Research on Specific Language Impairment
Recent researches shows that the incidence of SLI is 1% in general population, about 7-8% of kindergarten goers are affected by Specific Language Impairment each year where boys are more likely to get it. Specific Language Impairment (SLI) itself is a “pure” developmental language disorder. It is not related to any other disorders like – hearing loss or any brain injury present by birth. An SLI child shows defects in the below two:
- language functionalities i.e. to understand what others speak (receptive language) and to speak properly to others (expressive language).
- language capabilities i.e. use of words, sequences of words, forms of words to use socially and sounds of words.
Several Hypothesis in Association with SLI:
Till date very little is known about SLI. Few evidences support that it may be related to some brain deformity. But no visible lesions or any anatomical differences are seen. Sometimes this disorder is passed from parents.
- First hypothesis – delay in understanding and speaking basic functional vocabularies (e.g., the, a, is) and grammars (e.g., plural ‘-s’, past tense ‘-ed’).ch long after age-matched children with typical language development show consistent production of these elements. (Rice, 1994).
- Second hypothesis – difficulty in distinguishing between two sounds which are presented at brief intervals. (Tallal, et al., 1985).
- Third hypothesis – SLI victimized children have poor memory for short term speech sounds. (e.g., Gathercole, 1998).
- Fourthly , polymorphism in a single nucleotide (rs17236239) in CNTNAP2 gene may be responsible in causing SLI.
Specific Language Impairment In Comparison To Other Disabilities:
Language difficulties may be associated with other disabilities like autism spectrum disorders, hearing impairments etc. But SLI is a pure form of language disorder which is not associated with any other type of disorders. It is seen that most language disorder victims suffer from hearing loss or difficulties in hearing. But children with SLI have shown to have normal hearing functions. SLI children show normal behaviour during non-verbal interactions, playing, and many others like-feeding and dressing. Autistic kids show unnatural behaviours socially during non-verbal and verbal interactions which is not seen within SLI kids.
Prevention and Treatment:
No known way is at present found to prevent it. There are several scientifically unproven treatments which have shown fruitful results. Those are offered by therapists and specialised educators. But complete cure is yet to be researched.