Background and Aim: Learning disability(LD) is one of the most prevalent problems among elementary school children. Approximately 10 percent of all elementary school children suffer from this problem. It has been determined that learning disability is predominantly accompanied with subtle impairment in central auditory nervous system. The main idea of this study was to evaluate middle latency auditory evoked potential (MLAEPs) in learning disabled children.

Materials and Method: This cross-sectional study investigated middle latency auditory evoked potential in children with learning disability (n = 31) compared to normal children (n = 31). Latencies and amplitudes of MLAEPs results with different stimulus intensity and binaural stimulation were compared between two groups.

Results: Compared to control group, learning disabled children exhibited smaller amplitudes for all the components except the right ear Na and Pa. There is no significant difference between two groups for latencies of the components.

Conclusion: It seems that middle latency auditory evoked potential may be useful in diagnosis and evaluation of learning disabled children although more investigation is required.

Background and Aim: Blocking of the adenosine receptor in central nervous system by caffeine can lead to increasing the level of neurotransmitters like glutamate. As the adenosine receptors are present in almost all brain areas like central auditory pathway, it seems caffeine can change conduction in this way. The purpose of this study was to evaluate the effects of caffeine on latency and amplitude of auditory brainstem response(ABR).
Materials and Methods: In this clinical trial study 43 normal 18-25 years old male students were participated. The subjects consumed 0, 2 and 3 mg/kg BW caffeine in three different sessions. Auditory brainstem responses were recorded before and 30 minute after caffeine consumption. The results were analyzed by Friedman and Wilcoxone test to assess the effects of caffeine on auditory brainstem response.
Results: Compared to control group the latencies of waves III,V and I-V interpeak interval of the cases decreased significantly after 2 and 3mg/kg BW caffeine consumption. Wave I latency significantly decreased after 3mg/kg BW caffeine consumption(p<0.01).
Conclusion: Increasing of the glutamate level resulted from the adenosine receptor blocking brings about changes in conduction in the central auditory pathway.

Background and Aim: Premature birth and low birth weight are regarded as two risk factors for impaired language development. Hence, information about primary period of language development in these children is important for early detection of children&aposs needs during their language development period. The goal of this study was to determine the expressive lexicon size in 18 to 36 month-old premature children with low birth weight and to compare them with their full-term peers.
Methods: In this prospective historical survey, using form II of the MacArthur-Bates Communicative Development Inventories (CDI), expressive lexicon size of 42 premature children with low birth weight who were 18 to 36 month- old and 42 full-term peers in three age groups with six month-intervals is evaluated. Forms were completed individually by mothers of children.
Results: Data analysis showed that the difference in expressive lexicon between the two groups was significant (p=0.025). Nonetheless, in each group the difference in expressive lexicon size between the three age groups was not significant.
Conclusion: The results of this study suggest that expressive lexicon size in premature children with low birth weight was smaller than their full-term matches and the development of lexicon size is delayed in these children. However, by increasing age, these children follow a similar development pattern in terms of lexicon size and eventually catch up with their full term counterparts. This study shows the importance of early intervention to expedite this compensatory mechanism in these children.

Background and Aim: Specific language impiarment (SLI) is one of the most prevalent developmental language disorders its diagnosis is a problematic issue among researchers and clinicians because of the heterogeneity of language profiles in the affected population and overlapping with other developmental language disorders. The aim of this study was to review the suggested diagnostic criteria for this disorder, controversies about these criteria and identify the most accurate diagnostic methods.

Methods: Published article from 1980 to 2012 in bibliographic and publisher databases including Pubmed, Google scholar, Cochran library, Web of Science, ProQuest, Springer, Oxford, Science direct, Ovid, Iran Medex and Magiran about the diagnostic methods for discriminating preschoool children with specific language impiarment from normal developing children were reviewd in this article. These keywords were used for research: “specific language impairment”, “SLI”, “diagnosis or identification”, “standardized tests”, and “tests for language development”.

Conclusion: The results of this study show inspite of agreement of researchers and clinicians about exclusionary criteria as one basic part of the diagnosis of specific language impiarment , there is no consensus about the other part, inclusionary criteria. Different studies used different inclusionary criteria which can be divided to categories of clincal judgment, discrepancy-based criteria, standardized testing, clinical markers and markers from spontaneous speech samples. Advantages, disadvantages, and clinical applicability of each diagnostic method are discussed in this article.