Intended for healthcare professionals

Practice Rational Testing

Investigating sudden hearing loss in adults

BMJ 2018; 363 doi: (Published 12 November 2018) Cite this as: BMJ 2018;363:k4347

Re: Investigating sudden hearing loss in adults

I thank the authors, our colleagues Fishman and Cullen, for their response to our letter and I would like to use it as an opening for further debate.

Considering the aetiology of ISSHL, Fishman and Cullen wrote that acute oxygen shortage likely holds true for “a proportion of cases”. However, Nagahara and Fish described the low perilymphatic oxygenation in case of sudden deafness already in 1983; consequently, Ganesan et al. wrote that vascular compromise is the most likely pathogenesis involved in ISSHL, and Rhee et al. stated that the treatment of SSNHL to date has focussed mainly on the improvement of blood flow and increased oxygen supply in the inner ear. That part of medical history should not be ignored. So, like others, I think that acute oxygen shortage concerns more patients than just a belittling ‘proportion’.

As we admitted in our first response, the Cochrane Library states that the positive results regarding hyperbaric oxygen therapy (HBOT) should be interpreted cautiously. Still, Fishman and Cullen calculated the number needed to treat for HBOT based on the Cochrane Library data. But, I would urge them to apply this across the board: according to the current Cochrane Library data, no number needed to treat can be calculated at all for steroids.

(A number needed to treat of 5 is, by the way, not too bad for a devastating disease for which no other medication is proven effective. Especially not for a therapy that, besides barotrauma to sinus and middle ear – that is reversible after stopping the therapy - doesn’t have many side effects. In contrast, a short course of prednisone may affect the ability to work for a considerable time.)

Furthermore, in the last years three separate reviews (by Rhee, Eryigit, and Saesen) were written on this topic. All conclusions were to some extent in favour of HBOT.

Moreover, the Cochrane review concluded that there is a 15.6 dB gain among the group treated with HBOT. To explain the clinical benefit of this gain, suppose that a patient sustains, on average, a 60 db loss in the pure tone average and that he spontaneously (with steroids) recovers 25 dB. The residual loss is then 35 dB. In the Netherlands that is the norm for eligibility for hearing aid adjustment. With an extra 15.6 dB gain by means of HBOT, the patient sustains less than 20dB loss and still meets the required functional standard of our Ministry of Defense. So, doubts about the relevance of 15 dB are unwarranted from my point of view.

So, I would think it fair, if Fishman and Cullen agreed that hyperbaric oxygen should be discussed with patients as a possible treatment option, an option that was lacking in their original article.

Disregarding HBOT, but instead mentioning unproven therapies – even if they do offer hope for the future - that are in trial now is, in my opinion, misleading for the topic of the discussion. These medications cannot yet compete with a significant positive modality.

I do agree with Fishman and Cullen that if HBOT is not widely available or expensive, that might indeed be an argument for not choosing this therapeutic option. However that is a decision also for the patient to make after being sufficiently informed about all possible treatment options.

I was taught that there are two situations in which a tuning fork doesn’t fail: sudden deafness and a post-operative clinical setting in which one ear is packed with gauze and the ears were symmetrically, well-functioning before. In these situations they are still always used by all ENT consultants in my hospital.

Moreover, though a tuning fork is not 100% accurate – but which diagnostic tool is?? – it is easy to use, inexpensive, and in contrast to an electric audiometer, it fits in a Doctor's white coat. It is the best decisive clinical tool that an ENT doctor should always have with him.

So, as for the suggestion of Dr Nicholl, who wrote that we perhaps should drop the tuning fork test, I can only disagree. However, I do agree with Dr. Nicholl that it is not an instrument to be routinely used in a neurological setting. Indeed, the neurological patient with somewhat longer standing hearing problems should be scheduled for audiometry. But that is not the topic of this discussion; the topic is tuning forks in sudden deafness this time. In the responses to their manuscript in the Dutch Medical Journal, Verburg describes the never failing tuning fork in ENT. While exceptions to a rule can always be found, in my 20 years’ experience it also never lateralised to the wrong site in case of moderate, severe or profound sudden deafness. So, it is a very, very, very accurate instrument, and since audiograms are not available in my hospital 24/7, I do decide sometimes to start steroids based on the history and the tuning fork lateralization.

Furthermore, and no offence meant because I realise the difficulties of the job, the tuning fork makes less mistakes than the average GP. I have seen many otitis media and ceruminosis referrals ending with sudden deafness.

Doyle and Anderson wrote that two groups of people are critical of the tuning fork: those who never use it and those who do not know how to use it. I would like to add a third group, those who do not know when to use it.

Most medics aren’t very accurate when shooting with a sniper rifle. According to my Marine Corps Sergeant Major that doesn’t mean that sniper rifles don’t work, but that “a fool with a tool, is still a fool”.

Alexander de Ru

Competing interests: No competing interests

12 February 2019
J. Alexander De Ru
ENT consultant
Central Military Hospital Utrecht
Lundlaan 1, 3584CX Utrecht