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

We examined the brains of 385 mentally retarded adults aged 23-90 years without Down's syndrome (DS), metabolic disorder, or hydrocephalus to extend our knowledge about the occurrence of Alzheimer-type neuropathology in this population. Relevant measures of neuropathology also were related to selected information available from clinical records. The presence of one or more neurofibrillary tangles (NFT) and/or neuritic plaques (NP) was observed in 63.4% of all cases and varied with age. The prevalence of positive cases was higher when mental retardation was due to head trauma, congenital malformation, or familial factors and when a history of seizures was reported. Comprehensive morphometric analyses of neocortical, hippocampal and parahippocampal areas indicated that recommended age-specific quantitative criteria for the diagnosis of Alzheimer disease [Khachaturian ZS (1985) Arch Neurol 42:1097-1105] were met in 9.5% of cases less than 50 years of age, 54.2% between 50 and 65, 70% between 66 and 75, and 87% of the cases greater than 75 years of age. However, a limited immunohistochemical study revealed that in most cases the NP did not have a neuritic component containing paired helical filaments and in this respect most of the plaques observed in this population may differ from those most strongly associated with Alzheimer disease. In addition, substantial numbers of NFT were seen in frontal cortex, contrasting with results reported in the literature for nonretarded populations. The number of NP per mm2 consistently increased with age for all areas examined, while the relationship between NFT density and age varied across areas, and was clearly not monotonic.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Alzheimer neuropathology in non-Down's syndrome mentally retarded adults. 223 48

Findings from a Golgi study of the visual cortex in patients with the Down syndrome were compared with those from neurologically normal, age-matched control subjects. The dendritic atrophy seen in childhood continued into adulthood, with a marked decrease in dendritic branching, dendritic length, and spine frequency in elderly adults with the Down syndrome. Subject more than 30 years old occasionally had degenerating pyramidal neurons in the cerebral cortex and degenerated pyramidal neurons and aspiny stellate cells, particularly in the temporal cortex. These dendritic abnormalities may be related to mental retardation in children and early dementia in older adults who have the Down syndrome. The genetic and extrinsic factors may be important determinants of Alzheimer type dementia in the Down syndrome.
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PMID:Dendrites, dementia and the Down syndrome. 252 70

Both animal and vegetable life depend for their existence on appropriate amounts of various trace elements, albeit in very small amounts. This paper lists some of these trace elements and the ailments in which they play an important role. The elements discussed are gold, platinum, copper, lead, zinc, aluminium, silica, mercury, cadmium, selenium, arsenic, and iodine. The diseases involved range from multiple sclerosis, various cancers, arthritis, goitre, Down's Syndrome, and mental retardation. Less well known are Keshan, Alzheimer's, Itai-Itai, and Minamata diseases. Of particular interest in the latter part of the twentieth century is the discovery that serious deficiencies of either copper or zinc in the diet of animals may break down their immune defence mechanisms. The ability of certain plants selectively to concentrate particular heavy metals in their tissues and pollen is discussed.
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PMID:Geology, trace elements and health. 268 20

Trisomy of the whole or distal part of human chromosome 21 (HSA 21) (Ts21) results in Down Syndrome (DS), which is characterized in part by mental retardation and associated neurological abnormalities. Structural abnormalities observed frequently include reduced brain weight, decreased number and depth of sulci in the cerebral cortices, neuronal heterotopias, and reduced numbers of specific populations of neurons, such as granule cells, in the cerebral cortices. Abnormalities in the structure of cells, primarily of the dendrites, are observed in portions of the neuraxis, such as the hippocampus, cerebellum, and cerebral cortices. Functional abnormalities in membrane properties in peripheral structures and in neurotransmitter enzyme systems in both peripheral and central structures are observed also. Brains of DS individuals over the age of 40 exhibit the characteristic neuropathologic and neurochemical stigmata of Alzheimer's disease (AD). The cholinergic and noradrenergic systems appear to be particularly vulnerable. To elucidate the mechanisms responsible for these abnormalities, identification of the genes located in the distal part of HSA 21 and the systematic study of animal model systems with close genetic homology are essential.
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PMID:The neurobiologic consequences of Down syndrome. 287 70

Adaptive skills of 2,144 individuals with Down syndrome were compared to a similar group of 4,172 developmentally disabled people without Down syndrome. Activities of daily living and cognitive skills were examined across etiology, age group, and level of mental retardation. For individuals with Down syndrome at all levels of retardation, adaptive competence declined with increasing age to a greater extent than for retarded control subjects. Clear age-related deficits associated with Down syndrome were observed only in people older than 50 years of age. Findings support previous evidence of an increased risk for the clinical signs of Alzheimer's disease among people with Down syndrome; however, signs of dementia appeared later in life than would be predicted from available neuropathological data.
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PMID:Premature regression of adults with Down syndrome. 296 40

We measured the cerebral metabolic rate for glucose (CMRglc) with positron emission tomography and [18F]2-fluoro-2-deoxy-D-glucose in a 47-year-old man with trisomy 21 Down's syndrome (DS) and autopsy-confirmed Alzheimer's disease. Dementia was evident from a confirmed history of cognitive decline, memory loss, and personality change. CMRglc in the subject was compared with the mean obtained in 13 healthy younger DS subjects, aged 19 to 33 years. Test scores of general intelligence, visuospatial ability, language, and memory function showed poorer performance in the older subject compared with the younger group. Mean hemispheric CMRglc in the older DS subject was 28% less than in the young DS group, and marked hypometabolism was evident in parietal and temporal lobe association cortices. At autopsy, extensive neuropathology was noted, especially in the parietal and temporal cortical regions, more so than reported in DS subjects without documented dementia. This study is the first complete assessment of cerebral metabolism, neuropsychological competence, and neuropathology in a DS subject with a documented course of dementia, and demonstrates the superimposition of Alzheimer type dementia on previous mental retardation.
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PMID:Dementia in Down's syndrome: cerebral glucose utilization, neuropsychological assessment, and neuropathology. 296

There is an urgent need for efficient, non-invasive measures of neurotoxic insult in humans. The late positive component (LPC) of the event-related cortical potential may be such a measure. The latency and amplitude of the LPC have been related to both memory and response speed, two aspects of behavior which are indicators of neurological status. The LPC has been found to be altered in cases of known neurophysiological insult, including Alzheimer's disease, cerebrovascular disease, Parkinson's disease, surgical and traumatic damage, hyperkinesis, chronic alcoholism, mental retardation, and in schizophrenia. Further development of the LPC as a possible indicator of both the cognitive impairment due to neurotoxic substances as well as the site of neurological damage is warranted.
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PMID:The late positive component of the evoked cortical potential: application to neurotoxicity testing. 390 31

The typical neuropathological features of Alzheimer's disease, plaques and tangles, appear in virtually all patients with Down's Syndrome after the age of 40. Clinically, changes in cognitive performance and behavior appear to correlate with these neuropathological changes, although a satisfactory operational definition of dementia in a context of mental retardation is not available. It is unknown whether the cholinergic losses in the nucleus basalis, which are a feature of early onset Alzheimer's disease, also occur late in Down's syndrome. Two family studies have supported a greater than expected incidence of Down's cases among relatives of probands dying with Alzheimer-type dementia, but the association is not strong. It is noteworthy that in both studies, phenotypically normal carriers of the rare 15/21 translocation had severe early onset dementia, although this translocation is responsible for less than 0.4 per cent of Down's cases. An increased incidence of dementia among carriers of the more common 14/21 translocation has not been reported. In any case, it is proposed that a gene product originating from the long arm of chromosome 21 (21q) is necessary for Alzheimer-type pathology, since a segregating gene could not be responsible for the 100 per cent incidence of these changes among 21q trisomics.
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PMID:Down's syndrome and Alzheimer's dementia: defining an association. 624 13

A case-control study was performed to determine the possible roles of various environmental factors, prior illnesses, drug use, and personal habits in the development of Alzheimer's disease. Such information was collected from 40 patients with onset of dementia prior to age 70 and from 80 community control subjects matched for age, sex, and race. No significant differences were found between patients and control subjects in toxic environmental exposures, animal contacts, smoking, drinking, or unusual dietary habits. A significantly higher frequency of prior thyroid disease was found in women patients than in women control subjects (25.0% and 7.1%, respectively). A history of severe head injury was also obtained significantly more often among the patients than among the controls (15.0% and 3.8%, respectively). Aside from these differences, which may prove to be important associative factors in this illness, there appeared to be no major premorbid demographic or clinical factors associated with this form of dementia. There was evidence, however, of a genetic factor that was manifested in an excess of dementia and mental retardation (including Down's syndrome) in families of patients with Alzheimer's disease.
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PMID:Alzheimer's disease: a study of epidemiological aspects. 674 80

Primary degenerative dementia (Alzheimer's disease) is characterized by intellectual decline with impairment of memory, judgment, and abstract thinking. Also common are personality changes and disturbances of higher cortical function such as aphasia, apraxia, and agnosia. Standardized brief cognitive tests are useful for evaluating mental status, which is often limited by short attention span, distractibility, fatigability, mental retardation, illiteracy, and/or confusion. Data from 225 institutionalized patients support the mini-object test (MOT) as a valid, reliable, cost-effective, portable screening procedure for confirming the clinical diagnosis of aphasia-apraxia-agnosia associated with senile dementia of the Alzheimer type. Further studies are needed to demonstrate the diagnostic value of the MOT in other dementing disorders.
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PMID:Mini-object test: a new brief clinical assessment for aphasia-apraxia-agnosia. 682 78


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