Prevalence Of Severe Mental Retardation Research Articles

Aetiological factors and prevalence of severe mental retardation in children in a Swedish municipality: the possible role of consanguinity.

The prevalence of severe mental retardation (SMR) was studied in one of the 24 suburban municipalities in Stockholm. The study area had a high proportion of non-European nationals. The study population comprised 14138 children born between 1979 and 1992 who resided in this municipality on the census day, 31 December 1995. The total prevalence of SMR was 4.5 per 1000, being 3.7 per 1000 and 5.9 per 1000 in the European and in the non-European population, respectively. The majority of cases (66%) had a definite prenatal origin. Down syndrome was the cause in 20%. Six families (10%) had at least two children with SMR. It was concluded that the prevalence was higher than in previous Swedish studies. Many cases were attributed to genetic factors. Consanguineous marriages were assumed to be a factor of importance in the distribution of aetiologies. Demographic differences between areas in Sweden must be considered when planning habilitation services.

AN EPIDEMIOLOGICAL STUDY ON SEVERE MENTAL RETARDATION AMONG SCHOOLCHILDREN IN BOLOGNA, ITALY

The prevalence, causal origin of and impairments associated with severe mental retardation (SMR) were investigated among all school-age children (six to 13 years) living in the city of Bologna, Italy. 90 children (57 boys, 33 girls) with IQs less than or equal to 50 were identified. The prevalence of SMR was 4.2 per 1000 for males, 2.5 per 1000 for females and 3.4 per 1000 for both sexes. Causal origin was prenatal for 33.3 per cent, perinatal for 14.4 per cent, combined pre- and perinatal for 5.6 per cent and postnatal for 13.3 per cent. Another 12.3 per cent of the children with IQs less than or equal to 50 had autism or childhood psychosis, while there was no evident cause of mental retardation for the remaining 21.1 per cent. 50 per cent had at least one associated physical or neurological impairment other than mental retardation, with epilepsy and cerebral palsy predominating.

Effects of birth weight, gestational age, and maternal obstetric history on birth prevalence of cerebral palsy.

A register of children with cerebral palsy born to mothers resident in the Mersey region from 1966 to 1977 was compiled from health service records. Frequency distributions and prevalences of birth weight and gestational age differed for those with hemiplegia, diplegia, and quadriplegia. In particular, the children with diplegia showed a bimodal frequency distribution. Children of normal birth weight with diplegia had a higher prevalence of severe mental retardation than those of low birth weight. These differences may be due to survival bias and may not be of aetiological importance. Furthermore, the mothers of diplegic infants had a significantly higher proportion of spontaneous abortions, stillbirths, and low birthweight infants in their obstetric history. This suggests that prenatal factors predominate in the aetiology of diplegia.

Problems of Applying Behavioral Measures in Assessing the Incidence and Prevalence of Severe Mental Retardation in Developing Countries

(1981). Problems of Applying Behavioral Measures in Assessing the Incidence and Prevalence of Severe Mental Retardation in Developing Countries. International Journal of Mental Health: Vol. 10, Severe Mental Retardation Across the World: Epidemiological Studies, pp. 76-84.

The Development of a Questionnaire to Screen for Severe Mental Retardation in Developing Countries

(1981). The Development of a Questionnaire to Screen for Severe Mental Retardation in Developing Countries. International Journal of Mental Health: Vol. 10, Severe Mental Retardation Across the World: Epidemiological Studies, pp. 85-99.

Mental retardation in a national population of young men in the Netherlands. I. Prevalence of severe mental retardation.

The prevalence of severe mental retardation, derived from military records, is analyzed in terms of time trend, region, religious affiliation and urbanization of birth place. The data are singular in that they are national and virtually complete for a total population of young men, 19-year-old survivors of male births in the Netherlands over the years 1944 through 1947, and they include variables not previously studied. Previous local studies are shown to agree well with the national prevalence of 3.7 per 1,000. Prevalence rose through the four birth years for all forms of severe mental retardation, but most markedly for Down's syndrome. In this condition agency surveys usually yeild equivalent rates to population surveys, and are an economical means of monitoring prevalence. Differences in rates are quite likely to indicate substantive differences. The remarkable similarities in rates from past surveys may reflect a high proportion of chromosomal and genetic abnormalities. The divergence between urban and rural rates over time demonstrated in this paper for four annual cohorts is attributed by inference to disparate increases in survival in different ecologic settings.