The progressive hearing loss known as presbycusis develops slowly and insidiously, making it difficult to self-diagnose.
A mild/moderate high frequency sensorineural hearing loss – the most common pattern and degree of acquired hearing loss – is often not apparent to the person affected.
Restrictions due to lockdown have altered communication patterns. For some, the need to communicate more via telephone and online has led to an increased awareness of a previously unnoticed hearing loss. Please consider using a visual online platform when you are carrying out telehealth consultations with hearing-impaired patients to facilitate ease of communication by providing visual cues.
At our audiology clinic in Melbourne, with strict lockdown restrictions, we are finding that patients fitted with hearing aids for the first time need a longer period of support to ease into optimal levels of amplification as they slowly resume group communication and noisier activities.
The effect of face masks on hearing and communication
Face masks are a critical tool in slowing the spread of COVID-19, but they also make communication more difficult, especially for people with a hearing loss. Face masks have been shown to muffle high-frequency speech sounds and block visual cues. Mask wearing during a telephone conversation can be particularly difficult for people with a hearing loss.
Additionally, we are finding at our clinic that the elastic strap over the ear bends the top of the auricle so that behind-the-ear hearing aids fit less securely at the top of the ear. As a result, there has been an increased risk of hearing aids falling off the ear and being lost. Some of our patients are choosing not to wear their hearing aids while wearing a mask to prevent this occurring. Our largely elderly patient population is at particular risk from COVID-19, so masks are likely to be with us for some time, leading us to look at creative ways to manage this.
Face masks as an informal hearing loss screening tool?
An undiagnosed hearing loss will become accentuated and more evident when masks are being worn. So as a GP, communication difficulties noticed with your patients when you are wearing a mask can alert you to an undiagnosed hearing loss.
Hearing loss is very prevalent in people over 70 (74% of people aged 71+ are estimated to have a hearing loss1). Apart from helping your patients manage communication difficulties arising from a hearing loss, by referring them for assessment and management you will be supporting their cognitive health.
Hearing loss management has been identified as one of 12 modifiable risk factors over a lifetime which could delay or prevent 40% of dementia cases, according to an updated report by the Lancet Commission on dementia prevention, intervention, and care presented at the Alzheimer’s Association International Conference (AAIC 2020).2 According to the report, “using hearing aids appears to reduce the excess risk from hearing loss”.
The report cites several studies on hearing aid use among older adults with hearing loss, including a cross-sectional study that found worse cognitive outcomes in those who did not wear hearing aids.
A comparison of the effect on hearing of different types of face masks
A study was carried out examining the acoustic attenuation caused by different face masks, using a head-shaped loudspeaker and a live human talker.3 The results suggest that all masks attenuate frequencies above 1kHz, that attenuation is greatest in front of the talker, and that there is substantial variation between mask types, especially cloth masks with different materials and weaves. Transparent masks have poor acoustic performance compared to both medical and cloth masks.
The study tested a surgical mask, N95 and KN95 respirators, eight types of opaque cloth mask, two cloth masks with clear windows, and a plastic face shield.
All the masks tested attenuated high frequency sounds above 1kHz, with the worst attenuation above 4kHz. These high frequency signals are important for hearing sounds like “s”, “f”, and “th”, which are already poorly heard by most people with a hearing loss.
The performance of the masks appeared to depend mostly on material and weave, rather than thickness. The best masks overall were the surgical mask and the KN95 respirator, which had peak attenuation of around 4 decibels. The N95 respirator attenuated high frequencies by about 6dB.
Does COVID-19 cause hearing loss or tinnitus?
All cases of sudden-onset sensorineural hearing loss (SSHL or SSNHL) should be considered a medical emergency, because of the need for prompt treatment during the short window of time (two weeks) where steroid medication may be effective. Aetiology is most commonly attributed to an inner ear virus infection. Associated symptoms can include vertigo, tinnitus and a sensation of aural fullness. These symptoms can be readily misdiagnosed as due to Eustachian tube dysfunction.
Based on the limited published case reports, it appears that SSNHL can develop but is rarely a consequence of COVID-19.4-7
In a case report titled “Sudden irreversible hearing loss post COVID-19” presenting the first UK case of SSNHL following COVID-19, the authors explain that the virus has recently been found in epithelial cells of the middle ear, as well as the stria vascularis and spiral ganglion in mice.5
Medications used to treat COVID-19 can damage the hearing
Some medications used to treat COVID-19 carry a relatively high risk of hearing loss, tinnitus or vertigo as a side effect. These potentially ototoxic drugs include quinine, chloroquine and hydroxychloroquine.
Myriam Westcott is an audiologist and director of DWM Audiology in Heidelberg, Victoria. She has specialised interests in aural rehabilitation, tinnitus, hyperacusis, acoustic shock disorder and misophonia.
- Dementia prevention, intervention, and care: 2020 report of the Lancet Gill Livingston et al. Lancet 2020; 396: 413–46
- Acoustic effects of medical, cloth, and transparent face masks on speech signals. Corey R M, Jones U, Singer AC. arXiv:2008.04521[eess.AS]
- Koumpa FS, Forde CT, Manjaly JG. BMJ Case Rep 2020;13:e238419. doi:10.1136/bcr-2020- 238419
- Degen C, Lenarz T, Willenborg K. Acute profound sensorineural hearing loss after COVID-19 pneumonia. Mayo Clin Proc 2020;95:1801–3.
- Rhman SA, Wahid AA. COVID-19 and sudden sensorineural hearing loss: a case report. Otolaryngol Case Reports 2020;16:100198