Speech perception and brain function: Experimental and clinical studies Kenneth Hugdahl

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1 Speech perception and brain function: Experimental and clinical studies Kenneth Hugdahl Dept Biological and Medical Psychology, University of Bergen, Norway and Division of Psychiatry, Haukeland University Hospital, Bergen Martin

Medical Psychology, University of Bergen, Norway and

2 Dichotic presentations of consonant-vowel syllables: The Right Ear Advantage (REA) /ba/ /da/ /ga/ /pa/ /ta/ /ka/ University of Bergen DL database / Hugdahl, K & Davidson, R.J. (Eds.). The Asymmetrical Brain, (2003). MIT Press, USA # Subjects Histogram (NF_FR_FL bare_voksne.sta 34v*651c) N = 651 N = N = DIFF NF (RE-LE)

3 The strength of the REA in terms of intensity difference for the right and left ear stimulus N=20 12 Current effect: F(14, 266)=45,084, p=0,0000 Vertical bars denote 0,95 confidence intervals REPORT [max 12] db INTDIFF RE LE c.f. K. Hugdahl, R. Westerhausen, H. Hämäläinn et al. Neuroscience Letters, 2008

intervals 11 10 9 REPORT [max 12] 8 7 6 5 4 3 2 1 0-21 -18-15 -12-9 -6-3 0 +3 +6 +9 +12 +15 +18

4 ..where in the brain is the bottom-up REA located? Talairach & Tournaux standardised brain atlas MR structural image MR functional image LM Rimol, K. Hugdahl, R. Savoy et al, Neuroimage, 2005 M. Van den Noort, K. Specht, K Hugdahl et al. Neuroimage, 2008

image MR functional image LM Rimol, K. Hugdahl, R.

5 Latency asymmetry: ERP-responses T7 / Left temporal cortex T8 / Right temporal cortex T Eichele, LM Rimol, H Nordby, K Hugdahl, Cognitive Brain Research (2005)

6 and may have a glutamatergic mediation at the synaptic level Drug naive Memantine K. Hugdahl, E-M Løberg, H Wageningen et al., Frontiers in Human Neuroscience, 2008

7 If the REA is localized to the left STG/STS area, it should be attenuated or abolished after prolonged TMS stimulation

8 Laterality Effects of TMS Indices: over the left STG/HG Pre area on & thepost REA 1,2 TMS Change in REA Pre-Post TMS 1,0 0,8 0,6 0,4 0,2 0,0 Case 1 Case 2 Case 3 Case 4 Case 5 Pre-TMS Post-TMS Postdoc Chris Gore, University of Bergen

TMS 1,0 0,8 0,6 0,4 0,2 0,0 Case 1 Case 2 Case 3 Case 4

9 The effect of voice onset-time (VOT) ** p <. 01 ** p <.01 /pa/ voiceless Long VOT ** /ba/ voiced Short VOT ** ** ** ** ** ** L.M. Rimol, K. Hugdahl, K. Specht et al., Neuropsychologia, 2006

10 ERP in Dichotic Listening to CV-syllables: Effects of VOT C z /N LE-short / RE-short LE-short / RE-long LE-long / RE-short LE-long / RE-long P. Sandman, K. Specht, L. Jäncke, K. Hugdahl, et al. Restorative Neurology and Neuroscience, 2007

LE-long / RE-long -50 0 50 100 150 200 250 P. Sandman, K. Specht, L.

11 Genes Environment Dyslexia Structural brain anomalies (dysplasias, ectoopias in the planum temporale area) Functional brain anomalies (reduced blood flow in temporal lobe areas, increased blood flow in prefrontal areas) Deficit in phonological decoding General language abilities: speech development, articulation, language understanding General cognitive abilities: Working memory, exceutive functions, IQ Impaired reading and writing performance Secondary problems: sentence understanding, mathematics, self confidence, school performance, life-time achievements

abilities: speech development, articulation, language understanding General cognitive abilities: Working memory, exceutive functions, IQ

12 Reduced STG/STS grey matter volume in dyslexia 1250 Planum Temporale Asymmetry Hugdahl, Heiervang et al., Scand. Audiol., 1998; Heiervang, Hugdahl, Lundervold, Steinmetz et al. Neuropsychologia, 2000 PT area mm Hugdahl, Heiervang, Lundervold et al., Neuropsychologia, Left Planum Right Planum Dyslexics Controls

, 1998; Heiervang, Hugdahl, Lundervold, Steinmetz et al.

13 Dyslexia children with a phonological decoding deficit fare worse on the DL test than other types of dyslexics Dyslexia 1 = Diagnosis and no further assessment and/or training Dyslexia 2 = Diagnosis and referred to special education unit for further assessment and/or training M Cohen,G Hynd, & K Hugdahl, Brain and Lang., 1992 T Helland, A Asbjørnsen,AE Hushovd, K Hugdahl. Dyslexia, 2007

Diagnosis and referred to special education unit for further assessment and/or training M Cohen,G

14 Specific Language Impairment (I) Few words in lexicon. Late speech acquisition. Reduced speech frequency. Resembles the language ability in younger children. Have problems finding the correct word although they seem to learn adequately in other areas. VIQ < PIQ Affects morphology. Particularly word inflections. Frequent use of root morphems and contentwords, have problems with function words Male Female Impaired male Impaired female I family from Eastern Finland K. Hugdahl, J Niemi, T Thomsen et al., J. Speech, Language and Hearing Research (2004 )

Have problems finding the correct word although they seem to learn adequately in other areas. VIQ < PIQ Affects morphology.

15 Age- and sex-matched control group I-family group

16 Children (5 8 years) at risk for dyslexia Turid Helland, UiB (PI) Sonja Ofte, Statped Vest, Bergen Kenneth Hugdahl, UiB Longitudinal study of language, reading, and mathematic skills development At-risk group 25% (26) Rest 50% (57) Index based on questionnaire 1) Controls 25% (26) Index Index S a m p l e N=109 At-risk questionnaire: Birth complications General health Language development Motor development Special education services need Heredity factors

Rest 50% (57) Index based on questionnaire 1) Controls 25% (26) Index Index S a m p l e N=109 At-risk

18 7 AGE*VOT*EAR*GROUP; N=21 Current effect: F(9, 288)=,19454, p=,99464 Vertical bars denote 0,95 confidence intervals Factors: Levels Group: con Score AGE: 5 AGE: 6 AGE: 7 AGE: 8 RE LE

19 Group-effect 7 AGE*VOT*EAR*GROUP; N=15 Current effect: F(9, 288)=,19454, p=,99464 Vertical bars denote 0,95 confidence intervals Factors: Levels Group: risk Score AGE: 5 AGE: 6 AGE: 7 AGE: 8 RE LE

20 7 AGE*VOT*EAR*KJØNN; N=17 Current effect: F(9, 288)=,49469, p=,87773 Vertical bars denote 0,95 confidence intervals Factors: Levels KJØNN: Boys Score AGE: 5 AGE: 6 AGE: 7 AGE: 8 RE LE

21 7 AGE*VOT*EAR*KJØNN; N=19 Current effect: F(9, 288)=,49469, p=,87773 Vertical bars denote 0,95 confidence intervals Factors: Levels KJØNN: Girls Score AGE: 5 AGE: 6 AGE: 7 AGE: 8 RE LE

22 7 AGE*VOT*EAR*KJØNN*GROUP ; N=8 Current effect: F(9, 288)=1,2726, p=,25137 Vertical bars denote 0,95 confidence intervals Factors: Levels KJØNN: Girls Group: risk Score AGE: 5 AGE: 6 AGE: 7 AGE: 8 6 RE LE AGE*VOT*EAR*KJØNN*GROUP; N=7 Current effect: F(9, 288)=1,2726, p=,25137 Vertical bars denote 0,95 confidence intervals Factors: Levels KJØNN: Boys Group : risk 5 4 Score AGE: 5 AGE: 6 AGE: 7 AGE: 8 RE LE

23 Summary and conclusions Functional imaging and TMS data indicate that dichotic listening with CV-syllables tap a left lateralized phonological processing module Dyslexic children suffer from a phonological processing deficit, seen as a reduction in the right ear advantage, and corresponding left temporal lobe abnormality Children at-risk for dyslexia show a lack of VOT modulation, more evident in boys than in girls. A marker of phonological awareness?

24 FIN

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