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Drug-induced movement disorders in institutionalised adults with mental retardation: clinical characteristics and risk factors.

Fifty-three institutionalised adults with mental retardation, the majority (73.5%) moderate to severe, were examined for drug-induced movement disorders. Using a global AIMS score of 2 or more, 16 (34%) of the 47 subjects who had been exposed to neuroleptics had tardive dyskinesia (TD). Three of these had developed the dyskinesia upon withdrawal of neuroleptics. The dyskinetic movements were mainly seen in the lingual, perioral and other facial muscles. Two (33%) out of 6 subjects with no history of exposure to neuroleptics also had similar dyskinetic movements. The total neuroleptic dose significantly, and age marginally, but not sex, brain damage or level of mental retardation, emerged as risk factors for TD. Two (3.7%) subjects had definite akathisia and 16 (30.8%) significant extrapyramidal side effects. This study supports the findings of previous studies of considerable neurological adverse effects of neuroleptics in this patient group and cautions against their injudicious use. It provides further evidence for some putative risk factors for TD and is noteworthy for its lack of support for the contentious issue of brain damage as a risk factor.

Adult↗

Adaptation to visual--motor rearrangement of mentally retarded individuals: relationship to Adaptive Behavior Scale scores.

Thirty-five institutionalized, mentally retarded individuals navigated an obstacle course while viewing through an optical prism that displaced the visual field (visual--motor rearrangement). The degree of adaptation to visual--motor rearrangement was assessed and compared with scores on a research version of the Adaptive Behavior Scale (ABS). The results showed that those individuals who produced the expected patterns of prismatic visual--motor adaptation scored significantly higher on ABS Factors I and II but not III. Factors I and II include a number of items that depend upon sensorimotor integration. Thus, an explicit experimental technique for assessing sensorimotor adaptation was found to support the utility and validity of ABS assessment of mentally retarded individuals.

Adaptation, Psychological↗

Fragile X mental retardation protein is necessary for neurotransmitter-activated protein translation at synapses.

Fragile X mental retardation is caused by absence of the RNA-binding protein fragile X mental retardation protein (FMRP), encoded by the FMR1 gene. There is increasing evidence that FMRP regulates transport and modulates translation of some mRNAs. We studied neurotransmitter-activated synaptic protein synthesis in fmr1-knockout mice. Synaptoneurosomes from knockout mice did not manifest accelerated polyribosome assembly or protein synthesis as it occurs in wild-type mice upon stimulation of group I metabotropic glutamate receptors. Direct activation of protein kinase C did not compensate in the knockout mouse, indicating that the FMRP-dependent step is further along the signaling pathway. Visual cortices of young knockout mice exhibited a lower proportion of dendritic spine synapses containing polyribosomes than did the cortices of wild-type mice, corroborating this finding in vivo. This deficit in rapid neurotransmitter-controlled local translation of specific proteins may contribute to morphological and functional abnormalities observed in patients with fragile X syndrome.

Animals↗

Preparation process facilitation of a motor task through imagery practice with adolescents who have mental retardation.

The use of imagery practice to facilitate the preparation of adolescents with mild mental retardation to perform a motor task was explored. Thirty-two subjects with mental retardation and an equal number of subjects without retardation performed a response-type task that included reaction time (RT) and movement time (MT) components. Catch trials were used to manipulate the preparation levels of several experimental groups. Results suggest that with marked preparation decrements, imagery practice facilitated the execution of the RT component. Under certain conditions imagery practice also helped performance of the MT component. These findings indicate that the potential use of imagery practice to enhance motor performance should be investigated more extensively.

Adolescent↗

Ectomorphic habitus, severe mental retardation and characteristic face: a new MCA/MR syndrome?

Here we report on 2 mentally retarded sisters with clinical signs and symptoms not seen in a previously delineated MCA/MR syndrome, i.e., normal pre- and perinatal history, severe mental retardation with severe delay in psychomotor development and without development of primary motor abilities and speech, characteristic face with maxillary hypoplasia, large mouth with down-turned corners, short philtrum and everted lower lip, associated with a remarkable ectomorphic habitus.

Abnormalities, Multiple↗

Incidence and temporal patterns of adaptive behavior change in adults with mental retardation.

The age-associated incidence of significant decline in adaptive behavior and the temporal pattern of decline in specific functional skill domains were examined in 646 adults with mental retardation through 88 years of age. Cumulative incidence of significant decline for adults with Down syndrome increased from less than.04 at age 50 to.67 by age 72, whereas cumulative incidence of significant decline for adults with mental retardation without Down syndrome increased from less than.02 at age 50 to.52 at age 88. Among adults experiencing overall decline, four clusters of behaviors were identified based upon the sequence and magnitude of changes, suggesting a pattern of loss not unlike that noted in the population without mental retardation with dementia.

Adaptation, Psychological↗

Health-promoting physical activity of adults with mental retardation.

This literature review describes the physical activity behavior of adults with mental retardation consistent with the U.S. Surgeon General's recommendation of 30 minutes of moderate intensity physical activity on 5 or more days per week. The proportion of participants achieving this criterion ranges from 17.5 to 33%. These data are likely to be generous estimates of activity as individuals included in physical activity studies to date have been relatively young and healthy volunteers with mild to moderate limitations. Major sources of physical activity were walking and cycling for transport, chores and work, dancing, and Special Olympics. There is a pressing need to conduct studies using appropriately powered representative samples and to validate measures that assess physical activity less directly; including methodologies in which proxy respondents are used. Accurate information about existing patterns of behavior will enhance the development of effective strategies to promote physical activity among persons with mental retardation.

Adult↗

Improving the oral hygiene of institutionalized mentally retarded clients.

PURPOSE: The quality of oral health care of persons with mental retardation has been reported in the literature to be less than that of their normal peers. The purpose of this study, set in a Midwest institution for persons with developmental retardation, was to determine if a change in policy followed by staff training and monitored by an interested third party would improve the oral hygiene of clients living on wards. METHODS: Methods used to train staff in proper toothbrushing were developed. Three living units were randomly selected for study: control, training plus accountability (experimental group I), and training without accountability (experimental group II). The direct care staff of both experimental groups were trained in proper toothbrushing techniques. Staff of the control group received no training. A dental hygienist visited the living unit periodically to evaluate and provide feedback on the plaque index scores taken by the caregivers in both experimental groups. RESULTS: The plaque indexes of group I showed significant improvement over the control group and group II. CONCLUSION: The results of this pilot study support the other findings of higher plaque indexes for residents with mental retardation and that modifying toothbrushing policies and staff training are not as critical to the improvement of the clients' oral hygiene as is the presence of an involved, interested third party.

Adult↗

Linkage mapping of a new syndromic form of X-linked mental retardation, MRXS7, associated with obesity.

A new syndromic form of X-linked mental retardation associated to obesity, MRXS7, has been localised to Xp11.3-Xq23 in a large Pakistani family. The ten affected males show clinical manifestations of mental retardation, obesity and hypogonadism. The family was genotyped by a set of microsatellite markers spaced at approximately 10 cM intervals on the X chromosome. Linkage to five adjacent microsatellite markers, mapping in the pericentromeric area, was established and a maximum two-point lod score of 3.86 was reached at zero recombination with marker DXS1106. Reduced recombination events around the centromere prevented precise mapping of the gene.

Adolescent↗

Differences in adaptive functioning among people with autism or mental retardation.

This report describes differences in motoric and instrumental activity of daily living skills (MADLs and IADLs) between 1,442 people with autism and 24,048 people with mental retardation, using data from an adaptive behavior measure. Comparisons were made using groups defined by age (5-12, 13-21, and 21-35 years) and intellectual level. Diagnoses of record were confirmed through group analyses of rates of problem behaviors consistent with autism and comparison to an independent data base. Findings suggest that at ages 5-12 the skills of children with autism are more developed than those of children with mental retardation matched by age and intellectual level. However, in the older groups these differences diminish, and with increasing age (21-35 years) more developed instrumental skills are observed for people with mental retardation.

Activities of Daily Living↗

Regional localisation of two non-specific X-linked mental retardation genes (MRX30 and MRX31).

Two genes responsible for X-linked mental retardation have been localised by linkage analysis. MRX30 maps to a 28 cM region flanked by the loci DXS990 (Xq21.3) and DXS424 (Xq24). A significant multipoint lod score of 2.78 was detected between the loci DXS1120 and DXS456. MRX31 maps to a 12 cM region that spans the centromere from DXS1126 (Xp11.23) to DXS1124 (Xq13.3). Significant two-point lod scores, at a recombination fraction of zero, were obtained with the loci DXS991 (Zmax = 2.06), AR (Zmax = 3.44), PGK1P1 (Zmax = 2.06) and DXS453 (Zmax = 3.31). The MRX30 localisation overlaps that of MRX8, 13, 20 and 26 and defines the position of a new MRX gene on the basis of a set of non-overlapping regional localisations. The MRX31 localisation overlaps the localisations of many of the pericentromeric MRX loci (MRX 1, 4, 5, 7, 8, 9, 12, 13, 14, 15, 17, 20, 22 and 26). There are now at least 8 distinct loci associated with non-specific mental retardation on the X chromosome defined, in order from pter to qter, by localisation for MRX24, MRX2, MRX10, MRX1, MRX30, MRX27, FRAXE and MRX3.

Chromosome Mapping↗

Evidence for altered Fragile-X mental retardation protein expression in response to behavioral stimulation.

The Fragile-X mental retardation protein, the protein absent in Fragile-X syndrome, is synthesized near synapses upon neurotransmitter activation. Humans and mice lacking this protein exhibit abnormal dendritic spine lengths and numbers. Here we investigated Fragile-X protein levels in animals exposed to behavioral paradigms that induce neuronal morphological change. Fragile-X protein immunoreactivity was examined in visual cortices of rats reared in a complex environment for 10 or 20 days, motor cortices of rats trained on motor-skill tasks for 3 or 7 days, and either visual or motor cortices of inactive controls. Rats exposed to a complex environment for 20 days or trained for 7 days on motor-skill tasks exhibited increased Fragile-X protein immunoreactivity in visual or motor cortices, respectively. These results provide the first evidence for a behaviorally induced alteration of Fragile-X protein expression and are compatible with previous findings suggesting synaptic regulation of its expression. These results also strengthen the association of Fragile-X mental retardation protein expression with the alteration of synaptic structure.

Animals↗

Evidence for altered Fragile-X mental retardation protein expression in response to behavioral stimulation.

The Fragile-X mental retardation protein, the protein absent in Fragile-X syndrome, is synthesized near synapses upon neurotransmitter activation. Humans and mice lacking this protein exhibit abnormal dendritic spine lengths and numbers. Here we investigated Fragile-X protein levels in animals exposed to behavioral paradigms that induce neuronal morphological change. Fragile-X protein immunoreactivity was examined in visual cortices of rats reared in a complex environment for 10 or 20 days, motor cortices of rats trained on motor-skill tasks for 3 or 7 days, and either visual or motor cortices of inactive controls. Rats exposed to a complex environment for 20 days or trained for 7 days on motor-skill tasks exhibited increased Fragile-X protein immunoreactivity in visual or motor cortices, respectively. These results provide the first evidence for a behaviorally induced alteration of Fragile-X protein expression and are compatible with previous findings suggesting synaptic regulation of its expression. These results also strengthen the association of Fragile-X mental retardation protein expression with the alteration of synaptic structure.

Animals↗

Four families (MRX43, MRX44, MRX45, MRX52) with nonspecific X-linked mental retardation: clinical and psychometric data and results of linkage analysis.

Four families are described in which mental retardation segregates in an X-linked fashion. Mental retardation was the only consistent clinical finding in all affected males. The degree of retardation varied from mild to profound both between and within families. Linkage analysis localized the genetic defect of MRX43 to Xp22. 31-p21.2, MRX44 to Xp11.3-p11.21, MRX45 to Xp11.3-p11.21, and MRX52 to Xp11.21-q21.33 with LOD scores of >2 at straight theta = 0.0 in all four families.

Adult↗

Fragile-X mental retardation syndrome transmitted through intellectually normal males: implications for genetic counseling.

The fragile-X mental retardation syndrome is the second most common identifiable cause of mental retardation in man. This condition violates many of the expectations for X-linked disorders, including the transmission of the syndrome through men who carry the gene but, for unknown reasons, do not express it. Two new cases of male transmission are presented along with four other cases heretofore unidentified in the literature, bringing the total number of confirmed or probable cases of transmission through normal men to 32. The various unorthodox characteristics of the syndrome are reviewed in light of their influence on genetic counseling. Recommendations for counseling families with fragile-X include evaluating all sons of carrier women psychometrically and cytogenetically, abandoning termination of pregnancies with male fetuses as a means of preventing the fragile-X syndrome, assuming that all mothers of sporadic cases are carriers, and karyotyping at-risk female members at an early age.

Adolescent↗

Community integration of mentally retarded adults: community placement and program success.

The extent of community and program success of 166 mentally retarded clients placed into a community-based program was evaluated over a 9-year period. Twenty predictor variables measuring institutional factors, client characteristics, training variables, and community characteristics were related to community or program success. Successful community placement was associated with sensorimotor and work skills, appropriate social-emotional behavior, gender, and family acceptance of community placement and involvement with the interdisciplinary team process. Program success was associated with language and psychomotor skills, education received prior to community placement, community and institution size, and family involvement. Sixteen percent of the clients were reinstitutionalized into either the state mental retardation facility or a mental health facility. Factors associated with successful placement and program progression were discussed as was a model for future deinstitutionalization research.

Adult↗

Sex preferences of mentally retarded children depicted in the human figure drawn first.

This study was designed to investigate the effect of sex, age (5 to 18 yr), and IQ (20 to 78) of subjects on sex of human figures drawn first by 146 mentally retarded children. The results showed that the percentages of self-sex figures drawn first by mentally retarded boys and girls are statistically significantly lower than those for boys and girls of normal ability and that neither severity of retardation nor age is significant in determining the frequencies with which a self-sex figure is drawn first by mentally retarded boys and girls. It was suggested that minimal intelligence is required to learn the sex-identification and to identify with one's own sex.

Adolescent↗

MECP2 is highly mutated in X-linked mental retardation.

Following the recent discovery that the methyl-CpG binding protein 2 (MECP2) gene located on Xq28 is involved in Rett syndrome (RTT), a wild spectrum of phenotypes, including mental handicap, has been shown to be associated with mutations in MECP2. These findings, with the compelling genetic evidence suggesting the presence in Xq28 of additional genes besides RabGDI1 and FMR2 involved in non-specific X-linked mental retardation (MRX), prompted us to investigate MECP2 in MRX families. Two novel mutations, not found in RTT, were identified. The first mutation, an E137G, was identified in the MRX16 family, and the second, R167W, was identified in a new mental retardation (MR) family shown to be linked to Xq28. In view of these data, we screened MECP2 in a cohort of 185 patients found negative for the expansions across the FRAXA CGG repeat and reported the identification of mutations in four sporadic cases of MR. One of the mutations, A140V, which we found in two patients, has been described previously, whereas the two others, P399L and R453Q, are novel mutations. In addition to the results demonstrating the involvement of MECP2 in MRX, this study shows that the frequency of mutations in MECP2 in the mentally retarded population screened for the fragile X syndrome is comparable to the frequency of the CGG expansions in FMR1. Therefore, implementation of systematic screening of MECP2 in MR patients should result in significant progress in the field of molecular diagnosis and genetic counseling of mental handicap.

Adult↗