The impact of nonverbal ability on prevalence and clinical presentation of language disorder: evidence from a population study

Abstract

BackgroundDiagnosis of ‘specific’ language impairment traditionally required nonverbal IQ to be within normal limits, often resulting in restricted access to clinical services for children with lower NVIQ. Changes to DSM‐5 criteria for language disorder removed this NVIQ requirement. This study sought to delineate the impact of varying NVIQ criteria on prevalence, clinical presentation and functional impact of language disorder in the first UK population study of language impairment at school entry.MethodsA population‐based survey design with sample weighting procedures was used to estimate population prevalence. We surveyed state‐maintained reception classrooms (n = 161 or 61% of eligible schools) in Surrey, England. From a total population of 12,398 children (ages 4–5 years), 7,267 (59%) were screened. A stratified subsample (n = 529) received comprehensive assessment of language, NVIQ, social, emotional and behavioural problems, and academic attainment.ResultsThe total population prevalence estimate of language disorder was 9.92% (95% CI 7.38, 13.20). The prevalence of language disorder of unknown origin was estimated to be 7.58% (95% CI 5.33, 10.66), while the prevalence of language impairment associated with intellectual disability and/or existing medical diagnosis was 2.34% (95% CI 1.40, 3.91). Children with language disorder displayed elevated symptoms of social, emotional and behavioural problems relative to peers, F(1, 466) = 7.88, p = .05, and 88% did not make expected academic progress. There were no differences between those with average and low‐average NVIQ scores in severity of language deficit, social, emotional and behavioural problems, or educational attainment. In contrast, children with language impairments associated with known medical diagnosis and/or intellectual disability displayed more severe deficits on multiple measures.ConclusionsAt school entry, approximately two children in every class of 30 pupils will experience language disorder severe enough to hinder academic progress. Access to specialist clinical services should not depend on NVIQ.

Development of a language screening instrument for Swedish 4‐year‐olds

“…; Norbury et al . ; Tomblin et al . ) and lower than the prevalence found in previous Swedish studies (Miniscalco Mattsson et al .…”

“…Norbury et al . () found that 7.58% of 4‐year‐olds had LD of unknown origin (i.e., DLD). In Swedish studies, prevalence figures for LD reported are 10.3% of 2.5‐year‐olds (Miniscalco Mattsson et al .…”

Language growth in children with heterogeneous language disorders: a population study

“…The Surrey Communication and Language in Education Study (SCALES) used a two‐phase design (Norbury et al., ). In the first phase, reception (kindergarten) class teachers in 263 state‐funded primary schools were invited to complete the Children's Communication Checklist‐Short (CCC‐S, Bishop & Norbury, unpublished), a 13‐item checklist measuring language and communication skills in everyday contexts (maximum score = 39).…”

Phase 2 of CATALISE: a multinational and multidisciplinary Delphi consensus study of problems with language development: Terminology

“…Language problems are common in children, with prevalence estimates ranging from 3% to 7%, depending on age and definition (Norbury et al., ; Tomblin, Records et al., ; Weindrich, Jennen‐Steinmetz, Laucht, Esser, & Schmidt, ). In relation to their severity and prevalence, children's language problems receive considerably less research funding than other conditions such as attention deficit hyperactivity disorder (ADHD) or autism spectrum disorder (ASD), with which they frequently co‐occur (Bishop, ).…”