الفهرس 
Chapter (1): Mismatch NegativityOnly 14 pages are availabe for public view
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Abstract
Specific language impairment (SLI) is one of the most common language disorders of the childhood. The aetiology of SLI has been associated with a central auditory processing deficit disrupting the normal language development of affected children. One important aspect for language acquisition is the discrimination of different acoustic features, such as frequency information.
The mismatch negativity (MMN) is an endogenous event related potential, that is generated when an auditory stimulus deviates in some way from recent stimuli that were similar to each other .Mismatch negativity, an electrophysiological measure, evaluates the brain’s capacity to discriminate sounds, regardless of attentional and behavioral capacity. Thus, this auditory event-related potential is promising in the study of the neurophysiological basis underlying auditory processing.
The aims of this study was to asses cognitive function in children with SLI using mismatch negativity and to compare MMN in children with SLI with normal language development children.
The study group (SLI group)included 40 children in the age range of4–7 years, who attended the Phoniatric unit, University Hospitals, and had been diagnosed as having specific language impairment. The control group included 40 healthy with normal language development and age range 4-7 years.
The included patients were submitted to full history taking, language evalution, IQ assessment, otoscopic examination, audiological evaluation, MMN evalution.
The current study demonstrated statistically significant difference between MMN latency, amplitude of both groups. Latency of MMN was more prolonged in SLI group than control group with lower amplitude in SLI group. Abnormal MMN test either absent, abnormal latency or abnormal amplitude, was reported in ≈ 91 % of SLI cases. So ,the language impairment in SLI children reflects underlying auditory processing deficits.