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PubMed1987

[Chromosome characteristics of X-linked mental retardation. II. Autosomes].

The frequencies of chromosome and chromatid breaks and gaps were studied in blood lymphocytes of three groups of individuals: 21 males with X-linked mental retardation characterized by fragile X chromosome; 52 males with non-differentiated X-linked mental retardation having no fra(X) chromosome in their cells; 15 intellectually normal males. The lymphocytes were cultured both in medium 199 and in Eagle's medium supplemented with fluoro-deoxyuridine. The significantly higher frequencies of various autosomal lesions were observed in the individuals with the fragile X chromosome syndrome and in those with mental retardations without fra(X) chromosome, in comparison with normal males. The significant difference in some autosome lesions was also found between both groups of the patients. The distribution of chromosome lesions in autosomes of different groups was significantly higher in chromosomes A and lower in groups B, E, F and G, than expected in accordance with their relative length in the haploid set. In all the groups of individuals studied, the predominant localization of chromosome and chromatid breaks and gaps was observed in fragile sites 1p31, 3p14, 6q26 and 16q23.

Chromosome Aberrations↗
PubMed1988

Number-comparison learning by children classified as mentally retarded.

A training experiment was undertaken to determine whether children classified as mentally retarded could learn a general magnitude-comparison rule ("The number that comes after another in the number sequence is more than the preceding number"). After a pretest, 22 subjects were randomly assigned to an experimental or a control training group. On both immediate and delayed posttests, the experimental subjects significantly outperformed control children on trained number pairs. A modest amount of transfer was also evident. The results suggest that a counting-based approach that utilizes rule rehearsal can help children classified as mentally retarded to use their representation of the number sequence to make mental magnitude comparisons.

Adolescent↗
PubMed1992

Chromosomal screening of mentally retarded school children in Taipei.

The major concern of the national population policy in Taiwan in recent years has been to lower the incidence of hereditary diseases and mental retardation in the general population. It has been estimated that there are around 10,000 mentally retarded school children in Taiwan. If effective chromosomal screening can be extended to these children, some of the family members who are carriers of balanced chromosomal rearrangements may benefit from follow-up studies and genetic counseling. The present report is the result of a pilot study conducted from 1988 to 1991 to explore the possibility of chromosomal screening of mentally retarded school children in Taipei. A total of 871 blood samples were collected from 1,147 children registered in 46 schools or residing in homes for the retarded. Chromosomal analysis was successfully accomplished on 674 out of 871 blood samples. The following chromosomal abnormalities were observed: 28 Down's syndrome, four Klinefelter syndrome, one XYY, one triple X, 11 translocations, seven inversions, four mosaics, three duplications, one deletion and one with an extra marker chromosome. After follow-up cytogenetic analyses of 13 families with probands with structural chromosomal anomalies, three of these families were shown to have one or two carriers of balanced translocated chromosomes. It seems that the present screening system would not be practical or cost-effective if it were applied island-wide in the future.

Adolescent↗
PubMed1987

Developmental disorders of skin potential responses in mentally retarded children during nocturnal sleep.

Skin potential responses (SPRs) of 89 mentally retarded children were studied during their nocturnal sleep. Forty-three out of the 89 subjects showed more SPRs (type A) during NREM sleep than in REM sleep. The opposite was observed in 10 cases (type C), and 4 had evenly distributed SPRs during both sleep phases (type B). The remaining 32 subjects had mixed types AB (n = 19), AC (n = 6) or BC (n = 7). Types B and C (including the mixed type) were observed more frequently for subjects with low developmental quotient (DQ) and abnormal clinical EEGs than for those with high DQ and normal clinical EEGs. Since it has been well established that normal subjects of 3 months and over exhibit exclusively type A, SPRs may be used as an additional tool for the diagnostic assessment of mental retardation in early infancy.

Adolescent↗
PubMed2001

Association of Chiari I malformation, mental retardation, speech delay, and epilepsy: a specific disorder?

OBJECTIVE: The Chiari I malformation is defined as tonsillar herniation of at least 3 to 5 mm below the foramen magnum. Although Chiari I malformation is considered to derive from a mesodermal disorder resulting in underdevelopment of the posterior fossa relative to its content, evidence for a possible heterogeneous etiology also has been reported. The aim of the present study is to elucidate the relationship between Chiari I malformation and mental retardation, speech delay, and epilepsy to consider a possible specific pathogenetic background. METHODS: Thirty-five patients with Chiari I malformations were identified by use of magnetic resonance imaging during a period between 1993 and 1999. The study consisted of nine patients (four boys and five girls) who were affected by mental retardation, speech delay, and epilepsy. All patients underwent electroencephalography and brain and cervical spine magnetic resonance imaging. RESULTS: All patients were mentally retarded with a mean intelligence quotient of 50. Seven patients had a positive history for speech delay, and five were epileptic. Electroencephalograms demonstrated abnormalities in seven patients. The mean tonsillar displacement was 10.1 mm. A thin corpus callosum and a wide cavum septum pellucidum were present in three patients. Neither hydromyelia nor scoliosis was observed. No correlation between the degree of the ectopia and clinical manifestation was noted. CONCLUSION: The association of Chiari I malformation with epilepsy, speech delay, and mental retardation may not be a mere incidental finding but may be a marker for a different pathogenetic background.

Adolescent↗
PubMed1984

A classroom rating scale for use with mentally retarded children.

A behaviour rating scale intended primarily for use with mentally retarded children is described that is based on the behavioural descriptions of such children given by Pevsner (1963). A factor analysis showed that these descriptions could be viewed as being representable by two independent factors. The first of these factors, the AD factor may be seen to relate to attention/distractibility aspects of behaviour and shows a reliable correlation with verbal age and verbal quotient as assessed by the English Picture Vocabulary Test (EPVT), such that low EPVT scores predict greater distractibility. The second factor, the inhibition/excitation (IE) factor, did not correlate significantly with verbal age or verbal quotient but has, in other studies, shown relationships with style of social interaction and may be interpreted as relating to aspects of temperament. It is concluded that individual differences in the classroom behaviour of mentally retarded children may not be qualitatively different from those in non-retarded children and that the scale described is a useful instrument for measuring these individual differences.

Adolescent↗
PubMed1998

FRAXA and FRAXE prevalence in patients with nonspecific mental retardation in the Hellenic population.

Mutations at FRAXA and FRAXE loci are due to expansions of a CGG trinucleotide repeat and are characterized by mental retardation. Here we report a pilot screening survey by means of cytogenetic and molecular methods of 433 unrelated retarded individuals and their parents of Hellenic origin coming from various parts of Greece and Cyprus. The purpose of the study was to estimate the frequency of FRAXA mutation in individuals with nonspecific mental retardation without family history and phenotypic stigmata in the Hellenic population. Five FRAXA-positive children (1.15%) were identified, of whom four were found to carry a full mutation and one a premutation. Furthermore we present preliminary data on a screening of FRAXE mutation frequency. We screened 257 male patients with nonspecific mental retardation, finding none positive for FRAXE mutation.

Adolescent↗
PubMed1987

Screening and prevalence of mental retardation in four Finnish birth cohorts.

Four birth cohorts born in 1969-1972 and living at the time of the census in Kuopio Province, Finland, were screened for mental retardation in two phases using school achievement tests in reading and mathematics. The criterion of mental retardation was established using psychological tests of verbal and visual perception abilities. The control groups of the two screening phases were randomly sampled from the studied birth cohorts. The case group was obtained on the basis of the mean and standard deviation of the control group scores in the psychological tests. A score of more than 2 SD under the mean (IQ less than or equal to 0.70) was the criterion of mental retardation. The overlap between the school achievement and psychological test matrices was explained with a general type canonical variate. The prevalence results were similar to earlier screening studies, but were clearly different from studies using only registered populations.

Child↗
PubMed1984

Psychometric properties of the psychopathology instrument for mentally retarded adults.

One hundred and ten adults, from borderline to severe levels of mental retardation, were assessed through the outpatient clinic of a university-affiliated mental health center and a large state psychiatric hospital. These patients were included only after they had demonstrated the ability to respond to questions of similar difficulty to those presented in the Psychopathology Instrument for Mentally Retarded Adults. This measure was designed by the authors based on DSM III criteria, and covered seven types of psychopathology including schizophrenia, depression, psychosexual disorders, adjustment disorder, anxiety, somatoform disorders, and personality problems. In the present study the psychometric properties of the scale were reviewed and/or evaluated including internal consistency of items and test-retest reliability, and factor analysis.

Adolescent↗
PubMed1992

The Stanford-Binet: Fourth Edition and form L-M in assessment of young children with mental retardation.

The Stanford-Binet Intelligence Scale: Fourth Edition appears to be poorly suited for the intellectual assessment of children less than 5 years old who are thought to have mild mental retardation and for persons of any age who are thought to have severe mental retardation. The reasons for this conclusion were explained and reasons provided that support the continued use of Form L-M when assessing such children or older individuals with mental retardation.

Child↗
PubMed1988

Measuring musical responsiveness in autistic children: a comparative analysis of improvised musical tone sequences of autistic, normal, and mentally retarded individuals.

This study provided a systematic analysis of improvised tone sequences of autistic children, as compared to musical improvisations by normal and mentally retarded control subjects. The data indicate that autistic children's tone patterns, analyzed and scored for rhythm, restriction, complexity, rule adherence, and originality, almost reached the scores of normal children. The highest individual total score in the study was achieved by an autistic child. Autistic children scored significantly higher than a control group of mentally retarded individuals. The autistic children's tone sequences showed high scores on the rhythm, restriction, and originality scales which support the notion of unusual musical responsiveness and abilities when compared to results in other performance and behavioral areas. In terms of complexity and rule adherence, autistic children's tone sequences resembled those of the mentally retarded by being rather short and repetitive.

Adult↗
PubMed2002

Trapping of messenger RNA by Fragile X Mental Retardation protein into cytoplasmic granules induces translation repression.

Absence of Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein, is responsible for the Fragile X syndrome, the most common form of inherited mental retardation. FMRP is a cytoplasmic protein associated with mRNP complexes containing poly(A)+mRNA. As a step towards understanding FMRP function(s), we have established the immortal STEK Fmr1 KO cell line and showed by transfection assays with FMR1-expressing vectors that newly synthesized FMRP accumulates into cytoplasmic granules. These structures contain mRNAs and several other RNA-binding proteins. The formation of these cytoplasmic granules is dependent on determinants located in the RGG domain. We also provide evidence that FMRP acts as a translation repressor following co-transfection with reporter genes. The FMRP-containing mRNPs are dynamic structures that oscillate between polyribosomes and cytoplasmic granules reminiscent of the Stress Granules that contain repressed mRNAs. We speculate that, in neurons, FMRP plays a role as a mRNA repressor in incompetent mRNP granules that have to be translocated from the cell body to distal locations such as dendritic spines and synaptosomes.

Cytoplasmic Granules↗
PubMed1992

Postural sway characteristics of single leg stance in men with mental retardation.

This study examined the postural sway characteristics of 10 men with mental retardation and 10 each normal men and women during the one-legged stance test. Significant differences between the men with mental retardation and the other two groups were found on measures of lateral sway and on the sagittal sway:lateral sway ratio.

Adult↗
PubMed1994

Epidemiology and prevalence of psychopathology in people with mental retardation.

There is a general consensus that, for several reasons, people with mental retardation are at an increased risk of developing emotional disorders. Numerous research studies have examined the prevalence of psychiatric disorders among people with mental retardation, and a wide range of rates have been reported. Reasons for the variability in these results are discussed, including definitional and identification issues, and sampling issues. A summary of representative studies is presented and discussed in light of the above-mentioned issues. The need for updated epidemiological studies in this area is emphasized.

Adolescent↗
PubMed1992

Development and training of referential communication in children with mental retardation.

In referential communication, the speaker must communicate to the listener about how a referent is different from other stimuli (i.e., employ the "difference rule"--Whitehurst & Sonnenschein, 1985). In Experiment 1 we compared use of the difference rule by children with and without mental retardation matched for Quick Test MA. Participants with mental retardation were less likely to employ the difference rule. Experiment 2 demonstrated that perceptual feedback training, which teaches use of the difference rule, enhances referential communication of children with mental retardation.

Child↗
PubMed1995

Failure of naltrexone hydrochloride to reduce self-injurious and autistic behavior in mentally retarded adults. Double-blind placebo-controlled studies.

BACKGROUND: It is hypothesized that self-injurious behavior (SIB) and symptoms of autism may be due to overactivity in some opioid systems in the brain. We examined the efficacy and safety of naltrexone hydrochloride, an opioid antagonist, in the treatment of SIB and autism in mentally retarded adults. METHOD: Thirty-three mentally retarded adults with autism and/or SIB participated in double-blind, placebo-controlled crossover studies. Active treatment was first a single 100-mg dose of naltrexone hydrochloride. Subsequently, 19 subjects were treated with 50 mg/d and 14 with 150 mg/d of naltrexone hydrochloride for 4 weeks. The outcome was assessed by means of direct observations (n = 11) and on the basis of scores on a list of target behaviors, the Aberrant Behavior Checklist, and the Clinical Global Impression Scale. RESULTS: Thirty-two subjects (seven with autism, 16 with autism and SIB, and nine with SIB) completed the trial. Naltrexone treatment failed to have therapeutic effects on SIB and autism. On the contrary, naltrexone increased the incidence of stereotypic behavior on the Aberrant Behavior Checklist, and the care staff evaluated the effect of the 50-mg/d treatment as being significantly worse than that of the placebo treatment as measured by the Clinical Global Impression Scale. CONCLUSION: Our findings suggest that naltrexone has no clinical value for a broad group of mentally retarded subjects with SIB and/or autism.

Adolescent↗
PubMed2002

Transport of fragile X mental retardation protein via granules in neurites of PC12 cells.

Lack of fragile X mental retardation protein (FMRP) causes fragile X syndrome, a common form of inherited mental retardation. FMRP is an RNA binding protein thought to be involved in translation efficiency and/or trafficking of certain mRNAs. Recently, a subset of mRNAs to which FMRP binds with high affinity has been identified. These FMRP-associated mRNAs contain an intramolecular G-quartet structure. In neurons, dendritic mRNAs are involved in local synthesis of proteins in response to synaptic activity, and this represents a mechanism for synaptic plasticity. To determine the role of FMRP in dendritic mRNA transport, we have generated a stably FMR1-enhanced green fluorescent protein (EGFP)-transfected PC12 cell line with an inducible expression system (Tet-On) for regulated expression of the FMRP-GFP fusion protein. After doxycycline induction, FMRP-GFP was localized in granules in the neurites of PC12 cells. By using time-lapse microscopy, the trafficking of FMRP-GFP granules into the neurites of living PC12 cells was demonstrated. Motile FMRP-GFP granules displayed two types of movements: oscillatory (bidirectional) and unidirectional anterograde. The average velocity of the granules was 0.19 micro m/s with a maximum speed of 0.71 micro m/s. In addition, we showed that the movement of FMRP-GFP labeled granules into the neurites was microtubule dependent. Colocalization studies further showed that the FMRP-GFP labeled granules also contained RNA, ribosomal subunits, kinesin heavy chain, and FXR1P molecules. This report is the first example of trafficking of RNA-containing granules with FMRP as a core constituent in living PC12 cells.

Animals↗
PubMed1992

Enhancing the ability of adults with mental retardation to recognize facial expressions of emotion.

The ability to recognize accurately and respond appropriately to facial expressions of emotion is essential for interpersonal interaction. Individuals with mental retardation typically are deficient in these skills. The ability of 7 adults, 1 with severe and 6 with moderate mental retardation, to recognize facial expressions of emotion correctly was assessed. Then, they were taught this skill using a combination of a discrimination training procedure for differentiating facial movements, directed rehearsal, and Ekman and Friesen's "flashing photograph" technique. Their average increase in accuracy over baseline was at least 30% during the course of the training and over 50% during the last 5 days of the training phase. Further, these individuals were able to generalize their skills from posed photographs to videotaped role plays and were able to maintain their enhanced skills during the 8 to 9 months following the termination of training. This is the first study to show that individuals with mental retardation can be taught skills that enhance their ability to recognize facial expressions of emotion.

Adult↗