$6,556. The average expenditure for educating students with special-needs is 1.6 times that of a general education student. Special consequences for deaf students Deafness is a low-incidence disability, which means that a deaf child will often be the only student in the classroom with hearing loss. This leads to a special set of issues in the mainstream classroom. While students with other disabilities may experience isolation and bullying by their non-disabled peers, they often share a common language. This is not the case for deaf students. Very few people in the mainstream academic setting know sign language, which means the communication barrier is large and can have negative effects on both academic achievement and social development. Social skills are key to a child's healthy development and later success as an adult. Although many studies find good academic results for deaf children placed in a mainstream classroom, research also shows that mainstreamed deaf children experience higher degrees of isolation and psychological problems in comparison to deaf students who associate with other deaf peers. In order for friendships to form, communication is a necessity. For deaf children unable to use effective communication methods with the people around them, the difficulty in acquiring new friendships typically leads to isolation and a decrease in self-esteem. A study of preschool children showed that hearing preschoolers did not appear to adjust how they communicated with deaf children. Instead, they continued to use simple speech, which was effective with hearing, but not deaf, partners. This shows the isolation of the deaf child, and discredits the idea that the hearing and deaf child's communication skills will be enhanced by interaction with one another. In many cases, hearing children do not understand what it means when another child is deaf. This leads to frustration when a deaf child's speech is not clear or when the deaf child asks for continuous repetition. Communication strategies that are culturally acceptable to the deaf child, such as banging on a table or physically touching another person, can also cause the deaf child to be rejected by his or her peers because such behaviors are not always considered acceptable in mainstreaming hearing culture. Research has suggested that the placement of a deaf child in special schools or classes may be more desirable for deaf students than for those with other disabilities. This is primarily because of the greater social benefits for the students. The