5th Congress Autism-Europe
Articulos / Proceeding
Autism-Spain

SOUND THERAPY: AN AUDITORY TRAINING PROGRAMME

Speech disorders and disorders of auditory perception are typical and specific syrnptoms of childhood autism. These symptoms result in disturbances of the communication system and in social disintegration.

In the history of autistic children we often hear of arrest of speech development and of speech developmental retardation in early childhood, of disorders of directional hearing, of sound discrimination disorders, of auditory hypersensitivity and of retardation in phonological awareness. Twenty years ago Delacato gave us descriptions of hypersensitivity and hyposensitivity in autistic children.

The factors of auditory hypersensitivity are obvious in 80% of autistic children and cause a multitude of stressful and disturbing symptoms.

Auditory hypersensitivity is a symptom which does not only occur in children with autism. We found this symptom in children with speech disorders, in children with cerebral palsy, in children with postcontusional neurological diseases and in children with hereditary auditory hypersensitivity.

The neuropathological basis of developmental speech disorders and auditory perception disorders in autism have partly been investigated. Different authors have reported on the structural anomalies of the left hemisphere, the brainstem and the cerebellum. Nuclear magnetic resonance imaging studies in some cases revealed hypoplasia of the brainstem and of lobules VI and VII of the cerebellar vermis. Dysfunction of the hippocampus has often been postulated. The most important abnormalities of the neurobiological studies of Bauman and Kemper can be summarized as follows:

1. abnormally small neurons in the amygdala, the entorhinal cortex, the septal nuclei, and the hippocampus.

2. abnormally few Purkinje cells in the cerebellar cortex,

3. cellular dysplasia in the deep cerebellum and the inferior olivary nuclei.

These findings could support explanations of some pathological disturbances of emotion, memory, interaction, activity and attention. Additionally they may explain some neurophysiological anomalies of the primary hearing processes.

Different studies of evoked responses to auditory stimuli showed prolonged latency of wave I, II, and V and prolonged interpeak latencies. It seems reasonable to suppose that the cause could be a diffuse dysfunction of the brainstem. Furthermore: we suppose a dysfunction of the feedback between the brainstem, the olivary nuclei and the cochlea. Wave I abnormalities are expected in cases of cochlear involvement.

Our findings support the detailed meta-study of Klin who summarizes other important

vestibular reactions and abnormalities in long-latency, event-correlated brain potentials. Most of the auditory brainstem response studies are at present controversial rather than supportive of this thesis. Partially they are not comparable, for example in respect to the changing masking levels of the contralateral ear as children with autism often suffer from hypersensivity to background noise.

The neuroanatomic observations in the brainstem and in the cerebellum and the neurophysiological abnormalities in autism lead to the hypothesis that the cochlear and brainstem dysfunction may cause dysfunctions of the outer hair cells of the cochlea. The motile responses of the outer hair cells are specialised to perform a facilitatory function on sound discrimination at low levels, on white noise stimuli and on the regulatory processes which protect against loud noise. Transient-evoked otoacoustic emissions offer an objective way of evaluating the peripheral auditory system and the outer hair cell function. Our own studies of autistic children without hearing loss show increased numbers of abnormalities but faded to prove significant changes after hearing training.

Abnormalities have also been described in studies of event-correlated brainstem potentials: children with autism have a decreased amplitude of P3b, which might show their difficulty in anticipating everyday situations. It is hard for them to get used to repetitive similar stimuli and to primary event recognition: a result with relevance to social intercourse. Furthermore age-independent alterations of the nc-component point to an inborn dysfunction of basic auditory awareness. Children with autism often do not perceive short and intense stimuli like a door banging or a gun shot, whereas they are intolerant of longer stimuli like the blast of a hooter, the noise of flushing the toilet, or the buzz of a vacuum cleaner. Other children are scared of sudden unexpected sounds. They panic or they protect themselves by decreasing their auditory awareness.

This is how cooperative children are examined by our team:

Sound therapy has prooved to be an effective training of central hearing disorders. We

could demonstarte that marked improvements can be achieved: decreased auditory hypersensitivity, increase in auditory attention and in auditory background discrimination, decreased auditory reaction time and interstimulus interval.

Secondary effects are improvements in speech perception, in the quality of articulation, in voice modulation, and in social interaction. Auditory stereotypes are decreasing. Some children are then able to describe the hearing sensations they had before treatment. They speak about the disturbing internal sounds, about the white noise generated in the inner ear, about the irritating sounds of electrical houshold appliances, engine noise, animals, high frequency human voices, high frequency heater noice, high frequency television sounds, sounds of capacitators. They even sometimes give descriptions about their feelings when they were able to listen to conversations held in a distance and in adjoining rooms. Sometimes they feel relieved after the hearing training, sometimes they regret losing attractive capacity.

Hearing training and sound therapy are not age-limited. In principal auditory training should start as early as possible. Therapy should be able to profit from the physiological maturation processes of the brain. Children under the age of 4 years have rarely been treated. As a limiting factor handicaped and little children often don't tolerate the headphones.

We regard treatment-resistent convulsive disorders and latent epilepsy as the only contraindication of sound therapy. Anticonvulsive drugs or other previously prescribed medications should not be interrupted during the training period. Only psychopharmaceutical treatment should be decreased as far as possible before the training starts.

After finishing sound therapy some children go through a stage of overreactivity and hyperactivity. We are working on the assumption that this is a phenomena of change, in which the children learn how to take in and how to integrate alterated hearing events in their every day life. Changes in communicative and social behaviour often become evident only after going through that phase.

Our patients were treated by Claudia Nyffenegger in Bern (Switzerland) according to Dr. Bérard. The auditory training method has constantly been improved in the last few years. One treatment session takes two weeks. During these two weeks the patient listens to music for 30 minutes twice a day. Any music on CD is used: from classical to pop music, distorted for several seconds by a computer. Changes consist mainly in filtering and changing frequency and volume. They are either induced by random selection (thus impredictable for the patient) or can be synchronized with the rhythm or inserted with increasing volume.

The changes of high-frequency filtered music are audible and after some time strenuous. Volume, intensity and frequency of filtered-music intervals vary according to individual sensitivity. High-frequency filtered music seems to be very effective in the treatment of hyperacusis, prolonged speech perception time and sound discrimination disorders.

6-9 months after the sound therapy we start a training programme with high-frequency filtered music which is available on commercially produced CD's. This is classical music which has been altered by high-extension and envelope shape modulation. The effect of high-frequency filtered music can be obtained when listening with earphones. The same music on CD's is altered in another form called lateralisation which means that defined parts of the frequency spectrum move slowly from one ear to the other. It stays there for just a moment and then moves through the center to the other ear in an ever repeating pattern. The children's reactions to lateralisation are various. Changes in activity and awarenwss range between relaxation and agitation depending on lateralisation speed, hold-time on one ear and the basic psychological situatio. Dizziness and exhaustion can result trom too short lateralisation time. The effect is an improvement of the dichotic hearing and of the phonological awareness. The patient should listen to this music in a relaxed athmosphere 20-45 minutes daily at home. The treatment should be continued during 2 months.

The third stimulating factor, which we know to be of great importance for children with a good expressive speech development, is forced auditory feedback by microphone and headphone. Different training appliances are available and support feedback of the child's own speech, altered by high-frequency filters and by lateralisation. As input we use spontaneous speech in conversation as well as therapeutical concepts (sound discrirnination training) or reading of a text. Newly developed training devices support the possibility of time-variable lateralisation, high-frequency sound matrix in different intensities and frequencies and auditory feedback. Home training devices guarentee sufficient prolongation of the initial training effect. After an intense introduction time parents are enabled to continue the treatment during a three month period at home.

At the end of the ínitial training and after 3, 6 and 12 months we repeat the diagnostic block. Repeated pure tone audiometry testsoften show alterations: the auditory threshold has evened out and descended and adjusted between the two ears. Reaction times have decreased, discomfort-/pain-threshold has markedly lifted and better sound discrimination and phonological awareness have been achieved.

During the foflow-up we often recognize a weakening of the treatment's effects. In such cases we repeat the initial Bérard training, alternatively we fit in a training session with the training CD's or with the home training. By these methods the initial training effect can constantly be maintained.