Lexical abilities in children with specific language impairment

Abstract

Deficits of syntactic and phonological abilities are dominant symptoms of specific language impairment (SLI). However, these children have significant lexical deficits which are manifested as difficulties in learning, understanding, as well as in using words. In terms of lexical and semantic abilities the most dominant are difficulties in learning words, reduced vocabulary, difficulties in naming and in lexical-semantic processing, as well as in using words in spontaneous speech. The main objective of this study was evaluation of lexical abilities, as well as determination of the form and nature of lexical development in children with specific language impairment at preschool and early school age (5-8 yr.). Additionally, the aim of the research was also to determine the effect of neurological dysfunction risk factors on development of lexical abilities in children with specific language impairment. Sample consisted of 115 children between five and eight years of age. The experimental group consisted of 60 children with diagnosis of specific language impairment (expressive type), while the control group consisted of 55 typically developing children. The experimental group was divided into two subgroups, 30 children with SLI without risk factors of neurological dysfunction and 30 children with SLI with risk factors of neurological dysfunction. All aspects of lexical abilities were assessed, including the assessment of confrontation naming, lexical-semantic processing, as well as ability of using words in spontaneous speech. For the purposes of this assessment, the following tests were used: Boston Naming Test, test for naming verbs which was designed for the purpose of this study, Free Word Association Test and analysis of lexical diversity which was assessed in sample of spontaneous speech obtained through retelling of the "Cinderella" story. Summarizing the results of this study it was concluded that children with SLI have significantly poorer achievements in a term of confrontation naming (nouns and verbs), lexical-semantic processing, as well as in a term of using all type of words (open and closed class words) in spontaneous speech, compared to their typically developing peers. Additionally, it was concluded that SLI children with risk factors of neurological dysfunction have significantly poorer achievements in the field of lexical-semantic processing, as well in using of words in spontaneous speech. Also, development of confrontation naming ability in SLI children with risk factors is significantly slower comparing to children with SLI without factors of neurological dysfunction. Also, it was concluded that the score on naming verbs is a significant predictor of lexical and semantic diversity in the spontaneous speech of children with SLI. The obtained results of this study indicate a need for modernization of tests for lexical assessment in children with SLI, usage of new tests for a more detailed assessment of qualitative and quantitative aspect of lexical deficit in children with SLI, as well as the need for innovations in speech and language rehabilitation in order for more specific stimulation of lexical development in these children.

Deficiti sintaksičkih i fonoloških sposobnosti predstavljaju dominantne simptome specifičnog jezičkog poremećaja (SJP). Međutim, ova deca ispoljavaju i značajne leksičke deficite koji se manifestuju teškoćama u učenju, razumevanju, kao i u upotrebi reči. U pogledu deficita leksičko-semantičkih sposobnosti, kod dece sa SJP možemo izdvojiti teškoće u usvajanju reči, smanjen vokabular, teškoće u imenovanju, deficiti u leksičko-semantičkom procesiranju i teškoće u upotrebi reči u spontanom govoru. Osnovni cilj ovog istraživanja je bio da se utvrde leksičke sposobnosti, kao i obrazac i priroda leksičkog razvoja dece sa specifičnim jezičkim poremećajem na predškolskom i ranom školskom uzrastu (5-8 god.). Pored toga, cilj istraživanja je bio i da se utvrdi uticaj prisustva riziko faktora neurološke disfunkcije na razvoj leksičkih sposobnosti kod dece sa specifičnim jezičkim poremećajem. Istraživanje je sprovedeno na uzorku od 115 dece, uzrasta od pet do osam godina. Eksperimentalnu grupu je činilo 60 ispitanika kod kojih je dijagnostikovan specifični poremećaj u razvoju govora i jezika ekspresivnog tipa, dok je kontrolnu grupu činilo 55 dece tipičnog jezičkog razvoja. Eksperimentalna grupa je podeljena na dve podgrupe: 30 dece sa SJP bez prisustva riziko faktora neurološke disfunkcije i 30 dece sa SJP i prisutnim nekim od faktora neurološke disfunkcije. Leksičke sposobnosti procenjivane su multidimenzionalno, uključujući procenu izolovanog imenovanja, leksičkog procesiranja i upotrebe reči u spontanom govoru. Za potrebe navedene procene korišćeni su: Bostonski test imenovanja, za potrebe ovog istraživanja konstruisan Test glagola, Test slobodnih asocijacija reči i analiza leksičke raznovrsnosti u uzorku spontanog govora dobijenog pričanjem priče „Pepeljuga“. Sumiranjem rezultata i postignuća dece sa SJP i dece tipičnog razvoja zaključeno je da deca sa SJP imaju značajno lošija postignuća na planu izolovanog imenovanja (imenica i glagola), leksičkog procesiranja, kao i na planu upotrebe svih vrsta reči u spontanom govoru, u poređenju sa njihovim vršnjacima tipičnog razvoja. Pored toga, zaključeno je da deca sa SJP i prisutnim nekim od riziko faktora neurološke disfunkcije imaju značajno lošija postignuća na planu leksičkog procesiranja i upotrebe reči u spontanom govoru, kao i da značajno lošije napreduju u okviru sposobnosti izolovanog imenovanja, u poređenju sa decom sa SJP bez prisutnog nekog od faktora neurološke disfunkcije. Dodatno, zaključeno je da sposobnosti imenovanja aktivnosti predstavlja značajan prediktor upotrebe reči u spontanom govoru kod dece sa SJP. Dobijeni rezultati ukazuju na potrebu osavremenjivanja testova u proceni leksičkih sposobnosti kod dece sa SJP, uvođenja novih testova za detaljniju procenu kvalitativnog i kvantitativnog aspekta leksičkog deficita, kao i na potrebu inovacija u logopedskoj rehabilitaciji kojima bi se dodatno stimulisao razvoj leksičkih sposobnosti kod ove dece.