ABSTRACT
BACKGROUND: Research on the prevalence of autism in Iceland has indicated that one possible explanation of fewer autism cases in older age groups was due to an underestimation of autism in individuals with intellectual disabilities (IDs). The present study systematically searched for autism cases in the adult population of individuals with severe ID living in the city of Reykjavik, Iceland. METHODS: Potential participants (n = 256) were recruited through the Regional Office for the Affairs of the Handicapped in Reykjavik. First, a screening tool for autism was applied, followed by the Childhood Autism Rating Scale and finally the Autism Diagnostic Interview-Revised (ADI-R). RESULTS: The point prevalence of severe ID was 3.7/1000 (95% CI 3.2-4.1) with a male-female ratio of 1.2:1. Participation rate in the study was 46.5%. Participants were younger than non-participants and more often residents of group homes. The prevalence of autism was 21% (25/119) (95% CI 14.7-29.2) with a male-female ratio of 1.8:1. Of the individuals with autism, 10/25 (40%) were verbal according to the ADI-R definition, and 18/25 (72%) had active epilepsy and/or other neurological conditions and handicaps. CONCLUSION: The study identified twice the number of autism cases than those previously recognised within the service system. Autism is a prevalent additional handicap in individuals with severe ID, which should always be considered in this population. There are indications that the estimated prevalence of autism found should be considered minimal.
Subject(s)
Autistic Disorder/complications , Autistic Disorder/epidemiology , Intellectual Disability/complications , Intellectual Disability/psychology , Urban Population , Adult , Autistic Disorder/diagnosis , Epilepsy/complications , Female , Humans , Iceland/epidemiology , Male , Middle Aged , Nervous System Diseases/complications , Prevalence , Psychological Tests , Severity of Illness Index , Sex Distribution , Young AdultABSTRACT
We estimated autism spectrum disorder (ASD) prevalence in 7-9 year-old children in 2015 using data from three nationwide health registry systems (Denmark, Finland, Iceland) and two French population-based regional registries. Prevalence ranged from 0.48% in South-East France to 3.13% in Iceland (South-West France: 0.73%, Finland: 0.77%, Denmark: 1.26%). Male/female ratios ranged from 3.3 in Finland to 5.4 in South-West France. Between 12% (Denmark) and 39% (South-West France) of cases were diagnosed with intellectual disability. The variations in population-based ASD prevalence across four European countries with universal health care practices likely reflect variation in detection, referral and diagnosis practices and autism awareness across these areas. Using established population-based data systems is an efficient approach to monitor ASD prevalence trends over time.
Subject(s)
Autism Spectrum Disorder/epidemiology , Registries/statistics & numerical data , Child , Denmark , Female , Finland , France , Humans , Iceland , Male , PrevalenceABSTRACT
Several copy number variants have been associated with neuropsychiatric disorders and these variants have been shown to also influence cognitive abilities in carriers unaffected by psychiatric disorders. Previously, we associated the 15q11.2(BP1-BP2) deletion with specific learning disabilities and a larger corpus callosum. Here we investigate, in a much larger sample, the effect of the 15q11.2(BP1-BP2) deletion on cognitive, structural and functional correlates of dyslexia and dyscalculia. We report that the deletion confers greatest risk of the combined phenotype of dyslexia and dyscalculia. We also show that the deletion associates with a smaller left fusiform gyrus. Moreover, tailored functional magnetic resonance imaging experiments using phonological lexical decision and multiplication verification tasks demonstrate altered activation in the left fusiform and the left angular gyri in carriers. Thus, by using convergent evidence from neuropsychological testing, and structural and functional neuroimaging, we show that the 15q11.2(BP1-BP2) deletion affects cognitive, structural and functional correlates of both dyslexia and dyscalculia.
Subject(s)
Cognition/physiology , DNA Copy Number Variations/genetics , Dyscalculia/genetics , Dyslexia/genetics , Intellectual Disability/genetics , Adolescent , Adult , Aged , Chromosome Aberrations , Chromosome Deletion , Chromosomes, Human, Pair 15/genetics , Developmental Disabilities/genetics , Female , Functional Neuroimaging/methods , Functional Neuroimaging/standards , Heterozygote , Humans , Iceland/epidemiology , Magnetic Resonance Imaging/methods , Male , Middle Aged , Neuropsychological Tests/standards , Phenotype , Temporal Lobe/anatomy & histology , Temporal Lobe/diagnostic imaging , Young AdultABSTRACT
This clinic-based study estimated the prevalence of autism in Iceland in two consecutive birth cohorts, subjects born in 1974-1983 and in 1984-1993. In the older cohort classification was based on the ICD-9 in 72% of cases while in the younger cohort 89% of cases were classified according to the ICD-10. Estimated prevalence rates for Infantile autism/Childhood autism were 3.8 per 10,000 in the older cohort and 8.6 per 10,000 in the younger cohort. The characteristics of the autistic groups are presented in terms of level of intelligence, male:female ratio, and age at diagnosis. For the younger cohort scores on the Autism Diagnostic Interview-Revised and the Childhood Autism Rating Scale are reported as well. Results are compared with a previous Icelandic study and recent population-based studies in other countries based on the ICD-10 classification system. Methodological issues are discussed as well as implications for future research and service delivery.
Subject(s)
Autistic Disorder/epidemiology , Intellectual Disability/epidemiology , Adolescent , Adult , Age Distribution , Autistic Disorder/diagnosis , Child , Child, Preschool , Cohort Studies , Female , Humans , Iceland/epidemiology , Male , Population Surveillance , Prevalence , Psychiatric Status Rating Scales , Sex DistributionABSTRACT
OBJECTIVE: This is a pilot-study in Iceland of parents' concerns about language development of their children. Little is known about the rate and the expression of such concerns and such data is important for developmental surveillance. MATERIAL AND METHODS: This study forms a part of a larger study of the mental health of Icelandic children aged 2-18 years with the Child Behavior Checklist (CBCL). Parents' concerns of language problems were studied with the CBCL in 444 children aged two to seven sampled on a national level in Iceland. These concerns were examined by indipendent speech and language therapists and categorized as speech or language concerns, and graded by their possible seriousness. RESULTS: The CBCL picks up host of reasons for parents' concerns. According to the parents' completion of the CBCL about 13% of the sample were considered to have some language problems. The frequency of responses showing language problems was not related to the age of the children. The male-female ratio was 1.5:1. According to speech and language therapists' categorization of parents' concerns, parents described speech problems in majority of cases (72%) as opposed to language problems (18%). These specialists considered parents' concerns to reflect more serious complaints as the children grew older. CONCLUSIONS: The majority of parents' concerns were considered to reflect real problems according to specialists. There were indications that parents do not make a distinction between language and speech. This needs to be studied further in order to better inform parents on language development and its disorders, and to contribute to a better focused developmental surveillance.