Dissertations / Theses on the topic 'Mental retardation'

The 2002 Supreme Court decision (Atkins vs. Virginia, 536 U. S. 304), prohibiting the execution of mentally retarded persons, may potentially increase malingering of mental retardation (MR). There is limited research addressing the detection of feigned MR. The present study compared results from tests of intelligence, adaptive functioning, legal/courtroom knowledge, and psychiatric and neurocognitive feigning to determine how effectively these instruments discriminate between MR participants and community volunteers asked to either approach the test honestly (CVH group) or feign, or malinger, MR (CVM group). CVMs suppressed their IQ scores sufficiently to appear MR. CVMs overestimated deficits on individuals with genuine MR on tests of adaptive functioning and courtroom knowledge. Psychiatric feigning instruments did not discriminate between MR and CVM groups. Neurocognitive feigning instruments discriminated between groups, however specificity and Positive Predictive Power were unacceptably low. Revising cutting scores to hold specificity at .95 improved PPP significantly, suggesting the potential utility of these instruments to detect feigned mental retardation. Results from this study suggest that applying published decision rules to MR populations on tests commonly used in forensic neuropsychological evaluations will likely result in a high rate of false positive errors. Given the high stakes associated with classification errors in capital cases involving MR defendants, alternative cutting scores appropriate for this population should be determined.

In order to determine the proportion of MR due to fragile X, CGG repeat analysis was carried out on DNA from 723 mentally retarded patients in S.E. Scotland. This resulted in the identification of 8 new cases of fragile X syndrome (˜1% of the total number of referrals for developmental delay). This developmentally delayed cohort was also compared to normal and high IQ cohorts to address the possibility of a relationship between CGG repeat number and IQ variation in the general population. Two complicated prenatal diagnostic cases were studied in detail to answer important practical questions concerning the nature and timing of repeat expansion. Well over 100 other XLMR conditions have been described, of which approximately 50% have been regionally mapped. Some of these are non-specific forms of XLMR in which MR is the only manifestation; others are XLMR syndromes with a characteristic and well defined phenotype. A family with non-specific XLMR is described in which the proband presented as a non dysmorphic male with unexplained MR, for exclusion of fragile X syndrome. He had a CGG allele in the normal range and the MR segregating in the family was shown not to be linked to FMRI. Subsequent analysis of polymorphic X-linked markers showed linkage to Xq21. A new XLMR syndrome is represented by a large family with severe MR and spastic diplegia which was previously thought to be MASA syndrome, a condition caused by mutations in the LICAM gene in distal Xq28. Negative LOD scores with Xq28 markers led to a search for linkage to other regions; this was found in Xp22 where several other XLMR loci are located, although the clinical features of this family differ from those of other XLMR syndromes and conditions in Xp22.

Thesis (M.A. (Psychology)) --University of Limpopo, 2013
This study explored the phenomenological experiences of mothers of children with mental retardation in two special schools (i.e. Fulufhelo and Pfunanani). The former is in Vhembe while the later is situated in Mopani district in Limpopo province. A qualitative approach was followed and participants were selected using purposive sampling. The sample consisted of 24 members (12 for individual interviews and 12 for focus group) whose children were diagnosed with mental retardation at the time of the study. Data were collected through unstructured interviews and analysed using interpretative phenomenological analysis. The following psychological themes emerged from the study: mothers’ subjective understanding of mental retardation; mothers’ understanding of the causes of mental retardation; living with a mental retarded child; psychological reactions of mothers to a diagnosis of mental retardation and mothers’ causal explanation of mental retardation. The present study discovered that all families with mentally retarded children are directly or indirectly affected by this condition.

Thesis (M.A. (Clinical Psychology) -- University of Limpopo, 2012
The aim of this study was to profile the characteristics of children with mental retardation presenting at the Clinical Psychology Unit of Polokwane/Mankweng Hospital Complex over a period of five years. A descriptive methodological approach was chosen as a study design for the purpose of data collection and subsequent data analysis. Using the archival data method, the clinical files of all children presenting with mental retardation at this facility were retrieved and studied. A total of 326 (male = 169; female = 157) files covering the period under review were retrieved. The Statistical Package for Social Sciences (SPSS) was used to analyse the data. Categorical data were analysed by using frequency tables, descriptive statistics and crosstabulations. The study showed that 314 cases (96.3%) were reflected as Black, whilst the remaining 12 cases (3.7%) were reflected as White (2.15%); Indian (1.23%); and Other (0.30%). Several clinical methods that included clinical interviews, psychometric tests, clinical observations and collateral information sources were used by the psychologists for the purpose of making a diagnosis. The study further revealed that a huge number of cases (35.6%) were diagnosed with mental retardation. It was also found that 45.4% of the cases were diagnosed to have comorbid clinical conditions such as epilepsy, Down’s syndrome, visual problems etc. The majority of the persons were referred to the Clinical Psychology Unit to be assessed for school placement (50%) and disability grant (38.7%).With regard to interventions, psychologists who saw these persons tended to frequently refer them to special schools and other health professionals. Psychotherapy was the least utilised intervention method used by the psychologists. The findings of the present study reinforce the importance of and value of high quality management and treatment of mental retardation and related comorbid conditions. Based on these findings, it is recommended that more efforts be made to strengthen the working relationship between Polokwane/Mankweng Hospital Complex and the respective special schools where these persons that are diagnosed with mental retardation are referred to. It is further recommended that consideration be given to strengthening the relationship between Polokwane/Mankweng Hospital Complex and the social security agency so as to obviate any potential problems that could be associated with the allocation of the disability grants to persons with mental retardation.

Thesis (Ed. D.)--Illinois State University, 1989.
Title from title page screen, viewed October 21, 2005. Dissertation Committee: Lanny Morreau (chair), Ming-Gon Lian, Mack Bowen, Ramesh Chaudhari, Alan Repp. Includes bibliographical references (leaves 107-112) and abstract. Also available in print.

Thesis (M.P.A.)--Kutztown University of Pennsylvania, 1989.
Source: Masters Abstracts International, Volume: 45-06, page: 2952. Typescript. Volume contains facsimile documents with various foliations. Includes bibliographical references (leaf [112]).

The Indonesian archipelago comprises more than 17,000 islands, inhabited by ~200 million people constituting more than 350 recognizable ethnic and tribal groups which can be classified into two broad ethno-linguistic groups [the Austronesian (AN) and non-Austronesian (NAN) speaking peoples] and 3 physical anthropology groups (Deutero Malay, Proto Malay and Papuan). The origins of these groups are of considerable anthropological interest. The anthropology of Indonesia is extremely complex and still controversial. The present populations of Indonesia show very great diversity. The data presented below result from an investigation of the Fragile X A syndrome and the size and distribution of alleles at fragile sites on the X chromosome among Javanese males with developmental disability (DD) and unselected males from 10 major Indonesian ethnic groups. The Fragile X syndrome is caused by expansion of a CGG trinucleotide repeat array in the 5' untranslated region of the FMR-1 gene at Xq27.3. Normal X chromosomes have between 6-54 CGG trinucleotide repeats, whereas premutation alleles have 55-230 and full mutation alleles more than 230 repeats. In a study of predominantly Caucasian males with intellectual disability, the prevalence of Fragile X syndrome is estimated to be approximately 1:4,000. FRAXE mental retardation syndrome is caused by an expansion of a GCC trinucleotide repeat in the 5'UTR of FMR2 gene located 600 kb telomeric to FMR1. The prevalence of FMR2 is 1-2 per 100,000 live births. FMR2 common alleles consist of 11-30 GGC repeats; intermediate alleles between 31-60 GCC repeats; premutation alleles with 61-200 repeats and full mutation alleles have over 200 repeats with attendant methylation of the repeat array The first Indonesian screening program aimed at determining the presence and prevalence of fragile XA syndrome among individuals with mild DD (IQ above 50) from special schools (N=205) and isolated areas (N=50) of Java was undertaken in 1994-1996 by cytogenetic and molecular studies. In this first study 4 fragile X positive children were found among 255 males with DD. The estimated prevalence of fragile-X in males with mild DD from special schools was 1.95% (5/205) and the overall prevalence was 1.57% (4/255). The number of trinucleotide repeats in the 5' untranslated regions of the FMR1 and FMR2 genes were determined by PCR in 254 Fragile XA-negative Javanese male children with DD. The distribution of FMR1 and FMR2 trinucleotide repeat alleles was found to be significantly different in the Indonesian population with DD compared to that in equivalent Caucasian populations. The trimodal distribution of Indonesian FMR1 alleles (29, 30 and 36 repeats) is largely in agreement with findings from other Asian populations). This provides supportive evidence that the origin of Indonesians could be the same as that of the Chinese and Japanese. Sequence analysis was performed on the trinucleotide repeat arrays of the 27 individuals' FMR1 alleles in the 'grey zone' (35-52 repeats). The identification of 16 unrelated individuals with a (CGG)36 allele that also contains a (CGG)6 segment [(CGG)9AGG(CGG)9AGG(CGG)6 AGG(CGG)9 or 9A9A6A9 pattern] is in agreement with earlier observations in the Japanese population. It is proposed that this FMR1 array pattern may be specific for Asian populations and that Javanese and Japanese populations may have arisen from a single progenitor population. The presence of pure 25, 33 and 34 CGGs in FMR1 alleles with 36, 44 and 45 repeats respectively, suggests that these may represent alleles at high risk for instability and may therefore be at early stages of expansion to a premutation. The lack of the characteristic (CGG)6 in all three alleles with ?? 25 pure CGG arrays suggests that the most common Asian 36 repeat allele is not predisposed to slippage expansion. Seven of the 8 alleles with 36 CGG repeats could be sequenced. Seven of 36 CGG repeats FMR1 alleles from the Hiri population has been sequenced and 4 alleles indicated 9A9A6A9 pattern, 1 sample with 10A25 pattern Two of the remaining alleles showed 12A6A6A9 structure, which consisted of a tandem duplication of the (CGG)6 segment. The presence of a tandem duplication of (CGG)6 segments has never been reported in any other population. The other major findings of this study are that FRAXE syndrome is a rare cause of developmental disability in this predominantly-Javanese population. The most common FMR2 (GCC)20 allele in this selected Asian population is significantly longer than that previously reported for Caucasian populations. There was a weak correlation between the overall length of the FMR1 and FMR2 repeat arrays within the normal range (Spearman's Rank Correlation = 0.130, p-value=0.042) in the Indonesian population, which have been no previous associations reported for alleles within the normal range. One approach to studying the origins of the human populations is to study the genetic structure of polymorphic alleles such as those at the FMR1 locus and its linked microsatellite markers DXS548 and FRAXAC1. Length polymorphisms of the FMR1 gene (CGG)n repeat array, DXS548 and FRAXAC1 were studied in a total of 1,008 unselected males from 10 different Indonesian ethnic groups. FMR1 alleles were identified ranging from 8 to 57 CGG repeats. The most common CGG repeat allele was 29 (45.6%) followed by 30 (27.4%) and 36 repeats (8.0%). One hundred and forty four grey zone (3-52 CGG) alleles were found in the study population. Four people of the same ethnic group from an isolated island in Eastern Indonesia (Hiri, Ternate), a representative of the NAN ethnolinguistic group, had CGG repeat lengths of 55-57. The prevalence of these alleles is estimated to be 3.3% (4/120) in the population of Hiri or 0.4% (4/1008) of whole Indonesian population. Thirteen different alleles were found at the DXS548 locus, of which allele numbers 7 [194 bp] (44.1%), 6.5 [195bp] (43.5%) and 6 [196bp] (7.5%) are the most common. Seven rare alleles, some of which have not been previously found in Asian peoples were also identified (190, 191,192, 193, 197,198, 199, 202, 204 and 206) and accounted for 3.9% of the total. The odd number alleles were dominantly found in this study whereas almost none found in Caucasian. The finding of many "odd numbered" alleles DXS548 has never been found in other Asian population and has only been documented extremely rarely in Caucasians and Africans. Five different alleles of FRAXAC1 identified with alleles D [106 bp] (62.2%) and C [108bp] (35.6%) accounting for 97.8% of FRAXAC1 alleles in the population. Three rare alleles (104, 110, 112 bp = 2.2%) were identified that have not been previously found in other Asian populations (1-3). There is a striking linkage disequilibrium of FMR1 alleles with FRAXAC1 (p=0.0001), 88% of 29 (CGG)n repeats alleles associated with FRAXAC1 allele D (106bp) versus only 17% with the 30 (CGG)n repeat alleles, which is in agreement with other studies. The value of D' was calculated to be 0.7. The longer alleles of both DXS548 and FRAXAC1 were found mostly in the NAN ethnolinguistic group. Moreover the Irian Jaya people also showed a higher percentage of people with 30 CGG repeats and the 108 bp FRAXAC1. The Eastern Indonesian NAN groups demonstrate a different genetic background probably due to the contribution of Melanesian peoples. The Analysis of Molecular Variance (AMOVA) identified that the vast majority of genetic diversity occurs within, rather than between, ethnic groups. These data are consistent with a model where there is sufficient migration (~20 per generation) between populations to minimise differentiation of population through genetic drift. The results obtained are consistent with three clusters of populations that share similar allele frequencies at the fragile X locus. The most clearly defined cluster is based in the east of Indonesia and includes the two Irian populations, Minahasans and Hiri. A surprising finding was that the Minahasan who are Deutero-Malay in origin and physical appearance are genetically closer to the Irianese. This may reflect the admixture of Melanesian alleles or other eastern Indonesian alleles as a result of their geographic location in that part of Indonesia. The second major cluster is largely based in the west of the country and is composed of the following Deutero-Malay populations; Javanese, Balinese, Acehnese but which also includes people from Ternate (not including those from Hiri). Using Delta Mu and Nei's genetic distance for FMR1 locus in this study the Javanese were shown to have the closest distance to Balinese which is consistent with anthropological data and with published data. The third group is a "western and central" group composed of Bimanese, Dayak and Sundanese who share some features of the western and eastern clusters but mostly resemble the western Indonesian populations. Bima is located in the lesser Sunda in between west Indonesia and east Indonesia. The Bimanese are of mixed Deutero & Proto Malay origin that is consistent with their geographic location. The Bataks are distinctive and sit somewhat apart in this scheme. In this study, Bataks were found not to resemble the other Proto-Malay group studied (the Dayak). The Dayaks were found to have fewer alleles than the Bataks at FRAXAC1 and DXS548. In all four methods of calculating genetic distance Bataks showed a large genetic distance to almost all other ethnic groups. There are differences in allele frequency between east and west Indonesia as well as other Asian nations, but the genetic similarities between these groups are also very impressive. The findings from this study are consistent with other genetic anthropological evidence that the people of Indonesia have the same origin as North-east Asian groups. This model is referred to as the "express train from Taiwan" in which the Austronesian speakers are proposed to have radiated from Taiwan bringing the Malayo-Polynesian language group to the Philippines, Borneo and Sulawesi around 5000-4500 B.P.E. However Richards et al.(1998) have used the diversity in the mtDNA D Loop to propose an alternative to the "express train" model. The "two train7quot; model proposes that the Austronesian languages originated within eastern Indonesia during the Pleistocene era and spread through Melanesia and into the remote Pacific within the past 6,000 years. Unfortunately the high migration rates between population groups that were demonstrated in this thesis and the known migration patterns of populations through Indonesia preclude determining whether the observed allelic heterogeneity is a function of the original population or due to the admixture of several gene pools in more recent times.

Thesis (M.P.A.)--Kutztown University of Pennsylvania, 1993.
Source: Masters Abstracts International, Volume: 45-06, page: 2955. Abstract precedes thesis title page as [2] preliminary leaves. Typescript. Includes bibliographical references (leaves 54-55).

Thesis (Ph. D.)--Ohio State University, 2004.
Title from first page of PDF file. Document formatted into pages; contains xiv, 185 p.; also includes graphics. Includes bibliographical references (p. 134-145). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--Ohio State University, 2005.
Title from first page of PDF file. Document formatted into pages; contains x, 159 p.; also includes graphics. Includes bibliographical references (p. 148-159). Available online via OhioLINK's ETD Center

Mental retardation (MR) affects 23% of the population; those due to X linked mutations commonly result in moderate to severe MR. The OPHN1 gene (Ophn1 in mice) has been implicated in X linked mental retardation (XLMR) and encodes the RhoGAP protein, oligophrenin 1. Loss of function mutations alter Rho GTPase dependent signalling pathways and result in altered actin cytoskeleton dynamics which are important in dendritic spine structure, the site of neurotransmission. Here, using electrophysiological recordings combined with intracellular staining techniques and dendritic morphological analysis, I characterise synaptic (dys)function in neocortical and hippocampal neurons from the Ophn1 mouse model of MR. This study demonstrates an excitatory synaptic deficit in neocortical neurons combined with region specific changes in dendritic spine morphology. Inhibitory transmission was normal in both neocortical and hippocampal neurons. Kainate induced gamma oscillations were unaltered whereas spontaneous oscillations were reduced which lead to changes in synaptic function in CA3. Morphometric analysis showed ventriculomegaly in Ophn1 deficient mice that was associated with reduced cortical thickness. This study shows the loss of several previously reported phenotypes, including, altered inhibitory transmission, gamma oscillations and vesicle dynamics. Their loss, but preservation of morphological deficits, suggests that the model may be susceptible to genetic drift.

This study dealt with teaching archaeological skills and knowledge to adults with mental retardation using procedures and techniques of applied behavior analysis. The components of this research consisted of: (a) a descriptive study of archaeological field excavation procedures and activities; (b) an experimental study of three archaeological laboratory tasks that involved washing, counting, and sorting ceramic artifacts; and (c) a survey of opinions of archaeologists concerning the use of adults with mental retardation and other handicapping conditions to assist in archaeological research. Results from the descriptive study demonstrated the ability of three participants to successfully perform all skills required in the field excavation of artifacts, and their accurate identification in retrieval screens. Results from the experimental study of six participants demonstrated successful performance with respect to rigorous and specified criteria for all participants who completed training across all three tasks. In addition this study demonstrated the ability of archaeological personnel to successfully perform the teaching and monitoring procedures of the skills involved in this study. Results form the survey of opinions of three archaeologists provided a positive response to the inclusion of persons with mental retardation into archaeological projects and identified four areas of consideration for future projects in this area.

Thesis (Ed. D.)--Illinois State University, 1990.
Title from title page screen, viewed November 8, 2005. Dissertation Committee: Lanny E. Morreau (chair), John Ming-Gon Lian, Paul J. Baker, Ramesh B. Chaudhari, Pamela H. Wheeler, Alan C. Repp. Includes bibliographical references (leaves 90-100) and abstract. Also available in print.

Thesis (Ph. D.) -- University of Maryland, College Park, 2004.
Thesis research directed by: Counseling and Personnel Services. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Thesis (B.Sc)--University of Hong Kong, 1998.
"A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, April 30, 1998." Also available in print.

The mechanisms that govern the repression of 5-HT1A receptor gene expression mediated by a novel mental retardation gene, Freud-1, were examined in HEK293 and SKNSH cells. This study provides a possible mechanism of 5-HT1A receptor gene regulation by Freud-1, which, to mediate its action, recruits Swi/Snf and Sin3A/histone deacetylase (HDAC) complexes in non-neuronal HEK293 cells and Swi/Snf only in neuronal, 5-HT1A receptor-expressing SKNSH cells. Thus, Freud-1 has a dual mechanism of repression depending on cell type: HDAC dependent in HEK293 cells and HDAC independent in SKNSH cells. In addition, I present evidence that Freud-1 is not sumoylated at its consensus sumoylation sites and I present the lipid binding properties of Freud-1 and Freud-1 mutants.

Adults with mental retardation (MR) experience a greater number of falls than their non-disabled peers. To date, efforts to understand the causes for these falls have primarily involved qualitative studies that use largely subjective measures to quantify stability. Performing a more objective biomechanical gait analysis may better explain the reasons for these fall accidents and provide repeatable measures that can be used for comparison to determine the effectiveness of interventions intended to reduce slip-related falls. A gait analysis was conducted to quantify normal walking and slip response characteristics for adults with MR as well as a group of non-disabled age- and gender-matched peers. Kinetic and kinematic data were collected and a number of variables relating to gait pattern, slip propensity, and slip severity were calculated to compare the differences between groups. Results showed that adults with MR exhibit slower walking speeds, shorter step lengths, and greater knee flexion at heel contact suggesting that their gait patterns share more similarities with the elderly than with healthy adults of an equivalent age. Unexpectedly, the MR group demonstrated a lower required coefficient of friction (RCOF) and slower heel contact velocity which, alone, would suggest a reduced slip propensity as compared with the healthy group. A greater peak sliding heel velocity and greater slip distance measures, however, indicate greater slip severity for the MR group. The findings of this study suggest that falls in this population may be attributed to delayed response to slip perturbation as measured by slip distances.
Master of Science

Thesis (Ed. D.)--West Virginia University, 2001.
Title from document title page. Document formatted into pages; contains xiii, 175 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 76-84).

This study was concerned with the behaviours, actions, and patterns of interaction of profoundly mentally retarded non-verbal deinstitutionalized adults (PMRs). The methodology utilized field research techniques which are observations of participants in their natural setting. The observations were of five profoundly retarded deinstitutionalized adults and took place over a three month period in the participants' group home and day program. The observations were recorded daily in a field note book and were later transcribed into a protocol format. The protocols were then coded. The coding categories were developed by the researcher through abstractions which emerged from the data. The coding categories revealed insights into the PMRs. The participants exhibited a heirarchical social order, displayed consistent seating patterns, and understood property ownership. The participants were noted to anticipate daily-routines such as meals, outings, and bedtimes. The researcher observed preferences by the individual participants for specific staff members. One participant appeared to display a heterosexual erotic preference for one staff member. Autoerotic sexuality was observed in three participants. Individual preferences for food, music, activities, and people were also displayed by the participants. Stereotypic behaviours were prevalent behavioural patterns exhibited by participants who had individual and unique stereotypic motions. The coding of the stereotypic behaviour revealed that emotional responses were present during stereotic movement. The researcher hypothesized that stereotypic movement was an observable response to the inner thoughts or ideations of the participants. The literature on sensory deprivation suggests that individuals when exposed to a montonous environment develop their own sensory data (hallucinations) in the reticular area of the brain. Stereotypic behaviour appears to be an adaptation by the individual to monotony through self generated stimuli. The data from this study suggests that the degree of environmental stimulation influences the prevalence and incidence of stereotypic behaviour. There were data to support the hypothesis that the participants' stereotypic movement was interactive with the degree of environmental stimulation and the specific like or dislike of the participant to the stimulation.
Education, Faculty of
Educational and Counselling Psychology, and Special Education (ECPS), Department of
Graduate