Implicit and explicit learning in young adults with mental retardation

We examined intelligence-related differences in explicit and implicit learning using an artificial grammar paradigm. Young adults with and without mental retardation completed a sequence-learning and identification task. For some participants, sequences were constructed following an artificial grammar; for others, sequences were random. Explicit learning was determined by ability to learn and later identify random sequences. Implicit learning was determined by the tendency to incorrectly identify new grammatical sequences as seen before, relative to new nongrammatical sequences. Participants with mental retardation did more poorly than participants without mental retardation on explicit learning but just as well on implicit learning. Results suggest that learning of complex materials, when accomplished through implicit processing, is functionally equivalent in individuals with and without mental retardation.     

Injury prevalence among children and adolescents with mental retardation

Childhood injuries lead to increased morbidity and result in significant costs to public insurance programs. People with mental retardation, most of whom are covered by Medicaid, are at high risk for injury, which has implications for community inclusion, a central policy goal. Medicaid data from inpatient, outpatient, and long-term care settings represent an important new resource for injury surveillance in this population. Injury prevalence for 8.4 million Medicaid-eligible children in 26 states was measured using 1999 eligibility and claims data; 36.9% Medicaid beneficiaries ages 1 to 20 with mental retardation had at least one injury claim as compared with 23.5% of those without mental retardation. Prevalence rates are reported by gender and age for a variety of injury types.     

Assessing fears and related anxieties in children and adolescents with learning disabilities or mild mental retardation

The purpose of the present study was to examine self-reported fears and related anxieties in children and adolescents (7-18 years of age) having learning disabilities (LD) or mild mental retardation (MIMR), and whether these fears and related anxieties differ based on gender and age. Students responded to two well validated instruments, The Fear Survey Schedule for Children-Revised and Revised Children's Manifest Anxiety Scale. The results revealed age, gender, and disability interaction effects. Adolescent boys having mild mental retardation reported highest levels of fear related to failure and criticism, a finding that was different from those reported in previous studies. In addition, girls reported higher levels than boys of total fear, fears related to minor injury and small animals, and worry/oversensitivity. Age main effects were also observed where younger students from both the LD and the MIMR groups reported higher levels of non-specific general anxiety. Implications and directions for future research were presented.     

Cognitive profiles in adolescents with mental retardation

ABSTRACT. Cognitive profiles of performance were obtained from a selected group of adolescent subjects with mental retardation (MR) (n=32; mean age; 15.4 years, S.D.=3.7) by means of an ad hoc neuropsychological battery. On the basis of each subject's IQ, the experimental sample was divided into three homogeneous subgroups (severely, moderately and mildly retarded) and cognitive performances obtained in the banery tests were compared. Subsequently, in order to clarify the qualitative aspects of MR, the cognitive patterns of subjects with the same IQ and chronological age were examined. Altogether, from a neuropsychotogical point of view, the results of this study seem to support the hypothesis that MR is a heterogeneous condition of cognitive deficits (some abilities are better preserved than others) and indicate that a set of multiple tests exploring single cognitive functions is needed in order to describe cognitive profiles in MR.     

Preattentive orienting in adolescents with mental retardation

Visual attention is preattentively drawn to abrupt onsets of stimuli appearing in a visual array. In this experiment, I examined the speed of attentional capture for persons with and without mental retardation. Participants identified target stimuli that were signaled by a valid location cue (20% of the time), an invalid location cue (60% of the time), or no cue (20% of the time). Participants without mental retardation exhibited maximum influence of the cue at cue/target separations that were 100 msec shorter than did participants with mental retardation. These results indicate that processing-speed differences between persons with and those without mental retardation can be observed even when processing resources not involved in the information processing.     

Empirical classification of behavioral and psychiatric problems in children and adolescents with mental retardation

A quantitative method for typing psychopathology of youngsters with mental retardation was assessed. Parents of 601 students in special educational placements rated them with the ABC. The sample was randomly divided into two subgroups. We used Ward's hierarchical method of cluster analysis and derived eight clusters in Subsample 1 and satisfactory agreement, kappa =.64, for the eight-cluster solution in Subsample 2. Clusters were: Problem Free, Within Normal Limits, Conduct Problem, Shy/Inactive, Hyperactive, Social Withdrawal With Agitation, Undifferentiated Behavior Disturbance, and Autistic-Like Behavior. We also used demographic (age, gender, IQ, physical handicaps) and clinical variables (DSM diagnoses and target behaviors) extracted from school records of 228 participants to appraise validity of the empirically derived clusters. The external data provided modest to strong support for all except one cluster (Social Withdrawal With Agitation).     

Effects of different variations of mental and physical practice on sport skill learning in adolescents with mental retardation

The purpose of this study was to investigate the effect of five variations of imagery and physical practice on learning of Basketball free throws in adolescents with mental retardation (AWMR). Forty AWMR were randomly assigned to five groups and performed a variation of practice: physical practice, mental practice, physical practice followed by mental practice, mental practice followed by physical practice, and no practice. The groups exercised the task for 24 sessions. Following training, posttest and retention test were taken. All variations of practice resulted in performance improvement, yet the mental practice followed by physical practice resulted in better improvement. The results suggest that mental practice associated with physical practice results in an outstanding performance improvement in AWMR.     

Implicit memory in aging adults with mental retardation with and without Down syndrome

Effects of age and IQ on implicit memory in adults with mild or moderate mental retardation with and without Down syndrome were examined. When the etiologically defined groups were equated on age (and IQ), an age-associated difference in implicit memory performance was not evident. When data were reanalyzed, including only participants with unspecified mental retardation from a broader age range, we found a significant but small age-related difference and a significant but small IQ-related effect on implicit memory. In summary, although implicit memory showed an age-associated difference and IQ-associated variation in adults with mental retardation, these effects were relatively small. Data support existing theories proposing the relative invariance of implicit processes across a range of individual differences in age and intelligence.     

Body awareness in children with mental retardation

The body awareness of 124 toddlers with mental retardation and of 124 children developing normally matched to them on age and gender was examined. Twenty-nine of the children with mental retardation were diagnosed as Down syndrome (DS). The ‘Pointing and Naming’ Test of Bergès and Lézine [Bergès, J., & Lézine, I. (1978). Test d’imitation de gestes [Imitation test of gestures] (2nd ed.). Paris: Masson] was used to measure vocabulary skills on body parts. Results indicated that (a) the test used is reliable in terms of internal consistency; (b) children developing normally performed better than children with mental retardation on this test; (c) there were no significant differences in performance on this test between genders for the whole group; (d) children with DS performed as well as children with mental retardation of unknown origin on receptive vocabulary. On expressive vocabulary, they performed worse.     

A comparison of stress and coping by fathers of adolescents with mental retardation and fathers of adolescents without mental retardation.

This investigation was an attempt to provide comparative information regarding stress and coping in fathers of adolescents with mental retardation and fathers of adolescents without mental retardation. Subjects for the study were 40 fathers of adolescents with mental retardation and 31 fathers of adolescents without mental retardation.     

Chronological age, receptive vocabulary, and syntax comprehension in children and adolescents with mental retardation

This study was designed to examine the association of CA with syntax and vocabulary comprehension in children and adolescents with mental retardation. It was conducted using the PPVT-R and the Test for Reception of Grammar. The cognitive level of participants was estimated by means of three nonverbal intelligence tests. Results indicated that scores on intelligence tests account for 55% and 29% of the variability of syntax and vocabulary scores, respectively. For the vocabulary, the introduction of CA into the regression equation produced a significant increment of the variance explained (17%). However, its contribution to the variance of the syntax test was not significant. This finding suggests that CA-related experience is linked to on the receptive vocabulary of children and adolescents with mental retardation.     

Comparison of risperidone and methylphenidate for reducing ADHD symptoms in children and adolescents with moderate mental retardation

OBJECTIVE: To evaluate the short-term efficacy and tolerability of risperidone and methylphenidate for reducing symptoms related to attention-deficit/hyperactivity disorder (ADHD) in children and adolescents with moderate mental retardation. METHOD: In a 4-week, single-blind, parallel-group trial, 45 subjects with moderate mental retardation and ADHD were randomized to risperidone or methylphenidate and assessed using objective rating scales for efficacy (SNAP [Swanson, Nolan, and Pelham]-IV and Nisonger Child Behavior Rating Form) and side effects (Barkley's Side Effects Rating Scale and Udvalg for Kliniske Unders?gelser). RESULTS: Both groups had reduced ADHD symptoms during the trial. Repeated-measures analysis of variance yielded a significant effect for the interaction between time and group assignment in SNAP-IV Total scores (F = 3.26; p = .05), suggesting a more pronounced effect for risperidone. There was a significant weight reduction in the methylphenidate group and a weight gain in the risperidone group. CONCLUSIONS: Our findings suggest that risperidone is associated with greater reductions in ADHD Total score than methylphenidate in children with moderate mental retardation and ADHD. Comorbidity and the side effects profile might be of importance in choosing between the medications, although it is usually prudent to try stimulants before antipsychotics in such children.     

Eyewitness memory and suggestibility in children with mental retardation

We examined how well children with mental retardation were able to recall a live staged event one day later compared to CA- and MA-comparable peers. Children with mental retardation performed very well on many measures of eyewitness memory performance, reaching the level of the CA-comparable group for free recall, general questions, open-ended questions, and correctly leading questions. They were, however, more suggestible in response to closed misleading questions than were children in the CA-comparable group, although they were not more suggestible than those in the MA-comparable group. Some relationships were found between a standardized measure of suggestibility and performance on the eyewitness memory task, but most of these relationships were not the same within each of our study groups.     

Adjunctive lamotrigine for refractory epilepsy in adolescents with mental retardation

Epilepsy is a major comorbid condition in adolescents with mental retardation and is often characterized by multiple seizure types that are refractory to treatment. This study (n = 22) describes a subanalysis of data from a larger multicenter study of adjunctive lamotrigine therapy in patients with mental retardation and refractory epilepsy and focuses on the outcome measures of seizure reduction, safety and tolerability, and impact on behaviors in adolescents with mental retardation and refractory epilepsy. The study kept baseline antiepileptic drugs constant and titrated lamotrigine over 8 weeks to the target dose, followed by an 8-week maintenance phase and then a 12-week optimization phase during which all antiepileptic drugs and lamotrigine could be altered as clinically indicated. Sixty percent of subjects had a 50% decrease in seizures by the end of the maintenance phase and a mean 39% reduction in seizure frequency by the end of the maintenance phase (25% by end of study) compared with baseline. Global improvements were observed in most patients, with statistically significant improvements in the Aberrant Behavior Checklist and the Habilitative Improvement Scale, which is predictive of less need for supportive care in activities of daily living and thus enhanced potential for greater independence. Lamotrigine-associated improvements in behavior can be attributed to improved control of seizures, a reduction in concomitant antiepileptic drugs, and/or direct mood-stabilizing and behavior-enhancing properties independent of the antiseizure effects of the drug. The results of this study suggest that lamotrigine is an important treatment option in adolescents with mental retardation and comorbid epilepsy.     

精神发育迟滞的脑体感诱发电位（附50例分析）

作者对５０例诊断为精神发育迟滞儿童进行体感诱发电位（ＳＥＰ）检查，将其结果与临床资料、ＥＥＧ、智商及脑ＣＴ扫描作对照研究。结论认为ＳＥＰ对精神发育迟滞儿童的诊断有重要意义，异常率达８２％，无创伤，无痛苦，亦可作为观察疗效和估价预后的一项客观指标，较一般常规的客观神经系统检查更敏感。     

Implicit learning deficit in children with developmental dyslexia

Several neuropsychological deficits have been reported as characteristic of the cognitive profile of dyslexic children. Phonological and visual processing are often impaired as well as auditory processing, attention and information processing speed. We investigated whether implicit learning, is impaired in dyslexic children and adolescents. Tests of implicit and declarative learning were administered to 18 clinically defined dyslexics and 18 similar age controls. Dyslexics showed a reduced learning rate in the implicit but not in the declarative task, suggesting a specific deficit of implicit learning. Although alternative hypothesis cannot be ruled out, considering that implicit learning is a cognitive function primarily processed by the cerebellum and that recent neurological and physiological data suggest a cerebellar dysfunction in dyslexia, the present results suggest an impairment of cerebellar system in reading disabilities.     

Generalized anxiety disorder in adolescents and young adults with mild mental retardation

This report examines clinical features of generalized anxiety disorder in adolescents and young adults with mild mental retardation (MR), compared with children and adolescents with normal IQ. Frequency of symptoms, comorbidity, agreement between reports of subjects and parents, correlation between IQ and severity of disorder, and comparison between frequency of symptoms in the experimental and control groups are described. Twenty-two subjects with MR (12 males and 10 females aged 11-25 years; mean age = 16.3), 30 children (19 males and 11 females aged 7-11.11; mean age = 10), and 30 adolescents (18 males and 12 females aged 12.1-18; mean age = 15.2) participated in the study. All the subjects were comprehensively diagnosed with diagnostic interviews (K-SADS or DICA-R). According to our data, generalized anxiety disorder can be diagnosed in adolescents with mild MR, with high agreement between self-reports and parent reports. Phenomenology of GAD in mildly developmentally delayed persons grossly paralleled that of normal IQ people, except for brooding, somatic complaints, and sleep disorders. Number and severity of symptoms did not correlate with Full Scale and Verbal IQs. High rates of comorbidity with depression were evident both in normal IQ and in developmentally delayed subjects.