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GI Motility Research Laboratory

Gastrointestinal disorders, dysphagia, constipation,
faecal incontinence...

Video-Manometric findings consistent
with Pharyngeal Weakness


Research Summary

Functional gastrointestinal disorders (FGID) include abdominal pain, dysphagia (difficulty in swallowing), irritable bowel syndrome, diarrhoea and constipation. These chronic conditions induce major economic and social burdens because of their prevalence in society and their dramatic impact upon quality of life. Our GI motility research laboratory is at the forefront of the development of novel objective methods to assess swallowing and colonic disorders and their pathophysiology. Using state-of-the-art recording techniques of high-resolution impedance manometry and high-resolution fibre-optic manometry our methods quantify pressure and diameter profiles recorded within the gut and employ innovative analytical software to unlock a wealth of physiologically relevant information. These data highlight structural abnormalities, dysfunctions of neuro-sensory, and/or neuro-motor mechanisms. The accurate diagnosis of the pathophysiology in the pharynx, oesophagus or colon is critical to providing timely and appropriate treatments for FGID.


Upper GI - Taher Omari.

Lower GI - Phil Dinning.


Research Projects

Mechanical impacts of colonic dysmotility in patients with functional colonic disorders
Faecal incontinence, constipation and irritable bowel syndrome cause significant medical, societal and financial burdens. Altered colonic motility is implicated and these changes contributes to the troubling, distressful and at times embarrassing symptoms. Through state-of-the-art techniques, developed by our group, our research combines human and animal studies to provide the first clear description of colonic contractile abnormalities in these patients and how they contribute to the symptoms.

Oro-pharyngeal dysphagia is a commonly encountered co-morbidity of any disease or condition that affects the neural control and/or contractility of muscles of the head and neck or alters oro-pharyngeal anatomy. There is a need for our understanding of paediatric dysphagia to be grounded in detailed knowledge of swallowing biomechanics, physiology and pathophysiology. This ‘value-adding’ information will be critically important for generating sound hypotheses for clinical trials of tailored interventions. This project will establish a new point-of-care diagnostic paradigm-shift that elucidates dysphagia pathophysiology through the understanding of swallowing biomechanics. The project will have wide-ranging significance to paediatric dysphagia in terms of i) better understanding of pathophysiology, ii) better treatment outcomes through hypothesis-driven research, iii) improved quality of life through avoidance of unnecessary procedures and reduced reliance on long-term x-ray.

Utilising high resolution impedance manometry to diagnose and manage oesophageal dysfunction in children with oesophageal atresia
Oesophageal atresia (OA) is the most significant congenital oesophageal anomaly. Despite successful repairs in infancy, 85% of OA patients will have ongoing dysfunction in adulthood. Morbidity and mortality all relate to dysmotility, which is caused by a combination of congenitally impaired neural innervation and narrowing at the anastomotic (join) site of surgical repair. The resultant reduction in oesophageal wall compliance leads to poor transport of food boluses, choking events and, in some cases, death.
Currently we are unable to reliably predict which patients will develop dysmotility. Therefore, we are also unable to prevent the consequences of dysmotility. The advent of new technology, namely high resolution impedance manometry (HRIM), now allows accurate and reliable measurements of oesophageal wall compliance. This project will use HRIM to develop, for the first time, an understanding of how compliance relates to food bolus transport, what factors affect compliance, and how compliance changes over time. Through this we will develop a strategy for predicting and preventing morbidity and mortality that will be applicable nationally and internationally.

Dysphagia complicating acute stroke is common, infers a poorer outcome. It carries significant morbidity and mortality which is dictated in large part by dysphagia-related pulmonary aspiration. Existing techniques (bedside evaluation, MBS) lack accuracy in predicting aspiration-related complications and their sequelae; both in hospital and in the longer term. This project will determined whether objective biomechanical measures of pharyngeal swallowing can predict clinical outcomes in this population. The validation of a new technique as a predictor of poor short and long term outcome would profoundly influence management by impacting directly: a) feeding management and nutrition; b) decision making and cost implications of institution of non-oral feeding (eg PEG placement); c) follow up care and timing of PEG removal where appropriate.

Pharyngeal Augmentation for Dysphagia (PAD) Therapy: A Novel Surgical Approach to Dysphagia Management

Figure  – Video-Manometric findings consistent with Pharyngeal Weakness.
Pharyngeal contractile pressures in a 63 year old male patient 10 w after completion of chemo-radiotherapy for a T4 tonsillar SCC. The patient is currently complaining of pharyngeal stasis with solids. Radiological images 1-4 above clearly show failure of the tongue base to close (arrow in image 3) and post-swallow residue in the valleculae (arrow in image 4). The simultaneously recorded pharyngeal manometry plot is shown below. Here the lower pressures are blue in colour and higher pressures are yellow and red in colour. Pharyngeal weakness is indicated by contractile integrals that are at the lower end of the normative range.

Head and neck cancer patients develop significant injury to normal tissues following curative chemoradiation therapy. Dysphagia (swallowing problems) is a common co-morbidity that can range from being mild to severe and requiring total enteral nutrition. It has been reported that in up to 70% of head and neck cancer patients, chronic oropharyngeal dysphagia can persist to 12 months post-chemoradiation.
Treatment strategies to mitigate dysphagia following head and neck cancer therapy include prophylactic exercises to use and strengthen the swallowing muscles during and after treatment. Unfortunately targeted swallowing exercises have had only limited impact on dysphagia symptoms and therefore new approaches are needed.
Our research group has developed High Resolution Manometry to assess pressures generated throughout the pharynx during swallowing. This technique can objectively diagnose pharyngeal weakness and can precisely identify the site of weakness by separating the pharyngeal contractile sequence into its sub-components. We have identified that patients with dysphagia often present with weak, but appropriately sequenced, pharyngeal pressures. This indicates poor force generation capacity of the pharyngeal muscles and post-swallow pharyngeal residue is prevalent in such patients.
We will evaluate a novel therapeutic surgical approach called Pharyngeal Augmentation for Dysphagia (or PAD therapy) designed to improve luminal force generation by the pharynx. This pilot study will characterise, in dysphagic head and neck cancer patients, the effect of pharyngeal augmentation, on swallowing biomechanics, radiological signs and dysphagia symptoms.

This project will develop a specific world wide web-based platform for software called “AIMplot” which is now routinely used for the assessment of swallowing physiology and in the diagnosis of dysphagia (swallowing difficulty) which can occur for many reasons, in people of all ages. 
AIMplot will process pressure and impedance (flow) recordings acquired using existing technologies used to measure swallowing function in the clinic or at the bedside. AIMplot software derives unique pressure-flow variables which have already been shown to objectively assess swallowing within the context of age and illness. AIMplot gives a better understanding of swallowing physiology allowing physicians to more rapidly implement patient management strategies with the goal of improving clinical outcomes.
The Flinders research team was recently nominated as a finalist for a 2016 Eureka Prize in the category of Innovation in Medical Research for the development of the AIMplot analysis software.

Selected Publications

Costa M, Wiklendt L, Keightley L, Brookes SJH, Dinning PG, Spencer NJ (2017) New insights into neurogenic cyclic motor activity in the isolated guinea-pig colon. Neurogastroenterol Motil. [Epub ahead of print]


Omari TI, Savilampi J, Kokkinn K, Schar M, Lamvik K, Doeltgen S, Cock C (2017) The Reliability of Pharyngeal High Resolution Manometry with Impedance for Derivation of Measures of Swallowing Function in Healthy Volunteers. International Journal of Otolaryngology. [Epub ahead of print]


Shepheard SR, Wuu J, Cardoso M, Wiklendt L, Dinning PG, Chataway T, Schultz D, Benatar M, Rogers ML (2017) Urinary p75ECD: A prognostic, disease progression, and pharmacodynamic biomarker in ALS. Neurology, 88(12):1137-1143


Cock C, Jones CA, Hammer MJ, Omari TI, McCulloch TM (2017) Modulation of Upper Esophageal Sphincter (UES) Relaxation and Opening During Volume Swallowing. Dysphagia, 32(2):216-224


Carlson DA, Omari T, Lin Z, Rommel N, Starkey K, Kahrilas PJ, Tack J, Pandolfino JE (2017) High-resolution impedance manometry parameters enhance the esophageal motility evaluation in non-obstructive dysphagia patients without a major Chicago Classification motility disorder. Neurogastroenterol Motil, 29(3)


Dinning PG (2016) Recording In Vivo Human Colonic Motility: What Have We Learnt Over the Past 100 Years? Adv Exp Med Biol, 891:213-222


Omari TI, Jones CA Ms, Hammer MJ, Cock C, Dinning PG, Wiklendt L, Costa MC, McCulloch TM (2016) Predicting the Activation States of the Muscles Governing Upper Esophageal Sphincter Relaxation and Opening. Am J Physiol Gastrointest Liver Physiol, 310(6):G359-66


Dinning PG, Carrington EV, Scott SM (2016) Colonic and anorectal motility testing in the high resolution era. Current Opinion in Gastroenterology, 32(1):44-8


Omari TI, Jones CA Ms, Hammer MJ, Cock C, Dinning PG, Wiklendt L, Costa MC, McCulloch TM (2016) Predicting the Activation States of the Muscles Governing Upper Esophageal Sphincter Relaxation and Opening. American Journal of Physiology-Gastrointestinal and Liver Physiology, 310(6):G359-66.


Dinning PG, Sia TC, Raghu S, Rosli RM, Kyloh M, Wattchow DA, Wiklendt L, Brookes SJ, Costa M, Spencer NJ (2016) High-resolution colonic motility recordings in vivo compared with ex vivo recordings after colectomy, in patients with slow transit constipation. Neurgastroenterology & Motility, 28(12):1824-1835


Leibbrandt RE, Dinning PG, Costa M, Cock C, Wiklendt L, Wang G, Tack J, van Beckevoort D, Rommel N, Omari TI (2016) Characterization of Esophageal Physiology Using Mechanical State Analysis. Frontiers in Systems Neuroscience, 10:10


Arkwright JW, Underhill ID, Dodds KN, Brookes SJH, Costa M, Spencer NJ & Dinning PG (2016) A composite fibre optic catheter for monitoring peristaltic transit of an intra-luminal bead. Journal of Biophotonics, 9(3):305-10


Ferris L, Rommel N, Doeltgen S, Scholten I, Kritas S, Abu-Assi R, McCall L, Seiboth G, Lowe K, Moore D, Faulks J, Omari T (2016) Pressure Flow Analysis for Assessment of Pediatric Oropharyngeal Dysphagia. J Pediatr, 177:279-285


Wessel S, Koppen IJN, Wiklendt L, Costa M, Benninga MA, Dinning PG (2016) Characterizing colonic motility in children with chronic intractable constipation; a look beyond high amplitude propagating sequences. Neurogastroenterol Motil, 28(5):743-57


Cock C, Besanko L, Kritas S, Burgstad CM, Thompson A, Heddle R, Fraser RJL, Omari TI (2016) Impaired bolus clearance in asymptomatic older adults during high resolution impedance manometry. Neurogastroenterol Motil, 28(12):1890-1901


Patton V, Stewart P, Lubowski D, Cook I, Dinning PG (2016) Sacral nerve stimulation fails to offer long-term benefit in patients with slow transit constipation. Dis Colon Rectum, 59: 878-885


Doeltgen SH, Omari TI (2016) Correlating stroke lesion location with clinical outcomes – an example from deglutition research. Eur J Neurol, 23(7):1139-40


Spencer NJ, Dinning PG, Brookes SJ, Costa M (2016) New insights into the mechanisms underlying colonic motor patterns. J Physiol, 594(15):4099-116


Savilampi J, Omari T, Magnuson A and Ahlstrand R (2016) Effects of remifentanil on pharyngeal swallowing : A double blind randomized cross- over study in healthy volunteers. Eur J Anaesthesiol, 33(9):622-30


Zhang T, Szczesniak M, Maclean J, Bertrand P, Wu PI, Omari T, Cook IJ (2016) Biomechanics of Pharyngeal Deglutitive Function Following Total Laryngectomy. Otolaryngol Head Neck Surg, 155(2):295-302


Doeltgen S, Omari TI, Savilampi J (2016) Remifentanil alters sensory neuromodulation of swallowing in healthy volunteers: Quantification by a novel pressure-impedance analysis. American Journal of Physiology-Gastrointestinal and Liver Physiology. 310(11):G1176-82.


Vather R, O’Grady G, Cheng L, Arkwright J, Rowbotham D, Dinning PG, Bissett I (2016) Restoration of normal colonic motor patterns and meal responses after distal colorectal resections. British Journal of Surgery, 103:451-461


Omari TI, Wiklendt L, Dinning P, Costa M, Rommel N, Cock C (2015) Upper esophageal sphincter mechanical states analysis: A novel methodology to describe UES relaxation and opening. Frontiers in Systems Neuroscience, 8:241


Dinning PG, Wiklendt L, Maslen L, Patton V, Lewis H, Arkwright JW, Wattchow DA, Lubowski DZ, Costa M, Bampton PA (2015) Colonic motor abnormalities in slow transit constipation defined by high-resolution, fiber-optic manometry. Neurgastroenterology & Motility, 27(3):379-88


Dinning PG, Hunt LM, Patton V, Zhang T, Szczesniak MM, Gebski V, Jones M, Stewart P. Lubowski DZ,  Cook IJ (2015) Treatment efficacy of sacral nerve stimulation in slow transit constipation: A randomized, 2-phased, double -blind, placebo-controlled, crossover study. American Journal of Gastroenterology, 110(5):733-40


Dinning PG, Wiklendt L, Omari T, Arkwright JW, Spencer NJ, Brookes SJ, Costa M (2014) Neural mechanisms of peristalsis in the isolated rabbit colon: a neuromechanical loop hypothesis. Autonomic Neuroscience, 8:(Article 75)


Dinning PG, Wiklendt L, Maslen L, Gibbins I, Patton V, Arkwright JW, Lubowski DZ, O’Grady G, Bampton PA, Brookes SJ, Costa M (2014) Quantification of in vivo colonic motor patterns in healthy humans before and after a meal revealed by high-resolution fibre-optic manometry. Neurgastroenterology & Motility, 26(10):1442-1457



  • Taher Omari, PhD, BSc(Hon)

  • Phil Dinning, PhD, BSc(Hon)

Support Staff

  • Ann Schloithe, Technical Officer


  • Charles Cook, PhD Student

  • Lara Ferris, PhD Student

  • Helen Dockrell, PhD Student

  • Reizal Mohd Rosli, PhD Student

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