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

Visualization of the neuron in its entirety through the use of the rapid Golgi method has permitted detection of several pathobiological features of neurons that are intimately associated with profound mental retardation in infants and children. In cases of unclassified mental retardation, dendrites and particularly dendritic spines exhibit severe developmental abnormalities. Dendritic spines, the postsynaptic components of axospinodendritic synapses, may be absent or abnormally long and thin in retardates. Evidence is presented that some cases of progressive neurobehavioral deterioration in infancy and early childhood may be due to progressive degeneration of dendritic spine systems (dendritic spine "dysgenesis"). Golgi and electron microscopic studies of neurons in human and feline ganglioside storage diseases indicate that ganglioside accumulation in cortical neurons initiates several complex alterations in neuronal geometry and morphology. Small and medium pyramidal cells form massive structural compartments (meganeurites) that frequently give rise to secondary neurites and other embryonic growth processes. Meganeurites may possess spines and spine-synapses. Other cells such as large pyramidal neurons may exhibit many somatic spines, whereas intrinsic cells of the cortex (and caudate) are unaffected morphologically by ganglioside accumulation. It is suggested that neuronal geometry distortion and aberrant synaptogenesis are important factors in the onset of neuronal dysfunction in ganglioside storage disorders. These studies also point to an important role of gangliosides in neurite formation in immature mammalian cortical neurons. Perisomatic processes and somatic spines are normal morphological components of the cell body of Purkinje cells through the 28th fetal week of human gestation. By 36 weeks the Purkinje cell somas exhibit a smooth surface contour. Prominent polydendritic processes, perisomatic protuberances, and somatic spines are detectable by Golgi methods applied to Purkinje cells in Menkes' disease and Down's syndrome long after these somatic components should normally disappear. Thus Purkinje cell soma membrane differentiation is a particularly sensitive process that can provide information on mechanisms of site-specific membrane regulation.
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PMID:Pathobiology of cortical neurons in metabolic and unclassified amentias. 21 50

Aicardi's syndrome consists of abnormalities of the ocular fundus, myoclonic seizures, mental retardation, and congenital malformations of the brain and vertebral column in females. The pathognomonic chorioretinal lesions were noted on ophthalmologic examination of a 22-month-old girl, observed for 19 months with severe myoclonic seizures and profound mental retardation. Computerized tomography confirmed major malformation of the brain. Roentgenograms showed anterior fusion of two thoracic vertebrae. Electroretinography was normal, but visual evoked responses were abnormal. Only 72 children are known to have this syndrome; no affected siblings have been reported. The absolute sex limitation--all cases have been female--suggests that the disorder is produced by a mutation on one of the X chromosomes, and is nonviable in male conceptuses. These genetic considerations dramatically influence counseling of parents regarding likelihood of occurrence of the syndrome in subsequent offspring.
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PMID:Aicardi's syndrome. Case report, clinical features, and electrophysiologic studies. 41 7

The paper deals with a study of dematoglyphics in 458 oligophrenic patients (265 boys and 193 girls) from 7--18 years of age and 373 normal children of the same age. In all the ill boys, irrespective of the degree of mental retardation there was a decrease of arc patterns and an increase of the whorle frequency. In girls with oligophrenia in the degree of debility there was a significantly lower amount of arc patterns and an increase of whorles, the frequency of loops did not differ significantly with that of the control group. In girls in whom the oligophrenic defect was of the degree of imbecility or idiocy there was a more frequent amount of arc and whorle patterns at the expense of a decrease of loop patterns, while in the control group there was a somewhat more frequent amount of arc an loop patterns and less frequent--of whorles.
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PMID:[Dactyloscopy undifferentiated oligophrenia]. 67 21

Two siblings suffering since birth from convulsions, hypotonia, and mental retardation are presented. In the older sibling (eight and one-half years of age) frontal lobe biopsy revealed abnormal cytosomes with lamellar profiles in astrocytes, macrophages, and to a lesser degree in neurons. Similar cytosomes have not yet been reported in cases of sphingolipidoses or in late infantile-juvenile amaurotic idiocy. These cytosomes stained intensely with silver proteinate, an ultrastructural cytochemical stain for carbohydrate moieties. In contrast, lipofuscin did not stain with silver proteinate. Multilamellar (crescentic curvilinear) cytosomes from a reported case of late infantile amaurotic idocy (Batten-Vogt-Spielmeyer disease) did not stain with silver proteinate. Abnormal cytosomes were not found in blood cells, liver, and peripheral nerve. In the younger sibling (14 months old) postmortem ultrastructural studies of cerebral tissue showed very few abnormal cytosomes. On the basis of the clinical and ultrastructural findings, we conclude that these two cases can be distinguished from those with multilamellar (crescentic-curvilinear) inclusions and from cases of the so-called "neuronal ceroid-lipofuscinosis" syndrome.
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PMID:Mental retardation, hypotonia, and generalized seizures associated with astrocytic "residual" bodies. An ultrastructural study. 118 92

The prelinguistic intentional communicative behaviors of 10 noninstitutionalized children with profound mental retardation were analyzed according to five profile parameters: communicative rate, communicative function, discourse structure, communicative means, and syllable shape. Subjects used a predominance of regulatory communicative functions, initiated discourse structure, gestural communicative means, and nontranscribable vocalizations/vocalizations without consonants. Findings were compared to previously reported data from children without mental retardation and institutionalized children with severe and profound mental retardation.
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PMID:Profile of the prelinguistic intentional communicative behaviors of children with profound mental retardation. 141 33

A model of ongoing consultation was implemented in a community group home for 8 adults with severe and profound mental retardation. Two consultants, highly experienced in working with people with mental retardation and in the procedures used in group homes, taught staff members to use a token reinforcement system, to engage the adults in a variety of activities, and to improve the content and style of the staff members' interactions with the adults. The consultants taught skills to 9 staff members through brief mini-workshops, direct observation of the staff members' use of the skills during regular activities in the group home, and individual verbal feedback regarding a staff member's performance of the skills. Evaluation of the ongoing consultation process by the 2 consultants showed it to be effective in improving the performance of the staff members and in changing the behaviors of the adults who lived in the home. Continued implementation of the process, however, appeared to be necessary for the behavior changes of staff members to be maintained at high levels.
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PMID:Ongoing consultation as a method of improving performance of staff members in a group home. 142 14

There is at this time no conceptual model of psychopharmacology for individuals with severe or profound mental retardation who exhibit behavior disorders that unifies this area of psychopharmacology with general psychiatry practice while addressing the unique aspects of this population. The following article presents a 6-step program of diagnostic inquiry and treatment strategy that allows alternate etiological hypotheses to be tested in a clinical practice framework. This format unifies psychopharmacy practice in mental retardation with psychopharmacy practice in general psychiatry.
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PMID:Empirical approach to psychopharmacology for institutionalized individuals with severe or profound mental retardation. 143 82

A small community home model for severely and profoundly mentally retarded adults is defined in terms of its program orientation, program structure, and program procedures. The model is compared to institutional settings and larger community units by collection of two data sets. The small homes were found to produce beneficial client functioning and high levels of staff/client interaction appropriately related to clients' degree of mental retardation. How staff distributed their attention to clients differed between the three types of settings. A conclusion is offered that the quality of residential care is dependent on the interaction of variables rather than on the presence of any single overridingly powerful factor.
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PMID:The behavioral and social ecology of community houses. 158 20

Perceptions by staff of the classes of reinforcers and aberrant behaviors of a sample of 470 people with predominantly severe or profound mental retardation were explored. Principal components analysis of a 45-item survey suggested eight classes of reinforcers: consumable, verbal-speaker, visual-motor, social, physical-contact, passive-observer, play, and academic reinforcers. Stepwise multiple regression was used to predict five classes of maladaptive behaviors as measured by the Aberrant Behavior Checklist (irritability, lethargy, stereotypy, hyperactivity, and inappropriate speech) from the eight classes of reinforcers. Each class of psychopathology was related to a unique set of predictors. All classes of psychopathology could be predicted by staff perceptions of underresponsiveness to social reinforcers and overresponsiveness to consumable reinforcers. The findings of organized structures of reinforcers and their covariation with pathological behaviors have implications for research and intervention as well as theoretical value in defining aberrant behaviors in people with mental retardation.
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PMID:Staff perceptions of reinforcer responsiveness and aberrant behaviors in people with mental retardation. 159 66

Examined the effects of two instructional methods on language generalization and long-term retention in 23 adults with autism and severe to profound mental retardation. Analog language teaching employed discrete trials in a controlled setting concentrating on discrimination and identification of materials. Natural language teaching emphasized instruction through interactions that occurred incidentally to training students in the use of materials to perform functional tasks. Assessments were conducted under conditions favoring analog teaching to assure against partiality toward natural language teaching. Under such disadvantageous conditions, the methods of natural language teaching would be supported by results showing either no difference or an advantage in their favor. Both techniques increased initial and long-term generalization though the results suggest no relative superiority for either method under these assessment conditions. A significant interaction was found between prior functioning level and sequence of instruction. Because natural language teaching has many strengths, few drawbacks, and produces equal generalization and retention under disadvantageous conditions, it is strongly supported as preferable for people with autism and mental retardation.
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PMID:Analog language teaching versus natural language teaching: generalization and retention of language learning for adults with autism and mental retardation. 177 59


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