M Lechner1,2,3, J Liu2, N Counsell4, D Gillespie2, D Chandrasekharan1, N H Ta5, K Jumani1, R Gupta1, S Rao-Merugumala1, J Rocke6, C Williams6, A Tetteh7, R Amnolsingh8, S Khwaja8, R L Batterham9,10,11, C H Yan12, T A Treibel11,13,14, J C Moon11,13,14, J Woods15, R Brunton7, J Boardman16, S Paun1, N Eynon-Lewis1, B N Kumar6, S Jayaraj1, C Hopkins7, C Philpott5,17, V J Lund18. 1. ENT Department, Barts Health NHS Trust, London, UK. 2. UCL Cancer Institute, University College London, London, UK. 3. Division of Surgery and Interventional Science, University College London, London, UK. 4. CRUK and UCL Cancer Trials Centre, University College London, London, UK. 5. Norwich Medical School, University of East Anglia, Norwich, UK. 6. ENT Department, Wrightington, Wigan and Leigh NHS Foundation Trust, Wigan, UK. 7. ENT Department, Guy's Hospital, Guy's and St. Thomas' NHS Foundation Trust, London, UK. 8. Department of Otolaryngology, Manchester University NHS Foundation Trust, Manchester, UK. 9. Centre for Obesity Research, University College London, London, UK. 10. Bariatric Centre for Weight Management and Metabolic Surgery, University College London Hospitals NHS Foundation Trust, London, UK. 11. National Institute for Health Research, UCLH Biomedical Research Centre, London, UK. 12. Department of Otolaryngology-Head and Neck Surgery, University of San Diego School of Medicine, San Diego, USA. 13. Barts Heart Centre, St. Bartholomew's Hospital, London, UK. 14. Institute of Cardiovascular Sciences, University College London, UK. 15. The Norfolk Smell and Taste Clinic, Norfolk. 16. Fifth Sense, UK. 17. The Norfolk Smell and Taste Clinic, Norfolk and Waveney ENT Service, UK. 18. Royal National ENT Hospital, University College London Hospital NHS Foundation Trust, London, UK.
Abstract
BACKGROUND: Olfactory dysfunction is a cardinal symptom of COVID-19 infection, however, studies assessing long-term olfactory dysfunction are limited and no randomised-controlled trials (RCTs) of early olfactory training have been conducted. METHODOLOGY: We conducted a prospective, multi-centre study consisting of baseline psychophysical measurements of smell and taste function. Eligible participants were further recruited into a 12-week RCT of olfactory training versus control (safety information). Patient-reported outcomes were measured using an electronic survey and BSIT at baseline and 12 weeks. An additional 1-year follow-up was open to all participants. RESULTS: 218 individuals with a sudden loss of sense of smell of at least 4-weeks were recruited. Psychophysical smell loss was observed in only 32.1%; 63 participants were recruited into the RCT. The absolute difference in BSIT improvement after 12 weeks was 0.45 higher in the intervention arm. 76 participants completed 1-year follow-up; 10/19 (52.6%) of participants with an abnormal baseline BSIT test scored below the normal threshold at 1-year, and 24/29 (82.8%) had persistent parosmia. CONCLUSIONS: Early olfactory training may be helpful, although our findings are inconclusive. Notably, a number of individuals who completed the 1-year assessment had persistent smell loss and parosmia at 1-year. As such, both should be considered important entities of long-Covid and further studies to improve management are highly warranted.
BACKGROUND: Olfactory dysfunction is a cardinal symptom of COVID-19 infection, however, studies assessing long-term olfactory dysfunction are limited and no randomised-controlled trials (RCTs) of early olfactory training have been conducted. METHODOLOGY: We conducted a prospective, multi-centre study consisting of baseline psychophysical measurements of smell and taste function. Eligible participants were further recruited into a 12-week RCT of olfactory training versus control (safety information). Patient-reported outcomes were measured using an electronic survey and BSIT at baseline and 12 weeks. An additional 1-year follow-up was open to all participants. RESULTS: 218 individuals with a sudden loss of sense of smell of at least 4-weeks were recruited. Psychophysical smell loss was observed in only 32.1%; 63 participants were recruited into the RCT. The absolute difference in BSIT improvement after 12 weeks was 0.45 higher in the intervention arm. 76 participants completed 1-year follow-up; 10/19 (52.6%) of participants with an abnormal baseline BSIT test scored below the normal threshold at 1-year, and 24/29 (82.8%) had persistent parosmia. CONCLUSIONS: Early olfactory training may be helpful, although our findings are inconclusive. Notably, a number of individuals who completed the 1-year assessment had persistent smell loss and parosmia at 1-year. As such, both should be considered important entities of long-Covid and further studies to improve management are highly warranted.
Authors: Luigi Angelo Vaira; Giacomo De Riu; Giovanni Salzano; Fabio Maglitto; Paolo Boscolo-Rizzo; Jerome R Lechien Journal: Am J Otolaryngol Date: 2022-10-17 Impact factor: 2.873