.

Researchers at Vanderbilt University Medical Center and Monroe Carell Jr. Children’s Hospital at Vanderbilt have demonstrated that electrogastrograms, which reflect gastric function, can distinguish children with symptomatic chronic nausea from those without. Electrogastrograms provide high-resolution spatiotemporal characterization of neuromuscular electrical activity in the stomach.

This novel approach could inform and direct clinical decision-making for children with chronic nausea and may lead to further insight into the pathophysiology of this gastrointestinal (GI) disorder.

“One of the shortcomings in nausea research in the functional GI disorder field is that there is not an objective measure of nausea. It is merely a subjective description by the patient,” said Sari Acra, M.D., director of the Division of Pediatric Gastroenterology at Vanderbilt.

Impact of Functional GI Disorders and Nausea

The study, reported in Neurogastroenterology and Motility, was inspired by observations made during longitudinal studies of functional GI disorders in children led by Lynn Walker, Ph.D., who investigated functional GI disorders across a long career as chief of adolescent medicine in the Department of Pediatrics at Vanderbilt. Functional GI disorders are an array of different but related conditions, that typically include heightened visceral sensitivity or disordered movement of the GI tract, chronic diarrhea or constipation, and functional nausea.

“We found that children who have nausea as a component of a functional GI disorder had worse symptoms and symptoms that potentially extended into adulthood,” Acra said. “Nausea plus abdominal pain is much worse than just abdominal pain. So, when that component is present, children’s quality of life diminishes significantly due to functional disability, meaning missed school, work, or other activities.”

“We found that children who have nausea as a component of a functional GI disorder had worse symptoms and symptoms that potentially extended into adulthood.”

Collaboration Cultivates New Techniques

Another Vanderbilt faculty member, Alexandra Russell, M.D., an assistant professor of pediatrics, established the Nausea Program at Vanderbilt, providing a dedicated clinic for functional nausea care and research, ultimately including the present study.

At just the right moment, Acra attended a seminar by physicist and clinical researcher L. Alan Bradshaw, Ph.D., director of Gastrointestinal SQUID Technology Laboratory at Vanderbilt, who discussed a highly sensitive device capable of noninvasive measurements of both electrical activity and magnetic fields in the human GI tract called the SQUID (Superconducting Quantum Interference Device).

The resulting collaboration – led by Bradshaw and including Russell, Walker, and Acra as well as Suseela Somarajan, Ph.D., a biomedical engineer at Vanderbilt – has yielded not only the first high-resolution pediatric electrogastrograms, using 25 cutaneous electrodes compared to only one or four electrodes traditionally, but also novel data analysis techniques to filter extraneous electrical signals, such as those from the heart and intestines.

The First High-resolution Electrogastrograms in Children

In their latest study, the team evaluated chronic nausea symptoms via validated scales and measured high-resolution electrogastrograms in 10 pediatric patients with chronic nausea and 10 healthy children. They found parameters for gastric slow wave activity, which determine the functional status of peristalsis and digestion, were abnormal and indicated slow wave uncoupling in patients with chronic nausea relative to the controls.

“Functional nausea is definitely worth tackling, because of its underrecognized impact on the quality of life of both children and adults.”

Among children with nausea, the high-resolution electrogastrograms revealed retrograde, anterograde, and disrupted propagation patterns, and significant differences in the mean slow wave propagation direction prior to eating.

The team is hoping to look at various approaches, independently or combined, to treat these abnormal slow wave patterns and the associated nausea. These include medications, mind-body therapies (e.g. guided imagery and meditation), and modulation of input nerves to the stomach. “Functional nausea is definitely worth tackling, because of its underrecognized impact on the quality of life of both children and adults,” Acra said.

High-resolution electrogastrogram measurements may also be useful for monitoring and treating nausea in other situations, he added, such as post chemotherapy.