Jennifer M. Schaaf

Executive functions in young males with fragile X syndrome in comparison to mental age-matched controls: baseline findings from a longitudinal study.

The performance of 54 boys with fragile X syndrome (FXS), ages 7 to 13 years, was compared to that of a group of typically developing boys who were matched on mental age (MA) and ethnicity across multiple measures of executive function (EF). Boys with FXS varied in their ability to complete EF measures, with only 25.9% being able to complete a set-shifting task and 94.4% being able to complete a memory for word span task. When compared to the control group, and controlling for MA and maternal education, boys with FXS showed significant deficits in inhibition, working memory, cognitive flexibility/set-shifting, and planning. No group differences were observed in processing speed. Mental age significantly impacted performance on working memory, set-shifting, planning, and processing speed tasks for both groups. In boys with FXS, MA significantly predicted performance on working memory and set-shifting tasks. Our findings suggest that deficits in EF in boys with FXS are not solely attributable to developmental delays but, rather, present as a true array of neurocognitive deficits.

Developmental Differences in the Effects of Repeated Interviews and Interviewer Bias on Young Children's Event Memory and False Reports

The present study investigated developmental differences in the effects of repeated interviews and interviewer bias on childrens memory and suggestibility. Three- and 5-year-olds were singly or repeatedly interviewed about a play event by a highly biased or control interviewer. Children interviewed once by the biased interviewer after a long delay made the most errors. Children interviewed repeatedly, regardless of interviewer bias, were more accurate and less likely to falsely claim that they played with a man. In free recall, among children questioned once after a long delay by the biased interviewer, 5-year-olds were more likely than were 3-year-olds to claim falsely that they played with a man. However, in response to direct questions, 3-year-olds were more easily manipulated into implying that they played with him. Findings suggest that interviewer bias is particularly problematic when childrens memory has weakened. In contrast, repeated interviews that occur a short time after a to-be-remembered event do not necessarily increase childrens errors, even when interviews include misleading questions and interviewer bias. Implications for developmental differences in memory and suggestibility are discussed.

Mapping nonverbal IQ in young boys with fragile X syndrome

This study examines the developmental changes in nonverbal intellectual functioning evident in males with fragile X syndrome (FXS) measured by the Leiter International Performance Scales‐Revised (Leiter‐R). The Leiter‐R provides both IQ scores and associated growth scores which permit the examination of both age‐based IQ scores and overall intellectual growth. Participants were 45 males with full mutation FXS and ranged in age from 4.0 to 13.8 years. Each child was assessed annually using the Leiter‐R as part of a larger longitudinal battery for an average of 3.5 assessments per child and a range of 2–6 assessments, representing a total of 156 assessment occasions. Longitudinal analyzes of Leiter scores consisted primarily of hierarchical linear modeling, with the impact of chronological age, maternal education, fragile X mental retardation 1 protein (FMRP), autistic behaviors also being assessed. Findings revealed a significant linear decline in nonverbal IQ scores, with no effects of maternal education, autistic behaviors, or FMRP on mean level or rate of change in IQ scores over time. The decline slowed significantly around 8 years of age, but scores continued to decline into the 12th year of age. In contrast, a significant linear increase was observed in Leiter‐R growth scores, which was negatively influenced by autistic behaviors. The rate of increase did not change over time, and neither mean level nor rate of increase was influenced by maternal education or FMRP levels. These findings suggest that declines in IQ are the result of steady, but suboptimal intellectual growth, rather than a true deterioration in overall intellectual functioning.

Memory Skills of Boys With Fragile X Syndrome

Multiple aspects of memory were examined in 42 boys with fragile X syndrome and a comparison group of 42 typically developing boys matched on MA. Working memory, incidental memory, and deliberate memory were assessed with a battery that included both free-recall and recognition tasks. Findings indicated that boys with fragile X syndrome performed more poorly than their matches on most measures. The exception was free recall, in which their accuracy was equal to that of the control participants. Results from analyses of a subset of boys with fragile X syndrome who exhibit characteristics of autism and their MA matches, though preliminary, support the conclusion that memory deficits are especially marked in boys who have fragile X syndrome and evidence autistic behaviors.

Working memory subsystems and task complexity in young boys with Fragile X syndrome.

BACKGROUND Working memory problems have been targeted as core deficits in individuals with Fragile X syndrome (FXS); however, there have been few studies that have examined working memory in young boys with FXS, and even fewer studies that have studied the working memory performance of young boys with FXS across different degrees of complexity. The purpose of this study was to investigate the phonological loop and visual-spatial working memory in young boys with FXS, in comparison to mental age-matched typical boys, and to examine the impact of complexity of the working memory tasks on performance. METHODS The performance of young boys (7 to 13-years-old) with FXS (n = 40) was compared with that of mental age and race matched typically developing boys (n = 40) on measures designed to test the phonological loop and the visuospatial sketchpad across low, moderate and high degrees of complexity. Multivariate analyses were used to examine group differences across the specific working memory systems and degrees of complexity. RESULTS Results suggested that boys with FXS showed deficits in phonological loop and visual-spatial working memory tasks when compared with typically developing mental age-matched boys. For the boys with FXS, the phonological loop was significantly lower than the visual-spatial sketchpad; however, there was no significant difference in performance across the low, moderate and high degrees of complexity in the working memory tasks. Reverse tasks from both the phonological loop and visual-spatial sketchpad appeared to be the most challenging for both groups, but particularly for the boys with FXS. CONCLUSIONS These findings implicate a generalised deficit in working memory in young boys with FXS, with a specific disproportionate impairment in the phonological loop. Given the lack of differentiation on the low versus high complexity tasks, simple span tasks may provide an adequate estimate of working memory until greater involvement of the central executive is achieved.

Academic Skills of Boys With Fragile X Syndrome: Profiles and Predictors.

The academic achievement of boys with fragile X syndrome and the relation between several predictive factors and academic performance are reported. Boys with fragile X syndrome displayed significant deficits in all academic skill areas. Relative strengths were observed in general knowledge, reflecting the ability to integrate experiential information. In contrast, relative weaknesses were observed in prewriting skills and visuospatial-processing abilities. The rate of academic growth slowed over time, and the decrease in rate was more pronounced in measures of core academic skills (e.g., prereading and math skills) than in broad-based tasks. Nonverbal IQ and FMR protein expression were not associated with the level or rate of change; however, autistic behavior and maternal education were related to academic achievement scores.

Over a decade of research on children's eyewitness testimony: what have we learned? Where do we go from here?

Scientific understanding of childrens eyewitness memory has advanced colossally over the last 15 years. After more than a decade of intense research, it is possible to reflect on empirical knowledge gained about memory accuracy and interviewing strategies, and to propose directions for future inquiry. In the present article, past studies of the effects of leading questions, repeated interviews, and interview context are reviewed. The contribution of leading questions to allegations of satanic ritual abuse is addressed, as is the contribution of individual-difference factors, such as abuse history, to memory performance. The dilemma of designing an interview for children which simultaneously reduces both the dangers of false reports and the dangers of lack of disclosure is discussed. It is proposed that interviews should not be judged dichotomously as either leading or non-leading, but rather viewed as falling along a ‘leadingness continuum’. To guide future research, a call is made to integrate complex applied and theoretical issues in the study of child witnesses.

Research on fragile X syndrome and autism: Implications for the study of genes, environments, and developmental language disorders

Contents: M.L. Rice, S.F. Warren, Preface. M.L. Rice, S.F. Warren, Introduction. Part I:Phenotypes of Language Impairments Within Clinical Diagnoses. C. Lord, S. Risi, A. Pickles, Trajectory of Language Development in Autistic Spectrum Disorders. H. Tager-Flusberg, Do Autism and Specific Language Impairment Represent Overlapping Language Disorders? J.B. Tomblin, X. Zhang, A. Weiss, H. Catts, S.E. Weismer, Dimensions of Individual Differences in Communication Skills Among Primary Grade Children. L. Abbeduto, M.M. Murphy, Language, Social Cognition, Maladaptive Behavior, and Communication in Down Syndrome and Fragile X Syndrome. A. Zukowski, Investigating Knowledge of Complex Syntax: Insights From Experimental Studies of Williams Syndrome. D.B. Bailey, Jr., J.E. Roberts, S.R. Hooper, D.D. Hatton, P.L. Mirrett, J.E. Roberts, J.M. Schaaf, Research on Fragile X Syndrome and Autism: Implications for the Study of Genes, Environments, and Developmental Language Disorders. Part II:Investigating Language Impairments Across Diagnostic Categories. C.B. Mervis, Cross-Etiology Comparisons of Cognitive and Language Development. S.F. Warren, Intervention as Experiment. M.L. Rice, Growth Models of Developmental Language Disorders. C. Phillips, Linguistics and Linking Problems. Part III:Neural, Genetic, and Behavioral Elements of Inherited Factors. R-A. Muller, Genes, Language Disorders, and Developmental Archaeology: What Role Can Neuroimaging Play? S.D. Smith, Localization and Identification of Genes Affecting Language and Learning. C.A. Morris, Genotype-Phenotype Correlations: Lessons From Williams Syndrome Research. Part IV:Research Action Steps for the Short and Long Term. P. McCardle, J. Cooper, Next Steps in the Study of Genetics and Language Disorders.

Gating Out Misinformation: Can Young Children Follow Instructions to Ignore False Information?

The current study investigated the effects of misinformation on childrens memory reports after practice with the logic-of-opposition instruction at time of test. Four- and 6-year-old children participated in a play event in Session 1. During a two-week delay, parents presented their children with either misinformation or correct information about the play event. Prior to a memory interview in Session 2, some misled children were given a developmentally appropriate logic-of-opposition instruction to not report information provided by their parents. Results indicated that children were misled by the incorrect information, but that the logic-of-opposition instruction aided in the childrens retrieval of the original memory, particularly for the 6-year-olds. Implications of the results for memory malleability and social demand effects in children are discussed.

Issues in Eyewitness Testimony

Publisher Summary This chapter focuses on stress and eyewitness accuracy, eyewitness identification, interviewing techniques, and childrens eyewitness memory. The chapter presents a brief overview of basic memory processes. The accuracy of eyewitness testimony is determined by a complex interaction of perception, memory, and socio-emotional factors. Memory is typically divided into three stages: encoding, retention, and retrieval. In situations relevant to eyewitness testimony, encoding happens when a victim experiences or a bystander witnesses a criminal act. Eyewitness accuracy is constrained first by the conditions under which information was encoded. Many variables influence the probability that an event was properly encoded, such as observation conditions and exposure duration. There exists a consensus that, given the reconstructive nature of memory, stored information may undergo processes of change during the retention phase. Important for eyewitness testimony is the notion of retroactive interference. Because of the nature of criminal acts, victims and bystanders often experience elevated levels of stress during a crime. Eyewitness identification, one of the most direct kinds of evidence of guilt, links the suspect and the crime specifically.