Comparison of a New Non-invasive Device With the Current Invasive Gold-standard Investigation to Assess Movement and Function of the Large Bowel in Children

Validation of Body Surface Colonic Mapping, a Non-invasive Tool for Assessing Colonic Motility in Children

The goal of this clinical trial is to learn if the new non-invasive device (Body Surface Colonic Mapping) works to accurately assess colonic movement and function in children.The main questions it aims to answer are:

• Are Body Surface Colonic Mapping (BSCM) recordings comparable with gold-standard colonic manometry recordings (HRCM - High Resolution Colonic Manometry) in the paediatric population?
• What are the effects of bowel preparation on colonic function assessed using BSCM?

Children with clinical recommendation of colonic and/or anorectal manometry (clinical tests used to assess colonic function) for investigation of persistent bowel dysfunction symptoms will be invited to participate. We will perform and compare simultaneous recordings of manometry and BSCM in children, in order to demonstrate same colonic function measurements recorded by the two devices in this population. Eligible participants who consent to inclusion in the study will undergo colonoscopy and placement of a large bowel catheter, according to usual Royal Children's Hospital (RCH) practice. These involve administration of oral laxatives for bowel preparation and maintaining a clear fluids diet 24 hours prior to the investigation.

Ahead of the simultaneous devices recordings, patients will also be invited to attend the hospital 2-4 weeks prior to have non-invasive BSCM recording only. The aim of this part of the study is to have a BSCM recording in the same patient once with the "physiological state" colon (early hospital visit without any bowel preparation administration) and once with the "non-physiological state" colon (time of colonoscopy, colonic manometry and BSCM with bowel preparation).

Potential participants will be identified by RCH surgeon, Prof. Sebastian King (Paediatric Colorectal Surgeon). Patients will be identified following outpatient review or referral to RCH (Department of Paediatric Surgery), when colonic motility assessment is recommended for investigation of bowel dysfunction. All patients will be reviewed in clinic by an independent paediatric gastroenterologist (Dr Mark Safe), who has undergone post-fellowship training in the assessment of paediatric gastrointestinal motility.

All patients planned to undergo colonic motility assessment will be screened for study eligibility. Screening for eligibility will be undertaken by study investigators the electronic medical record (EPIC).

Once identified, patients will be reviewed in the monthly motility clinic with Prof. King and Dr Safe, which is part of the standard of care at RCH prior to colonic manometry. At that time, after completion of the clinical review, families and patients will be given verbal information about the opportunity to take part to the research study while undergoing colonic manometry. Further information about the study (Recruitment letter and Participant information) will be emailed to them after the consultation. This will follow-up with a phone call to the family by Dr Comella after a week to establish if the family and patient are interested in taking part to the research study. If consenting, this will be documented and the relevant hospital admissions organised. Written consent will be obtained on the day of the first in-person appointment. It will be explicit in the initial and all subsequent contact that there is no imperative for the child to participate; patient care will not be compromised by electing not to participate in the project.

Participants will be able to stop the study at any time they would like if they do not want to complete it. They will be undertaking colonic manometry as part of their clinical indication by their physician, who will run the test to gain information for their clinical management. The BSCM data will be part of the research project, which aims to compare these data to the current colonic motility assessment gold-standard that is colonic manometry. The family or patient can stop the research side of the study at any stage.

Participants will not receive incentives or compensation for participation.

As previously specified, eligible participants who consent will undergo colonoscopy and placement of the colonic motility catheter for colonic manometry, according to usual RCH practice as per their clinical indication for the test. This is the current gold-standard of care for colonic motility assessment. The study recruits patients that are already undertaking colonic manometry as part of their clinical care. These data will therefore be clinical data that will be recorded independently from the research project. The research project aims to ask the families to be willing for those recordings to be used for research purposes as well and be compared to BSCM recordings that would be taken at the same time as colonic manometry if the family/patient are willing to consent to the research study. If participating in the research study, the family/patient will be asked to also attend a hospital appointment to have BSCM recording only a couple of weeks ahead of the HRCM/BSCM recording, in order to have BSCM data from the same patient with the unprepared and prepared colon.

BSCM includes a sticky grid pad device connected to a reader that detects bowel motility. The application of body surface mapping in paediatric populations is supported by established research. Humphrey et al. (2026) successfully utilized gastric body surface mapping in a cohort of 107 patients aged 12-17. Furthermore, subsequent data from Dr. Humphrey's doctoral research (currently pending peer-review) demonstrates that the electrode array is effective in children as young as 5 years of age.

Adaptability for Paediatric Use:

To accommodate the smaller physical stature of younger patients, the surface electrode array is designed to be customized (cut to fit) the child's abdominal dimensions without compromising signal integrity.

As previously stated, BSCM includes a sticky grid pad device connected to a reader that detects bowel motility. Under the initial guidance of a consultant from Alimetry, Dr. Comella will oversee the application of the BSCM electrode array to the patient's abdomen. This is a standardised, non-invasive procedure that has been safely performed on hundreds of adult patients.

1. Simultaneous HRCM and BSCM Recording:

   For patients undergoing concurrent colonic manometry, an abdominal X-ray is already standard clinical practice to verify the precise anatomical location of the catheter sensors. During these sessions:

   • The BSCM array will be positioned on the abdomen directly over the catheter.
   • Specific care will be taken to ensure the array is aligned to capture signals from the descending and sigmoid colon.

2. Standalone (Unprepared Colon) Recording

When recording from the unprepared colon (where no manometry catheter is present), no X-ray will be taken, minimizing unnecessary radiation exposure. Instead, placement will rely on established anatomical landmarks:

• Positioning: The array will be cantered 2-4 cm to the left of the midline on the lower abdomen.
• Orientation: The lower boundary of the array will typically align with the patient's waistline.

The device will be on the patients' abdomen until for the whole duration of the investigation.

To be useful as a diagnostic tool, BSCM must detect and differentiate two major types of motility:

1. high amplitude propagating contractions (HAPC);
2. cyclic motor patterns.

Clinical Benchmarks for Response:

We will apply our established manometric criteria to the BSCM data to determine clinical significance:

• Meal Response: a > 20% increase in MI.
• Pharmacological Response: a > 60% increase in MI following bisacodyl administration.

Validation Strategy:

Beyond the numerical MI, our analysis will compare the timing and duration of the contractile increases across both modalities. This methodology mirrors a recent study involving combined colonic manometry and BSCM in adults with chronic constipation; a study currently under its second revision with the American Journal of Gastroenterology.

Preliminary studies by Professor Greg O'Grady in healthy adults showed BSCM could detect an electrical increase in activity after a meal and this was later correlated with colonic manometry . There is also evidence that BSCM can detect a laxative stimulant-induced HAPC using bisacodyl. This is a hugely important step because it means that, in adults, it is possible to identify distinct spectral signatures that represent the two commonly recorded manometry signals. All these data are from studies carried in an adult population. There is now need to show the same recording may be made in children and then develop the automated algorithms to reliably extract these signals, similar to what has already been achieved with body surface gastric mapping in people aged 12yo and older.

Inclusion Criteria:

1. Is aged 18 years or less at enrolment.
2. Has undergone a repeat rectal biopsy to exclude a retained segment of aganglionic colon (Hischsprung disease (HD) cohort only).

Exclusion Criteria:

1. Has undergone primary surgical repair of HD or (anorectal malformation (ARM) within 12 months of the study. Is less than twelve months following primary surgical correction of HD or ARM (HD or ARM cohorts only).

2. Has a prior diagnosis of:

   i. Intellectual disability or a spinal abnormality, such that continence is unlikely to be attainable; ii. Malignant (cancer) conditions, receiving chemotherapy; iii. GMFCS IV or V.

3. Is unable to attend for and/or engage in consent process or assessments, including due to language restriction.