Better hearing in eight steps – basic CI training at the German Hearing Center Hannover and the Department of Otorhinolaryngology at MHH
In most cases, having a cochlear implant (CI) means a tremendous increase in the quality of life. CI recipients can regain their sense of hearing and – even more important – obtain speech understanding. Until this goal is reached, they need time to get used to the new and unfamiliar auditory sensations generated by their implant. However, they can speed up this process considerably by practising – again and again. This is why MHH offers individuals who have undergone cochlear implantation a five-day basic training course at the German Hearing Center (Deutsches HörZentrum, DHZ) in Hannover.
A typical week of basic training consists of eight successive steps, which have different levels of difficulty and are tailored to each individual’s learning progress.
Step 1: Basic training starts with listening activities to differentiate between different sounds and noises in general. The CI user learns to distinguish between different characteristics of sounds and noises. What do drums sound like – or a triangle? How loud or quiet is the sound of a rattle? Next, the focus is on the melodic and rhythmic elements of speech. It is important for the CI user to recognise the number of syllables and the word stress.
Step 2: Speech recognition exercises place emphasis on phoneme discrimination (i.e. distinguishing between isolated sounds). The CI user is given a closed list of five nonsense words (in German ‘Baat, Beet, Biit, Boot, Buut’). After having mastered this exercise with the aid of lipreading, it is repeated using hearing alone so that the CI user learns to differentiate between different phonemes.
Step 3: The next step involves consonant differentiation. The CI user receives a list of sixteen nonsense words that need to be recognised (e.g. in German ‘Asa’ or ‘Awa’).
Step 4: Experience has shown that CI users first recognise numbers. The range is restricted to numbers up to one hundred as this includes all the expected hearing signals.
Step 5: A closed-set word discrimination test is used to improve word understanding. Two words which differ in the number of syllables, word stress, vowels or consonants, are presented to the CI user, who must try to listen out for these specific characteristics and identify the word. In another word understanding exercise, the CI user is given words from specific thematic areas, such as ‘cutlery’ because these words (in this case ‘knife’, ‘fork’, etc.) are then easier to recognise.
Step 6: The next step is sentence understanding. The easiest level of difficulty is understanding sentences from a closed set. The next level includes a gap exercise, in which the CI user is asked to fill in single words in a sentence using only auditory skills. The hardest level involves the CI recipient repeating sentences from a special thematic area that are read out aloud.
Step 7: Once the sentence understanding tests are successfully completed, the CI user is given a speech tracking exercise. This involves listening to phrases from a continuous narrative, which must be repeated back, either with our without lipreading.
Step 8: The eighth step is using the telephone. The CI user is placed in a different room from the speech therapist and asked to repeat sentences which are read aloud. If at first this proves too difficult, a written sheet is provided for assistance. The exercise can be made more difficult by not informing the CI recipient about the subject of the telephone conversation in advance.
As technology has been greatly improved in recent years, the CI user’s speech understanding skills will increase rapidly during the first week of training. Speech understanding in noise is still regarded as difficult. A large number of tests are therefore also carried out in background noise (e.g. audio training using special CDs with speech in noise). It has already become clear for us that the training model needs to be developed to include speech understanding in noise as the ninth step.
A visit to a rehabilitation centre may be necessary to provide additional support with basic training, to intensify auditory speech training and to improve the programming of the implant. For this purpose, close collaboration is maintained with the ‘Wilhelm Hirte’ Cochlear Implant Center (CIC) in Hannover and the rehabilitation clinics in Bad Nauheim and St. Wendel.