Hearing Sciences

CROSSSD Study: Identifying what is critical and important to measure when evaluating hearing interventions for adults with Single Sided Deafness (SSD)



1. What is the study about and why is it important?

Single Sided Deafness (SSD) refers to the condition where there is normal or near-normal hearing in one ear and a severe to profound hearing impairment in the other ear.

Good hearing in both ears is important for everyday listening tasks such as understanding speech in noisy environments, locating where sounds are, and identifying threats such as oncoming traffic.

Researchers don’t yet agree on what benefits and harms (known as ‘outcomes’) should always be assessed when evaluating whether or not an intervention for SSD is effective.  These inconsistencies hinder progress to find the most effective intervention.

The CROSSSD Study group will work closely with patients and professionals across the world who are all experts in Single Sided Deafness. We will find agreement on what outcomes are critical and important to measure when evaluating interventions for SSD.

2. Study duration

This project will be completed by October 2022.

3. What does it involve?

The CROSSSD study is supported by the NIHR Nottingham BRC and follows methods developed by the COMET initiative (MRC North West Hub for Trials Methodology).

Identifying appropriate outcome domains is crucial when designing clinical trials to evaluate the effects of different interventions.

The selected outcomes need to be important to key stakeholders such as patients, healthcare professionals or budget holders in order to minimise bias when making decisions about healthcare.

You can also view a video describing CROSSSD which is hosted on YouTube.*

4. Funders

The CROSSSD study is supported by the NIHR Nottingham BRC.

5. Research team

Project Lead:

Roulla Katiri, PhD Student and Chief Audiologist, Mater Misericordiae University Hospital, Dublin, Ireland.

Nottingham BRC Study Management Team:

Associate Professor Pádraig T. Kitterick

Associate Professor Derek J. Hoare

Professor Deborah A. Hall

PPI Manager Dr Adele Horobin

Steering Group:

Professor Iain A. Bruce, NIHR Manchester Biomedical Research Centre

Professor Paul Van de Heyning, Antwerp University Hospital - University of Antwerp, Belgium                                                                    

Professor Jill B. Firszt, Washington University School of Medicine, USA.


(*See the University website terms and conditions for information about third-party websites.)

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COMET database entry

PROSPERO project entry







Hearing Sciences

Division of Clinical Neuroscience
School of Medicine
University of Nottingham
Medical School, QMC
Nottingham, NG7 2UH

telephone: University Park +44 (0) 115 74 86900
Ropewalk House +44 (0) 115 82 32600
Glasgow +44 (0) 141 242 9665 email:hearing-research@nottingham.ac.uk