Speaking out on mentally retarded and mentally ill, or mentally ill and mentally retarded.
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Humans↗
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[Genetics of mental retardation].
Mentally retarded patients can be grouped in two categories: severe forms seen in 4 of every thousand live births and mild forms that occur approximately five times more often. Approximately half of severe cases of mental retardation are genetically determined, and half of these fall under the category of X-linked mental retardation (XLMR) disease. The XLMR group is currently comprised of 105 highly varied types of retardation that can be associated with a fragile X chromosome, biochemical defect, neurologic alterations, bony dysplasia and a range of malformations. Along with such syndromes (which are specific), some 40 familial XLMR entities (nonspecific) can be identified in which mental retardation is the only sign. Cytogenetic testing to identify dysmorphic syndromes caused by chromosomal disease and molecular biology studies are indispensable for identifying the genes responsible for XLMR syndromes. Healthy carriers can also be found. It thus becomes possible to provide appropriate genetic counseling for families and to achieve a prenatal diagnosis in some cases.
Chromosome Aberrations↗
[MR imaging in mental retardation].
Mental retardation is considered idiopathic or not otherwise specified when no etiological diagnosis can be identified in spite of comprehensive history, physical examination and metabolic or genetic investigations. In such cases, brain MRI is indicated for patients with abnormal head size or shape, craniofacial malformation, somatic anomalies, neurocutaneous findings, seizures, focal neurological findings or behavioral and/or developmental problems. Brain anomalies are now considered a main category for the etiology of mental retardation. MRI evaluation should include axial images of the entire brain, sagittal images through the midline structures, and coronal images of the posterior fossa or entire brain. MRI allows detection of major and or minor cerebral anomalies or malformations, sometimes multiple. In the literature, the most frequently involved structures include: 1/ corpus callosum (hypoplasia, short corpus callosum and verticalized splenium), 2/ septum pellucidum (cavum septum pellucidum or cavum vergae), 3/ ventricles (ventriculomegaly), 4/ cerebral cortex (cortical dysplasia), 5/ cerebellum (hypoplasia), and 6/ extra-axial CSF spaces (enlargement). In our patient population, dysplasia involving the cerebellum and vermis have been identified, a finding that has not yet been described in the literature. MRI allows detection of multiple minor morphological anomalies. Most have classically been considered as normal variants but they may in fact be markers of cerebral dysgenesis and are currently the only anomaly detected in the work-up of patients with mental retardation. Their role in the pathogenesis of mental retardation is under evaluation.
Adolescent↗
The use of genomic microarrays to study chromosomal abnormalities in mental retardation.
Mental retardation affects 2 to 3% of the US population. It is defined by broad criteria, including significantly subaverage intelligence, onset by age 18, and impaired function in a group of adaptive skills. A myriad of genetic and environmental causes have been described, but for approximately half of individuals diagnosed with mental retardation the molecular basis remains unknown. Genomic microarrays, also called array comparative genomic hybridization (array CGH), represent one of several novel technologies that allow the detection of chromosomal abnormalities, such as microdeletions and microduplications, in a rapid, high throughput fashion from genomic DNA samples. In one early application of this technology, genomic microarrays have been used to characterize the extent of chromosomal changes in a group of patients diagnosed with one particular type of disorder that causes mental retardation, such as deletion 1p36 syndrome. In another application, DNA samples from individuals with idiopathic mental retardation have been assayed to scan the entire genome in attempts to identify chromosomal changes. Genomic microarrays offer both a genome-wide perspective of chromosomal aberrations as well as higher resolution (to the level of approximately one megabase) compared to alternative available technologies.
Chromosome Aberrations↗
Genes responsible for nonspecific mental retardation.
Mental retardation (MR) is a group of heterogeneous clinical conditions. There are more than 900 genetic disorders associated with MR and it affects around 3% of the general population. MR can be subdivided into syndromic, if it is characterized by consistent and distinctive clinical findings, and nonspecific, if mental retardation is the only primary symptom among affected individuals. Many MR conditions described are syndromic, fragile X syndrome being the most common clinical entity among them. In the past years, knowledge of the molecular basis of mental retardation has increased remarkably. Eight genes involved in nonspecific X-linked MR have been identified so far, including FMR2, OPHN1, GDI1, PAK3, IL1RAPL, TM4SF2, VCX-A, and ARHGEF6. Two other genes also located on the X chromosome have been involved both in syndromic and in MRX forms (RSK2 and XNP/ATR-X). New insights into the pathogenesis of mental retardation are being provided by the discovery of these genes involved in different cellular signaling pathways in the central nervous system although many others remain to be identified.
Cloning, Molecular↗
Cerebral angiography in children and adults with mental retardation. II. Mentally retarded group.
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Age Factors↗
Visual and auditory affect recognition in singly diagnosed mentally retarded patients, mentally retarded patients with autism and normal young children.
Five groups were tested for facial and postural affect recognition by use of word and tonal prompts. Group 1 contained normal young children. Groups 2 and 3 were moderately retarded and Groups 4 and 5 were severely retarded. Retardation was complicated by autism in Groups 3 and 5. There were eight conditions. In Condition 1, happy, sad and angry faces were displayed simultaneously in each of 18 trials, with the subjects prompted verbally to point to one of the affects (e.g., the angry face) in a given trial. In Condition 2, full figures (with facial features omitted) were used instead of the faces, and emotion was conveyed by use of body position and muscle tone. The same procedure was followed as before. Conditions 3 and 4 were repeated of 1 and 2, except that descriptive word prompts were used (e.g., point to the yelling picture). Conditions 5 and 6 were the same as 1 and 2, except that affective voice intonations were used instead of word prompts. The subjects had to identify the voice tones by using affective words (e.g., happy) in Condition 7, and descriptive words (e.g., laughing) in Condition 8. An analysis of the error data indicated that retarded subjects had particular difficulty recognizing angry stimuli with both affective and descriptive word prompting. In addition, they tended to confuse happy with angry voice tones.
Auditory Perception↗
Liver transplantation and mental retardation.
Mental retardation has been a controversial relative contraindication to organ transplantation. We present a case report of a 54 year old man with alcoholic cirrhosis and mental retardation who was sent for evaluation for liver transplantation. We discuss the ethical considerations of transplantation in the mental retarded patient.
Belgium↗
Genetics of mental retardation.
Mental retardation can follow any of the biological, environmental and psychological events that are capable of producing deficits in cognitive functions. Recent advances in molecular genetic techniques have enabled us to understand more about the molecular basis of several genetic syndromes associated with mental retardation. In contrast, where there is no discrete cause, the interplay of genetic and environmental influences remains poorly understood. This article presents a critical review of literature on genetics of mental retardation.
Chromosome Aberrations↗
Genetic factors in the etiology of mental retardation.
Mental retardation is a condition with multiple, disparate causes, both environmental and genetic. In this article we have tried to characterize, in a general fashion, the nature of the genetic factors through a discussion of polygenic inheritance, single gene errors, and chromosomal anomalies. Despite the existence of a large and complex body of knowledge, which has only been touched upon here, it is sobering to realize that we cannot diagnose almost half of the mentally retarded. Even in those in whom a genetic etiology is obvious, we know little about the intervening processes that operate between the gene and the mental deficiency it produces. Under the conditions, therapy holds little promise, while prevention assumes a high priority. Prevention of mental retardation due to genetic factors requires the physician to have a basis knowledge of genetic principles and syndromes, of prenatal diagnostic technology, and a determination to inform, even when the patient does not ask.
Adolescent↗
Mental retardation.
Mental retardation is defined using two criteria: intelligence quotient and adaptive functioning. Subclassification based on IQ is helpful in predicting outcome and determining educational program. Advances continue to be made in identifying specific medical causes of intellectual deficits. As the natural history of conditions such as fragile-X becomes better understood, treatment approaches based on medical diagnosis will likely evolve. Clinicians working with mentally retarded patients should pursue vigorously medical diagnosis because of its implications for genetic counseling, family management, and full recognition of other handicapping conditions which may affect the patient. Psychopathology in the mentally retarded resembles that in nonretarded individuals, but occurs more frequently. Treatment of psychiatric disorders must be individualized. Mildly and some moderately retarded persons can benefit from psychotherapy. Behavioral approaches, particularly applied behavior analysis, are the most effective treatment for specific aberrant behaviors. Pharmacotherapy should be based on psychiatric diagnosis. Medications may be used, together with behavioral interventions, to treat specific destructive behaviors, but the scientific support for such use is new and somewhat limited.
Adolescent↗
The Drosophila homolog of Down's syndrome critical region 1 gene regulates learning: implications for mental retardation.
Mental retardation is the most common phenotypic abnormality seen in Down's syndrome (DS) patients, yet the underlying mechanism remains mysterious. DS critical region 1 (DSCR1), located on chromosome 21, is overexpressed in the brain of DS fetus and encodes an inhibitor of calcineurin, but its physiological significance is unknown. To study its functional importance and role in mental retardation in DS, we generated Drosophila mutants of nebula, an ortholog of human DSCR1. Here, we report that both nebula loss-of-function and overexpression mutants exhibit severe learning defects that are attributed by biochemical perturbations rather than maldevelopment of the brain. These results, combined with our data showing that the same biochemical signaling pathway is altered in human DS fetal brain tissue overexpressing DSCR1, suggest that alteration of DSCR1 expression could contribute to mental retardation in DS.
Animals↗
Identification and evaluation of mental retardation.
Mental retardation in young children is often missed by clinicians. The condition is present in 2 to 3 percent of the population, either as an isolated finding or as part of a syndrome or broader disorder. Causes of mental retardation are numerous and include genetic and environmental factors. In at least 30 to 50 percent of cases, physicians are unable to determine etiology despite thorough evaluation. Diagnosis is highly dependent on a comprehensive personal and family medical history, a complete physical examination and a careful developmental assessment of the child. These will guide appropriate evaluations and referrals to provide genetic counseling, resources for the family and early intervention programs for the child. The family physician is encouraged to continue regular follow-up visits with the child to facilitate a smooth transition to adolescence and young adulthood.
DiGeorge Syndrome↗
Handedness in mental retardation.
Mentally retarded and age-matched normal controls with no history of parental sinistrality were examined for their handedness with the Waterloo Handedness Questionnaire (Singh & Bryden, 1994). Normal controls showed a clear rightward bias, with the effect being significantly higher for skilled as compared to unskilled hand items. Mentally retarded subjects showed mixed handedness with a nonsignificant difference in performance between skilled and unskilled hand items.
Journal Article↗
The biochemistry of brain development and mental retardation.
Mental retardation may be associated with a number of environmental factors such as undernutrition, lead poisoning or exposure to neuroactive drugs during a critical period of brain development. Possible biochemical mechanisms operating in these various conditions and in animal models are reviewed in relation to the vulnerable period hypothesis. Small brains are common in the mentally retarded, and this may be related to a developmental abnormality particularly at the level of the synapse.
Age Factors↗
Effects of Snoezelen room, Activities of Daily Living skills training, and Vocational skills training on aggression and self-injury by adults with mental retardation and mental illness.
Multi-sensory stimulation provided in a Snoezelen room is being used increasingly for individuals with mental retardation and mental illness to facilitate relaxation, provide enjoyment, and inhibit behavioral challenges. We observed aggressive and self-injurious behavior in three groups of 15 individuals with severe or profound mental retardation and mental illness before, during, and after being in a Snoezelen room. All participants were receiving psychotropic medication for their mental illness and function-derived behavioral interventions for aggression, self-injury, or both. Using a repeated measures counterbalanced design, each group of participants was rotated through three experimental conditions: Activities of Daily Living (ADL) skills training, Snoezelen, and Vocational skills training. All other treatment and training activities specified in each individual's person-centered plan were continued during the 10-week observational period. Both aggression and self-injury were lowest when the individuals were in a Snoezelen room, followed by Vocational skills training and ADL skills training. The levels in the Snoezelen room were significantly lower than in both the other conditions for aggression but only in ADL skills training for self-injury. The difference in levels before and after Snoezelen were statistically significant with self-injury but not with aggression. The order of conditions showed no significant effect on either behavior. Snoezelen may provide an effective context for reducing the occurrence of self-injury and aggression.
Activities of Daily Living↗
Using principles of ACT to integrate community care for people with mental retardation and mental illness.
The authors describe the use of an Assertive Community Treatment (ACT) approach in a community living program for persons with both mental retardation and mental illness. The development of the program occurred in the context of a statewide project to serve more than 1,000 dually diagnosed persons who were members of a class action lawsuit against the State of North Carolina. The use of ACT principles marked a substantive departure from the residential supervision and brokered service model employed for the Class throughout the State. The authors describe the public policy context within which the program was developed, discuss the rationale for selecting the ACT model, describe its implementation, and summarize service utilization and outcome information. Changes by the funding agency in its expectations of program staffing and reimbursement methodology that were made after the program was approved led to its early demise. Although the program lasted less than 2 years, during its tenure most participants realized marked improvement in symptoms and community adjustment. Results may cautiously be interpreted as indicating that ACT may reduce the reliance on 24-hour residential and community supervision for many persons with both mental retardation and mental illness.
Journal Article↗
A habilitation center for individuals with a dual diagnosis of mental retardation and mental illness.
The ICF/MR provides services to individuals with a dual diagnosis of mental retardation and mental illness. These services prepare these individuals to the least restrictive environment analogous to the norms and patterns of the mainstream of society. The individuals served are more than 22 years of age and have behavioral problems associated with mental retardation and/or mental illness. In addition, they have multiple medical problems which are related or unrelated to their physical or mental disabilities. These individuals have multiple changing needs which are addressed by an interdisciplinary team. The team develops a unified Individual Program Plan which is the framework for a comprehensive care for these individuals. This is to enable them to live a normal life as possible and to achieve gainful occupational pursuits like any other citizen in the State of South Carolina.
Adult↗