Autistic symptomatology and language ability in autism spectrum disorder and specific language impairment.
BACKGROUND
Autism spectrum disorders (ASD) and specific language impairment (SLI) are common developmental disorders characterised by deficits in language and communication. The nature of the relationship between them continues to be a matter of debate. This study investigates whether the co-occurrence of ASD and language impairment is associated with differences in severity or pattern of autistic symptomatology or language profile.


METHODS
Participants (N = 97) were drawn from a total population cohort of 56,946 screened as part of study to ascertain the prevalence of ASD, aged 9 to 14 years. All children received an ICD-10 clinical diagnosis of ASD or No ASD. Children with nonverbal IQ > or =80 were divided into those with a language impairment (language score of 77 or less) and those without, creating three groups: children with ASD and a language impairment (ALI; N = 41), those with ASD and but no language impairment (ANL; N = 31) and those with language impairment but no ASD (SLI; N = 25).


RESULTS
Children with ALI did not show more current autistic symptoms than those with ANL. Children with SLI were well below the threshold for ASD. Their social adaptation was higher than the ASD groups, but still nearly 2 SD below average. In ALI the combination of ASD and language impairment was associated with weaker functional communication and more severe receptive language difficulties than those found in SLI. Receptive and expressive language were equally impaired in ALI, whereas in SLI receptive language was stronger than expressive.


CONCLUSIONS
Co-occurrence of ASD and language impairment is not associated with increased current autistic symptomatology but appears to be associated with greater impairment in receptive language and functional communication.
Loucas
Tom
T
School of Psychology and Clinical Language Sciences, University of Reading, UK. t.loucas@reading.ac.uk
Charman
Tony
T
Pickles
Andrew
A
Simonoff
Emily
E
Chandler
Susie
S
Meldrum
David
D
Baird
Gillian
G
D000293:Adolescent; D001321:Autistic Disorder / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D002648:Child; D015331:Cohort Studies; D003142:Communication; D015897:Comorbidity; D005260:Female; D006801:Humans; D007406:Interview, Psychological / Q000379:methods; D007804:Language Development; D007806:Language Disorders / Q000453:epidemiology* / Q000523:psychology; D008297:Male; D012720:Severity of Illness Index; D012917:Social Adjustment; D006113:United Kingdom / Q000453:epidemiology