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PubMed1989

The development of social group formation in normal and mentally retarded persons from early childhood through old age: neuropsychiatric, developmental, and cognitive implications.

To test the hypothesis that mentally retarded persons exhibit identifiable styles of social grouping, the size and sex composition of spontaneous social groups were studied in 570 mentally retarded and 3,030 nonretarded persons from preschool-elderly ages. Both populations showed similar developmental trends: group sizes increased through childhood, decreased thereafter until middle age, and increased again in the elderly. However, mentally retarded persons formed smaller groups at all ages: solitary individuals predominated with few groups larger than dyads. A subgroup of lower-functioning retarded persons formed even smaller groups. Nonretarded females were more aggregative than males, but mentally retarded persons showed no such sex differences.

Adolescent↗
PubMed1979

Perception of contingency and mental retardation.

It is argued that the general learning difficulties exhibited by mentally retarded persons are similar in many respects to the learning difficulties of nonretarded persons who are in a state of learned helplessness (Seligman, 1975) or who are external in locus of control orientation. It is suggested that studies of locus of control and learned helplessness as theoretical constructs both directly concern the perceiving of relationships between behavior and outcomes, and that a systematic investigation of perception of contingency might increase our understanding of some of the learning difficulties of mentally retarded persons. An overview is given of the results of the few studies that have addressed perception of contingency and mental retardation, and suggestions for future research are offered.

Humans↗
PubMed2001

Neuroendocrine features of pubertal development in females with mental retardation.

In order to evaluate the hypothalamic-pituitary effects of mental retardation during pubertal development, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) responses to gonadotropin-releasing hormone (GnRH) administration were evaluated at various pubertal stages in a female population with mental retardation (MR) compared to a healthy control group of adolescents. Fifty-six girls aged 8-16 years with MR and 146 normal females of the same age participated in the study. The analyzed subjects were divided into different pubertal stages, ranging from P2 to P5, in line with their degree of sexual maturation. Each patient underwent a GnRH test (100 micrograms); blood samples were collected basally and 15, 30, 60, 90 minutes after the GnRH injection. FSH and LH were assayed in each sample; the gonadotropin response to GnRH administration was evaluated as incremental area. No differences were found at any pubertal stage between the two studied groups with regard to the age, body mass index, or age at menarche. Patients with mental retardation during stages P2 and P3 showed lower FSH secretion in response to GnRH bolus compared with control subjects (P2, p < 0.05; P3, p < 0.01). In conclusion, our data show that MR is related to an impaired response of the FSH-secreting pituitary cells to their appropriate stimulus; this feature is present only in the initial pubertal stages, whereas it disappears during sexual development.

Adolescent↗
PubMedDate not supplied

Mental disorder in adults with mental retardation and epilepsy.

The controversy regarding the exact nature of the relationship between psychopathology and epilepsy continues. We studied the rate of mental disorder in 150 adults with mental retardation and epilepsy among the residents of a health district of the United Kingdom who lived either in institutions or in the community, and compared them with an age-, sex-, and IQ-matched nonepileptic adult mentally retarded population from the same institution and community. Mental disorder was assessed under three headings, namely severe maladaptive behavior, psychiatric illness according to ICD-9 criteria, and personality disorder. Sixty-five percent of the whole cohort had a diagnosis of mental disorder, and 55% showed severe maladaptive behavior. No significant difference in the rate of mental disorder emerged between the epileptic and nonepileptic groups, although the institutionalized subjects as opposed to the community-based subjects and severely mentally retarded adults compared with the mild to moderately mentally retarded adults showed a significantly higher rate of mental disorder in general and severe maladaptive behavior in particular. We hypothesized that underlying brain damage rather than epilepsy per se is a stronger determinant of psychopathology in the studied patient group.

Adult↗
PubMed1992

Supraspinal influences on recurrent inhibition in humans. Paralysis of descending control of Renshaw cells in patients with mental retardation.

The recurrent inhibition of alpha motoneurons was studied in 8 mentally retarded subjects (age 16-35 years), six of whom also had non-pyramidal or extrapyramidal motor alterations, manifesting as rigid and inflexible voluntary and/or postural movements. Despite a similar degree of mental retardation (Raven spatial general intelligence test), the other 2 cases showed much more modest changes in motor behavior. At rest, recurrent inhibition on soleus motoneurons was normal in all patients. In the 6 cases exhibiting more severe motor abnormality, the changes in Renshaw cell excitability, which occur during postural or voluntary contractions in normal subjects, were not found. This expressed the lack of supraspinal influences on Renshaw cells in these patients. On the other hand, supraspinal modulating influences on Renshaw cells were virtually normal in the remaining 2 patients. The absence of excitability changes of recurrent inhibition to postural or voluntary movements is discussed in relation to the abnormality of motor behavior observed in these patients. In addition, since paralysis of adaptive changes of recurrent inhibition has so far only been described in spastic subjects, the present study demonstrates that the descending pathways, which control recurrent inhibition gain, are different from those which, when damaged, lead to spasticity. Finally, our results indicate that the changes in motor behavior often associated with mental retardation cannot be regarded merely as the consequence of defective motor learning.

Adolescent↗
PubMed2004

Field dependence-independence of normally developing and mentally retarded boys of low and upper/middle socioeconomic status.

The field dependence-independence of normally developing and mentally retarded boys of low and upper/middle socioeconomic status was examined. To test the cognitive style, the 96 young participants were subdivided into four groups (n=24 per group) matched on mean mental age, using the Raven Colored Progressive Matrices. Two groups of mentally retarded boys (Groups A and B) and two groups of normally developing boys (Groups C and D). Groups A and C were matched on mental age at 5.6 yr.; Groups B and D were matched on mental age at 7.6 yr. Each pair of groups differed significantly in mean chronological age. Within each subgroup, 12 boys came from upper/middle socioeconomic status families and 12 from low socioeconomic status families. Analysis indicated absence of significant differences between Groups A and C on field dependence-independence, but there were statistically significant differences between Groups B and D. Moreover, analysis showed that boys from families of upper/middle socioeconomic status, both normally developing and mentally retarded, were consistently more field independent than boys from families of low socioeconomic status. Finally, conclusions were drawn concerning the empirical and theoretical benefits for psychology and education, which arise from the study of field dependence-independence of mentally retarded individuals.

Child↗
PubMed1992

Profile of the prelinguistic intentional communicative behaviors of children with profound mental retardation.

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.

Child↗
PubMed1992

Linkage to Xq28 in a family with nonspecific X-linked mental retardation.

Linkage analysis was performed in a family with nonspecific X-linked mental retardation (MRX). Affected individuals had no clinical characteristics other than mental retardation. Linkage was detected to the marker loci DXS477, DXS465, DXS52, DXS15 and F8C with maximum lod scores of 1.70, 1.32, 2.52, 1.70, and 1.09, respectively (theta = 0.0). The results strongly indicate that the gene for mental retardation in the family studied maps close to DXS52.

Female↗
PubMed2002

Level of Activity in Profound/Severe Mental Retardation (LAPMER): a Rasch-derived scale of disability.

Classification of Mental Retardation (MR) into severe and profound is based on IQ threshold (<35 and 20% respectively) and on quite generic descriptions of deficits in adaptive behavior. The LAPMER scale (after Level of Activity in Profound/severe Mental Retardation) was developed as a measure of severity through observed behavior in adult patients. The Rasch analysis (RA, in its rating scale model) was adopted as a guide for selection of items, conceptualization of item levels, and validation of the overall instrument. The RA provides estimates on a continuum measure corresponding to the discrete cumulative score. A model prescribes the expected scores on each subject-item interaction. Discrepancies between observed and expected scores allow diagnostic procedures on coherence (fit) of both subjects and items. The final version included 8 items: Feeding, Sphincters, Communication, Manipulation, Dressing, Locomotion, Spatial Orientation and Praxiae, scored 0/1 or 0/1/2 (cumulative range for the total set of items was 0-13) the higher the score, the better the performance. The test can be administered in 15 minutes through observation or inquiry from proxies and personnel. A psychologist rated 146 permanent hosts of a large Institute for mentally retarded adults (51 profound and 95 severe, 91 male, age 18-63, median 36). Median score was 6/13, IQR 1-9, range 0-12, 19% of cases scored 0. Cronbach a for internal consistency was 0.90. Fifty-seven patients were also independently scored by another psychologist. Between-rater Cohen's k reliability index ranged from 0.77-0.96 across items. Median raw scores were 1 and 8 in profound and severe cases, respectively (p<0.001). Rasch person reliability coefficient, a 0 to 1 index of internal consistency analogous to Crohnbach a, was 0.92. For each item the standardized differences between observed and model-expected scores (residuals) were c2 tested (a level 0.05) across sub-groups of patients. These were: profound vs. severe cases, and classes of motor impairment (tetra-,hemi-,para-plegic and unimpaired), matched for overall ability measure. For 6 items some residuals were found to be statistically significant. Absolute differences ranged from 0 to 0.7 raw score points, with no systematic patterns. Gender, age group and rater did not bias the measure. Residuals did not correlate meaningfully across pairs of items (r<(0.5)), further supporting the unidimensionality of the measure. The scale seems a valid tool for classification of adult severe and profound MR cases.

Activities of Daily Living↗
PubMed1991

Moderate and mild mental retardation in the Martin-Bell syndrome.

A survey of children attending schools for the moderately or the mildly mentally handicapped has shown that two out of 25 boys and two out of 22 girls with idiopathic moderate mental retardation had the Martin-Bell syndrome, while none of 75 boys and one out of 51 girls with mild mental retardation were FRAXA positive. Consideration of these figures along with published studies suggests that 7% of moderate and 3.8% of mild idiopathic mental retardation in boys, and 2.5% of moderate and 3.3% of mild idiopathic mental retardation in girls may be due to the Martin-Bell syndrome.

Child↗
PubMed1989

Hepatitis B virus infection among mentally retarded patients in institutions, Okinawa, Japan.

To determine whether transmission of hepatitis B virus occurs among mentally retarded patients in six institutions, from 1986 to 1988, 373 patients (males 203, females 170, 18-53 years of age, mean age 29.9) were tested for hepatitis B markers. Seventy five of them had Down's syndrome. Overall prevalences were 9.1% for hepatitis B surface antigen (HBsAg), 39.7% for antibody to HBsAg (anti-HBs) and 48.0% for antibody to hepatitis B core antigen (anti-HBc). Prevalence of HBsAg was significantly higher in patients with Down's syndrome than in other mentally retarded patients. Five patients (three males and two females) in four institutions were infected with hepatitis B virus during the two years of observation. Four of these five patients were the other mentally retarded and became both anti-HBs and anti-HBc positive. The remaining one, who was 29 years old and Down's syndrome, became an HBsAg carrier. These observations indicate that hepatitis B virus transmission frequently occurs among mentally retarded patients in institutions and therefore vaccination of susceptible institutionalized patients is necessary. Vaccination to patients with Down's syndrome is particularly warranted, because they are uniquely predisposed to develop chronic hepatitis B infection following exposure.

Adolescent↗
PubMed1989

Constitutional protection of confessions made by mentally retarded defendants.

Criminal confessions made in response to custodial questioning are excluded from evidence unless a defendant voluntarily, knowingly and intelligently waived his Miranda rights. In Connelly, the Supreme Court erred by holding that, absent explicit police coercion, a mentally ill individual's waiver is valid. The Court failed to consider the defendant's subjective impairments that might invalidate his waiver. By contrast, the Patterson Court suggested that a defendant's right to counsel may attach at an early stage in a criminal proceeding if the defendant has a significant need for counsel. This Note addresses the special needs of a mentally retarded person in the criminal justice system. The Note argues that mentally retarded suspects require careful explanation of Miranda rights in order to understand them. The intellectual and adaptive deficiencies which characterize mental retardation also necessitate an inquiry into a valid waiver that accounts for these disabilities. Furthermore, the special needs of the mentally retarded mandate that the right to counsel attach as early as the precustodial stage of an investigation. Early access to counsel most effectively assures that a mentally retarded person's waiver of constitutional rights is voluntary, knowing and intelligent.

Criminal Law↗
PubMed1992

The ability to encode facial and emotional expressions by educable mentally retarded and nonretarded children.

The object of the present study was to investigate whether 20 educable mentally retarded (EMR) children matched for verbal mental age on the Peabody Picture Vocabulary Test (PPVT; Dunn, 1965) with 20 nonretarded (NR) controls were adept in identifying emotional facial expressions and producing the equivalent word adjectives. I also reassessed the relationship between the phase of identifying facial expressions (i.e., happy, sad, angry, and scared) and the phase of producing emotional word adjectives, consisting of 16 emotional linguistic constructions (4 short stories for each of the adjectives) between higher in verbal ability educable mentally retarded (HEMR) children and higher in verbal ability nonretarded controls (HNRC) and between low in verbal ability educable mentally retarded (LEMR) children and low in verbal ability nonretarded controls (LNRC). There were no significant differences between EMR and NR children in general, despite the fact that EMR children had deficits in receptive linguistic competence.

Child↗
PubMed2006

The ARX mutations: a frequent cause of X-linked mental retardation.

The ARX gene mutations have been demonstrated to cause different forms of mental retardation (MR). Beside FMR1, in families with X-linked mental retardation (XLMR), the ARX dysfunction was demonstrated to be among the most frequent causes of this heterogeneous group of disorders. Nevertheless, in sporadic cases of MR, ARX mutations are extremely rare. In order to evaluate the frequency of ARX mutation in XLMR, we performed mutational analysis of ARX in 165 mentally retarded probands negative for FRAXA and belonging to families in which the condition segregates as an X-linked condition. The same recurrent mutation, an in frame 24 bp insertion (c.428-451 dup (24 bp)), was identified in five patients. In one family, the mother of two affected boys was found not to carry the mutation detected in her sons. These data suggest the presence of germline mosaicism for the mutation in the mother. Our results confirm the significant contribution of ARX mutations in the etiology of MR, especially in this group of patients selected for XLMR (3%). These data, together with those reported in the literature, imply that screening for c.428-451 dup (24 bp) mutation should be recommended in all patients with suspected XLMR.

Adolescent↗
PubMed2000

Mental retardation and developmental disabilities influenced by environmental neurotoxic insults.

This paper sets a framework for the discussion of neurotoxicity as a potentially major contributor to the etiology of many types of mental retardation and developmental disabilities. In the past the literatures on developmental neurotoxicology and on mental retardation have evolved independently, yet we know that the developing brain is a target for neurotoxicity in the developing central nervous system through many stages of pregnancy as well as during infancy and early childhood. Our definitions and theories of mental retardation and developmental disabilities affect the models of neurotoxicity we espouse. For instance, models of developmental risk in neurotoxicology have guided environmental regulation to reduce the likelihood of neurotoxic effects. On the other hand, models of developmental risk for mental retardation aim not only at primary prevention,but also at secondary and tertiary prevention through early intervention. In the future, dynamic models of neuroplasticity based on the study of gene-brain-behavior relationships are likely to guide our views of developmental neurotoxicology and prevention of mental retardation and other disabilities.

Developmental Disabilities↗
PubMed1987

REM sleep latency during nocturnal sleep in mentally retarded infants.

REM sleep latency observed in 61 mentally retarded infants (4-13 months of age) was studied throughout nocturnal sleep. Mentally retarded infants revealed a J distribution of short (less than 8 min) and long (more than 8 min) REM sleep latencies. This feature of distribution was similar to that obtained by other authors from normal infants under 3 months of age. REM sleep latency did not depend on the duration of prior wakefulness. Long REM sleep latencies were no more often preceded by long episodes of wakefulness than were short REM sleep latencies. No correlation was found between REM sleep latency and age, developmental quotient or daytime clinical EEG abnormalities.

Aging↗
PubMed1981

A new malformation syndrome of long palpebral fissures, large ears, depressed nasal tip, and skeletal anomalies associated with postnatal dwarfism and mental retardation.

Five unrelated patients with a previously unrecognized mental retardation malformation syndrome are presented. Clinical features common to them include moderate mental retardation, postnatal dwarfism, susceptibility to infection in infancy, and peculiar craniofacial dysmorphia characterized by long palpebral fissures, high-arched and abnormal eyebrows, heavy and long eyelashes, large ears, short nasal septum and/or depressed nasal tip, and cleft palate. Other anomalies are stubby fingers, deformed vertebra and other bone and joint anomalies, and abnormal dermatoglyphics. The absence of familial occurrence and of consanguinity suggests some environmental causation, but the possibility of an autosomal dominant or X-linked mode of inheritance remains. Based upon our five patients and other five of Niikawa et al, we propose this syndrome as a new disease entity.

Abnormalities, Multiple↗
PubMed2004

Rethinking mental retardation: education and eugenics in Connecticut, 1818-1917.

This case study of mental retardation in Connecticut during 1818-1917 questions the existing model of interpretation. The discovery of mental retardation in Connecticut did not emanate from social fear over those who were different, difficult, or dangerous. Nor did state government initiate the institutionalization of the feeble-minded. Instead, Dr. Henry M. Knight, who founded the private Connecticut School for Imbeciles in 1858, was motivated by antebellum religious benevolence. His altruism was additionally motivated by cultural concerns to shape behavior according to middle-class, Protestant norms. By the end of the century, his son and successor Dr. George H. Knight departed from his father's emphasis on education and assimilation to embrace eugenics and segregation of the mentally retarded. Connecticut's pioneering marital ban (1895) and sterilization law (1909) were, however, virtually ineffective. Instead, the state sponsored in 1917 a large-scale custodial facility that sought to isolate the feeble-minded, whom reformers now portrayed as a menace to society. In sum, the Knights show a clear departure in policy between the first and second generation of administrators.

Attitude to Health↗