Loss of language in early development of autism and specific language impairment.
BACKGROUND
Several authors have highlighted areas of overlap in symptoms and impairment among children with autism spectrum disorder (ASD) and children with specific language impairment (SLI). By contrast, loss of language and broadly defined regression have been reported as relatively specific to autism. We compare the incidence of language loss and language progression of children with autism and SLI.


METHODS
We used two complementary studies: the Special Needs and Autism Project (SNAP) and the Manchester Language Study (MLS) involving children with SLI. This yielded a combined sample of 368 children (305 males and 63 females) assessed in late childhood for autism, history of language loss, epilepsy, language abilities and nonverbal IQ.


RESULTS
language loss occurred in just 1% of children with SLI but in 15% of children classified as having autism or autism spectrum disorder. Loss was more common among children with autism rather than milder ASD and is much less frequently reported when language development is delayed. For children who lost language skills before their first phrases, the phrased speech milestone was postponed but long-term language skills were not significantly lower than children with autism but without loss. For the few who experienced language loss after acquiring phrased speech, subsequent cognitive performance is more uncertain.


CONCLUSIONS
Language loss is highly specific to ASD. The underlying developmental abnormality may be more prevalent than raw data might suggest, its possible presence being hidden for children whose language development is delayed.
Pickles
Andrew
A
Biostatistics, Health Methodology Research Group, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom. andrew.pickles@manchester.ac.uk
Simonoff
Emily
E
Conti-Ramsden
Gina
G
Falcaro
Milena
M
Simkin
Zoë
Z
Charman
Tony
T
Chandler
Susie
S
Loucas
Tom
T
Baird
Gillian
G
D000293:Adolescent; D000367:Age Factors; D001321:Autistic Disorder / Q000453:epidemiology*; D002648:Child; D015331:Cohort Studies; D015897:Comorbidity; D004827:Epilepsy / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D007360:Intelligence; D007805:Language Development Disorders / Q000453:epidemiology; D007806:Language Disorders / Q000453:epidemiology*; D008297:Male; D012720:Severity of Illness Index; D013064:Speech Disorders / Q000453:epidemiology; D006113:United Kingdom / Q000453:epidemiology