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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This article examines the epidemiological data on chronic akathisia, tardive akathisia, and withdrawal akathisia. The limitations of the data are discussed--in particular, the lack of consistent definitions of the syndromes. The studies suggest that a significant proportion of patients chronically treated with neuroleptics suffer from akathisia. The prevalence may be as high as 40 percent, although a conservative estimate would be closer to 30 percent. Risk factors for the development of chronic akathisia and tardive akathisia are poorly understood, but old age, female sex, iron deficiency, negative symptoms, cognitive dysfunction, and affective disorder diagnosis need to be studied further for their potential role. While there is convincing evidence that akathisia may develop after neuroleptic cessation or reduction in dose, the prevalence and risk factors for withdrawal akathisia are not known. Reports of akathisia in children and the elderly have been few, and more systematic research is necessary. Akathisia appears to be common in individuals with mental retardation treated chronically with neuroleptics.
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PMID:The epidemiology of drug-induced akathisia: Part II. Chronic, tardive, and withdrawal akathisias. 748 75

Fifty nonspeaking or minimally speaking subjects with moderate, severe, or profound mental retardation underwent evaluation of handedness. Results confirmed previously reported increased prevalence of non-right handedness and the occurrence of a large subtype of ambiguous handedness. Results suggest that incidence of atypical hand preference is not closely linked to level of cognitive impairment, especially as represented by significant speech-language impairment in this population, as has been previously hypothesized. Atypical handedness of persons with mental retardation probably depends on language organization, and there is little support for the view that such subtypes represent bilateral hemispheric damage.
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PMID:Handedness distribution in a nonspeaking population with mental retardation. 767 63

There is a high incidence of psychiatric disorders in mentally retarded subjects: one third to two thirds of mentally retarded subjects exhibit psychiatric disorders, a proportion which is much higher than that found in subjects with normal intelligence. The issue is to clarify the nature of the relationship between cognitive and psychiatric disorders (generally analyzed in a dichotomous approach). A way to analyze the phenomenon is to consider a psychopathological approach, which can define the underlying mechanisms responsible for this incidence. The aim of this paper is to analyze the explicatory value of deficient cognitive development, as the main factor determining a specific personality organization. Direct and indirect effects of cognitive impairment on the development of personality disorders are described: the first, in terms of how cognitive deficit (i.e. severity, homogeneity in several cognitive domains, pattern of development) disorganizes personality; the second, in terms of impact that cognitive deficit could have on the child's relationship with the external world, especially with the mother. In order to illustrate these viewpoint, the paper discusses the role of cognitive functions in the development of personality. Specifically, the way the normal child processes his perceptual and motor experiences is analyzed, that is pursuit of new causal links in his knowledge seeking activity of mastering the world. The child's primitive relationship with the world is then aimed at learning, exploring and searching for new causal links. In the light of these considerations, what the child with Mental Retardation experiences is discussed. A series of psychopathological mechanisms in Mental Retardation are postulated. The organization of the Mentally Retarded child's internal world is described, as reflected in Rorschach protocols, which outline a chaotic and primitive internal world, but with a specificity of its own. Finally, the paper discusses the hampering effect that cognitive impairment has on the quality of the relationship with the caregiver. This effect can be seen in terms of the child's interactive capacity and, at the same time, in terms of the emotional impact on the caregiver that derives from interacting with a mentally retarded child. From the above considerations a global approach to the psychopathology of cognitive and affective aspects of Mental Retardation seems warranted. Both aspects acquire a specific significance when seen in light of a specific personality organization. Defining the characteristic of this specific organization seems to be the key to a more comprehensive approach to psychiatric disorders of Mental Retardation.
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PMID:[Considerations of psychopathology in mental retardation]. 793 39

Cognitive disorders affect thinking and perceptual processes and the acquisition of knowledge and new information. They have an enormous societal impact because special educational resources are required, and independent living often cannot be achieved. Learning problems may lead to behavioral disorders in the home and community. The pathogenesis of most mild and moderate cognitive disorders is poorly understood. Severe cognitive impairment is usually accompanied by somatic abnormalities, and an etiology can be identified in many cases. Specific treatments are available for disorders such as cogenital hypothyroidism, some metabolic acidurias, and congenital toxoplasmosis. Other disorders affecting cognition such as fetal alcohol syndrome, maternal cocaine and heroin exposure, HIV encephalopathy, and prematurity require aggressive prevention and education to reduce their occurrence. The recent advances in molecular genetics offer a faster and better method of diagnosing fragile X syndrome, now recognized as the most common inheritable cause of mental retardation. In the future, DNA analysis may elucidate the basis of many other cognitive disorders.
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PMID:Cognitive disorders in children. 812 19

In this 1986-1987 study, the demographic and diagnostic characteristics, problem behaviors, self-care skills, community living skills, domestic expectations, and program goals for personal competence of 336 persons with mental retardation living in a national sample of 181 foster care and small group care settings with 6 or fewer residents was assessed. The findings indicated relatively more severe cognitive impairment among persons in small ICFs-MR, less severe cognitive impairment and fewer functional limitations among non-ICF-MR group home residents, and more functional limitations among residents in foster homes. Neighborhood integration was relatively high for foster home residents, but there were fewer expectations for their development of home and community living skills. Implications for future research and program development in small, community-based residential settings were discussed.
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PMID:Personal characteristics and competence of people with mental retardation living in foster homes and small group homes. 851 42

Although the occurrence of cognitive impairment and behavioral disturbances in patients with metopic synostosis has been described, the incidence of this dysfunction has not been established. The records of 36 consecutive children with metopic synostosis followed at one craniofacial center from 1978 to 1993 were reviewed and parental questionnaires were completed to establish the frequency of mental retardation, learning disabilities, and behavioral problems associated with this synostosis. Documentation of syndromes, abnormal karyotype, and central nervous system anomalies also was done. The study group consisted of 27 males and 9 females. The average age at most recent follow-up was 7 years and 1 month (range 6 months to 22 years). Two patients had chromosomal abnormalities (9p syndrome and trisomy 21). On the basis of CT and MRI scans, intracranial anomalies were identified for only one patient having an absent corpus callosum. Thirty-two of the study patients had adequate information for longitudinal assessment. Twenty patients have normal development without apparent disability. Of these, those of school age are at appropriate grade level. Eight patients have mild to moderate learning disabilities or behavioral problems, including attention deficit/hyperactivity disorder and impaired language development. Four patients have significant mental impairment. Impaired cognitive development was not limited to children with abnormal karyotype or central nervous system anomaly. Cognitive and behavioral abnormalities occur in at least a third of patients with metopic synostosis. The, at times, subtle nature of these abnormalities mandates longitudinal developmental and neurologic evaluation for infants with metopic synostosis.
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PMID:Long-term studies of metopic synostosis: frequency of cognitive impairment and behavioral disturbances. 855 9

Wechsler's Deterioration Index (WDI) was developed as an indicator of cognitive impairment in adults but has been applied to children, because neuropsychological deficits have often been hypothesized to account for learning difficulties during the development period. Renamed the Wechsler Developmental Index, this measure has been used to discriminate among groups of children with and without learning disabilities. The present study replicated those findings with the Wechsler Intelligence Scale for Children-Third Edition, but also applied more appropriate diagnostic efficiency statistics to analyze the actual diagnostic utility of the WDI. These analyses revealed that the WDI performed at chance levels when distinguishing 611 students diagnosed with learning disabilities from those diagnosed with emotional disabled (n = 80) or mental retardation (n = 33), as well as from 2,200 simulated random nondisabled cases. It was concluded that mean group differences were not adequate and that ipsative indicators must be definitively validated in experimental environments before they can be applied in practice.
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PMID:Diagnostic utility of the WISC-III developmental index as a predictor of learning disabilities. 873 92

Expansion of a polymorphic GCC-repeat at the FRAXE locus has been associated with expression of chromosome fragility at this site and cognitive impairment in some individuals previously testing negative for CGG-repeat expansion in the fragile X mental retardation-1 (FMR1) gene. To determine the frequency of FRAXE triplet repeat expansion among persons with developmental disability, 396 individuals from two institutions were studied, all of whom were negative for FMR1 repeat expansion. Clinically, there was a wide range of mental impairment, with the majority (61.1%) being severely to profoundly affected. The distribution of FRAXE GCC-repeat numbers in the study population was 5-38: 28 (5.6%) with 10-14 repeats; 366 (73.8%) with 15-19 repeats; 74 (14.9%) with 20-24 repeats; 20 (4.0%) with 25-29 repeats; and 5 (1.0%) with 30-38 repeats, with no individuals demonstrating repeat expansion. One profoundly retarded male was found to have a deletion of about 40 bp. Southern blots of HindIII-digested DNAs from individuals with > or = 26 repeats all showed normal patterns. These results suggest that FRAXE GCC-repeat expansion is not a common cause of developmental disability in institutionalized persons with mild to profound mental retardation.
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PMID:Trinucleotide repeat expansion in the FRAXE locus is not common among institutionalized individuals with non-specific developmental disabilities. 884 96

This study examined the relationship between adaptive functioning on the Vineland Adaptive Behaviour Scale (VABS) and intellectual functioning on the Stanford-Binet Intelligence Scale, 4th edition (SB-IV) in autistic children and nonautistic retarded children of comparable CA and SB-IV composite score (IQ). The autistic group had lower scores than the retarded group in VABS adaptive composite, Socialization domain, and Communication domain, and SB-IV Verbal Reasoning area. VABS domain scores yielded higher classification rates than the SB-IV area scores in discriminating the two groups. Correlations between the two measures were much higher for the autistic group than for the retarded group. Results support the conclusion that the cognitive impairment in autism is reflected in greater impairment in adaptive behaviors than in mental retardation without autism.
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PMID:Adaptive and intellectual functioning in autistic and nonautistic retarded children. 898 47

Primary or nonspecific X-linked mental retardation (MRX) is a heterogeneous condition in which affected patients do not have any distinctive clinical or biochemical features in common apart from cognitive impairment. Although it is present in approximately 0.15-0.3% of males, most of the genetic defects associated with MRX, which may involve more than ten different genes, remain unknown. Here we report the characterization of a new gene on the long arm of the X-chromosome (position Xq12) and the identification in unrelated individuals of different mutations that are predicted to cause a loss of function. This gene is highly expressed in fetal brain and encodes a protein of relative molecular mass 91K, named oligophrenin-1, which contains a domain typical of a Rho-GTPase-activating protein (rhoGAP). By enhancing their GTPase activity, GAP proteins inactivate small Rho and Ras proteins, so inactivation of rhoGAP proteins might cause constitutive activation of their GTPase targets. Such activation is known to affect cell migration and outgrowth of axons and dendrites in vivo. Our results demonstrate an association between cognitive impairment and a defect in a signalling pathway that depends on a Ras-like GTPase.
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PMID:Oligophrenin-1 encodes a rhoGAP protein involved in X-linked mental retardation. 958 72


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