Auditory training – a natural way to affect impaired
tone matching in dyslexia
Korpilahti P.1,2,3, Zachau S.2,3, Heinänen, K. 2,3, Ervast L.2,3, Rytky S.2
PohjoisPohjois-Pohjanmaan
sairaanhoitopiiri
1 School
of Finnish and General Linguistics, University of Turku, Finland
Laboratory, Clinical Neurophysiology, Oulu University Hospital, Finland
3 Department of Finnish, Information Studies and Logopedics, University of Oulu, Finland
2 Cognitive
University of Turku
Background
Introduction and Intervention
Subjects and Stimuli
• Deficient auditory processing is often reported in dyslexia 1,2.
• Impairment in tone matching is quite permanent and in most cases stays
unchangeable even in adulthood 3.
IADT ® (Individual Auditory Discrimination Training) has it’s background in
the theory of Tomatis 4. The auditory perceptual profile (both monaural and
dichotic testing in tones and words) is used as a starting point for the
intervention to increase sensitivity for the central frequencies of the speech.
IADT® is based on synthesized music that is moulded individually according
the hyper- and hypoactive features when compared with the optimum
hearing reference curve by Tomatis. In many individuals suffering from
sensory problems, atypical auditory sensations and primitive reflexes are
related to each other, so the auditory intervention is often combined with
sensomotor training.
• SynAmps, Scan (NeuroScan), 1000Hz sampling rate, onon-line bandband-pass 0,050,05-200 Hz, offoffline bandband-pass 0,50,5-20 Hz, reference: linked mastoids, artifacts rejected if +/+/- 150 µV
Young adult dyslexics, N = 10, mean 18,6 years (range 17-20 yrs)
Typically developed, age matched controls, N = 10
The oddball paradigm was used to declare:
1) if the brain activation can be normalised by intensive auditory training
2) if simultaneous changes can be seen in behavioural skills:
technical and comprehensive reading, naming (Table 1.), and
profiles of adaptive and maladaptive behaviour (ASEBA 5).
Intervention 6 months (15 minutes per day) in controlled conditions
Auditory ERPs recordings:
at the beginning of the study
after 6 months training
after 3 months follow-up
ERP conditions: sine tones 1800/2000/2200 Hz and 3600/4000/4400 Hz, 100 ms
syllables AMA/ANA/ALA, 400 ms
(each deviant p=.10)
Results and Conclusions
Baseline: In dyslexics the ERP pattern was atypical for adults. The latency of N1 was long, showing immature response and primary deficits in auditory orienting.
After training: Latencies of N1 decreased statistically (1800/2000/2200 Hz, p=.009; 3600/4000/4400 Hz, p=.017) especially over the LH (Fig. 1). The intervention
activated auditory potentials (both for standards and deviants), and after the follow-up also the discriminative component MMN was growing in amplitude, Fz
p=.003 (Fig. 2). The lateralization for verbal stimuli was normalized to the LH, and the amplitude of MMN was increasing, Cz p=.013 (Fig. 3.). Our results show that
adult brains have plasticity for auditory training and that dyslexic learning difficulties can be relieved with individually planned and intensive intervention.
Fz Dev ANA Std
Fz Dev 2200 Hz Std
[µV]
[µV]
PRE
Fz-M1M2 Av eDev 1M AveDev 2M
[µV]
-4.5
PRE
-4.5
PRE
-9
-8
-4.0
-4.0
-7
-3.5
-3.5
-6
-3.0
-3.0
-5
-2.5
-2.5
-2.0
-4
-2.0
-1.5
-3
-1.5
-1.0
-0.5
100 - 125 ms
-1.0
-2
125 - 150 ms
0.0
100 - 200 ms
200 - 300 ms
-1
-0.5
0.5
0
0.0
1.0
1.5
1
0.5
2.0
2
1.0
2.5
3
1.5
3.0
3.5
4
2.0
4.0
5
2.5
4.5
-50
0
50
100
150
200
250
300
350
400
450
500
550
[ms]
6
3.0
7
3.5
151 - 176 ms
Fz-M1M2 Av eDev 1 Av eDev 2
176 - 201 ms
POST (6 mo) + FOLLOW-UP (3 mo)
-9
-8
0
100
200
300
400
500
[ms]
-2.0 µV
0 µV
0
2.0 µV
Fz Dev 2000 Hz Std
POST
-4.5
-4.0
-3
200
300
400
500
600
700
[ms]
-2.0 µV
0 µV
2.0 µV
[µV]
-5
-4
100
Fz Dev ANA Std
[µV]
-6
400 - 500 ms
9
4.5
-7
300 - 400 ms
8
4.0
[µV]
POST
-9
-8
-3.5
-7
-3.0
-6
-2.5
-5
-2
-1
0
1
-2.0
-4
2
-1.5
-3
3
-1.0
4
5
100 - 125 ms
-2
125 - 150 ms
-0.5
-1
0.0
0
0.5
1
1.0
2
1.5
3
2.0
4
2.5
5
100 - 200 ms
200 - 300 ms
6
GIRL; 19 years
7
8
9
-50
0
50
100
150
200
250
300
350
400
450
500
550
[ms]
Fig. 1. N1 elicited by 1800/2000/2200 Hz.
Black: standard 1800 Hz. Red: deviant 2000 Hz.
Blue: deviant 2200 Hz.
3.0
6
3.5
7
4.0
151 - 176 ms
176 - 201 ms
100
200
300
400
500
[ms]
-2.0 µV
0 µV
0
2.0 µV
Fz Dev 2200 Hz Std
PRE
POST +
FOLLOWUP
8;9
18,5
9;8
29,4 **
P = .006
Boston
Naming
Test
45,6
48,2
FOLLOW-UP
300
400
500
600
[ms]
-2.0 µV
0 µV
2.0 µV
FOLLOW-UP
-9
-4.0
-8
-3.5
-7
-3.0
-6
-2.5
-5
-2.0
-4
-1.5
-3
-1.0
100 - 125 ms
-2
125 - 150 ms
-0.5
-1
0.0
0
0.5
1
1.0
2
1.5
3
2.0
4
2.5
5
3.0
100 - 200 ms
200 - 300 ms
6
3.5
7
151 - 176 ms
4.0
176 - 201 ms
4.5
0
Table 1. Changes in behavioral skills.
Mean values (N=10).
200
[µV]
-4.5
Spelling
(subtest in
technical
reading)
100
Fz Dev ANA Std
[µV]
Reading
age in ALLU
yrs; mo
400 - 500 ms
9
0
Testing
300 - 400 ms
8
4.5
100
200
300
400
500
[ms]
-2.0 µV
0 µV
GA ERPs N = 10
2.0 µV
Fig 2. Non-verbal 1800/2200 Hz (dev 10 %).
301 - 401 ms
8
401 - 501 ms
9
0
100
200
300
400
500
600
[ms]
-2.0 µV
0 µV
2.0 µV
Fig 3. Verbal AMA/ANA (dev. 10 %).
Panels on the left: standard, deviant, MMN.
Maps: MMN distribution over the scalp.
Top: before training. Middle: after intervention (6 mo). Bottom: follow-up (3 mo).
Literature & Framework
Supported by:
Habib M (2000) The neurological basis of developmental dyslexia: an overview and working hypothesis. Brain, 123, 2373-2399.
Kujala T (2002) The MMN as an index of auditory dysfunction in dyslexia. In E Witruk, AD Friederici & T Lachmann (Eds.)
Basic functions of language, reading and reading disability. Dortrecht: Kluwer Academic Preublishers, pp. 359-368.
3 Shaywitz SA, Fletcher JM, Holahaan J, et al. (2002) Persistence of dyslexia. Pediatrics, 104, 1-9.
4 Tomatis, A.A. (1991) The conscious ear. New York: Station Hill Press.
5 Achenbach, T.M. & Rescorla, L.A. (2001). Manual for the ASEBA School-Age Forms & Profiles. Burlington, VT: University of Vermont.
IADT ® (Individual Auditory Discrimination Training); Modified and further developed by H. Hätinen (www.pekuoy.fi) from the
method of K. Johansen, Baltic Dyslexia Research Lab ApS.
1
2
Finland’s Slot Machine
Association, RAY
awarded to Dyslexia
Association in Ylä-Savo,
Finland
Correspondence:
Pirjo Korpilahti, Logopedics,
School of Finnish and General
Linguistics, Itäinen Pitkäkatu 3a,
20014 University of Turku,
Finland
pirjo.korpilahti@utu.fi