Hearing loss (Part 2): Cochlear Implants and Hearing Aids

Hearing loss is the reduction in hearing ability that develops when electrical sound signals do not reach the brain. The loss of hearing can affect one or both ears, be temporary or permanent, and range in degree from mild to profound. Some types of hearing loss may also be present at birth, whilst others may occur later in life.

Following on from the first part which discussed the signs and tests of hearing loss, leading consultant ENT surgeon Mr Harry Powell offers here an expert insight into the use of cochlear implants and hearing aids as treatment options, in this conclusion of a two-part series on hearing loss.

How effective are cochlear implants for adult patients? Are they as beneficial as cochlear implants for paediatric patients?

Deafness can either be pre-lingual or post-lingual, depending on the age at which deafness occurs and whether the patient was able to develop his/her speech before becoming deaf.

In the beginning, more adults than children received cochlear implants, because patients with post-lingual deafness (adults in the majority) knew what it was like to have some hearing, and were thus believed to gain more benefit from cochlear implant surgery. Today, research has shown that the brain has extensive neural plasticity (the ability to change and adapt) and that binaural hearing (with two ears) provides significant advantages. As a result, pre-lingual deaf babies who meet the criteria for cochlear implantation are now provided with bilateral implants as early as possible. It is important, however, to understand that normal hearing is not restored with a cochlear implant; what the implant does instead, is provide access to sound, helping patients to speak clearly and to receive and understand spoken language.

In the UK, the first single-channel cochlear implant (that only uses one electrode) was inserted in 1984, at University College London. Over the last 15 years, cochlear implant surgery has evolved and become an established procedure and now, any patient with severe to profound sensorineural hearing loss who does not benefit from hearing aids may be a candidate for cochlear implantation. The cochlear implant itself costs about £20,000.

What risks are involved with the use of cochlear implants?

Cochlear implantation is a complex process which involves a multidisciplinary team of surgeons, audiologists and rehabilitation experts. The suitability of patients who consider having cochlear implants is assessed in various hospital visits, where several audiological tests including speech discrimination are undertaken. MRI and CT scans are also carried out, to analyse the cochlea anatomy and the presence of auditory nerves. Moreover, patients and parents need to be in good mental health and understand what the surgery entails exactly.

Cochlear implantation is currently the best stimulation method available of the auditory pathway for patients who have a hearing impairment.

All patients receive a vaccination for pneumococcal meningitis before undergoing surgery, as patients with an implant are at a higher risk for this infection. Besides pneumococcal meningitis, there are inherent surgical and general anaesthetic risks with cochlear implantation as well as intra-operative risks, such as facial nerve damage, and the post-operative risk of infection.

During post-operative outpatient care (including switch on and monitoring), patients are required to attend regular appointments, where their recovery is monitored and they are able to receive support to gain the maximum benefit from their implants.

Although hearing with a cochlear implant will never be the same as hearing with an ear, patients will be able to have a normal life, due to the brain’s capacity to interpret the sounds it is presented with. Some patients will even be able to listen to music and experience situations where there is background noise.

In terms of modern hearing aids, they appear to be becoming smaller. However, this results in them having no ‘T’ setting for use with induction loops most of the time. Are there patients who benefit specifically from the use of induction loops? How do induction loops exactly work?

An induction loop is a cable that passes around a listening area, such as in a TV room at home, and transfers a sound signal in the form of a magnetic field. The hearing aid’s ‘T’ (telecoil) setting then picks up this signal. Either the hearing aid or the implant user will hear the speech (sound) signal through the induction loop, regardless of the extent of background noise.

Induction loop systems work by reducing the effect of background noise for people with all degrees of hearing loss who wear a cochlear implant or a hearing aid, which helps to hear sounds with more clarity. Nevertheless, the loop system has to be used in tandem with a cochlear implant or a hearing aid that is switched on to the ‘T’ setting, to operate correctly. Due to their size, some of the smaller hearing aids, like the In The Canal or the In The Ear hearing aids, may lack a ‘T’ setting because they cannot house the induction loop pick-up coil. For cosmetic reasons, some patients may also choose to give up the advantage of better hearing in noise.

What is the link between hearing problems and tinnitus? Can improved hearing support the management of tinnitus?

Tinnitus is a symptom of different conditions which mainly affect the ear. The most common of these ear conditions include acoustic trauma that leads to noise-induced sensorineural hearing loss, presbycusis and Ménière’s disease. Compared to the predominance of tinnitus in patients with normal hearing (15 to 35 per cent), reports of tinnitus in patients with severe to profound hearing loss vary considerably, from 27 to 81 per cent.

Psychological concerns, stress and anxiety have been shown to trigger the onset or the aggravation of tinnitus, and thus, a watchful and considerate patient approach is required for the management of tinnitus. At the moment, there are no controlled and approved trials for tinnitus therapies. Hearing aids are the first treatment option for patients with hearing loss and tinnitus, although their success as a treatment can differ.

What level of hearing loss may indicate that a patient could benefit from specialist adaptations such as text relay on the phone?

Patients with severe or profound hearing loss will often find it challenging to have an interactive conversation on the phone. In many cases, this group of patients will also have problems or be unable to follow quiet-room conversations if they cannot see the speaker’s face.

A textphone is a phone device with a keyboard and a display screen for the communication of text in real-time, that is also connected to the phone network. With a textphone, users can type what they want to communicate instead of speaking the message into a mouthpiece.

Patients who would like to receive more information about textphones and/or other hearing loss specialist adaptations should contact their local social services department or visit the Royal National Institute for Deaf People’s official website.

If you are experiencing, or have developed, hearing problems and you wish to know more about how cochlear implants and hearing aids could help, don’t hesitate to visit Mr Powell’s Top Doctors profile today.