1 Manchester Head and Neck Centre, Manchester Royal Infirmary, Manchester University NHS Foundation Trust, Manchester, UK.
2 Department of Speech and Language Therapy, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
3 Milton Keynes University Hospital, Milton Keynes, UK.
4 Department of Otolaryngology, Head and Neck Surgery, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK, and Blenheim Head and Neck Unit, Churchill Hospital, Oxford, UK.
5 Beatson West of Scotland Cancer Centre, Glasgow, Scotland, UK.