Mismatch negativity in children with dyslexia speaking Indian languages

Maruthy, Shankarnarayan Vanaja, Maruthy Sandeep

Description

Several studies in the past have found that phonological processing is abnormal in children with dyslexia. Phonological processing depends on the phonological rules of the language learnt. Western languages do not have a good phoneme to grapheme correspondence while many of the Indian languages do have it. Also phonological rules of western languages are different from that of Indian languages. Thus it would be erroneous to generalize the results of phonological processing obtained on children speaking western languages to those speaking Indian languages. Hence the present study was aimed to investigate the auditory processing in children with dyslexia who spoke and studied Indian languages. Methods Standard group comparison design was used in the study. The study was conducted on fifteen children with dyslexia and fifteen control children. Mismatch negativity was elicited for speech and tonal stimuli. Results obtained on the clinical group were compared with that of control group using mixed design Analysis of variance. Children in both the groups were native speakers of Kannada (a south Indian language). Results A subgroup of children showed abnormalities in the processing of speech and/or tonal stimuli. Speech elicited mismatch negativity showed greater abnormalities than that of tonal stimuli. Though higher for spectral contrasts, processing deficits were also shown for durational contrasts. Conclusion Inspite of having different phonological rules and good phoneme-grapheme correspondence in Indian languages, children with dyslexia do have deficits in processing both spectral and durational cues.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2007
• Nombre de lectures: 12
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Behavioral and Brain Functions

BioMedCentral

Open Access Research Mismatch negativity in children with dyslexia speaking Indian languages Vanaja Chittinahalli Shankarnarayan and Sandeep Maruthy*

Address: Department of Audiology, All India Institute of Speech and Hearing, Mysore, India Email: Vanaja Chittinahalli Shankarnarayan  [e-mail]; Sandeep Maruthy*  [e-mail] * Corresponding author

Published: 31 July 2007Received: 17 July 2006 Accepted: 31 July 2007 Behavioral and Brain Functions2007,3:36 doi:10.1186/1744-9081-3-36 This article is available from: http://www.behavioralandbrainfunctions.com/content/3/1/36 © 2007 Shankarnarayan and Maruthy; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:Several studies in the past have found that phonological processing is abnormal in children with dyslexia. Phonological processing depends on the phonological rules of the language learnt. Western languages do not have a good phoneme to grapheme correspondence while many of the Indian languages do have it. Also phonological rules of western languages are different from that of Indian languages. Thus it would be erroneous to generalize the results of phonological processing obtained on children speaking western languages to those speaking Indian languages. Hence the present study was aimed to investigate the auditory processing in children with dyslexia who spoke and studied Indian languages. Methods:Standard group comparison design was used in the study. The study was conducted on fifteen children with dyslexia and fifteen control children. Mismatch negativity was elicited for speech and tonal stimuli. Results obtained on the clinical group were compared with that of control group using mixed design Analysis of variance. Children in both the groups were native speakers of Kannada (a south Indian language). Results:A subgroup of children showed abnormalities in the processing of speech and/or tonal stimuli. Speech elicited mismatch negativity showed greater abnormalities than that of tonal stimuli. Though higher for spectral contrasts, processing deficits were also shown for durational contrasts. Conclusion:Inspite of having different phonological rules and good phoneme-grapheme correspondence in Indian languages, children with dyslexia do have deficits in processing both spectral and durational cues.

Background Developmental dyslexia is a specific disability in learning to read and spell adequately despite at least normal intel ligence, adequate instruction, adequate sociocultural opportunities, and the absence of sensory defects in vision and hearing [1]. In India, prevalence of dyslexia varies between 3% and 10% [2].

The causes of dyslexia are numerous and often are poorly defined. There are several theories that attempt to account for dyslexia. Snowling [3] classifies the theories that have received most attention into two general approaches. The first is domain specific view, which posits that the dyslexia arise from deficits in systems that are specifically linguis tic; in phonological processing and memory. The second school of thought claims the core deficits in underlying

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