Clinical Trials

Clinical Trials

In the late 1990’s Dr. Shaheen Hamdy and his group were able to demonstrate for the first time that delivering Pharyngeal Electrical Stimulation (PES) to the nerves in the throat could result in therapeutic changes in the brain. Most importantly they showed that the positive changes they were able to cause in the brain still remained even when the stimulation was stopped. This groundbreaking research was published in one of the most prestigious scientific journals in the world read more – Nature Neuroscience 1998 May;1(1):64-8.

Clinical studies in patients soon followed and it was shown that the positive changes in the brain also led directly to improvements in swallowing function in patients with dysphagia. A very significant reduction in the amount of food or liquid accidentally entering the patients airways could be seen after treatment read more – Neuron. 2002 May 30;34(5):831-40.

The clinical trial found that after pharyngeal stimulation over 75% of patients recovered the ability to swallow safely. They showed improvements in oral nutritional intake and were able to eat more independently.

The study also found that patients who received pharyngeal stimulation left hospital an average of 5 days sooner than patients who didn’t read more.

There were no adverse events reported during any of the clinical trials. Phagenesis® is committed to ongoing research and development that will transform the lives of people with dysphagia.


Hamdy S, Aziz Q, Rothwell JC, et al. The cortical topography of human swallowing musculature in health and disease. Nat Med 1996; 2: 1217-1224 read more.

Hamdy S, Aziz Q, Rothwell JC, et al. Explaining oropharyngeal dysphagia after unilateral hemispheric stroke. Lancet 1997; 350: 686-692 read more.

Hamdy S, Aziz Q, Rothwell JC, et al. Recovery of Swallowing after Dysphagic Stroke Relates to Functional Reorganisation in Intact Motor Cortex. Gastroenterology 1998; 115: 1104-1112 read more.

Hamdy S, Rothwell JC, Aziz Q, Sigh Kd, Thompson DG. Long-term reorganization of human motor cortex driven by short-term sensory stimulation. Nat Neurosci 1998; 1: 64-68 read more.


Fraser C, Hamdy S, Power M, et al. Driving Plasticity in Adult Human Motor Cortex Improves Functional Performance after Cerebral Injury. Neuron 2002; 34: 831-840 read more.

Singh S, Hamdy S, et al. Dysphagia in stroke patients. Postgrade Med J 2006 Jun;82(968):383-91 read more.

Jayasekeran V, Singh S, Tyrrell P, et al. Adjunctive functional pharyngeal electrical stimulation reverses swallowing disability after brain lesions. Gastroenterology 2010; 138: 1737-1746 read more.


Mistry S, Michou E, et al. Direct and Indirect Therapy: Neurostimulation for the Treatment of Dysphagia After Stroke. In: Ekberg O. (eds) Dysphagia. Medical Radiology. Springer, Berlin, Heidelberg 2011 read more.

Geeganage C, Beavan J, et al. Interventions for dysphagia and nutritional support in acute and subacute stroke. Cochrane Database Syst Rev. 2012 Oct 17; 10:CD000323 read more.

Restivo DA, Casabona A, Centonze D, et al. Pharyngeal electrical stimulation for dysphagia associated with multiple sclerosis: a pilot study. Brain Stimulation Volume 6, Issue 3 2013 418 – 423 read more.

Michou E, Mistry S, Jefferson S, et al. Characterising the mechanisms of central and peripheral forms of neurostimulation in chronic dysphagic stroke patients. Brain Stimulation 7 (2014) 66-73  read more.

Suntrup S, Marian T, Schröder J B, et al. Electrical pharyngeal stimulation for dysphagia treatment in tracheotomized stroke patients: a randomised controlled trial. Intensive Care Medicine , Volume 41, Issue 9, pp 1629-1637 read more

Aida S, Ryosuke T, Magaia J, et al. Peripheral and central control of swallowing initiation in healthy humans. Physiology & Behaviour 151 (2015) 404-411 read more.

McLaughlin C, Gilzeane N, Rehman H, et al. Treatment of Post-Stroke Dysphagia with Pharyngeal Electrical Stimulation: the MAPS Clinical Registry. Presented at UKSF 2015 read more.

Scutt P, Lee HS, Hamdy S, et al. Pharyngeal Electrical Stimulation for Treatment of Poststroke Dysphagia: Individual Patient Data Meta-analysis of Randomised Controlled Trials. Hindawi Publishing Corporation, Stroke Research and Treatment, Volume 2015, Article ID 429053, 8 pages read more.


Wann L, Rehman H, et al. The use of Pharyngeal Electrical Stimulation for Treatment of Post-Stroke Dysphagia. British International Doctor’s Association, Issue No.1, Volume 22, January 2016.

Bath PM, Scutt P, et al. Pharyngeal Electrical Stimulation for Treatment of Dysphagia in Subacute Stoke: A Randomized Controlled Trial. Stroke 2016 read more.

Köstenberger M, Likar R, et al. Pharyngeal Electrical Stimulation (PES) – a novel treatment for dysphagia in mechanically ventilated neuro-ICU patients. ÖGARI 2016.

Vasant DH, Michou E, et al. Pharyngeal Electrical Stimulation in Dysphagia Poststroke: A Prospective, Randomized Single-Blinded Interventional Study. Neurorehabilitation and Neural Repair 1-10 2016 read more.

Michou E, Sasegbon A, et al.Direct and Indirect Therapy: Neurostimulation for the Treatment of Dysphagia After Stroke. In: . Medical Radiology. Springer, Berlin, Heidelberg 2017 read more.

Köstenberger M, Neuwersch S, et al. Dysphagia on the intensive care unit – an additional therapy option?!. ÖGARI 2017 read more.

Muhle P, Suntrup-Krueger S, et al. Increase of Substance P Concentration in Saliva after Pharyngeal Electrical Stimulation in Severely Dysphagic Stroke Patients – an Indicator of Decannulation Success?. Neurosignals 2017; 25: 74–87 read more.

Restivo DA, Hamdy S, et al. Pharyngeal electrical stimulation device for the treatment of neurogenic dysphagia: technology update. Medical Devices: Evidence and Research 2018; 11: 21-26 read more.

Dziewas R, Mistry S, et al. Design and implementation of Pharyngeal electrical Stimulation for early de-cannulation in TRACheotomized (PHAST-TRAC) stroke patients with neurogenic dysphagia: a prospective randomized single-blinded interventional study. Int J Stroke 2017 Jun;12(4):430-437. Epub 2016 Nov 2 read more.


Dziewas R, Stellato R, et al. PHAryngeal electrical STimulationfor early decannulation in TRACheotomised patients with neurogenic dysphagia after stroke (PHAST-TRAC): a prospective, single-blinded, randomised trial. Lancet Neurol 2018; 17: 10: 849-859; Epub 2018 Aug 28 read more.

Koestenberger M, Neuwersch S, et al. A Pilot Study of Pharyngeal Electrical Stimulation for Orally Intubated ICU Patients with Dysphagia. Neurocrit Care 2019; Epub 2019 Jul 16 read more.

Zuercher P, Moret CS, et al. Dysphagia in the intensive care unit: epidemiology, mechanisms, and clinical management. Critical Care (2019) 23:103 read more.

Bath PM, Woodhouse LJ, et al. Pharyngeal Electrical Stimulation for Early Decannulation in Tracheotomised Stroke Patients With Dysphagia: A Meta-analysis of Individual Patient Data From Randomised Controlled Trials. International Stroke Conference 2020 Moderated Poster Abstracts Title: Clinical Rehabilitation and Recovery Moderated Poster Tour; Stroke ;51:ATMP40 read more.

Everton LF, Benfield JK, Hedstrom A, et al. Psychometric assessment and validation of the dysphagia severity rating scale in stroke patients. Sci Rep 10, 7268 (2020) read more.

Florea C, Bräumann C, et al. Therapy of Dysphagia by Prolonged Pharyngeal Electrical Stimulation (Phagenyx) in a Patient with Brainstem Infarction. Brain Sci. 2020, 10, 256 read more.

Beirer S, Grisold W, et al. Therapy-resistant dysphagia successfully treated using pharyngeal electrical stimulation in a patient with the pharyngeal-cervical-brachial variant of the Guillain-Barré syndrome. eNeurologicalSci 20 (2020) 100255 read more.