Idiopathic Sudden Sensorineural Hearing Loss – Is it time to challenge definitions of hearing recovery?

This week’s blog comes from Rebecca Collingwood (MSc, Adv Dip, BSc, NMP), Advanced Clinical Practitioner ENT Head and Neck Surgery at Hull University Teaching Hospitals NHS Trust (@BCol81090) and Dr Clare Whitfield (PhD RGN PGCE FHEA), University of Hull (@CWhitHealthcare).

Sudden sensorineural hearing loss affects an estimated 5 per 100,000 people annually (1) and usually presents as unilateral loss, affecting both genders equally, with average age of onset of 40 years (1,2). In some cases, a cause of hearing loss can be found; however, in 90% of diagnoses this is ‘idiopathic’, where no cause can be determined. Idiopathic sudden sensorineural hearing loss (ISSNHL) is a frightening condition characterised by sudden deafness which develops over 72 hours and a decrease in hearing ability of 30 decibels or more affecting at least three consecutive frequencies with no identified cause (1,2).

ISSNHL can be temporary or permanent and range from mild to moderate hearing loss and impacts quality of life. The impact on patients is considerable; communication difficulties compound perceptions of social isolation and low mood, especially if accompanied by a hearing deficit on the unaffected side (3). Diagnosis, examination and management of patients with ISSNHL is carried out by advanced clinical practitioners (ACP) within the ENT department. The AAO-HNSF (2019) advise prompt diagnosis and steroid treatment within 2 weeks to ensure recovery and improved quality of life. However, management of steroid drug, dose, and regimes vary (2,3,4).

Different hearing recovery criteria are used in practice resulted in confusion over definitions and how hearing recovery is identified5. Improvement is seen as synonymous with recovery, although identified changes may have little impact on a patient’s quality of life. Other approaches aim for ‘normal’ hearing when in fact baseline hearing may not have been within normal ranges. Some set hearing recovery thresholds such as an improvement of 10 decibels are labelled as recovery, this can be misleading, as in some cases this would not significantly improve the patient’s quality of life.

Most patients with ISSNHL do not have a pre- ISSNHL audiogram; baseline is usually established through patient verification – a subjective measurement that is not always reliable. This can lead to unattainable treatment goals and difficulties in defining recovery, which is meaningful for the patient (2). Using a standardised set of hearing recovery criteria would provide clarity around what constitutes meaningful recovery and allow for direct comparisons of treatment. AAO-HNSF (2019) have recommended an approach involving pure tone audiometry and word recognition scores to evaluate hearing recovery as well as using the unaffected ear as a comparison unless previous hearing asymmetry was known or suspected. This seems a reasonable recommendation, particularly as many patients may not have had a pre-ISSNHL audiogram but are likely to be aware of a hearing asymmetry (2).

Common accompanying symptoms such tinnitus and vertigo, which can be very debilitating and distressing for the patient should also be considered when providing care to patients and evaluating hearing recovery. Accompanying symptoms are not always included in the assessment and treatment of ISSNHL (6,7) and this is essential when striving for holistic, meaningful recovery and improved quality of life. The standardised AAO-HNSF (2019) hearing recovery criterion clearly define meaningful recovery and allow for treatment comparison highlighting the importance of pure tone audiometry, word recognition scores and accompanying symptoms such as tinnitus and vertigo. This provides useful guidance for practitioners and researchers, and can if implemented successfully improve evaluation of the condition and effectiveness of treatment and patient care.

References
1. Corbridge, R. & Steventon, N. (2020) Oxford Handbook of ENT and Head and Neck Surgery Third Edition United Kingdom: Oxford University Press
2. Chandrasekhar, S., Tsai Do, B., Schwartz, S., Bontempo, L., Faucett, E., Finestone, S., Hollingsworth, D., Kelley, D., Kmucha, S., Moonis, G., Poling, G., Roberts, J., Stachler, R., Zeitler, D., Corrigan, M., Nnacheta, L. & Satterfield L. (2019) Clinical Practice Guideline: Sudden Hearing Loss (Update). Otolaryngology Head and Neck Surgery.161 (1S) S1- S45 American Academy of Otolaryngology- Head and Neck Surgery Foundation (AAO-HNSF) Available online: https://pubmed.ncbi.nlm.nih.gov/31369359/ [Assessed: 25/02/2021]
3. National Institute for Health and Care Excellence, NICE (2018) Hearing loss in adults: assessment and management NICE Guideline (NG98) Available online: https://www.nice.org.uk/guidance/ng98/resources/hearing-loss-in-adults-assessment-and-management-pdf-1837761878725 [Assessed: 25/02/2021]
4. Twigg, V., Lawrence, R., Thevasagayam, R., Fergie, N. & Daniel, M. (ENTUK) (2020) Management of suspected unilateral idiopathic sudden sensorineural hearing loss in adults. ENTUK Available online: https://www.entuk.org/sites/default/files/files/SSNHL%20SSO.pdf [Assessed: 25/02/2021]
5. Gao, Y. & Liu, D. (2016) Combined intratympanic and systemic use of steroids for idiopathic sudden sensorineural hearing loss: a meta-analysis. European Archives Otorhinolaryngology 273(11): 3699-3711 Available online: https://pubmed.ncbi.nlm.nih.gov/27071771/ [03/04/2021]
6. Wei, BPC., Stathopoulos, D. & O’Leary, S. (2013) Steroids for idiopathic sudden sensorineural hearing loss (Review) The Cochrane Collaboration. John Wiley & Sons. Available online: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD003998.pub3/epdf/full [Assessed: 25/02/2021]
7. Ahmadzai, N., Kilty, S., Wolfe, D., Bonaparte, J., Schramm, D., Fitzpatrick, E., Lin, V., Cheng, W., Skidmore, B., Moher, D. & Hutton, B. (2018) A Protocol for a Network Meta-Analysis of Interventions to Treat Patients with Sudden Sensorineural Hearing Loss Systematic Reviews 7 (1) 74

 

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