BSGM to Evaluate Patients With GI Symptoms

Healthy children will be recruited to provide BSGM reference range data. Control data will be used to compute normative data ranges for each key BSGM metric before and after the test meal: slow wave direction, pattern, velocity, frequency, and amplitude.

For reference ranges:

• BMI-adjusted amplitude: normal reference range at 5-95% CI
• Rhythm-Index: normal reference range with cutoff <5% CI
• Frequency: 5-95% CI
• Fed: fasted amplitude ratio: <5% CI
• Slow wave pattern: descriptive

These outcomes will be measured via the myoelectric activity picked up by the BSGM device.

Abnormal BSGM patterns in participants with GI disorders will be measured by correlating physiological outcomes with symptoms. This will be done by correlating the spectral and spatial data of the stomach collected by the BSGM array with patient symptoms that are entered directly into a symptom-logging app throughout the duration of the BSGM study visit.

The FDI is a validated tool that uses child and parent-reported measure of limitations in children's physical and psychosocial functioning due to their physical health. The instrument consists of 15-items concerning activity limitations during the past two weeks. The four levels of disability are scored as followed: No/Minimal (0-12), Mild (13-20), Moderate (21-29) and Severe (≥30).

Nausea severity will be assessed by the subject's self-report responses on the Nausea severity scale (NSS) about chronic nausea. The NSS assesses four characteristics of nausea during the past two weeks: number of days with nausea, number of nausea episodes per day, typical nausea duration, and typical intensity of nausea episodes. A total score ranging from 0 - 4 represents the severity of nausea.

The correlation of abdominal pain to functional disability will be measured and quantified by the subject's response to the Abdominal Pain Index (API). The API assesses characteristics of abdominal pain during the previous 2 weeks including the number of days with pain, number of pain episodes per day, typical pain episode duration, and typical pain intensity. A total score ranging from 0 (no pain) to - 4 (severe pain) represents the severity of abdominal pain.

Quality of life will additionally be measured by the participant's completion of the Patient-Reported Outcomes Measurement Information System (PROMIS-25) pediatric profile instrument. The PROMIS-25 is a set of measures from 7 PROMIS domains that evaluate and monitor physical, mental, and social health. This instrument scores questions with a scale from 1 to 5.

Quality of life will additionally be measured by the completion of the Patient Assessment of Upper-GI Disorders Quality of Life (PAGI-QoL) instrument. The PAGI-QoL is a 30-item symptom assessment tool used to assess 6 domains to quantify QoL in adults who have upper GI distress. The PAGI-QoL will be given to subjects aged > 25 years. This instrument scores questions with a scale from 0 to 5.

Quality of life and patient reported outcomes will be measured by participants completion of the Pediatric Quality of Life Inventory (PedsQL) and the Pediatric Quality of Life Gastrointestinal Symptom Module Inventory (PedsQL-GI). The PedsQL and PedsQL-GI questionnaires are well-validated measures of child health-related quality of life for children. They are developmentally appropriate, with child self-report and parent-report instruments available for ages 2-25. Scores from each section of these questionnaires are transformed to a 0-100 scale with 0=100 and 4=0. The total score is then calculated by summing all the items over the number of items answered on all the scales.

The outcome of the BSGM test, the correlation of the spatial and spectral stomach data with patient symptoms, will be directly compared with the outcomes of each patient that has had a gastric scintigraphy. This will be done by directly comparing the BSGM metrics with the metrics of the gastric scintigraphy (% meal emptied/retained in the stomach, overall clinical assessment of gastric scintigraphy results).

Antoduodenal manometry is a diagnostic test that can be done at the same time as the BSGM study. The data collected by the BSGM study will be directly compared with the sensor data and the ADM for each patient.

A BSGM test will be done before and after subjects complete a series of heart rate variability biofeedback (HRVB) sessions. The BSGM patterns will be reviewed for any significant changes that may have been a result of the HRVB sessions.

A BSGM test will be done before and after subjects have percutaneous electrical nerve field stimulation (PENFS). The BSGM patterns will be reviewed for any significant changes that may have been a result of the PENFS sessions.

A BSGM test will be done before and after subjects have pyloric Botulinum toxin (Botox) injections. The BSGM patterns will be reviewed for any significant changes that may have been a result of the pyloric Botox injection.

A BSGM test will be done before GES placement and again while the GES is placed. The BSGM patterns will be reviewed for any significant changes that may be a result of the gastric electrical stimulator.

The outcome of the colonic BSGM test, the correlation of the spatial and spectral colonic data with patient symptoms, will be directly compared with the outcomes of healthy control subjects through descriptive statistics. An aggregate measure of BSGM will consist of: a stability metric, velocity (mm/s), frequency (cpm), and amplitude (µV).

Colonic BSGM patterns in participants with GI disorders will be correlated with gastrointestinal symptoms that are entered directly into a symptom-logging app throughout the duration of the study visit. Parameters inputted for each patient to this correlation model will include demographics, psychosocial variables (as above), and Colonic BSGM patterns. This model will be reported as an aggregate of demographics, psychosocial variables, and Colonic BSGM patterns.