An epidemiological study on severe mental retardation among schoolchildren in Bologna, Italy

Prevalence and incidence of physical health conditions in people with intellectual disability - a systematic review

OBJECTIVE

To synthesize evidence on the prevalence and incidence of physical health conditions in people with intellectual disability (ID).

METHODS

We searched Medline, PsycInfo, and Embase for eligible studies and extracted the prevalence, incidence, and risk of physical health conditions in people with ID.

RESULTS

Of 131 eligible studies, we synthesized results from 77 moderate- to high-quality studies, which was mainly limited to high-income countries. The highest prevalence estimates were observed for epilepsy, ear and eye disorders, cerebral palsy, obesity, osteoporosis, congenital heart defects, and thyroid disorders. Some conditions were more common in people with a genetic syndrome. Compared with the general population, many health conditions occur more frequently among people with ID, including asthma and diabetes, while some conditions such as non-congenital circulatory diseases and solid cancers occur at the same or lower rate. The latter associations may reflect under-detection.

CONCLUSIONS

People with ID have a health profile more complex than previously known. There is a pressing need for targeted, evidence-informed population health initiatives including preventative programs for this population.

Prevalence of epilepsy among people with intellectual disabilities: A systematic review

PURPOSE

Epilepsy is more common in people with intellectual disabilities than in the general population. However, reported prevalence rates vary widely between studies. This systematic review aimed to provide a summary of prevalence studies and estimates of prevalence based on meta-analyses.

METHOD

Studies were identified via electronic searches using Medline, Cinahl and PsycINFO and cross-citations. Information extracted from studies was tabulated. Prevalence rate estimates were pooled using random effects meta-analyses and subgroup analyses were conducted.

RESULTS

A total of 48 studies were included in the tabulation and 46 studies were included in meta-analyses. In general samples of people with intellectual disabilities, the pooled estimate from 38 studies was 22.2% (95% CI 19.6-25.1). Prevalence increased with increasing level of intellectual disability. For samples of people with Down syndrome, the pooled estimate from data in 13 studies was 12.4% (95% CI 9.1-16.7), decreasing to 10.3% (95% CI 8.4-12.6) following removal of two studies focusing on older people. Prevalence increased with age in people with Down syndrome and was particularly prevalent in those with Alzheimer's/dementia.

CONCLUSION

Epilepsy is highly prevalent in people with intellectual disabilities. Services must be equipped with the skills and information needed to manage this condition.

Massively parallel sequencing for diagnosing clinically and genetically heterogeneous disorders

Massively parallel sequencing technology has great potential to identify the precise molecular causes of human disorders, which were once considered difficult to diagnose for either inherited Mendelian or oncological diseases. Besides being a valuable tool for gene discovery, this technology has also gained tremendous momentum in clinical molecular diagnostic laboratories. There are a wide variety of clinical applications recently developed to meet the clinical demands for personalized medicine. This article discusses these up-to-date massively parallel sequencing clinical applications and emphasizes various disorders that can be targeted, as well as some challenges faced in the process of implementing these assays in the clinical setting.

6,220 institutionalised people with intellectual disability referred for visual assessment between 1993 and 2003: overview and trends

AIMS

To summarise the results of visual performance tests and other data of institutionalised people with intellectual disability referred to a visual advisory centre (VAC) between 1993 and 2003, and to determine trends in these data.

METHODS

A retrospective medical record review was undertaken of 6,220 consecutive people examined ophthalmologically according to a standard protocol by one VAC that specialised in visual assessment and treatment of people with intellectual disability, between 1993 and 2003. chi2 test for linear trend was used and linear regression coefficients were calculated.

RESULTS

The proportion of people aged > or =50 years increased from 19.3% to 34.2% between 1995 and 2003 (p<0.001); the combined figure of severe or profound intellectual disability decreased from 80.0% to 52.6% (p<0.001); the proportion of mobile people increased from 52.1% to 98.0% (p<0.001); the combined proportion of people with visual impairment or blindness decreased from 70.9% to 22.9% (p<0.001), and that of people with visual disorders decreased from 89.6% to 75.3% (p<0.001). Causes of intellectual disability were identified in 58.4% people; 20.8% had Down's syndrome.

CONCLUSION

Many ocular diagnoses were found, indicating the need for ophthalmological monitoring. Specialised centres are helpful, because assessment and treatment of people with intellectual disability is complicated and time consuming. Protocols for efficient referral will have to be developed. A major task lies ahead to improve the treatment rates of refractive errors, cataract and strabismus, and to find specific causes of intellectual disability.

Different neurological outcome of liver transplantation for Wilson's disease in two homozygotic twins

Wilson's disease is a genetic disorder characterized by accumulation of copper in many organs and tissues. Phenotypic manifestations are wide-ranging from neuropsychiatric disorders, to severe liver disease requiring liver transplantation. Clinical presentation is not often related to the genetic defect and siblings may have different type of disease. Liver transplantation is indicated for all patients with Wilson's disease and decompensated liver cirrhosis unresponsive to medical therapy, but its efficacy in resolving the neurological symptoms is still controversial, because as far now, very different outcomes have been reported. We describe here on the exceptional case of two homozygotic twins, both with liver cirrhosis due to Wilson's disease, one of them with severe neuropsychiatric involvement, who both underwent liver transplantation and subsequently had very different outcome despite same genetic background. The presence of neurological clinical manifestations in Wilson's disease should recommend caution indicating liver transplantation, because irreversible brain damage may exist.

Autism and intellectual disability: a study of prevalence on a sample of the Italian population

BACKGROUND

In 1994, the American Association on Mental Retardation with the DSM-IV has come to a final definition of pervasive developmental disorders (PDD), in agreement with the ICD-10. Prevalence of PDD in the general population is 0.1-0.15% according to the DSM-IV. PDD are more frequent in people with severe intellectual disability (ID). There is a strict relationship between ID and autism: 40% of people with ID also present a PDD, on the other hand, nearly 70% of people with PDD also have ID. We believe that in Italy PDD are underestimated because there is no agreement about the classification system and diagnostic instruments.

METHOD

Our aim is to assess the prevalence of PDD in the Italian population with ID. The Scale of Pervasive Developmental Disorder in Mentally Retarded Persons (PDD-MRS) seems to be a very good instrument for classifying and diagnosing PDD.

RESULTS

The application of the PDD-MRS and a clinical review of every individual case on a sample of 166 Italian people with ID raised the prevalence of PDD in this population from 7.8% to 39.2%.

CONCLUSIONS

The study confirms the relationship between ID and autism and suggests a new approach in the study of ID in order to elaborate a new integrated model for people with ID.

Epilepsy in children with cerebral palsy

OBJECTIVE

To describe the prevalence and characteristics of epilepsy in patients with cerebral palsy in a tertiary center.

METHODS

a total of 100 consecutive patients with cerebral palsy were retrospectively studied. Criteria for inclusion were follow-up period for at least 2 years. Types and incidence of epilepsy were correlated with the different forms of cerebral palsy. Other factors associated with epilepsy such as age of first seizure, neonatal seizures and family history of epilepsy were also analysed.

RESULTS

follow-up ranged between 24 and 151 months (mean 57 months). The overall prevalence of epilepsy was 62%. Incidence of epilepsy was predominant in patients with hemiplegic and tetraplegic palsies: 70.6% and 66.1%, respectively. First seizure occurred during the first year of life in 74.2% of patients with epilepsy. Generalized and partial were the predominant types of epilepsy (61.3% and 27.4%, respectively). Thirty-three (53.2%) of 62 patients were seizure free for at least 1 year. Neonatal seizures and family history of epilepsy were associated with a higher incidence of epilepsy.

CONCLUSIONS

epilepsy in cerebral palsy can be predicted if seizures occur in the first year of life, in neonatal period and if there is family history of epilepsy.

Factors affecting the risk of behaviour problems in children with severe intellectual disability

In order to examine the importance of a range of potential risk factors for behaviour problems in children with severe intellectual disability, a sample was identified by the administration of a screening version of the Vineland Adaptive Behaviour Scales (VABS) to the parents of children aged 4-11 years attending six special needs schools in three adjacent inner London boroughs. Parents whose children had a VABS standard score of < or = 50 were interviewed using the Disability Assessment Schedule and both parents and teachers completed the Aberrant Behaviour Checklist. Most behaviour problems were more common in ambulant children, but problems less dependent on the ability to walk, such as sleeping difficulties, screaming and self-injury, were equally common in ambulant and non-ambulant children. Among ambulant children, there were few significant associations between the severity of the child's behaviour problems and the age or sex of the child, the presence or absence of epilepsy, and various indices of socio-economic disadvantage. Sleeping difficulties, overactivity, self-injury, destructive behaviour and autistic features, such as social withdrawal and stereotypies, were strongly associated with skills deficits, but aggression, temper tantrums and general disruptive behaviour were not. Limitations in daily living skills were better predictors of behaviour problems than were poor communication skills.

Reported biomedical causes and associated medical conditions for mental retardation among 10-year-old children, metropolitan Atlanta, 1985 to 1987

This report describes biomedical causes of mental retardation (MR) among school-age children and associated medical conditions in children for whom no cause was reported. This study involved 715, 10-year-old children with MR (intelligence quotient [IQ] 70 or less) born between 1975 and 1977. We determined biomedical causes of MR using a hierarchical approach based on the timing of the event (i.e. prenatal, perinatal, or postneonatal). Among children with no identified biomedical cause the occurrence of associated medical conditions was examined. No reported biomedical cause could be found in 78% of children with MR (87% mild, IQ 50 to 70; 57% severe, IQ < 50). Prenatal causes were present in 12%, perinatal causes in 6%, and postneonatal causes in 4%. On the basis of these findings it was concluded that intensive use of public health prevention strategies can reduce the number of children who receive a diagnosis of MR.

Severe mental retardation in 2 to 24-month-old children in Lahore, Pakistan: a prospective cohort study

Severe mental retardation (developmental quotient (DQ) < 50) was investigated in 1303 children from 2 to 24 months of age, born during 1984-87 in four population groups representing different socio-economic levels in and around Lahore, Pakistan. The incidence per 1000 live births was 22 in the periurban slum, 9 in the urban slum, 7 in the village and 4 in the upper middle class group. The aetiology was prenatal in 79%, perinatal in 14% and untraceable in 7% of cases. Down's syndrome was the most common cause of severe mental retardation (36%). Impairments were studied at 2 years of age. Impairment of language was present in all, while locomotor dysfunction was seen in 89% of cases. Epilepsy and cerebral palsy were each present in 22% of cases. Mortality among these severely mentally retarded children was 36%.

An epidemiological/genetic study of mental subnormality in Assiut Governorate, Egypt

The aim of this investigation was to study the epidemiologic and genetic aspects of mental subnormality (MS) in Assiut Governorate, representing the Egyptian population. The sample comprised 3000 randomly selected subjects from three localities: one urban (Assiut City) and two adjacent rural villages. Age-matched controls were chosen for comparison. The Stanford-Binet test was administered to each individual. During history-taking special attention was paid to consanguinity and categorization on a genetic basis. The results revealed 116 cases with MS, showing an overall prevalence of 3.9%, which varied in the three locations: 3.4% in Assiut City, and 3.8% and 4.4% in the two rural locations. Clinico-genetic classification revealed the following: idiopathic MS 27.6%, MCA/MR syndromes 24.1%, primary CNS defect 12.9%, Martin-Bell syndrome 10.3%, inborn errors of metabolism 9.5%, tetratogenic and environmental causes 5.2%, MS and epilepsy 4.3%, chromosomal disorders 3.4% and MS associated with psychiatric disorder 2.6%. Parental consanguinity was found in 65% of the total sample, which emphasizes the role played by that factor in the etiology of mental subnormality in Egypt.