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Effects on specific auditory stimulation on language processing
Introduction:
At the Secondary School BC Broekhin Roermond has been carried out a Pilot Study about the
possible effects of specific auditory stimulation on language processing. This study needs
some international comparison to find out if children from other countries and other languages
also can benefit from this specific auditory stimulation.
Three schools from Norway, Sweden and Italy are interested in a similar study. Is it possible
to make use of a subsidy to finance this study in the next two years?
Purpose of the study:
The recent developments in understanding our auditory perceptual abilities, their
development, their disruption and their relation to language ability, have led some clinicians,
educators and researchers to suggest that it might be possible to train or stimulate the auditory
system in individuals with language problems in such a way that their perceptual abilities
improve and that such stimulation after some time may also have an effect on language
production (Merzenich et al. 1996; Tallal et al. 1996).
Tallal et al. (1981) concluded that many language problems in school are a result of auditory
perceptual impairments, particularly in temporal aspects of sound recognition. An area of
interest was the effective use of acoustically modified speech and adapted neuroplasticity
training to improve language processing (Tallal et al. 1996 and Merzenich et al. 1996). This
conclusion led to a focus on strengthening the relevant neural pathways through modified
presentation of acoustic stimuli (Tallal & Merzenich, 1997). Moncrieff & Wertz (2001)
trained children with left ear deficits intensively in two phases of dichotic listening training.
In phase I and II children showed improved dichotic listening after training. A promising
additional finding was that by phase II, subjects were also showing significant improvements
in language comprehension and word recognition.
The purpose of this Pilot Study was to determine whether often heard claims from teachers
and parents, that some methods of non-verbal auditory stimulation are beneficial for some
students, could be validated.
For more than fifty years a very large number of therapists and educators in Europe and in
North America have found that specific non-verbal stimulations with music and/or sounds
seem to have beneficial effects on language and learning impaired students’ development
when used to support remedial teaching. I found that the stimulation method developed in
Denmark by Dr. Kjeld V. Johansen was addressing each individual student’s needs and at the
same time made it possible to control development during the stimulation period so rigorously
that this system was optimally suited for a controlled study.
Research questions:
What are the effects of HSAS (Hemisphere Specific Auditory Stimulation) on language in
dyslexic students (compared to a control-group of dyslexic students and a control-group of
non-dyslexic students initially at the same level) in:
-reading
-spelling
-writing
-rapid naming
-memory
Study: “Effects on specific auditory stimulation on language processing ”.
-2-phonemic analysis
-hearing curves
-auditory laterality
-What are the effects on attention/concentration, co-ordination and behaviour.
-Is there an effect on automaticity of any kind (like tying shoelaces, learning computer games,
etc.), not concerning the items mentioned above.
Description of the study:
Subjects
In this pilot study we worked with 28 pupils (age 13-17) divided into three groups. Two
groups (1 and 2) of pupils (N=10, f: 3, m: 7) diagnosed as dyslexic and one group (N=8, f: 3,
m: 5) of non-dyslexic pupils. All pupils and their parents gave oral and/or written consent to
participate in the study.
To get a well-balanced classification of three, qua level, equal groups the following criteria
were considered:
-age
-grade
-gender
-total IQ
-verbal IQ
-performance IQ
-technical reading (decoding)
-reading comprehension
-spelling
-mathematics / calculation.
This information was obtained from the pupils’ personal files.
(It was extremely difficult to find dyslexic and non-dyslexic pupils with the same levels in
mathematics / calculation).
Subgroup 1 had: 7 right-hander’s, 1 left hander and 2 ambidextrous, group 2: 10 righthander’s and group 3: 5 right hander’s, 1 lefthander and 2 ambidextrous.
Subgroup 1 (the treatment group) was formed after talks with the pupils and their parents
where the pupils stated that they were willing to listen for 10 min. a day through the full
training period and where the parents agreed to supervise.
Based on the data from these tests an analysis of variance (ANOVA) was performed between
the three groups involved in the experiment:
Group 1: Dyslexics with special remedial education and auditory stimulation.
Group 2: Dyslexics only with special remedial education.
Group 3: Non-dyslexics.
Tests used
The following skills were tested before and after the period of auditory stimulation. All three
groups were tested with the same tests.
Technical Reading (decoding)
Reading comprehension
Spelling
Study: “Effects on specific auditory stimulation on language processing ”.
-3Writing / copying
Auditory memory
Visual memory
Phonemic Analysis
Rapid Naming
Audiometric testing including:
Audiogram (hearing curves of R and L ear)
Auditory Laterality (Binaural Pure Tone Audiometry / Dichotic Listening)
Completed with:
Parent and student questionnaires (group 1) on attention, behaviour, concentration and
automaticity.
Technical equipment
The audiometric assessments were carried out using a computer based, calibrated audiometer
developed by Mediacenter Mjölby, Sweden. The audiometer (to determine the hearing
thresholds of the R and L ear) is placed on an Acer Travel Mate 662LCi using Telephonics
TDH-39P earphones. Calibration showed less than 0.1% deviance on any frequency and less
than 0.5% deviance on any dB level. Also on the computer (called a Sensograph, SG) is a
dichotic listening test developed by Baltic Dyslexia Research Lab.
Method of stimulation
Based on the audiometric assessment a CD with selected music is recorded on the computer.
The audiometric data are transported to a built-in equalizer (part of the SG) which applies an
audiometric adjustment procedure by which the amplitude for each frequency is lowered or
raised to fit pre-programmed reference values.
Each pupil listened to a number of individually customized CDs in periods of 8-12 weeks.
Listening to the CD takes place via stereo earphones at home for 10 min. a day. The pupil
listens in a relaxed state either sitting or lying down. The type of CD player does not seem
crucial while the type of earphone does. (Some earphones give an extra boost in the lower
frequencies. This influences the music on the CD.) For this study all participants used
Sennheiser HD477.
Each recording was based on an audiogram made just before the customization took place. In
the recording process the SG uses pre-programmed levels as reference values, referred to as
the optimum hearing curve, (OHC) (Johansen, 2002; Tomatis, 1963, pg. 101). OHC: 125 Hz:
20dB, 250 Hz: 15 dB, 500 Hz: 12 dB, 750 Hz: 10 dB, 1000 Hz: 5 dB, 1500 Hz: 0 dB, 2000
Hz: -5 dB, 3000 Hz: -10 dB, 4000 Hz: -10 dB, 6000 Hz: -5 dB, 8000 Hz; 0 dB.
After a period of 8-12 weeks the pupil is re-assessed and a new recording following the same
principles is made. Some pupils will need 3-4 CDs, others will need as many as 8-10 CDs. In
this pilot study the average number of CDs used was 8. In the study reported by Johansen
(2002) the average length of the stimulation period was 29 weeks ranging from 10 weeks to
65 weeks.
The music
The music used has been designed especially for Hemisphere Specific Auditory Stimulation
(HSAS) by Bent-Peder Holbech and Kjeld Johansen and has been in use since 1984. Initially
it was produced on individually recorded cassette tapes but is now produced on individually
customized CDs. Each CD contains 60 minutes of music selected and combined from a
number of 5 or 10 minute compositions each in a narrow frequency range (1½ octaves), using
the seven major keys and with 60 beats per minute. In total the frequency range 50 Hz to
12000 Hz is covered. To ease the customization and recording process all music is stored on
Study: “Effects on specific auditory stimulation on language processing ”.
-4the hard disk of the SG. The selection of the right music for each individual pupil is a
professional task.
Data analysis
Comparisons between the three groups showed significant variances in the following areas:
Sound processing (Klepel non-word test and phonemic analysis). Not surprisingly, group 3
showed the best results initially (higher score on non-words and less errors in phonemic
analysis), but this group showed no improvements during the period. Groups 1 and 2 both
improved and the improvements in group 1 reached statistical significance.
Technical reading/decoding (EMT and reading aloud). Results from these tests again
showed that group 3 had higher scores but fewer improvements than group 1 on EMT and
than group 1 and 2 on reading aloud. On both tests the results from group 1 reached statistical
significance.
Spelling. The improvement in group 1 reached statistical significance. Group 2 showed
improvement as well but group 3 did not improve.
Information processing (rapid naming). The total scores from group 1 showed significant
improvement. Groups 2 and 3 also showed improvements, but the results did not reach
statistical significance. Six out of eight subtests administered to group 1 showed statistically
significant improvements. Two subtests (letter naming and color naming) showed no
statistically significant improvements in group 1, but in the color naming subtest a larger
improvement was found in group 1 than in group 2 or group 3.
Visual memory. Groups 1 and 2 both showed statistically significant improvements. Group 3
also showed improved results. The improvements found in group 1 were the largest.
Audiometry. Hearing curves for left and right ear. Hearing curves for group 1 improved very
significantly compared to the two other groups. Improvement of hearing (altered sensitivity)
is part of the theory behind HSAS.
Auditory laterality. Dichotic listening test. A statistically significant improvement for the
right ear was seen in group 1. Group 3 also showed a significant improvement, but most of the
pupils in this group already showed a right ear advantage (REA) from the beginning.
Obtaining or improving REA is also part of the underlying theory behind HSAS.
On the following subtests no statistically significant improvements were found in group 1:
Reading comprehension (total score). On the pretest group 3 scored less than group 1 and 2,
but this group had a statistically significant improvement from pre- to post-test. Groups 1 and
2 also showed improved results but they did not reach statistical significance. (It is interesting
to note that in the result “macro score” for reading comprehension group 1 showed more
improvement than did group 2 and 3. In “micro score” as well as in “meso score” the
opposite results were found).
Writing/copying. Group 1 showed a larger improvement than group 2 and 3 but the result did
not reach statistical significance. The results from group 3 were, according to pre- and post
tests better than the results from group 1 and 2, but interestingly showed a slight decrease
from pre- to post test.
Auditory memory. No group had statistically significant improvements. Group 3 even had a
decrease in score from pre- to post test.
From earlier studies it is known that the Johansen Sound Therapy can improve reading and
spelling. However, dyslexics can have problems in other areas. Therefore, other tests were
involved in this study. It wasn’t surprising to find significant improvement with reading and
spelling. Remarkable was the improvement on sound processing and information processing.
These processing abilities are fundamental for reading and spelling. Very remarkable was the
Study: “Effects on specific auditory stimulation on language processing ”.
-5significant improvement of visual memory. The visual and auditory centers in the brain are
situated closely to each other. (Together with the motoric centre). Indirectly these areas are
also stimulated by this therapy. Most remarkable was that the auditory memory didn’t
improve significantly. On the other hand writing / copying improved significantly as well.
Reading comprehension did improve, but not significantly. I thought that, after this treatment,
the students would have enough tools to improve this as well. Probably this is not the case.
Reading still can be seen as an unavoidable task that often is carried out without motivation
and enthusiasm.
Conclusion:
Dyslexics most often show impaired phonological processing. Some research has
concentrated on the temporal aspects of language sounds (Merzenich et al., 1993) while
others have looked more at the categorical perception of vowel sounds (Bertucci et al., 2003).
To our knowledge few researchers have tried to link ear advantage and even fewer basic
auditory skills in the perception of pure tones at different frequencies to language
development and to language problems including specific reading and spelling difficulties.
This project shows that statistically significant improvements in auditory sensitivity
documented by altered audiograms and statistically significant changes of auditory laterality
documented by dichotic listening, obtained by non-verbal auditory stimulation, are
accompanied by statistically significant improvements in decoding, spelling, reading aloud,
phonemic analysis, rapid naming, visual memory and behavior.
More research addressing individuals with different auditory and visual profiles is necessary,
especially in other language areas, but this pilot study seems to indicate that carefully planned
intervention using an empirical method with selected individuals suffering from specific
sensory problems alongside with dyslexia may be beneficial.
The Johansen-IAS therapy is successfully applied at our school. There is an international
interest in this therapy. It would be of a great value to have the possibility to compare our
results with results obtained abroad. We hope that students with language problems from
different European countries can benefit from this therapy to have a successful school career.
Wim de Zwart, MA
Remediaal Specialist – Johansen-IAS therapist
BC Broekhin Roermond
Study: “Effects on specific auditory stimulation on language processing ”.