Background and Aim: Learning language is acquired in early childhood and gradually developed by new words and new structures. Hearing sense is the most important acquisition for learning this skill. Hearing disorders are barriers for natural language learning. The purpose of this study was to investigate the relationship between writing sentences and perception of written sentences in hearing-impaired and normal-hearing students.
Methods: A cross-sectional study was conducted among thirty hearing-impaired students with hearing loss of 70-90 dB and thirty normal hearing students. They were selected from 3^rd grade primary school students in Hamadan, a large city in Western Iran. The language skills and non language information was assessed by questionnaire, Action Picture Test, and Sentence Perception Test.
Results: Results showed that there was a significant relation between writing sentences and perception of written sentences in hearing impaired students (p<0.001), (r=0.8). This significant relation was seen in normal-hearing students as well (p<0.001), (r=0.7).
Conclusion: Disability of hearing-impaired students in verbal communication is not only related to articulation and voice disorders but also is related to their disability to explore and use of language rules. They suffer lack of perception of written sentences, and they are not skilled to convey their feelings and thoughts in order to presenting themselves by using language structures.

Background and Aim: Hearing is one of the most vital sensational abilities. Learning, which is the most basic ability for human compatibility to mental development, is affected by hearing ability. The main goal of this article was to review the effect of hearing impairment on educational achievement of hearing-impaired students, especially in the field of basic learning skills (reading, writing, and mathematics).

Methods: In this article, the researches on the effect of hearing impairment on educational achievement were reviewed. There were 37 articles extracted from different databases such as Iran Medex, Scopus, PubMed, Magiran, Iran Journal, Google Scholar, and 12 credible books published from 1944 to 2013. In order to search in these databases, educational achievement and other related keywords were used.

Conclusion: Hearing impairment affects listening skills, which is a mental process and is known as the first lingual skill. Subsequently, other lingual skills and learning abilities like educational achievement are affected as well. In order to decrease the educational gap in hearing-impaired students, it is very important to interfere in early stages and use of presentation methods to improve lingual skills in educational system.