Trajectory of adaptive behavior in males with fragile X syndrome

Daily Living Skills in Adolescent and Young Adult Males With Fragile X Syndrome

By adulthood, most males with fragile X syndrome (FXS) require support to navigate day-to-day settings. The present study cross-sectionally: (1) characterized the profile of daily living skills in males with FXS and (2) examined associated participant characteristics (i.e., fragile X mental retardation protein [FMRP] expression, nonverbal cognition, language, autism symptomatology, and anxiety symptomatology) using the Waisman-Activities of Daily Living questionnaire. Males with FXS (n = 57, ages 15-23 years) needed more help/support in the areas of domestic and community daily livings skills, than in the area of personal daily living skills. Significant associations were observed between reduced daily living skills and lower nonverbal cognition, receptive language, expressive language, and increased autism symptomatology. Receptive language emerged as the strongest unique predictor of daily living skill performance.

Concurrent Associations between Expressive Language Ability and Independence in Adolescents and Adults with Fragile X Syndrome

BACKGROUND

Few individuals with fragile X syndrome (FXS) successfully meet adult normative expectations in education, employment, peer relations, and habitation, although there is within-syndrome variability in this regard. The primary goal of this study was to determine whether expressive language skills contribute to the capacity for independent functioning in adulthood even after controlling for nonverbal cognitive ability.

METHODS

Participants were 18- to 23-year-olds with FXS. Expressive language was assessed using the psychometrically validated Expressive Language Sampling (ELS) conversation and narration procedures. The language produced was transcribed and analyzed to yield measures of expressive vocabulary, syntax, and intelligibility. Parents concurrently completed questionnaires on the independent functioning of the participants with FXS.

RESULTS

All three ELS measures were significantly corelated with multiple measures of independence. The magnitudes of the correlations were reduced when nonverbal IQ was controlled through partial correlation. Nonetheless, many of the partial correlations were medium to large and several were statistically significant.

CONCLUSIONS

Expressive language skills appear to contribute uniquely to the capacity for independence, although longitudinal data are needed to evaluate the possibility of a bidirectional relationship between these domains. Thus, language intervention may be a prerequisite for preparing youth with FXS for an independent adult life.

Adaptive Skills in FXS: A Review of the Literature and Evaluation of the PEDI-Computer Adaptive Test (PEDI-CAT) to Measure Adaptive Skills

As adaptive skills (AS) are dynamic and may indicate the success of an intervention, they are a common domain measured in clinical trials. Typical interview tools for measuring AS are time-consuming, and questionnaire measures often lead to inconsistent information. The present study was designed to evaluate the feasibility, validity and test-retest performance of the Pediatric Evaluation of Disability Inventory Computer Adaptive Test (PEDI-CAT) in Fragile X syndrome (FXS). The PEDI-CAT is administered via tablet and uses the item response theory to efficiently determine the items administered. The PEDI-CAT was administered to 42 individuals with FXS (27 males; 15 females) aged 1.6-50.9 years (M = 14.9; SD = 11.2), followed by the Vineland-3 (VABS-3) interview for comparison. Administration was efficient (M = 21.7 min; SD = 9.5; range 8-45 min; mode = 19). Males and females did not significantly differ on the PEDI-CAT domains, except for daily activities (t(40) = -2.22, p = 0.037). Floor effects were significant for both measures, although the PEDI-CAT showed more floor effects in the mobility (35.7%) and social-cognitive (50%) domains. PEDI-CAT daily activities, mobility, social-cognitive and responsibility domains were all significantly correlated with most of the VABS-3 domains (all rho > 0.5; p < 0.01). Test-rest of the PEDI-CAT was comparable to the VABS-3. Results suggest that the PEDI-CAT is efficient, and minimal training is needed to administer it; however, it lacks specificity and shares a high rate of floor effects with the VABS-3.

A comparison of functional academic and daily living skills in males with fragile X syndrome with and without autism

BACKGROUND

Adaptive behaviors, such as functional academic and daily living skills, are critical for independence in adults with intellectual and developmental disabilities. However, little is known about these skills in fragile X syndrome (FXS), the most common form of inherited intellectual disability.

AIMS

The purposes of this study were to describe the functional academic and daily living skills of males diagnosed with FXS across different age groups and compare skill attainment by autism status and other common co-occurring conditions.

METHODS AND PROCEDURES

We used survey methods to assess parent-reported functional academic and daily living skills in 534 males with FXS. Functional academic skills included time and schedules, money, math, reading, and writing skills. Daily living skills included hygiene, cooking, laundry and housekeeping, transportation, and safety skills.

OUTCOMES AND RESULTS

Analyses examined functional academic and daily living skills in a cross-sectional sample of males between ages 5 and 67. Differences in skill attainment were found by child age, co-morbid autism status, total number of co-occurring conditions, and respondent education. Functional academic and daily living skills were predictive of community employment and independent living.

CONCLUSIONS AND IMPLICATIONS

These data provide important information on the mastery of both foundational and more complex adaptive skills in males with FXS. Both functional academic and daily living skills were predictive of measures of independence above and beyond other child and family characteristics. These findings point to the need to focus interventions to support the attainment of independence in males with FXS.

Adaptive behavior in infants and toddlers with Down syndrome and fragile X syndrome

Individuals with Down syndrome (DS) experience deficits across all domains of adaptive functioning, however little is known about the emergence and age-related changes of these impairments compared to other neurogenetic disorders with similar intellectual disability impairments, such as fragile X syndrome (FXS). Adaptive behavior is key for optimal functioning in these populations. Participants aged 5-45 months comprised three age-matched groups, DS (n = 64), FXS (n = 69), and typically developing controls (TD; n = 69). Adaptive behavior was measured on the Vineland Adaptive Behavior Scales-II. Regressions were used to examine adaptive behavior in a cross-sectional design across age. DS infants and toddlers evidenced deficits across all areas of adaptive behaviors compared to the age-matched TD group, with clear impairments present in the first year of life. Motor skills were the area of greatest weakness in children with DS with significant impairment evident at 12 months of age that remained low through 3 years. Compared to age-matched children with FXS, children with DS showed initially lower standard scores at 12 months of age, but slower declines in standard scores across age, resulting in less impaired functioning at 36 months. This is the first study to compare adaptive behavior in infants and toddlers with DS to FXS, and demonstrate the phenotypic specificity of adaptive profiles in this diagnostic group. These findings provide evidence that adaptive behavior should be a major target of intervention in children with FXS and DS, and that these differences are potentially driven by unique etiologies attributable to each disorder.

Visuo-spatial construction trajectories in Fragile X Syndrome (FXS) and Autism Spectrum Disorders (ASD): Evidence of cognitive heterogeneity within neurodevelopmental conditions

BACKGROUND/AIMS

There have been discrepancies reported in visuo-spatial construction ability in children with Autism Spectrum Disorders (ASD), fragile X Syndrome (FXS) and those with a comorbid diagnosis of FXS and ASD (AFXS). This study aimed to provide a better understanding of the visuo-spatial processing styles in these heterogeneous neurodevelopmental disorders.

METHODS AND PROCEDURE

Navon-type tasks were used to assess visuo-spatial construction ability across 5 groups of children: typically developing, FXS, AFXS, ASD children who scored low-moderate (HFA) and ASD children that scored severe (LFA) on the Childhood Autism Rating Scale (CARS). Analyses of their developmental trajectories compared the performance of these groups.

OUTCOMES AND RESULTS

Each group produced their own distinct trajectory. HFA achieved higher scores from an earlier age than the TD group, while the LFA group's performance was driven by a bias in local processing. The FXS performance was normalised by using mental age as a predictor while neither mental nor chronological age predicted the AFXS group performance.

CONCLUSIONS AND IMPLICATIONS

The study showed unique processing styles. These findings highlight the importance of taking comorbidity and the severity of symptoms within each condition into account in order to understand cognitive abilities and cognitive profiles.

The Longitudinal Effects of Parenting on Adaptive Behavior in Children with Fragile X Syndrome

Several studies have reported declines in adaptive behavior amongst children with fragile X syndrome (FXS) starting in middle childhood. We examined the effects of maternal responsivity on adaptive behavior in 55 children with FXS visited 5-6 times in their homes from early through middle childhood. Our analyses indicated that sustained maternal responsivity had a significant positive impact on the trajectories of communication and to a lesser extent other adaptive behavior domains through middle childhood with many effects remaining significant after controlling for autism symptoms and developmental level. For children who showed declines in adaptive behavior during middle childhood, sustained high levels of maternal responsivity minimized the amount of decline observed in the communication, socialization, and daily living domains.

Cognitive and Behavioural Development of Israeli Males with Fragile X and Down Syndrome

Hebrew translations of the Kaufman Assessment Battery for Children (KABC) and the Vineland Adaptive Behaviour Scales (VABS) were administered to 17 Israeli males with fragile X and 17 with Down syndrome matched for chronological and mental ages. When differences in the initial baselines were considered, the pattern of findings was generally consistent with previous reports. On the K-ABC, the males with fragile X scored higher on some subtests of the Simultaneous Domain but not on any of those of the Sequential Domain. On the VABS, superior scores of the males with fragile X on the Daily Living Skills and Communication domains is consistent with prior evidence of their relative strength on the former and the specific weakness of persons with Down syndrome on the latter. These differences between the males with fragile X and Down syndrome with regard to functioning on various domains and subdomains highlight the need to carefully examine the profiles of aetiologically homogeneous groups of persons.

Do Children With Fragile X Syndrome Show Declines or Plateaus in Adaptive Behavior?

This study explores if children with fragile X syndrome (FXS) show advances, declines, or plateaus in adaptive behavior over time and the relationship of nonverbal cognitive abilities and autistic behavior on these trajectories. Parents of 55 children with FXS completed the Vineland Adaptive Behavior Scales ( Sparrow, Balla, & Cicchetti, 1984 ; Sparrow, Cicchetti, & Balla, 2005 ) between 3 and 6 times from 2 to 10 years of age. Using raw scores, results indicate that about half of the sample showed advances in adaptive behavior, whereas the other half showed declines, indicating a regression in skills. Children who were more cognitively advanced and had less autistic behaviors had higher trajectories. Understanding the developmental course of adaptive behavior in FXS has implications for educational planning and intervention, especially for those children showing declines.

Longitudinal profiles of adaptive behavior in fragile X syndrome

OBJECTIVE

To examine longitudinally the adaptive behavior patterns in fragile X syndrome.

METHOD

Caregivers of 275 children and adolescents with fragile X syndrome and 225 typically developing children and adolescents (2-18 years) were interviewed with the Vineland Adaptive Behavior Scales every 2 to 4 years as part of a prospective longitudinal study.

RESULTS

Standard scores of adaptive behavior in people with fragile X syndrome are marked by a significant decline over time in all domains for males and in communication for females. Socialization skills are a relative strength as compared with the other domains for males with fragile X syndrome. Females with fragile X syndrome did not show a discernible pattern of developmental strengths and weaknesses.

CONCLUSIONS

This is the first large-scale longitudinal study to show that the acquisition of adaptive behavior slows as individuals with fragile X syndrome age. It is imperative to ensure that assessments of adaptive behavior skills are part of intervention programs focusing on childhood and adolescence in this condition.

Fragile X syndrome: an aging perspective

Cognitive and behavioral correlates of molecular variations related to the FMR1 gene have been studied rather extensively, but research about the long-term outcome in individuals with fragile X spectrum disorders remains sparse. In this review, we present an overview of aging research and recent findings in regard to cellular and clinical manifestations of aging in fragile X syndrome, and the FMR1 premutation.

Behavioural phenotypes and special educational needs: is aetiology important in the classroom?

BACKGROUND

A number of genetic conditions with associated intellectual disability and/or special educational needs have increasingly well-defined behavioural phenotypes. Thus, the concept of 'behavioural phenotype' and aetiology of intellectual disability may be important with regard to school-based interventions.

METHOD

The evidence for distinctive cognitive and behavioural aspects of five of the most common genetic syndromes (Down syndrome, fragile X syndrome, Williams syndrome, Prader-Willi syndrome and velo-cardio-facial syndrome) associated with special educational needs is reviewed with respect to key studies and findings. The possible utility of aetiology-related interventions in education is discussed with reference to arguments for and against such approaches with respect to published guidelines and published research.

RESULTS

Behavioural phenotypes are probabilistic and many children with a specific genetic syndrome will share commonalities with other children with other genetic syndromes and within syndrome variability is not uncommon. There is evidence that teachers and parents have limited knowledge of aspects of the proposed cognitive and behaviour profiles associated with the reviewed syndromes. While there are published guidelines in the area of learning and behaviour for each of the five reviewed syndromes there is a limited amount of evidence of the efficacy of such approaches in school settings.

CONCLUSION

It is likely that knowing the aetiology of a child's special educational needs will be helpful for staff who work in school settings in relation to cognitive and behavioural implications. However, how such knowledge might inform teaching practice or behavioural interventions has not been studied. A model is proposed that might help inform educators about the possible role of aetiology in the classroom.

Developmental trajectories in syndromes with intellectual disability, with a focus on Wolf-Hirschhorn and its cognitive-behavioral profile

Few studies exist of developmental trajectories in children with intellectual disability, and none for those with subtelomeric deletions. We compared developmental trajectories of children with Wolf-Hirschhorn syndrome to other genetic disorders. We recruited 106 children diagnosed with fragile X, Williams-Beuren syndrome, or Wolf-Hirschhorn syndrome, assessing their intellectual and adaptive behavior abilities. We retested 61 children 2 years later. We compared Time 1 and Time 2 difference scores related to genetic disorder, age, initial IQ, or adaptive behavior composite. Results show genetic disorder and initial IQ score were significant factors for IQ differences, but only genetic disorder affected adaptive behavior differences. Results suggest different gene-brain-behavior pathways likely exist for these genetic disorders. Different developmental trajectories will influence the type and intensity of intervention implemented by caregivers.

Aberrant frontal lobe maturation in adolescents with fragile X syndrome is related to delayed cognitive maturation

BACKGROUND

Fragile X syndrome (FXS) is the most common known heritable cause of intellectual disability. Prior studies in FXS have observed a plateau in cognitive and adaptive behavioral development in early adolescence, suggesting that brain development in FXS may diverge from typical development during this period.

METHODS

In this study, we examined adolescent brain development using structural magnetic resonance imaging data acquired from 59 individuals with FXS and 83 typically developing control subjects aged 9 to 22, a subset of whom were followed up longitudinally (1-5 years; typically developing: 17, FXS: 19). Regional volumes were modeled to obtain estimates of age-related change.

RESULTS

We found that while structures such as the caudate showed consistent volume differences from control subjects across adolescence, prefrontal cortex (PFC) gyri showed significantly aberrant maturation. Furthermore, we found that PFC-related measures of cognitive functioning followed a similarly aberrant developmental trajectory in FXS.

CONCLUSIONS

Our findings suggest that aberrant maturation of the PFC during adolescence may contribute to persistent or increasing intellectual deficits in FXS.

Auditory and visual cortical activity during selective attention in fragile X syndrome: a cascade of processing deficiencies

OBJECTIVE

This study examined whether attention deficits in fragile X syndrome (FXS) can be traced back to abnormalities in basic information processing.

METHOD

Sixteen males with FXS and 22 age-matched control participants (mean age 29 years) performed a standard oddball task to examine selective attention in both auditory and visual modalities. Five FXS males were excluded from analysis because they performed below chance level on the auditory task. ERPs were recorded to investigate the N1, P2, N2b, and P3b components.

RESULTS

N1 and N2b components were significantly enhanced in FXS males to both auditory and visual stimuli. Interestingly, in FXS males, the P3b to auditory stimuli was significantly reduced relative to visual stimuli. These modality differences in information processing corresponded to behavioral results, showing more errors on the auditory than on the visual task.

CONCLUSIONS

The current findings suggest that attentional impairments in FXS at the behavioral level can be traced back to abnormalities in event-related cortical activity. These information processing abnormalities in FXS may hinder the allocation of attentional resources needed for optimal processing at higher-levels.

SIGNIFICANCE

These findings demonstrate that auditory information processing in FXS males is critically impaired relative to visual information processing.

The course of cognitive-behavioral development in children with the FMR1 mutation, Williams-Beuren syndrome, and neurofibromatosis type 1: The effect of gender

The course of cognitive-behavioral development in children with intellectual disabilities produced by genetic disorders has only recently begun to be examined systematically. Unfortunately, these studies are few in number. Previously, we examined cognitive-behavioral development in children with the fragile X (FMR1) mutation and found longitudinal decreases in both IQ and adaptive behavior (DQ) scores in most males and females with the full mutation. In this study, we examine longitudinal changes in IQ and DQ in children with neurofibromatosis type 1 (NF1) and Williams-Beuren Syndrome (WBS) by examining differences in composite IQ and DQ scores between the first test (T1) and retest (T2), and compare their developmental trajectory to children with the FMR1 mutation. Sixty-five children with the FMR1 mutation, or NF1, or WBS, ages 4-16 years, were retested two years after initial testing with the Stanford-Binet 4th Edition (SBFE) and the Vineland Adaptive Behavior Scale (VABS). In addition to significant longitudinal declines in IQ and DQ noted previously in children with the FMR1 mutation, we found significant decreases in IQ in males compared to females in the remainder of our sample. We also observed statistically significant decreases in DQ scores among children the FMR1 mutation, as noted previously, but not among children with NF1 or WBS. Moreover, significant declines were found only among males with the FMR1 mutation. Unlike declines in IQ scores, decreases in DQ were not significantly different between males and females.

Direct magnitude estimation of articulation rate in boys with fragile X syndrome

PURPOSE

To compare the perceived articulation rate of boys with fragile X syndrome (FXS) with that of chronologically age-matched (CA) boys and to determine segmental and/or prosodic factors that account for perceived rate.

METHOD

Ten listeners used direct magnitude estimation procedures to judge the articulation rates of 7 boys with FXS only, 5 boys with FXS and a diagnosis of autism spectrum disorder (ASD), and 12 CA boys during sentence repetition. Sentences had similar articulation rates in syllables per second as determined acoustically. Four segmental/prosodic factors were used to predict perceived rate: (a) percentage consonants correct, (b) overall fundamental frequency (F(0)) level, (c) sentence-final F(0) drop, and (d) acoustically determined articulation rate with the final word of the sentence excluded.

RESULTS

Boys with FXS and ASD were judged to talk faster than CA controls. Multiple linear regression indicated that articulation rate with the final word of the sentence excluded and sentence-final F(0) drop accounted for 91% of the variance for perceived rate.

CONCLUSIONS

Descriptions of speakers with FXS as having fast and/or fluctuating articulation rates may be influenced by autism status. Also, atypical sentence-final prosody may be related to perceived rate in boys with FXS and ASD.

Functional skills of individuals with fragile x syndrome: a lifespan cross-sectional analysis

Parents of 1,105 male and 283 female children with fragile X syndrome described functional skill attainment in eating, dressing, toileting, bathing/hygiene, communication, articulation, and reading. The majority of adult children had mastered many skills independently. Most adults were verbal, used the toilet, dressed, ate independently, bathed, and used a towel independently. However, some skills were not as well-developed, such as using complex sentences, reading, or speaking at a typical rate. As expected, significant differences were found between males and females. The findings highlight major skill attainments, identify skills that should be the target of specific intervention programs, suggest variable trajectories to be tested more precisely through direct assessments and longitudinally, and provide baseline data for treatment studies.

Expression of fragile X mental retardation protein within the vocal control system of developing and adult male zebra finches

Individuals with fragile X syndrome (FXS) are cognitively impaired and have marked speech delays and deficits. Our goal was to characterize expression of fragile X mental retardation protein (FMRP), encoded by Fmr1 fragile X mental retardation 1 gene or transcript (FMR1), in an animal model that learns to vocalize, namely the zebra finch Taeniopygia guttata (Tgu). We cloned and sequenced the zebra finch ortholog of FMR1 (TguFmr1) and developed an antibody that recognizes TguFmrp specifically. TguFmrp has structural features similar to its human ortholog FMRP. Because FXS patients exhibit sensorimotor deficits, we examined TguFmrp expression prior to, during, and after sensorimotor song learning in zebra finches. We found that TguFmrp is expressed throughout the brain and in four major song nuclei of the male zebra finch brain, primarily in neurons. Additionally, prior to sensorimotor learning, we observed elevated TguFmrp expression in the robust nucleus of the arcopallium (RA) of post-hatch day 30 males, compared with the surrounding telencephalon, suggesting a preparation for this stage of song learning. Finally, we observed variable TguFmrp expression in the RA of adolescent and adult males: in some males it was elevated and in others it was comparable to the surrounding telencephalon. In summary, we have characterized the zebra finch ortholog of FMRP and found elevated levels in the premotor nucleus RA at a key developmental stage for vocal learning.

The Social Orienting Continuum and Response Scale (SOC-RS): a dimensional measure for preschool-aged children

Children with autism show deficits in social referencing, joint attention, orienting to their names, and social smiling as early as the first year of life. The present study describes the development of the Social Orienting Continuum and Response Scale (SOC-RS), a quantitative scale assessing each of these behaviors during the course of video-recorded Autism Diagnostic Observation Schedule (ADOS) sessions. The SOC-RS was shown to be reliable and valid, and when applied to a longitudinal sample of children studied at 2 and 4 years of age, was shown to be sensitive to decreased levels of social referencing, joint attention, orienting to name, and social smiling in autism. The implications of these findings and potential applications of the SOC-RS are discussed.

Communication in young children with fragile X syndrome: a qualitative study of mothers' perspectives

PURPOSE

To provide descriptive and qualitative information about communication in young children with fragile X syndrome (FXS) and about how families react to and accommodate communication differences in their children.

METHOD

In-depth interviews were conducted with 55 mothers of young children with FXS. Interviewers asked mothers to describe their children's communication, strategies they used to help promote their children's communication, communication-related frustrations, their expectations for their children, and the roles that they perceive for themselves.

RESULTS

Over half the children were nonverbal and learning to communicate with augmentative and alternative communication. Mothers reported using strategies that were developmentally appropriate and recommended by early childhood experts, such as reading and talking to their children. Many mothers identified challenges faced in helping their child to communicate, and some cited difficulty obtaining speech-language services as a challenge. Mothers identified their roles as caregiver, teacher, therapist, and advocate.

CONCLUSIONS

The perspectives offered by mothers are valuable because they indicate how children with FXS communicate in natural contexts. Information about mothers' expectations and roles may help clinicians to be sensitive to variables that will affect working with young children and their families.

Handicaps and the development of skills between childhood and early adolescence in young people with severe intellectual disabilities

BACKGROUND

While a number of studies have examined the development of skills in children with intellectual disabilities (ID), most have been cross-sectional, most have been concerned with particular syndromes such as Down's syndrome or autism and few have attempted to identify factors associated with improvements in skills.

METHODS

From a sample of 111 children with severe ID who had been identified from the registers of six special schools at 4-11 years of age, 82 were traced and reassessed 5 years later at the age of 11-17 years. On both occasions, information on the children's handicaps and skills was collected by interviewing their main carers using a shortened version of the Vineland Adaptive Behaviour Scales and the Disability Assessment Schedule.

RESULTS AND CONCLUSIONS

There were small but statistically significant improvements in Vineland age-equivalent communication and daily living skills scores, but not in Vineland Socialization scores, over the 5-year period of follow-up. This pattern of improvement was observed in most aetiological subgroups. Improvement in skills was greatest in younger children, and was associated with reductions in behaviour problems and in levels of parental stress. In spite of the improvements in age-equivalent scores, Vineland standard scores showed significant declines over the same period of time, indicating that the improvements observed were smaller than would be expected in a general population sample of children of the same age. The dangers of using standard scores or quotients to quantify the level of functioning of children with severe ID are highlighted.

Adaptive functioning and behaviour problems in relation to level of education in children and adolescents with intellectual disability

BACKGROUND

The interrelationship between adaptive functioning, behaviour problems and level of special education was studied in 186 children with IQs ranging from 61 to 70. The objective was to increase the insight into the contribution of adaptive functioning and general and autistic behaviour problems to the level of education in children with intellectual disability (ID).

METHODS

Children from two levels of special education in the Netherlands were compared with respect to adaptive functioning [Vineland Adaptive Behavior Scales (VABS)], general behaviour problems [Child Behavior Checklist (CBCL)] and autistic behaviour problems [Autism Behavior Checklist (ABC)]. The effect of behaviour problems on adaptive functioning, and the causal relationships between behaviour problems, adaptive functioning and level of education were investigated.

RESULTS

Children in schools for mild learning problems had higher VABS scores, and lower CBCL and ABC scores. The ABC had a significant effect on the total age equivalent of the VABS in schools for severe learning problems, the CBCL in schools for mild learning problems. A direct effect of the ABC and CBCL total scores on the VABS age equivalent was found, together with a direct effect of the VABS age equivalent on level of education and therefore an indirect effect of ABC and CBCL on level of education.

CONCLUSIONS

In the children with the highest level of mild ID, adaptive functioning seems to be the most important factor that directly influences the level of education that a child attends. Autistic and general behaviour problems directly influence the level of adaptive functioning. Especially, autistic problems seem to have such a restrictive effect on the level of adaptive functioning that children do not reach the level of education that would be expected based on IQ. Clinical implications are discussed.

The Psychometric Properties of the Vineland Adaptive Behavior Scales in Children and Adolescents with Mental Retardation

The psychometric properties of the Vineland Adaptive Behavior Scales Survey Form were studied in a total population of children and adolescents with MR, and in the specific levels of functioning (n=826, age 4-18 years). The original division into (sub)domains, as assigned by the authors, was replicated in the total population and in the mild and moderate levels of functioning. In the severe and profound levels of functioning the structure was less well recognized. The reliability of the instrument proved to be good in the total population and the subgroups. The construct validity was high in all groups. The implications of these findings are discussed with respect to the usefulness of the Vineland for the population with MR.

Self-injurious behavior in young boys with fragile X syndrome

In this study, we distributed surveys to 67 families of young boys with fragile X syndrome to determine the prevalence, onset, form, function, location, and correlates of self-injurious behavior. Fifty-five surveys were completed (82%). The mean age of the boys at the time of the survey was 80 months (range = 20-144). Self-injurious behavior (SIB) was reported for 58% of the participants with a mean age of onset of 31 months. The mean number of forms of self-injury was 2 per participant. Biting was the most commonly reported form of self-injury with the fingers and back of the hand disproportionately targeted as the most prevalent self-injury body site. There was no linear increase in risk of SIB with age past 25 months. SIB was reported as most likely to occur following the presentation of difficult task demands or changes in routine. Significant group differences were found between overall ratings of problem behavior for boys with self-injury compared to those without self-injury. Groups did not differ on measures of fragile X mental retardation protein (FMRP), autism status, adaptive behavior, or age first medicated. Results are discussed in terms of future research designed to further elucidate the behavioral phenotype of fragile X syndrome.

Early development in males with Fragile X syndrome: a review of the literature

This article reviews the current bibliographic knowledge on early neurobehavioral development and milestones in Fragile X syndrome (FraX), with emphasis on males affected by the condition. Three broad areas of early development were examined: (1) gross and fine motor, (2) speech and language, and (3) social. The result of the current review indicates very limited information on the developmental milestones in all three areas. The scarce literature on motor development shows that in FraX there is an early developmental delay. Research on speech and language demonstrates pervasive deficits in conversational skills and severe developmental delay, with increasing discrepancy between language level and chronological age in young males with FraX. Finally, deficits in social development in FraX include abnormal gaze, approach and avoidance conflict, and high incidence of autistic spectrum disorders.

Advances in research on the fragile X syndrome

Fragile X syndrome is a neurodevelopmental disorder that results from a single gene mutation on the X chromosome. The purpose of this review is to summarize key advances made in understanding the fragile X premutation gene seen in carriers and the full mutation gene seen in persons with the syndrome. DNA testing has replaced cytogenetic testing as the primary method for identification of fragile X, although the efficacy of protein level screening is being explored. The premutation is associated with no effects, although there is evidence of physical effects-primarily premature menopause and mild outward features of the fragile X syndrome-among premutation carriers. There is much controversy regarding premutation effects on psychological development. The few experimental studies carried out to date do not suggest noticeable or significant effects. One challenge in addressing this controversy is the sometimes ambiguous differentiation between premutation and full mutation genes. There is a well-established yet highly variable phenotype of the full mutation. Research from this decade has helped to address specific aspects of this phenotype, including the early course of its development in males, the influence of home and family environments, the nature of social difficulties and autistic features seen in boys and girls with fragile X, and the potential role of hyperarousal or hyper-reactivity. Studies in these areas, and on the role of FMR protein, will contribute towards ongoing advances in our understanding of fragile X syndrome and its mechanisms. The variability in physical, social, and cognitive features, as described in this review, is one that prohibits clear-cut screening guidelines designed to avoid high rates of both false positives and false negatives. Results from recent studies indicate the need to consider behavioral features in selecting candidates for fragile X screening. MRDD Research Reviews 2000;6:96-106.

Longitudinal assessment of adaptive and maladaptive behaviors in fragile X males: growth, development, and profiles

As young fully mutated fragile X [fra(X)] males age, cognitive levels (IQ scores) and adaptive behavior levels (DQ scores) decline. Given the variable behavioral profiles reported previously, we wondered whether changes in specific attributes of adaptive behavior are related to declines in composite adaptive behavior levels. We also examined maladaptive behavior to determine if changes are related to age. Therefore, we evaluated three areas of adaptive behavior, as well as maladaptive behavior, in 28 fully mutated fra(X) males, ages 4-14 years. To develop a profile of adaptive behavior, we analyzed nine subscale scores from the Vine-land Adaptive Behavior Scale (VABS). To assess maladaptive behavior, we graded part I of the VABS Maladaptive Behavior Scale. Subjects were sorted into three age cohorts, according to their initial test age: younger than 6 years; 6 to 9 years; older than 9 years. Results indicate that, in all age groups, the communications domain is the most severely impacted compared with either the socialization domain or daily living skills and that, in all age groups, the socialization domain is a relative strength compared with either the communications domain or daily living skills. The youngest cohort manifested significant increases in age-equivalent community living skills. Significant differences in age-equivalent scores between cohorts were observed in written language and play skills. Maladaptive behavior scores were available from cross-sectional data only. Twenty males (74%) showed significantly higher maladaptive scores than expected from other children their age. Our data analysis also revealed a moderate and significant negative correlation between maladaptive behavior levels and age (r = -0.54; P < 0.01). Curiously, adaptive and maladaptive behaviors did not correlate with each other.

Autism: the point of view from fragile X studies

The relationship between the fragile X syndrome (FXS) and autism is reviewed. Shortly after the FXS was first described, it was noted that certain behaviors commonly found in afflicted individuals resemble certain features of autism. Research concerning a possible relationship between these conditions is summarized. The outcome of this research indicates that FXS is not a common cause of autism, although the number of individuals with FXS who meet diagnostic criteria for autism is higher than can be accounted for by chance. The major focus of this paper highlights that FXS is a well-defined neurogenetic disease that includes a cognitive behavioral phenotype, and has both a known biological cause and an increasing well-delineated pathogenesis. Autism is a behaviorally defined syndrome whose syndromic boundaries and biological causes are not known. These profound differences complicate comparisons and causal discussions. However, the behavioral neurogenetic information available about FXS suggests certain pathways for future research directed at elucidating the syndrome of autism.

Mental retardation: a review of the past 10 years. Part I

OBJECTIVE

To review the literature over the past decade on mental retardation, particularly as regards its definition, prevalence, major causes, and associated mental disorders.

METHOD

A computerized search was performed for articles published in the past decade, and selected papers were highlighted.

RESULTS

The study of mental retardation has benefited considerably by advances in medicine generally and by developments in molecular neurobiology in particular. Increasing awareness of psychiatric comorbidity in the context of intellectual disability highlights the need for studies of the phenomenology and treatment of mental disorders in this population.

CONCLUSIONS

Although the study of developmental disorders has advanced significantly over the past decade, considerable work remains. Mental retardation is a model for the utility of the biopsychosocial approach in medicine.

Cognitive, behavioral, and neuroanatomical assessment of two unrelated male children expressing FRAXE

Standardized cognitive, behavioral, and neuroanatomical data are presented on 2 unrelated boys with the FRAXE (FMR2) GCC expansion mutation. In the context of normal IQ, both boys had a history of developmental delay, including significant problems with communication, attention, and overactivity. Additionally, one child was diagnosed with autistic disorder. Data from these 2 cases are compared to analogous information from previous reports about individuals with the FRAXE or FRAXA (FMR1) mutation. These comparisons support the idea that FRAXE is associated with nonspecific developmental delay and possibly high-functioning autism.

Longitudinal study of cognitive abilities and adaptive behavior levels in fragile X males: a prospective multicenter analysis

Retrospective longitudinal studies have noted declines in IQ scores in many but not all fra(X) (fragile X) males and females. We report on a prospective investigation of longitudinal changes in cognitive ability (IQ) and adaptive behavior (DQ) in 24 fra(X) males from four test sites. Individuals who were tested ranged in age from 3-15 years. To determine cognitive ability, all males were administered the Stanford-Binet test (4th Edition). To assess adaptive behavior, all males were evaluated using the Vineland Adaptive Behavior Scales. Mean interest interval was 2.3 years. Using identical DNA protocols, all subjects were identified as bearing the fra(X) mutation. Results showed declines in IQ scores in 18/24 (75%) males. Four males showed no change in scores. Declines in DQ scores were noted in 22/24 (92%) of those tested. DQ scores were higher than IQ scores in 20/24 (83%) subjects. From a descriptive cohort analysis, decreases in IQ scores appear to follow a well-defined, negatively decelerating function. Declines in DQ were steeper and more nearly linear. Declining scores are not indicative of regression of intellectual and/or social skills, but of a relative inability to keep pace with their age-normed cohort. We conclude that the fra(X) mutation affects cognitive abilities in a uniform, nonlinear manner comparable to outcomes observed in earlier retrospective studies. Adaptive behavior also declines, but in a more linear fashion.

A controlled study of longitudinal IQ changes in females and males with fragile X syndrome

The aim is this study is to compare the longitudinal changes in IQ scores of females and males with fragile X syndrome and controls and to assess the impact on IQ of molecular variations of the FMR-1 gene in males. Medical records from the child development unit at a university-affiliated children's hospital were retrospectively reviewed. Chart review yielded 35 males with fragile X (19 with a fully methylated full mutation, 9 with a mosaic pattern, and 7 with a partially unmethylated full mutation) 16 females with fragile X and a full mutation, 9 female controls, and 9 male controls who had repeated standardized IQ testing separated by 7 months to 13 years. The differences between the first and last IQ scores from the same IQ test were compared by t tests and subsequently by analysis of variance. Overall, a significant IQ decline was seen in 10/35 (28%) of fragile X males, 0/9 (0%) of control males, 6/16 (36%) of fragile X females, and 1/9 (11%) of control females. The initial t tests and analysis of variance showed a significant difference in IQ (p = 0.02) between fragile X males and control males but did not show a significant difference between males and females with fragile X syndrome or between fragile X and control females. When an analysis of covariance was carried out with the initial IQ as a covariable, a significant difference persisted between fragile X and control males, with a greater IQ decline in fragile X males. There were limitations in using the same IQ test. A comparison among the molecular subgroups of males yielded a significant IQ decline in 3/9 (33%) of mosaic males, 6/19 (32%) of fully methylated full mutation males, and 1/7 (14%) of partially methylated full mutation males. An analysis of covariance using the initial IQ and the intertest interval as covariables demonstrated significant differences between the fragile X molecular subgroups and the controls. Our findings show that a substantial percentage of both male and female fragile X patients and female control patients demonstrated significant IQ decline. There was a significant difference in the IQ change between fragile X and control males. There were no significant differences between fragile X and female controls. There were also significant differences in IQ decline among males with different molecular patterns compared with controls. Males with a mosaic pattern versus control males had the most significant decline of the molecular subtypes. Although the numbers were limited, there was no significant IQ decline in males with less than 50% methylation of the full mutation. This suggests that a small amount of FMR-1 protein production, which is often seen in males with less than 50% methylation, protects against significant IQ decline.

Mosaicism for the FMR1 gene influences adaptive skills development in fragile X-affected males

Fragile X syndrome is one of the most common forms of inherited mental retardation, and the first of a new class of genetic disorders associated with expanded trinucleotide repeats. Previously, we found that about 41% of affected males are mosaic for this mutation in that some of their blood cells have an active fragile X gene and others do not. It has been hypothesized that these mosaic cases should show higher levels of functioning than those who have only the inactive full mutation gene, but previous studies have provided negative or equivocal results. In the present study, the cross-sectional development of communication, self-care, socialization, and motor skills was studied in 46 males with fragile X syndrome under age 20 years as a function of two variables: age and the presence or absence of mosaicism. The rate of adaptive skills development was 2-4 times as great in mosaic cases as in full mutation cases. There was also a trend for cases with autism to be more prevalent in the full-mutation group. These results have implications for prognosis, for the utility of gene or protein replacement therapies for this disorder, and for understanding the association between mental retardation, developmental disorders, and fragile X syndrome.

Trajectories and profiles of adaptive behavior in males with fragile X syndrome: multicenter studies

We conducted two multicenter studies on adaptive trajectories and profiles in males with fragile X syndrome. Study 1 longitudinally assessed 29 males ages 1-20 years using age-equivalent scores from the Vineland Adaptive Behavior Scales. Fragile X boys ages 1-10 years showed significant gains in adaptive skills from first to second testing; males ages 11-20 years were stable in their adaptive development. Study 2 cross-sectionally examined 132 males ages 1-20 years. Significant age-related gains were found in boys ages 1-10, particularly in preschool children. Subjects ages 11-20 showed increased variability and nonsignificant relations between age and adaptive skills. Preliminary findings from 26 young adults with fragile X syndrome ages 21-40 years showed stable age-equivalent adaptive scores during these years. Relative strengths in daily living skills and weaknesses in communication were only evident among older subjects. Significant relations were found between adaptive behavior standard scores and IQ; these two scores also showed age-related declines that likely parallel one another. Findings are related to adaptive features in other genetic syndromes, and to directions for future adaptive behavior research.

Effects of Special Olympics International on social competence in persons with mental retardation

OBJECTIVE

To evaluate the social and emotional goals of Special Olympics International, specifically whether Special Olympics facilitates social competence and self-esteem in persons with mental retardation.

METHOD

Findings were "triangulated" across three studies on the social competence, adaptation, and self-perceptions of 104 athletes from 1993 Team USA (mean age = 22 years; mean IQ = 59). Study 1 related behavior to athletes' length of time in Special Olympics. Study 2 compared Team USA to an appropriately matched group of non-Special Olympians. Study 3 assessed Team USA before and 4 months after their participation in the World Games held in Salzburg, Austria.

RESULTS

Relative to age and IQ, length of time in Special Olympics was the most powerful predictor of social competence. Special Olympics athletes had higher social competence scores and more positive self-perceptions than the comparison group. Team USA's behavioral data remained stable over time, suggesting that high pre-Game scores were not simply a function of parental or athlete pre-Game excitement.

CONCLUSIONS

Based on the most conservative meaning of triangulation, more support was found linking Special Olympics to social competence than to remaining behavioral domains.

The relationships among facial emotion recognition, social skills, and quality of life

Forty-six adults with mild or moderate mental retardation living in a large residential facility were administered the socialization domain of the Vineland Adaptive Behavior Scales, a subjective measure of quality of life, and a facial emotion recognition test. There were significant differences in accuracy of emotion recognition among specific emotions. However, the only significant correlate of facial emotion recognition was IQ. Possible relationships among facial emotion recognition and basic versus more subtle indices of socialization are explored.

Is fragile X syndrome a pervasive developmental disability? Cognitive ability and adaptive behavior in males with the full mutation

In addition to mental retardation (MR), fragile X [fra(X)] syndrome has been associated with various psychopathologies, although it appears that the link is secondary to MR. It has been proposed that individuals with the full mutation be classified as a subcategory of pervasive developmental disorders (PDD). If fra(X) males are to be categorized as PDD, how do they compare with other types of developmental disabilities? We examined 27 fra(X) males aged 3-14 years, from 4 sites in North America. Measures of cognitive abilities were obtained from the Stanford-Binet Fourth Edition (SBFE), while levels of adaptive behavior were evaluated using the Vineland Adaptive Behavior Scales (VABS). Control subjects were sex-, age-, and IQ matched children and adolescents ascertained from the Developmental Evaluation Clinic (DEC) at Kings County Hospital. At the DEC, control subjects were diagnosed as either MR (n = 43) or autistic disorder (AD; n = 22). To compare subjects' adaptive behavior (SQ) with their cognitive abilities (IQ), a ratio of [(SQ/IQ) x 100] was computed. Results graphed as cumulative distribution functions (cdf) revealed that the cdf for AD males, who by definition are socially impaired, was positioned to the left of the cdf for MR controls, as expected. Mean ratio for AD males (70) was lower than for MR males (84). On the other hand, the cdf for fra(X) males was positioned far to the right of either AD or MR controls (mean ratio = 125). Statistical tests showed that SQ of fra(X) males was significantly higher than controls.(ABSTRACT TRUNCATED AT 250 WORDS)