Costs and benefits of alternative rehabilitation models

Adaptive behavior skills of 2,144 adults with Down syndrome aged 20–69 years were compared to those of a matched group of 4,172 developmentally disabled people without Down syndrome. Adaptive competence in eight skill domains was examined as a function of etiology, age-group and level of mental retardation. In all behavioural domains, and at all levels of mental retardation, individuals with Down syndrome displayed significantly more age-related deficits than did age-matched controls. In individuals with Down syndrome, substantial age-related deficits in adaptive competence were observed after 49 years of age and were most pronounced after 59 years of age. Our findings support previous suggestions of increased risk for Alzheimer disease among adults with Down syndrome. However, Alzheimer neuropathology is found in people with Down syndrome by 40 years of age; signs of regression in adaptive behavior occur 10–15 years after the presumed onset of pathological processes. These results may suggest that the processes underlying dementia in individuals with Down syndrome can have an extremely prolonged course.     

Premature regression of adults with Down syndrome

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.     

Prevalence of epilepsy in adults with mental retardation and related disabilities in primary care

Two primary care practices were used to recruit adults with and without disability. Disability groups included autism, Down syndrome, cerebral palsy, and mental retardation. The patients without disability had an epilepsy prevalence rate of 1%. The prevalence of epilepsy within the disability groups was 13% for cerebral palsy, 13.6% for Down syndrome; 25.4% for autism, 25.5% for mental retardation, and 40% for adults with both cerebral palsy and mental retardation. During the decades of adulthood, the prevalence of epilepsy declined for those with cerebral palsy and mental retardation. The prevalence of epilepsy increased with advancing years for adults with Down syndrome, autism, and those without disability. Nonetheless, during each decade the prevalence of epilepsy was higher in all of the disability groups compared to those without disability.     

Mental retardation and subnormality in a birth cohort of 12,000 children in Northern Finland

The occurrence of mental retardation and subnormality were investigated in a one-year birth cohort (N = 12,058) from two provinces in Northern Finland; 96% of the children were followed-up to the age of 14. Of these children 253 (2.2%) were unable to go to an ordinary school and 449 (3.8%) were attending an ordinary school in a class lower than that appropriate for their age. The cumulative incidence of severe mental retardation (IQ less than 50) was 7.4 per 1,000; for mild mental retardation (IQ 50 to 70), 5.5 per 1,000; and for mental subnormality (IQ 71 to 85), 13.4 per 1,000. The corresponding prevalence rates were 6.3, 5.6, and 13.7 per 1,000. The total cumulative incidence of children with IQ less than 86 was 27.0 per 1,000 and the prevalence 25.6 per 1,000. There were 39 cases with Down syndrome, 3.2 per 1,000.     

Cognitive deterioration in adults with Down syndrome: effects on the individual, caregivers, and service use

Individuals with Down syndrome (N = 49) who had participated in serial neuropsychological assessments were assigned to one of three groups comparable in level of premorbid mental retardation: those showing cognitive deterioration, those comparable in age but not showing cognitive deterioration, and those not showing cognitive deterioration but younger. Those experiencing cognitive deterioration were less likely to receive day services, had more impoverished life experiences, and required more support compared to groups without cognitive deterioration. When age was controlled for, cognitive deterioration was significantly positively associated with caregiver difficulties and service use and negatively associated with life experiences for the individual. Results suggest a potential role for caregiver difficulties in influencing life experiences of adults with Down syndrome showing cognitive decline.     

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.     

Stability and change in health, functional abilities, and behavior problems among adults with and without Down syndrome

Changes in health, functional abilities, and behavior problems among 150 adults with Down syndrome and 240 adults with mental retardation due to other causes were examined with seven assessments over a 9-year period. Adults were primarily younger than 40, the age at which declines begin to be evident in individuals with Down syndrome. Adults with Down syndrome were advantaged in their functional abilities and lack of behavior problems, comparable in health, and exhibited comparable rates of change on these measures as adults with mental retardation due to other causes. Placement out of the parental home and parental death were predictors of change in health, functional abilities, and behavior problems.     

Personal competence of institutionalized adult males with or without Down syndrome

The Personal Competence Profile was administered to 30 male adults with Down syndrome and 30 male adults without Down syndrome matched on age, IQ, and years of institutionalization. Down syndrome subjects rated higher on attention, calmness, and niceness but lower on sensation, language, and boldness. The results were consistent with the classical personality stereotype of Down syndrome and suggest the utility of using personal competence as a framework for studying behavioral aspects of mental retardation.     

Differences in cardiovascular disease risk between nondiabetic adults with mental retardation with and without Down syndrome

A reduced expression of the insulin resistance syndrome, a common neuroendocrine disorder underlying atherosclerosis, may play a role in reduced atherosclerosis in adults with Down syndrome. We compared selected components of the insulin resistance syndrome between 75 adults with Down syndrome and 70 with mental retardation due to other causes. After adjusting for age differences, residence, cigarette smoking, and medication use, women with Down syndrome had lower fasting plasma glucose and lower systolic blood pressure than comparison women. Men with Down syndrome had lower systolic and diastolic blood pressure than comparison men. Results suggest that women with Down syndrome may be less likely to express the insulin resistance syndrome, and men and women with Down syndrome may possess fewer atherosclerotic risk factors than the comparison groups.     

Incidence and prevalence of dementia in elderly adults with mental retardation without down syndrome

Rates of dementia in adults with mental retardation without Down syndrome were equivalent to or lower than would be expected compared to general population rates, whereas prevalence rates of other chronic health concerns varied as a function of condition. Given that individual differences in vulnerability to Alzheimer's disease have been hypothesized to be due to variation in cognitive reserve, adults with mental retardation, who have long-standing intellectual and cognitive impairments, should be at increased risk. This suggests that factors determining intelligence may have little or no direct relationship to risk for dementia and that dementia risk for individuals with mental retardation will be comparable to that of adults without mental retardation unless predisposing risk factors for dementia are also present.     

Repetition priming in adults with Williams syndrome: age-related dissociation between implicit and explicit memory

We examined implicit and explicit memory in adults with Williams syndrome. An age-related dissociation was found; repetition priming (reflecting implicit memory) did not show change with age, but free recall (reflecting explicit memory) was markedly reduced. We also compared the performance of adults with Williams syndrome to adults with Down syndrome and those with unspecified mental retardation. A similar dissociation was observed in adults with Down syndrome but not in adults with unspecified mental retardation. An IQ-related dissociation was also found. Implicit and explicit memory, therefore, show different degrees of association with age and IQ, supporting theories of these memory processes. Results also suggest that Williams syndrome, similar to Down syndrome, may be associated with precocious aging, resulting in the loss of some cognitive abilities.     

Fifteen-year follow-up of thyroid status in adults with Down syndrome

Background The natural history of thyroid function in adults with Down syndrome is relatively unknown with limited long‐term follow‐up data. Method This study investigated annual thyroid function tests in 200 adults with Down syndrome over a 15‐year period. Results For healthy adults with Down syndrome there is a gradual increase in thyroxine and possible gradual decline in thyroid‐stimulating hormone with age. The 15‐year incidence for definite hypothyroidism remains low and subclinical hypothyroidism is not a precursor for the onset of definite hypothyroidism. Conclusions The incidence of thyroid dysfunction is markedly less than would be expected from prevalence studies. Subclinical hypothyroidism is not necessarily a precursor to definite hypothyroidism. Prevalence studies have overstated the association between thyroid dysfunction and Down syndrome. Routine screening for adults with Down syndrome who are euthyroid can be reduced to every 5 years rather than the 1–2 years, as is the present policy.     

Walking habits of adults with mental retardation

The walking activity of men and women with mental retardation residing in community settings was described. Participants were 38 women (M age=.7, SD=9.5) and 65 men (M age=35.9, SD=11.2). They wore pedometers for 7 days. A 2 x 2 factorial ANOVA indicated no significant gender differences in total step counts or between participants with and those without Down syndrome. A post-hoc analysis revealed that participants walked less on Saturday than during the weekdays. Only 21.1% of the women and 21.5% of the men with mental retardation accumulated the recommended 10,000 steps per day.     

Behavior Problems of Children with Down Syndrome and Life Events

Behavior problems of 44 children with Down syndrome between the ages of 6 and 15 and 44 controls without mental retardation matched for age, sex, and socioeconomic status were compared on the basis of mother and teacher ratings. Ratings from both sources indicated that children with Down syndrome had more behavior problems, in particular attention deficit, noncompliance, thought disorder, and social withdrawal. Life events from the past year were significantly associated with mother but not teacher ratings of Down syndrome behavior problems.     

Task-related social behavior in children with Down syndrome

The specificity and stability of task-related social behaviors in children ages 5 to 12 was examined. Social behaviors during solvable and unsolvable puzzles were compared among children with Down syndrome, children with mental retardation, and typically developing children matched on mental age (MA). Compared to children without Down syndrome, those with the disorder looked to an adult and requested help more frequently. They also took longer to complete the tasks. These findings suggest that the overuse of social behaviors observed in young children with Down syndrome remains stable over the early school years and are specific to children with Down syndrome.     

Dendrites, dementia and the Down syndrome

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.     

Emotion recognition by children with Down syndrome

In three studies, children with Down syndrome were presented with emotion recognition tasks designed to tap their knowledge of simple emotions, their ability to label emotions, and their understanding of emotions from simple, story-based contexts. Results indicate that young children with Down syndrome perform similarly to typical controls matched on MAs of approximately 3 years. However, by developmental age of 4 years, children with Down syndrome performed worse than both MA-matched typical children and children with non-Down syndrome types of mental retardation. Although the MAs of children with Down syndrome increased over 2-years, their emotion recognition abilities did not. Taken together, findings suggest both etiological and developmental differences in the emotion recognition abilities of children with Down syndrome.     

The prevalence and incidence of mental ill-health in adults with Down syndrome

Background While there is considerable literature on adults with Down syndrome who have dementia, there is little published on the epidemiology of other types of mental ill‐health in this population. Method Longitudinal cohort study of adults with Down syndrome who received detailed psychiatric assessment (n = 186 at the first time point; n = 134 at the second time point, 2 years later). Results The prevalence of Down syndrome for the 16 years and over population was 5.9 per 10 000 general population. Point prevalence of mental ill‐health of any type, excluding specific phobias, was 23.7% by clinical, 19.9% by Diagnostic Criteria for Psychiatric Disorders for use with Adults with Learning Disabilities/Mental Retardation (DC‐LD), 11.3% by ICD‐10 Classification of Mental and Behavioural Disorders: Diagnostic Criteria for Research (DCR‐ICD‐10) and 10.8% by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Revised (DSM‐IV‐TR) criteria. Two‐year incidence of mental ill‐health of any type was 14.9% by clinical and DC‐LD, 9.0% by DCR‐ICD‐10 and 3.7% by DSM‐IV‐TR criteria. The highest incidence was for depressive episode (5.2%) and dementia/delirium (5.2%). Compared with persons with intellectual disabilities (ID) of all causes, the standardized rate for prevalence of mental ill‐health was 0.6 (0.4–0.8), or 0.4 (0.3–0.6) if organic disorders are excluded, and the standardized incidence ratio for mental ill‐health was 0.9 (0.6–1.4), or 0.7 (0.4–1.2) if organic disorders are excluded. Urinary incontinence was independently associated with mental ill‐health, whereas other personal factors, lifestyle and supports, and other types of health needs and disabilities were not. Conclusions Mental ill‐health is less prevalent in adults with Down syndrome than for other adults with ID. The pattern of associated factors differs from that is found for other adults with ID, with few associations found. This suggests that the protection against mental ill‐health is biologically determined in this population, or that there are other factors protective for mental ill‐health yet to be identified for the population with Down syndrome.     

Parental vocalizations and perceived immaturity in down syndrome

Previous findings suggest that children with Down syndrome may be perceived as more youthful than other children with mental retardation. In this study whether perceptions of youthfulness can be linked to parenting behavior, in particular increased prosodic adjustments characteristic of infant-directed speech, is investigated. The prosodic characteristics of parental language targeted to children with Down syndrome and children with other etiologies of mental retardation were compared. Results show that parents of children with Down syndrome raised their voice pitch significantly more (i.e., spoke in a higher register) and spoke with a significantly wider mean pitch variance than parents of children in the comparison group. Implications are discussed for parent-child interactions in children with different genetic mental retardation syndromes.     

Correlation between dental maturation and chronological age in patients with cerebral palsy, mental retardation, and Down syndrome

Determining a child's chronological age and stage of maturation is particularly important in fields such as paediatrics, orthopaedics, and orthodontics, as well as in forensic and anthropological studies. Some systemic conditions can cause abnormal physiological maturation, and skeletal maturation is usually more delayed than dental maturation. The aim of this study was to determine dental age in a group of patients with the most prevalent congenital or perinatally occurring physical and mental disabilities. The study group comprised 155 white Spanish children aged 3-17 years (35 with cerebral palsy, 83 with mental retardation and no associated syndromes or systemic conditions, and 37 with Down syndrome). The dental maturation indices described by Nolla and Demirjian were used to generate regression lines for the dental age of individuals in a control group (688 white Spanish children aged 3-17 years) and the formulae were then used to determine the dental age of patients in the study group. No significant differences were found between dental and chronological age in boys with cerebral palsy, mental retardation, or Down syndrome. In contrast, dental age (calculated from the linear regression model that included values for the Demirjian index) was significantly delayed compared with chronological age in girls with cerebral palsy or Down syndrome.