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Use of laxatives in institutions for the mentally retarded.

OBJECTIVE: To study, in institutionalized mentally retarded patients, the prevalence of regular laxative use, and to identify its correlates. METHODS: Twenty-one of the 22 institutions for the mentally retarded in Flanders (Belgium) provided the setting for the study, which included a population of 3712 residents with an IQ of < 50. This was a descriptive cross-sectional study of a random sample of 20 patients per institution, consisting of a structured interview of the personnel responsible for daily care of the selected patients. The study population consisted of 420 mentally retarded patients. Their median age was 29 years (range 2-72 years). Twenty-six percent of patients had an IQ of 35-49, 40% an IQ of 20-34 and 34% an IQ of <20. Sixteen percent of the patients were non-ambulant. RESULTS: Regular laxative use was found in 26.4% (111/420) of the residents. In addition, occasional laxative use was found in 2% (10/420) of the residents. Oral laxatives were used daily by 13% (56/420) and oral laxatives daily in combination with enemas were used by 9% (39/420). Enemas but no oral laxatives were used by 3% (11/420); manual evacuation in combination with oral laxatives and enemas was used by 1% (5/420). Seventy-eight percent (78/100) of the oral laxative users used them for more than 1 year. Seventy-one percent (71/100) used one laxative, 23% two and 6% three. Thirty different brands of oral laxatives were used. Sixty-seven percent (67/100) used osmotic laxatives alone or in combination, 30% used stimulant laxatives, 19% used bulk forming laxatives and 19% mineral oil. Oral laxatives were always prescribed by attending physicians, while enemas were also initiated by nurses in 35% (18/52). Laxative use was positively and independently correlated with female gender, with being non-ambulant, with oral motor dysfunction and with the use of medication other than laxatives. It did not correlate with age. Within the institutions, laxative use varied from one to 15 users out of the 20 randomly selected patients (median 4/20). CONCLUSION: Laxative use is frequent in institutions for the mentally retarded, with a large inter-institution variation, indicating that constipation is an important problem and underlining the need for research into cost-effective treatment.

Adolescent↗

Hospital to community: a pilot rehabilitation project for elderly mentally retarded.

Four mentally handicapped patients, three of whom were aged 75 years plus, with a mean age of 67 years (in 1981) and a total institutional life of 160 years, have been successfully rehabilitated in a group home in an active community community environment since August 1981. The process of preparing them for independent living, the social services and community nursing support need, the qualitative change in their life style are described. The success is defined as a fuller community integrated living, free of institutional rigidity and freedom to do what they like with some support and using all the community services as used by other people.

Activities of Daily Living↗

Identifying the referents of spoken messages: use of context and clarification requests by children with and without mental retardation.

The ability of children with mental retardation and of children without mental retardation matched to them on nonverbal MA to use (a) contextual information and (b) clarification requests to resolve referential ambiguity was evaluated. Each child pretended to be a storekeeper and responded to an adult customer's ambiguous requests. The context disambiguated the request in some cases, but not in others. Both groups of children selected the appropriate referent when the context was informative. Only the children without mental retardation appropriately requested clarification when the context was uninformative. Referential performance was not related to their receptive language level or nonverbal MAs.

Child↗

Capacity of persons with mental retardation to consent to participate in randomized clinical trials.

OBJECTIVE: Adults with mental retardation have histories of cognitive and adaptive deficits posing unique ethical challenges for research consent assessment. This study examined the capacity of persons with mental retardation to consent to participate in randomized clinical trials. METHOD: A total of 150 adults (50 each with mild and moderate mental retardation and 50 comparison subjects without mental retardation) responded to a set of consent questions for a hypothetical randomized clinical trial testing a medication for aggressive disorders. Intelligence, adaptive behavior, medical treatment history, and consent history were evaluated. Univariate and multivariate methods were used to compare performance across and within groups. RESULTS: Comparison subjects scored significantly higher on measures of consent capacity than participants with mild mental retardation, who scored higher than those with moderate mental retardation. Most subjects with mental retardation were able to make a participation choice, and many understood research methods and appreciated the protagonist's disorder and the consequences of participation. Almost half of those with mild mental retardation understood human subject protections. Performance was weakest on understanding the purpose of research and reasoning about whether to participate, suggesting vulnerability to the therapeutic misconception. Psychiatric and experiential factors did not predict consent capacity. CONCLUSIONS: While adults with mental retardation as a group showed consent deficits, many attained consent capacity scores comparable to those of comparison subjects. Investigators should consider individual differences and a consent format suited to deficits in language, memory, and attention before restricting consent opportunities for persons with mental retardation.

Adult↗

The FMR2 gene, FRAXE and non-specific X-linked mental retardation: clinical and molecular aspects.

FRAXE fragile site associated mental retardation remains unique among X-linked mental retardation phenotypes due to its very mild to borderline nature (50< IQ< 85). It is the most prevalent form of non-specific X-linked mental retardation so far delineated, with an estimated incidence of at least 1/50-100,000 males, and with more than 50 families known worldwide. The FRAXE site is within, or immediately adjacent to, the 5' untranslated region of the FMR2 gene. Hyperexpansion of the FRAXE CCG repeat silences transcription of the gene. The structure of FMR2 has been characterized, but its function remains unknown. Gene localizations for numerous (> 75) large families with non-specific X-linked mental retardation (MRX) have been determined so far. Recently the molecular basis for some of them has been unravelled by identification of the responsible genes, which participate in complex common signalling pathways. This review summarises the new data on FRAXE associated mental retardation and the FMR2 gene in the light of the recent discoveries of new genes responsible for other forms of non-specific X-linked mental retardation.

Chromosome Fragile Sites↗

Linkage analysis in three families with nonspecific X-linked mental retardation.

Nonspecific X-linked mental retardation (XLMR) is a common disorder. The number of genes involved in this condition is not known, but it is estimated to be more than 10. We present a clinical and linkage study on 3 families with XLMR. All families were analyzed using highly polymorphic markers covering the X chromosome; screening for the fragile X mutation was negative. The first family (MRX 36) consisted of 1 female and 4 male patients in 3 generations and 7 healthy individuals. Considering the female as an expressing heterozygous carrier, a maximum LOD score of 3.41 was reached in region Xp21.2-Xp22.1. Considering her phenotype to be unknown, a LODmax of 1.97 was reached in the same region. The second family consisted of 5 affected and 6 healthy males with mild to borderline mental retardation. Linkage analysis using an X-linked recessive model with full penetrance and no phenocopies excluded linkage over almost the entire X chromosome. Using alternative models, including an affecteds-only analysis, a LODmax of 1.49 was found in region Xq24-28. The third family, consisting of 4 male patients with moderate mental retardation in 1 generation yielded a LODmax of 0.9 in region Xp22.13-11.3. However, even in this small pedigree, exclusion mapping was able to exclude very large parts of the X chromosome and in this way identify a likely candidate region.

Child, Preschool↗

Psychiatric illness among the mentally retarded. A swedish population study.

Object--The aim of this investigation was in the first place to study the relation between mental retardation and other mental disturbances. The second aim was to study the frequency of severe and mild mental retardation in an adult Swedish population and to throw some light on the socio-medical situation of the adult mentally retarded. Methods--A primary sample, stratified with respect to population density, was extracted from the population in the age group 20-60 years, resident in Kopparberg County, Sweden, on 1 July 1977. The mildly and severely mentally retarded in this sample were identified. Enquiry was made into the presence of additional handicaps in the mentally retarded. Social conditions including alcohol consumption and the occurrence of abuse and criminality were studied in the two retarded groups and a control group representing the rest of the population. The three groups were compared by rating with the Comprehensive Psychopathological Rating Scale (CPRS), by classification of any mental illness present according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) and by determining their intake of psychotropic drugs and anti-epileptics. The mildly mentally retarded and the control group were also compared with respect to neuroticism and extraversion-introversion by rating with the Eysenck Personality Inventory (EPI). Results--The study revealed a prevalence of 0.27% for severe (IQ less than 53) and 0.32% for mild (IQ 53-73.7) mental retardation in the age group 20-60 years. All the severely retarded, but only just over half the mildly retarded, were known to the care authority. The majority of the former were living in some form of institution, whereas this applied to only 15% of the mildly retarded. Nineteen per cent of the severely retarded and 4% of the mildly retarded had manifest epilepsy. Defects of movement and of hearing were most prominent among the mildly retarded, while the frequency of specific speech disturbances was greater among the severely retarded, approximately 10% of whom had no power of verbal communication. Visual defects were recorded in about one-third of both groups. The study showed that alcohol intake was lower among both the severely and mildly mentally retarded than among the persons in the control group and that the frequency of abuse and criminality was as high among persons of higher intelligence as among the mentally retarded. The severely retarded, particularly the men, showed a raised psychiatric morbidity as compared with the mildly retarded and the control group.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

[An analysis of simple reaction time in mentally retarded and nonretarded children matched on mental age: examination using intertrial interval as a variable].

The simple reaction times (RTs) in mentally retarded children and nonretarded children matched on mental age (MA) were analyzed, and the relationship between mental ability and RT performances was discussed. RTs in both groups were obtained under three temporal conditions. In Experiment I, it was found that: (a) The shorter intertrial interval (ITI), the shorter RTs in both groups and (b) in the retarded group, RTs of MA5 and MA6-8 subjects were significantly different, presumably because of motor and/or sensory disabilities in the younger subjects, irrelevant to mental ability. In Experiment II, different response characteristics were found for both groups under the complex temporal condition. Retarded subjects showed remarkably slow RT only on those trials in which a long ITI was followed by a short ITI. Nonretarded subjects had remarkable variation in RT over all trials. It was inferred that different psycho-behavioral characteristics of the subjects of both groups were reflected in the different response tendencies observed.

Adolescent↗

In utero exposure to A-bomb radiation and mental retardation; a reassessment.

The prevalence of mental retardation in children exposed in utero to the atomic bombs in Hiroshima and Nagasaki has been re-evaluated in reference to gestational age and tissue dose in the fetus. There was no risk at 0-8 weeks post-conception. The highest risk of forebrain damage occurred at 8-15 weeks of gestational age, the time when the most rapid proliferation of neuronal elements and when most, if not all, neuroblast migration to the cerebral cortex from the proliferative zones is occurring. Overall, the risk is five or more times greater in these weeks than in subsequent ones. In the critical period, damage expressed as the frequency of subsequent mental retardation appears to be linearly related to the dose received by the fetus. A linear model is not equally applicable to radiation-related mental retardation after the 15th week, the observed values suggesting that there a threshold may exist. The data are consistent with a probability of occurrence of mental retardation of 0.40% per cGy or 40% per gray.

Brain↗

Trinucleotide CGG repeat in the FMR1 gene in Chinese mentally retarded patients.

The fragile X syndrome of mental retardation is related to the number of trinucleotide CGG repeats at the 5'-untranslated region of the FMR1 gene located on the X-chromosome. We have studied X-chromosomes from 649 unaffected Chinese subjects and 324 patients with mild mental retardation. All study subjects were unrelated. The CGG repeat number was analysed by electrophoresis of a polymerase chain reaction followed by gel transfer and hybridisation with a 32P-labeled (CCG)5 probe. The DNA samples having detectable CGG expansion were further analysed by Southern blot analysis with probe StB12.3 after restriction digestion by EcoR I and Eag I. For the unaffected Chinese subjects, a different distribution pattern of CGG allele size from Caucasians was observed. It was a bimodal pattern and the CGG repeat number ranged from 19 to 54. The most common CGG repeat allele was 29 compared with 30 in Caucasians. The second mode appeared at 36 repeats. There was mild statistical difference in the repeat patterns between the mentally retarded patients and unaffected subjects, although the essential features were similar. Among the mentally retarded patients, one male had an unmethylated full mutation and one female had a full mutation. The fragile X prevalence was 0.6%, which is lower than two previous studies in Chinese mentally retarded patients utilising cytogenetic analysis. Our results indicate that a large-scale screening program would be worthwhile to determine the prevalence of the fragile X syndrome in the Chinese population.

China↗

Type and frequency of social interaction among workers with and without mental retardation.

The social/verbal interactions of 6 employees with moderate or severe mental retardation and 6 workers without mental retardation were observed in six restaurants. Results showed that target workers without mental retardation gave more directions, asked more work-related questions, initiated more jokes, and had more general work-related comments than did target workers with mental retardation. The latter received more greetings and social amenities. Interactions between workers with mental retardation and the job coach correlated negatively with the workers' initiation of interactions with co-workers who did not have mental retardation. Implications for job placement and training as well as future research needs were discussed.

Adult↗

The development of persuasive strategies by mentally retarded children.

The persuasive strategies of educable mentally retarded children were examined in terms of their level of perspective-taking ability. Forty mentally retarded children and 40 non-mentally retarded children constructed persuasive messages to a familiar and unfamiliar target. There were 10 children from each group in the mental ages of 6, 8, 10, and 12 years. Significant differences were found for age and target but not between the groups. The results are discussed in terms of the social-cognitive and communicative skills of educable mentally retarded children.

Adolescent↗

Recognition of facial expressions of emotion by persons with mental retardation. A matched comparison study.

Children and adults with mental retardation were tested on their ability to recognize facial expressions of emotion. The sample consisted of 80 children and adults with mental retardation and a control group of 80 nonhandicapped children matched on mental age and gender. Ekman and Friesen's normed photographs of the six basic emotions (anger, disgust, fear, happiness, sadness, and surprise) were used in a recognition task of facial expressions. Subjects were individually read two-sentence stories identifying a specific emotion, presented with a randomized array of the six photographs of the basic facial expressions of emotion, and then asked to select the photograph that depicted the emotion identified in the story. This procedure was repeated with 24 different stories, with each of the six basic emotions being represented four times. Results showed that, as a group, individuals with mental retardation were not as proficient as their mental-age-matched nonhandicapped control subjects at recognizing facial expressions of emotion. Although adults with mild mental retardation were more proficient at this task than those with moderate mental retardation, this finding was not true for children. There was a modest difference between the children with moderate mental retardation and their nonhandicapped matched controls in their ability to recognize facial expression of disgust.

Adolescent↗

The genetics of mental retardation.

Genetic abnormalities frequently give rise to a mental retardation phenotype. Recent advances in resolution of comparative genomic hybridization and genomic sequence annotation has identified new syndromes at chromosome 3q29 and 9q34. The finding of a significant number of copy number polymorphisms in the genome in the normal population, means that assigning pathogenicity to deletions and duplications in patients with mental retardation can be difficult but has been identified for duplications of MECP2 and L1CAM. Novel autosomal genes that cause mental retardation have been identified recently including CC2D1A identified by homozygosity mapping. Several new genes and pathways have been identified in the field of X-linked mental retardation but many more still await identification. Analysis of families where only a single male is affected reveals that the chance of this being due to a single X-linked gene abnormality is significantly less than would be expected if the excess of males in the population is entirely due to X-linked disease. Recent identification of novel X-linked mental retardation genes has identified components of the post-synaptic density and multiple zinc finger transcription factors as disease causing suggesting new mechanisms of disease causation. The first therapeutic treatments of animal models of mental retardation have been reported, a Drosophila model of Fragile X syndrome has been treated with lithium or metabotropic glutamate receptor (mGluR) antagonists and a mouse model of NF1 has been treated with the HMG-CoA reductase inhibitor lavastatin, which improves the learning and memory skills in these models.

Chromosome Aberrations↗

Nonspecific X-linked mental retardation II: the frequency in British Columbia.

Data on nonspecific mental retardation in two or more sibs ascertained from the British Columbia Health Surveillance Registry are utilized to calculate the frequency of X-linked mental retardation in the population of British Columbia (B.C.). In the 1950-1969 birth cohort there are 107 sibships with only males affected and 35 sibships with only females affected giving an excess of 72 male-affected sibships. Family histories of the sibships with two more more mentally retarded males provide evidence that the mothers of the excess of male-affected sibships are carriers of X-linked mental retardation. Thus, a frequency of 1.83 per 1,000 males for X-linked mental retardation and carrier frequency of 2.44 per 1,000 females are calculated. This frequency can account for all the excess of males in the population who are affected with nonspecific mental retardation. We estimate that seven to 19 X-linked genes exist to cause nonspecific mental retardation, and that the frequency of the marker-X chromosome, associated with X-linked mental retardation in some families, may be 0.92 per 1,000 male births.

British Columbia↗

Psychomotor development in the first year and mental retardation--a prospective study.

The psychomotor development of mentally retarded children (IQ less than or equal to 85) in their first year is compared here with that of healthy children on the basis of a 1-year birth cohort (1966) from northern Finland which comprised a total of 12 058 live-born children. Data on the age of reaching the main developmental milestones in the first year, standing without support, walking with and without support and speech at 12 months were obtained by means of information collected prospectively in the children's welfare centres for this purpose. Detailed information on mental retardation covering the age group 0-14 years was obtained from the school health authorities, the national hospital discharge register and other regional or national registers. The results show that mental retardation is associated with subnormal motor development in the first year, as this finding persists even after the exclusion of children with a CP syndrome. Children who could neither walk with support nor speak by the age of 12 months constituted a high-risk group for mental retardation, the risk being 14-fold higher in this group than among the other children. Even so, only 65.2% of the children with severe mental retardation and 38.2% of those with mild mental retardation fulfilled these criteria, demonstrating that psychomotor development in the first year can be apparently normal in these groups.

Child Development↗

Identification by STS PCR screening of a microdeletion in Xp21.3-22.1 associated with non-specific mental retardation.

X-linked non-specific mental retardation (MRX) is a heterogeneous condition in which mental retardation (MR) appears to be the only consistent manifestation. The genetic and phenotypic heterogeneity exclude any possibility of pooling families and, therefore, of fine-mapping the related disease genes. In order to identify genomic critical regions involved in the MRX condition assigned to Xp21.3-22.1 region, we have implemented the PCR screening of non fragile X MR patients for the presence of deletions in this region. The amplification by PCR of 12 markers located between POLA and DXS704 using genomic DNA from 192 MR males led to the identification, in a 9 year old mentally retarded boy, of a microdeletion which extends from DXS1202 to DXS1065. None of the known genes, POLA, MAGE genes cluster, DAX1, GK and DMD, that map in the Xp21.3-22.1 region is affected by this deletion. This approach, which could easily be applied to several other MRX loci, allowed not only a confirmation of the presence of a potential locus in Xp21.3-22.1 involved in non-specific mental retardation, but also a better definition of the genomic critical region corresponding to this locus.

Child↗

Research in mental retardation: toward an etiologic approach.

Over the past two decades, mental retardation research converges on three general themes: co-occurring mental retardation and psychopathology; families of offspring with mental retardation; and the developmental approach regarding behavioral sequences and profiles. Intertwined with each theme is a mounting body of research on genetic mental retardation syndromes. We first review recent progress in each of the three domains--psychopathology, families, and development--based on studies of groups with heterogenous or nonspecific mental retardation. We then show how new findings from specific genetic syndromes take this knowledge even further, as well as aid in the search for genetic, physiological, and environmental mechanisms associated with certain behaviors. We end the review by briefly summarizing our reasons for promoting an etiological approach to future mental retardation research, as well as by discussing methodological and other challenges.

Adolescent↗