[01] Mehdi Akbari, Cellular and Molecular Research Centre (CMRC), Iran University of Medical Science (IUMS), Tehran, Iran. [02] Mohammad Taghi Joghataei, Cellular and Molecular Research Centre (CMRC), Iran University of Medical Science (IUMS), Tehran, Iran. [03] Akram Pourbakhat, Department of Audiology, Iran University of Medical Science (IUMS), Tehran, Iran. [04] Mohammad Sadegh Jenabi, Department of Speech Therapy, Iran University of Medical Science (IUMS), Tehran, Iran.

Objective: dyslexia is a neurological problem, therefore, auditory mismatch negativity was investigated in dyslexic children. Methods: 52 children with dyslexia (30 male, 22 female) and 52 controls were studied using speech and tonal stimuli. Intensity was used at 65 dB nH. The study focused on latency, amplitude and topographic distribution of MMN in both groups. Results: at the present study with speech stimulus, larger latency and smaller amplitude were found in dyslexic children when compared with controls. Topographic distribution showed larger MMN in right hemisphere than left side in dyslexic children. With tone stimulus we found no differences between two groups. Conclusions: these results provide evidence for MMN and its function in central auditory processing. The MMN using speech can be used to concentrate on the relationship between central auditory processing and learning deficits in children with dyslexia.

MMN, Dyslexia, Auditory System

[01] Ahmmed A.U., Clarke E.M., Adams C. (2008) Mismatch negativity and frequency representational width in children with specific language impairment. Dev Med Child Neurol 50(12):938–944. [02] Baker K., Baldeweg T., Sivagnanasundaram S., Scambler P., Skuse D. (2005) COMT Val108/158 Met modifies mismatch negativity and cognitive function in 22q11 deletion syndrome. Biol Psychiatry 58(1):23–31 [03] Banai, K., Ahissar, M. (in press) Auditory processing in dyslexia: task or stimulus related? Cerebral Cortex, in press. [04] Bradley, L., Bryant, P.E. (1983) Categorizing sounds and learning to read – a causal connection. Nature, 301, 419–421. [05] Bradlow, A.R., Kraus, N., Nicol, T.G., McGee, T.J., Cunningham, J., Zecker, S.G. (1999) Effects of lengthened formant transition duration on discrimination and neural representation of synthetic CV syllables by normal and learning-disabled children. J. Acoust. Soc. Am., 106, 2086–2096. [06] Datta H., Shafer V.L., Morr M.L., Kurtzberg D., Schwartz R.G. (2010) Electrophysiological indices of discrimination of long-duration, phonetically similar vowels in children with typical and atypical language development. J Speech Lang Hear Res 53(3):757–777 [07] Davids N., Segers E., van den Brink D., Mitterer H., van Balkom H., Hagoort P., Verhoeven L. (2011) The nature of auditory discrimination problems in children with specific language impairment: an MMN study. Neuropsychologia 49(1):19–28 [08] Desjardin R.N., Trainor L.J., Hevenor S., Polak C.P. (1999) Using mismatch negativity to measure auditory temporal resolution thresholds. NeuroReport 10, 2079–2082 [09] Demp, J.B., Boynton, G.M., Heeger, D.J. (1998) Functional magnetic resonance imaging of early visual pathways in dyslexia. J. Neurosci., 18, 6939–6951 [10] Galaburda, A.M. (1999) Developmental dyslexia: a multilevel syndrome. Dyslexia, 5, 183–191. [11] Horvath J., Czigler I., Jacobsen T., Maess B., Schroeger E., Winkler I. (2008) MMN or no MMN: no magnitude of deviance effect on the MMN amplitude.Psychophysiology 45(1):60–69 [12] Kraus, N., McGee, T., Carrell, T., King, C., Tremblay, K., 1995. Central auditory system plasticity associated with speech discrimination learning. J. Cogn. Neurosci. 7, 27–34. [13] Kujala, T., Belitz, S., Tervaniemi, M., Naatanen, R. (2003) Auditory sensory memory disorder in dyslexic adults as indexed by the mismatch negativity. Eur. J. Neurosci., 17, 1323–1327. [14] Kujala, T., Karma, K., Ceponiene, R., Belitz, S., Turkkila, P., Tervaniemi, M., Naatanen, R. (2001b) Plastic neural changes and reading improvement caused by audio-visual training in reading-impaired children. Proc. Nat. Acad. Sci. USA, 98, 10509–10514. [15] Kujala, T., Naatanen, R. (2001) The mismatch negativity in evaluating central auditory dysfunction in dyslexia. Neurosci. Biobehav. Rev. 25, 535–543. [16] Kujala T., Lepistoe T., Nieminen-von Wendt T., Naatanen P., Naatanen R. (2005) Neurophysiological evidence for cortical discrimination impairment of prosody in Asperger syndrome. Neurosci. Lett. 383(3):260–265 [17] Mody, M., Studdert-Kennedy, M., Brady, S. (1998) Speech perception deficits in poor readers: auditory processing or phonological coding? J. Exp. Child Psychol. 64, 199–231. [18] Naatanen, R., Picton, T. (1987) The N1 wave of the human electric and magnetic response to sound: a review and an analysis of component structure. Psychophysiology, 24, 375–425. [19] Nittrouer S. (2012) A new perspective on developmental language problems: perceptual organization deficits. Perspect Lang Learn Educ. 19(3):87–97 [20] Rinne T., Sarkka A, Degerman A., Schroeger E., Alho K. (2006) Two separate mechanisms underlie auditory change detection and involuntary control of attention. Brain Res. 1077(1):135–143 [21] Ramus, F., Rosen, S., Dakin, S.C., Day, B.L., Castellote, J.M., White, S., Frith, U. (2003) Theories of developmental dyslexia: insights from a multiple case study of dyslexic adults. Brain, 126, 841–865. [22] Renvall, H., Hari, R. (2003) Diminished auditory mismatch fields in dyslexic adults. Ann. Neurol., 53, 551–557. [23] Schulte-Koerne, G., Deimel, W., Bartling, J. & Remschmidt, H. (1998) Auditory processing and dyslexia: evidence for a specific speech processing deficit. Neuroreport, 9, 337–340. [24] Schulte-Koerne, G., Deimel, W., Bartling, J., Remschmidt, H. (1999) Preattentive processing of auditory patterns in dyslexic human subjects. Neurosci. Lett., 276, 41–44. [25] Shafer V.L., Morr M.L., Datta H., Kurtzberg D., Schwartz R.G. (2005) Neurophysiological indexes of speech processing deficits in children with specific language impairment. J Cogn Neurosci. 17(7):1168–1180 [26] Sharma A., Dorman M.F. (1998) Exploration of the perceptual magnet effect using the mismatch negativity auditory evoked potential. J Acoust Soc Am. 104(1):511–517 [27] Sharma, M., Purdy, S.C., Newall, P., Wheldall, K., Beaman, R., & Dillon, H. (2006). Electrophysiological and behavioral evidence of auditory processing deficits in children with reading disorder. Clinical Neurophysiology, 117, 1130–1144 [28] Snowling, M.J. (2000) Dyslexia. Blackwell Publishers, Oxford [29] Sussman E. (2007) A new view on the MMN and attention debate: auditory context effects. J. Psychophysiol. 21(3–4):164–175 [30] Sussman, E., Kujala, T., Halmetoja, J., Lyytinen, H., Alku, P., Naatanen, R. (2004) Automatic and controlled processing of acoustic and phonetic contrasts. Hear. Res., 190, 128–140 [31] Tallal, P. (1980) Auditory temporal perception, phonics, and reading disabilities in children. Brain Lang. 9, 182–198. [32] Temple, E., Deutsch, G.K., Poldrack, R.A., Miller, S.L., Tallal, P., Merzenich, M.M. & Gabrieli, J. (2003) Neural deficits in children with dyslexia ameliorated by behavioral remediation: evidence from functional MRI. Proc. Nat. Acad. Sci. USA, 1000, 2860–2865.