AspiRate – An automated device to detect silent aspiration in patients with swallowing difficulties

Stroke and other neurological disorders commonly lead to swallowing problems where the windpipe is not protected.  This aspiration can lead to chest infections which can be potentially life threatening.  The AspiRate project aims to develop a portable, non-invasive, simple-to-operate and automated device that can be used to screen for silent aspiration.

Project Lead and Organisation

Mr Matthew Smith, Cambridge University Hospitals NHS Foundation Trust

Prof. Sue Pownall, Sheffield Teaching Hospitals

When did project start?


Clinical Requirement

If a person has swallowing difficulties (dysphagia) they may be prone to food or liquid entering their airway (aspiration).  Aspiration may trigger a protective cough reflex to clear the material, but in some people this protective mechanism is absent, and they have no indication that they have aspirated: this is called silent aspiration.  Aspiration predisposes to chest infection, which has a significant mortality rate in older people or those with disabilities.  It is therefore important to know whether someone is aspirating, as their diet or feeding methods can be changed to reduce the risk of aspiration and it’s complications.  The current gold standard is a video fluoroscopic assessment of the swallow, during which the person is asked to swallow a variety of thick and thin fluids whilst undergoing x-ray examination.  This investigation has good sensitivity and specificity, but it exposes the patient to radiation, is expensive, requires specialist assessors, is difficult for people with cognitive issues or disabilities and can only be done in an appropriate x-ray suite.

The Solution

The team hope to develop a portable, non-invasive, simple-to-operate and automated device that can be used to screen for silent aspiration.  The team believes that subtle changes to breath sounds arising in the trachea and below the vocal cords may indicate if particles of liquid or food have been aspirated.  The unique element to our work is a multi-channel approach using an array of microphones, and sophisticated processing of the sensor inputs.  The team will start with recording swallow and tracheal sounds via multiple microphones, in conjunction with sensors recording other parameters.  Signal processing experts will pick out characteristic signals associated with the normal swallow and episodes of aspiration.  Through the development process the team will narrow down the minimum set of sensors required to optimise test sensitivity and specificity.

D4D will be responsible for working with University of Cambridge Engineering Department in trialling different detection methods, producing a robust prototype device, managing a clinical study, and overall project management.


The proposed device could revolutionise the way that dysphagia and aspiration are managed.  A quick, automated screening test would allow anyone with basic training to test a patient with suspected aspiration at any time.  In particular, regular non-specialist re-assessment would become possible, as would screening and testing in difficult circumstances.  There is no existing commercial equivalent device to compare to the proposed innovation, but we believe that it would appeal to both primary and secondary care institutions, adopted in particular by speech and language therapists and specialist nurses working with patients with a neurological deficit or head/neck malignancy.  There may also be up-take in some community care homes.


  • NIHR Devices for Dignity HTC
  • Sheffield Teaching Hospitals NHS Foundation Trust
  • University of Cambridge
  • EPSRC Network – Promoting Real Independence through Design Expertise (PRIDE)
  • Cambridge University Healthcare Partners

Image Attribution

Image ‘Oreo milkshake heaven’ courtesy of Farouk Ates. Image reproduced unaltered and licensed under CC BY 2.0. Source.