Hearing Implant Invisible
A cochlear implant is an electronic hearing prosthesis. It converts sound into electrical signals and transmits them directly to the auditory nerve. The damaged areas in the ear can thus be bypassed.
For a long time, treatment with a cochlear implant was considered only in exceptional cases of unilateral deafness, because it was feared that the cochlear implant might impair speech understanding in the normally hearing ear. However, the University Hospital of Freiburg has clearly refuted this.
Late effects of unilateral deafness
Causes of unilateral deafness can include congenital malformations of the ear, tumors on the auditory nerve (known as schwannomas in the organ of balance or the cochlea), head injuries, or a hearing loss. Medical studies have shown that long-term unilateral deafness can have serious consequences for those affected. For example, it leads to impaired memory and other mental abilities and increases the risk of developing dementia.
More than that, over time this impairment can also lead to social isolation, as, for example, large family gatherings or restaurant visits with friends represent an enormous burden and effort for those affected. They often end up avoiding such situations.
Surgery behind the ear
A cochlear implant can help these patients hear again in the deaf ear. The electronic hearing prosthesis consists of a speech computer and coil with an electrode.
During surgery, a coil with an electrode is implanted into the bone behind the patient's ear. From there, the one-millimeter-thin electrode is carefully inserted into the cochlea up to the auditory nerve, where it electrically stimulates the auditory nerve. In this way, external sounds are transmitted directly and without detours to the auditory nerve.
For a long time, the use of a cochlear implant was considered impossible in patients whose cause of unilateral deafness is a schwannoma, a benign tumor in the cochlea. Usually, the tumor completely fills the cochlea and sometimes the organ of balance. Once the tumor is removed, there is not enough tissue left to insert the implant.
New surgical technique also provides remedy for tumor patients
A new surgical technique has been developed at Halle University Hospital that now makes this possible. First, the hard capsule of the cochlea is surgically removed, in contrast to the classic method. However, it is important that the area where the auditory nerve cells are located is preserved.
The tumor is then completely removed and the electrode of the cochlear implant is placed around the remaining stump of the cochlea containing the auditory nerve cells. The capsule of the cochlea is then reconstructed, i.e. filled with the patient's own body material. To date, 30 patients have been successfully fitted with a cochlear implant in this way.
Normalization only after six months
The first impression of hearing after the cochlear implant is "turned on" is different for each patient. It is not uncommon for the wearer to recognize the technician's voice immediately and also to understand his or her words directly. However, the sound impression is unusual in every case: tinny, mechanical, artificial like a computer voice. In other cases, acoustic perception is limited to sounds and tones during the first few days.
Slowly, the brain begins to analyze the new auditory impressions and match them with familiar sound patterns. This happens all by itself, but can be supported and accelerated by appropriate exercises in aftercare and rehabilitation. Gradually, speech understanding returns and the sound of voices, tones and sounds becomes more natural. It takes at least six months, often longer, until a clear, differentiated sound perception is achieved that is once again perceived as "beautiful".