Chemotherapy Induced Hearing Loss

Reducing the impact of chemotherapy induced hearing loss with new hearing aid technology

Cisplatin-based chemotherapy is a known risk factor for hearing loss. Although most literature suggests hearing loss with cisplatin occurs at higher frequencies and with higher doses of the drug, traditional teaching has been that patients with pre-existing hearing loss should not receive cisplatin, meaning these patients often have inferior cancer outcomes.

However, if these patients are adequately counselled, it is thought many would prefer to have better cancer outcomes if there was some ability to correct hearing loss, or retune hearing aids to address further falls in hearing. Another question is whether modern hearing aids can reduce tinnitus.

In order to find out more, ANZUP member A/Prof Andrew Weickhardt spoke to Alison Hennessy from Alison Hennessy Audiology.

Hearing aids are capable of amplifying more high frequency sounds than previously. ‘Frequency’ refers to the pitch of the sound (treble or bass). Higher frequency speech sounds tend to be the consonants. These provide clarity. Lower pitched speech sounds tend to be vowels. Thirty years ago, the upper limit of amplification was 3-4kHz. Now it is fairly typical to see hearing aids amplifying up to 6-8 kHz and sometimes to 10kHz. Generally speaking, if someone has hearing loss only at 6kHz and above, they would not be considered hearing aid candidates as the impact of such a hearing loss is not regarded as functionally significant.

Earlier hearing aids often produced feedback when providing significant high frequency amplification. Nowadays, feedback cancelling technology is quite advanced, allowing high frequency amplification without feedback and without needing to close/occlude the ear canal (our earlier way of dealing with feedback). This has improved comfort and cosmetics drastically for people with high frequency hearing loss.

Hearing aids do not restore normal hearing. This is typically noticed more in noisy/ challenging situations. We know that hearing loss (sensorineural loss) causes not just a loss of sensitivity, but also a reduced ability to ignore the background noise and focus on the signal of interest. There are a number of factors including age and cognitive function, in addition to the degree of sensorineural hearing loss. I do a screening test of the ability to hear speech in noise with appropriate amplification in order to counsel the person appropriately regarding expectations, and in order to decide the level of noise reduction technology likely to be required. Modern hearing aids aim to identify/reduce the background noise. For some people this is very effective, for others, no amount of high tech processing overcomes their reduced ability to cope in challenging situations (e.g. multi-talker conversations).

Current thinking about tinnitus is that much of the issue of dealing with tinnitus is due to underlying fears regarding the tinnitus (e.g. “it will get worse” and “it will make me deaf”). It is thought that these may be subconscious thoughts. Therefore, management of tinnitus typically involves reassurance in the first instance. The aim of tinnitus management is habituation (i.e. it is still there, but it is not noticed, or noticed only infrequently). Sound therapy can be part of the management and most modern hearing aids have ‘tinnitus’ programs – where a sound generated in the hearing aid is used to reduce awareness of the person’s tinnitus. In my experience, the best sound therapy for people with significant tinnitus issues and hearing loss is the use of hearing aids (tinnitus programs usually not required).

Many people are reluctant to consider hearing aids as they have only seen big hearing aids. My comment is that many people are wearing hearing aids that you do not see – you only see the obvious ones.”

THE COST OF HEARING AIDS Hearing Services Program Under the Hearing Services Program, the Federal Government funds hearing services (tests, etc) and hearing aids if required. The hearing aids are low-end technology, but do feature some noise reduction and feedback cancelling capabilities. More expensive hearing aids may be partially funded by the scheme. Hearing aids If paying privately, it is approximately $3,000 – $8,000 for a pair of hearing aids. This will generally include fitting and review/re-tuning appointments for a certain period of time. Health insurance extras cover typically provides a reimbursement of $300 – $1,500. The NDIS has strict criteria regarding the degree of hearing loss, but will also fund hearing aids and services. The expected ‘life’ of hearing aids is five years. Hearing tests Some clinics are able to bulkbill everyone while some can bulkbill only as part of Team Care Arrangement (referred by GP) or if referred by an ENT or neurologist. Therefore, patient costs can vary from nothing up to $150 or more. Re-tuning/review appointments after the initial period attract a similar consultation fee. ANZUP UPdate Spring 2018 | 31