Journal of Language, Linguistics and Literature Vol. 1, No. 2, 2015, pp. 7-11 http://www.publicscienceframework.org/journal/j3l * Corresponding author E-mail address: akbari.me@iums.ac.ir (M. Akbari) Comparison Between Speech and Non-Speech Stimulus in Dyslexia: A MMN Study Mehdi Akbari 1, * , Mohammad Taghi Joghataei 1 , Akram Pourbakhat 2 , Mohammad Sadegh Jenabi 3 1 Cellular and Molecular Research Centre (CMRC), Iran University of Medical Science (IUMS), Tehran, Iran 2 Department of Audiology, Iran University of Medical Science (IUMS), Tehran, Iran 3 Department of Speech Therapy, Iran University of Medical Science (IUMS), Tehran, Iran Abstract 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. Keywords MMN, Dyslexia, Auditory System Received: March 1, 2015 / Accepted: March 15, 2015 / Published online: March 20, 2015 @ 2015 The Authors. Published by American Institute of Science. This Open Access article is under the CC BY-NC license. http://creativecommons.org/licenses/by-nc/4.0/ 1. Introduction Event-related potentials (ERPs) are voltage associated with physical or mental events, recorded from the human scalp. It can provide important results about information processing in the human brain, and about neurological or psychiatric disorders. These data extracted from the electroencephalogram (EEG) by signal averaging and filtering. These waveforms contain components that can be exogenous potentials, eliciting by the physical characteristics of the event in the external world, and the endogenous potentials. Because of the temporal resolution of the ERPs on the milliseconds, ERPs can have accurate information during the processing activities. We must concentrate on each peak, includes typical latencies, cortical distributions, and possible brain sources of observed activity. These electrophysiological recording techniques are generally noninvasive and relatively inexpensive. In contrast, the ERP approach permits investigators to link recorded signals with stimulus events more directly by focusing on the change in electrophysiological signal that occurs immediately following the stimulus event (Callaway et al. 1975; Rockstroh et al. 1982). The smaller size of the ERPs relative to other brain waves can make it difficult to be extracted and recognized. In order to recording these components, researchers used repeated presentations of the evoking stimuli to average out potentially unrelated events. ERP waveforms are typically described in terms of positive and negative peaks. The ERPs are reflected as post-synaptic (dendrite) potentials of a fairly extensive set of neurons activity. Characteristics of ERP: peak latency, amplitude, cognitive functional significance, scalp distributions, and