Clinical Evidence

Information about how SRAVI has been evaluated

Hospital Trials

SRAVI has been in trial by the Lancashire Teaching Hospitals NHS Foundation Trust since 2019.

ICU patients under the care of Consultant Shondipon Laha participated in Phase 1 of the trial, from May to November 2019.

The trial was funded in part by Innovate UK.

Phase I

These trial patients lost their ability to speak, from having tracheostomies. SRAVI is a communications aid that can help improve their health outcomes. During this initial phase, 15 patients and 33 staff members helped to capture data for SRAVI, and to determine which phrases they would most commonly use in their care setting.

From this research, we compiled a list of 20 phrases that SRAVI can understand.

Because SRAVI is based upon artificial intelligence (AI) algorithms, it was critical to demonstrate that the app will read the patients’ lips better as they continue using it. The longer the patients used SRAVI, the better the app got at understanding what they were saying.

Critically, Phase I proved that SRAVI returns the correct phrase that has been lip-read with greater than 90% accuracy. The recognition system is able to identify the correct phrase in the top 3 with 100% accuracy.

Phase II

The second phase of the SRAVI trial is now underway at Royal Preston Hospital. Patients will be using the app to communicate with their doctors, nurses, family and friends. We will be analyzing and publishing results from this study as they become available.

Case Studies

Nathan Armstrong

Nathan has experienced having a tracheostomy and understands how valuable SRAVI can be.

Read Nathan's Case Study

Dr. Shondipon Laha

Shond is a consultant at Lancashire Teaching Hospital's Trust. Read about his experience with SRAVI.

Read Shond's Case Study


  • Flesher, W., Twamley, J., Verlander, M., Nanda, S., Madanapalli Raghunath, S., Williams, A., Laha, S. "SRAVI - Speech Recognition App for the Voice Impaired. A feasibility study into the use of Visual Speech Recognition software to aid communication in the ICU environment." Intensive Care Society State of the Art Meeting, December 2019


  • Nanda, S., Twamley, J., Laha, S., Campbell-West, F., "SRAVI: Speech Recognition for the Voice Impaired"
  • Nanda, S., "Augmentative and Alternative Communication Strategies for Hospital Inpatients with Acutely Impaired Communication - A Systematic Review"

What's Next?

The worldwide Covid-19 pandemic has resulted in a large increase in patients undergoing tracheostomy procedures. The SRAVI team are working hard to make SRAVI available to patients and medical professionals.

Future features include:

  1. Ability to add new phrases
  2. Customisation of voice - gender, region, pitch etc
  3. Integration with text messaging and video calls