Receptive vocabulary analysis in Down syndrome

Non-word repetition and vocabulary in Kuwaiti Arabic-speaking children with down syndrome and typically developing children

OVERVIEW

Non-word repetition (NWR) is one of the most effective predictors of language impairments in children as it has been found to correlate with various language measures and the association between NWR and vocabulary is well documented in typically developing (TD) studies. However, there is a dire need for investigations of language skills in Kuwaiti Arabic individuals with Down Syndrome, and this study set out to fill a gap in this field.

METHOD

In this paper, we compare the vocabulary and NWR skills of a group of 48 individuals with DS aged 6-20 years to a group of 44 TD children aged 3-10 years matched on nonverbal IQ. Furthermore, we investigate the correlations among these language measures in the two groups and examine whether NWR can predict receptive and expressive vocabulary in these two groups.

RESULT

Results found DS participants performed significantly less than the TD group on the three language measures (receptive vocabulary t(90)= -3.17, p < .01, expressive vocabulary t(90)= -3.27, p < .01, and NWR t(90)= -8.32, p < .01). Moreover, there were strong correlations between NWR and vocabulary (receptive and expressive) in the TD group but not the DS group.

CONCLUSION

Findings supported the working memory model and the phonological processing account for the TD group. On the other hand, the poor association between NWR and vocabulary in the DS group might be due to poor phonological discrimination difficulties and speech discrimination difficulties.

Category-Based Effect on False Memory of People with Down Syndrome

Background: People with Down syndrome (DS) are deficient in verbal memory but relatively preserved in visuospatial perception. Verbal memories are related to semantic knowledge. Receptive ability is better than expressive ability in people with DS but still seriously lags behind their age-matched controls. This lag may result in the weak semantic integration of people with DS. Aims: This study aimed to examine the ability of semantic integration of people with DS by using false-memory tasks. Possible differences in the number of false memories induced by nouns and verbs were of focus. Methods and Procedures: Two phases were involved in the false-memory task. In the study phase, ten-word lists with semantically related associates were presented. In the recognition phase, judgments were to be made about whether the words presented had been heard before. Three types of words were tested: previously presented associates, semantically related lures, and semantically unrelated new words. Outcomes and Results: People with DS overall showed the lowest accuracy among groups in response to tested word types. In the processing of lures, people with DS were worse in recognition than MA controls. In processing unrelated words, people with DS responded least accurately to all types of words compared to control groups. In the processing of associates, people with DS showed similar recognition rates as the MA controls but were less accurate than the CA controls. No difference was observed between nouns and verbs in recognizing word types among groups, though faster responses to nouns than to verbs emerged in college students. Further analyses on topic-wised comparisons of errors across syntactic categories revealed differences in specific concepts among groups, suggesting people with DS were atypical in semantic organization. Conclusions and Implications: People with DS showed mixed patterns in semantic integration by false-memory tasks with delay to associates and deviance to lures together with unrelated words. People with DS showed distinct patterns in processing nouns and verbs while conducting topic-wise comparisons, suggesting that they formed false memories differently based on distinct syntactic categories. We concluded that people with DS develop a deviant semantic structure, hence showing problems in language and social cognition. Category-based rehabilitation is suggested to be implemented for people with DS to improve their semantic knowledge through lexical connections.

Strategies for Teaching Verbs to Children with and without Language Impairment

The aim of this feasibility study was to extend the current evidence base on intransitive verb learning by evaluating and comparing three strategies (syntactic cues, semantic cues, combined cues) for teaching novel verbs to expand the vocabularies of children with and without language impairment. Twenty-three children with typical development, seven children with developmental language disorder, and eight children with Down syndrome participated in Studies 1, 2, and 3, respectively. They were taught novel, intransitive verbs using syntactic, semantic, and combined cues and then asked to receptively identify and expressively label the novel verbs. Across all conditions, participants learned novel verbs receptively with large effect sizes and participants with typical development and Down syndrome also learned the verbs expressively with large effect sizes. There were no significant differences between conditions. This study extends word-learning research by evaluating not only receptive but also expressive intransitive verb learning to expand one's vocabulary. The results provide positive evidence for three effective strategies for teaching intransitive verbs to children with and without language impairment.

The Effects of Syntactic, Semantic, and Pragmatic Prominence on Pronoun Interpretation in Adults With Intellectual and Developmental Disabilities

PURPOSE

Pronouns are referentially ambiguous: For example, "she" could refer to any female. Nonetheless, errors in pronoun interpretation rarely occur for adults with typical development (TD) due to several strategies implicitly shared between the talker and listener. The purpose of this study was to test the impacts of syntactic, semantic, and prosodic prominence on pronoun interpretation for adults with intellectual and developmental disabilities (IDD) and TD.

METHOD

Adults with IDD (n = 28) and TD (n = 27) listened to ministories involving a pronoun with two potential antecedents that varied in syntactic, semantic, and pragmatic prominence. Subject/first-mentioned antecedents are more syntactically prominent than object antecedents. Semantic prominence was manipulated via verb transitivity: Subjects are more semantically prominent when the verb is highly transitive (e.g., "hit" vs. "see," a low-transitivity verb for which the subject is merely experiencing the action). Pragmatic prominence was manipulated by placing prosodic focus on one of the two potential antecedents. Eye gaze to images representing the potential antecedents was tracked as a measure of online processing. Responses to a follow-up pronoun interpretation question were also recorded.

RESULTS

Adults with TD used syntactic, semantic, and-in early processing-pragmatic prominence when interpreting ambiguous pronouns. Adults with IDD were sensitive to syntactic prominence but to a significantly lesser extent than their peers with TD.

CONCLUSIONS

Pronouns are an integral part of everyday conversation, and when the conversational partners do not share common strategies to link ambiguous pronouns with their antecedents, misunderstandings will occur. Results show that adults with IDD only weakly share pronoun interpretation strategies with adults with TD, suggesting that pronouns may be an important focus for intervention for this population.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23875809.

Searching for Best Predictors of Paralinguistic Comprehension and Production of Emotions in Communication in Adults With Moderate Intellectual Disability

Paralinguistic comprehension and production of emotions in communication include the skills of recognizing and interpreting emotional states with the help of facial expressions, prosody and intonation. In the relevant scientific literature, the skills of paralinguistic comprehension and production of emotions in communication are related primarily to receptive language abilities, although some authors found also their correlations with intellectual abilities and acoustic features of the voice. Therefore, the aim of this study was to investigate which of the mentioned variables (receptive language ability, acoustic features of voice, intellectual ability, social-demographic), presents the most relevant predictor of paralinguistic comprehension and paralinguistic production of emotions in communication in adults with moderate intellectual disabilities (MID). The sample included 41 adults with MID, 20–49 years of age (M = 34.34, SD = 7.809), 29 of whom had MID of unknown etiology, while 12 had Down syndrome. All participants are native speakers of Serbian. Two subscales from The Assessment Battery for Communication – Paralinguistic comprehension of emotions in communication and Paralinguistic production of emotions in communication, were used to assess the examinees from the aspect of paralinguistic comprehension and production skills. For the graduation of examinees from the aspect of assumed predictor variables, the following instruments were used: Peabody Picture Vocabulary Test was used to assess receptive language abilities, Computerized Speech Lab (“Kay Elemetrics” Corp., model 4300) was used to assess acoustic features of voice, and Raven’s Progressive Matrices were used to assess intellectual ability. Hierarchical regression analysis was applied to investigate to which extent the proposed variables present an actual predictor variables for paralinguistic comprehension and production of emotions in communication as dependent variables. The results of this analysis showed that only receptive language skills had statistically significant predictive value for paralinguistic comprehension of emotions (β = 0.468, t = 2.236, p < 0.05), while the factor related to voice frequency and interruptions, form the domain of acoustic voice characteristics, displays predictive value for paralinguistic production of emotions (β = 0.280, t = 2.076, p < 0.05). Consequently, this study, in the adult population with MID, evidenced a greater importance of voice and language in relation to intellectual abilities in understanding and producing emotions.

Emotional Lexicon in Down Syndrome

We studied comprehension of emotion versus concrete/abstract words in Down syndrome (DS). Study 1 compared 26 participants with DS and 26 typically developing (TD) children matched on verbal ability. Results showed no difference between groups. Study 2 assessed whether chronological age (CA) and (non)verbal abilities predicted developmental trajectories of comprehension in 36 children with DS and 143 TD children. For the latter, these variables predicted comprehension of all three word types. For the former, receptive vocabulary predicted comprehension of all word types, but CA and nonverbal reasoning only predicted comprehension of concrete words. This suggests that people with DS have no specific emotional lexicon deficit. Supporting their general lexical development would help them access abstract and emotional meanings.

Associations of Motor Performance and Executive Functions: Comparing Children with Down Syndrome to Chronological and Mental Age-Matched Controls

Background. Children with Down syndrome (DS) exhibit lower motor and cognitive performance than typically developing children (TD). Although there is a relationship between these two developmental domains, only a few studies have addressed this association in children with DS compared to groups of the same chronological age (CA) or mental age (MA) within one study. This study aimed to fill this research gap. Method and Procedures. The Movement Assessment Battery for Children-2 and the Trail-Making Test was used to assess motor and cognitive performances in 12 children (M = 10.5 ± 10.08) with DS, 12 CA-matched, and 12 MA-matched controls. Results. There are significant group differences in the motor dimension (total test score; p < 0.001, η²_p = 0.734), for processing speed (p < 0.001, η²_p = 0.396), and cognitive flexibility (p < 0.001, η²_p = 0.498). Between TD-CA and both other groups, the differences in the magnitude of correlations for the motor dimension balance are also significant (compared to DS: z = −2.489; p = 0.006, and to TD-MA: z = −3.12; p < 0.001). Conclusions. Our results suggest that the relationships depend on the studied cognitive and motor skills. It seems crucial to select a wide range of tasks for both domains that are as isolated as possible for future studies, to better understand the relationships between cognitive and motor skills in children with DS.

On the Developmental Trajectories of Relational Concepts Among Children and Adolescents With Intellectual Disability of Undifferentiated Etiology

The aim of this study was to examine the developmental trajectories of comprehension of relational concepts among 557 participants with intellectual disability (ID) of undifferentiated etiology (M age  =  12.20 years, SD  =  3.18) and 557 typically developing (TD) participants (M age  =  4.57 years, SD  =  0.80). Logistic regression analyses, with nonverbal cognitive level entered first in the equations, showed only negligible differences with regard to the discriminative power of each of the 72 concepts used as outcome variables, and moderate differences in difficulty for only three items. A moderate mixed effect (i.e., combining a group difference in difficulty and discriminative power) was observed for a fourth item. It is concluded that the developmental trajectories of relational concepts are similar for participants with or without ID. The implications and limitations of the study are discussed.

Executive function in Down syndrome: A meta-analysis

BACKGROUND

Executive function (EF) refers to a set of cognitive processes involved in goal-oriented behavior-especially inhibition, attention shifting, and working memory. EF has been identified as a probable area of difficulty in Down syndrome (DS), but the exact nature of the difficulty has not been well-established.

AIMS

The meta-analysis sought to confirm or disconfirm EF as an area of difficulty in DS and elucidate an EF profile.

METHODS AND PROCEDURES

A random-effects meta-analysis was conducted on 57 studies that compared a group with DS to a typically developing (TD) mental age matched group on one or more executive function tasks. Heterogeneity was examined and moderators analyzed.

OUTCOMES AND RESULTS

The overall mean weighted effect size was large (d = -0.87), indicating poorer EF in groups with DS vs TD groups. Heterogeneity was significant, and moderator analysis revealed an EF profile with a very large effect for verbal WM/STM, a large effect for shifting, and moderate effects for inhibition and nonverbal WM/STM. Skewness analysis suggested that mean effect sizes might have been dampened, especially for WM/STM and shifting.

CONCLUSIONS AND IMPLICATIONS

Individuals with DS display a pronounced difficulty in EFs; implications for interventions and future research are discussed.

Neuropsychological profile of adults with Down syndrome and moderate intellectual disability

BACKGROUND

The neuropsychological profile of individuals with Down syndrome (DS) has been described as being characterized by dissociations between verbal and visual abilities, as well as between verbal comprehension and production abilities (higher visual than verbal abilities and higher verbal comprehension than verbal production abilities). However, the studies that reached these conclusions based these conclusions mainly on inter-group differences in children but not on intra-group differences.

AIMS

The study explores dissociations in adults with DS, taking inter-group and intra-group differences into account.

METHOD AND PROCEDURES

The sample was composed of 40 adults with DS and 38 adults with moderate intellectual disability (ID) but without DS, matched for chronological age, sex, and intellectual level.

OUTCOMES AND RESULTS

The participants with DS, unlike the other group, exhibited similar performance in their verbal and visual abilities, as well as in their verbal comprehension and production abilities (intra-group differences). In addition, they showed worse performance in verbal general measures and verbal comprehension abilities but similar performance in visual general measures and verbal production abilities (inter-group differences) compared with those without DS with similar intellectual levels on standardized measures.

CONCLUSIONS AND IMPLICATIONS

The observed intra-group differences highlight that a lack of dissociation between verbal and visual abilities, as well as between verbal comprehension and production abilities, seems to be a specific feature of adults with DS.

Exploring motor-cognitive interference in children with Down syndrome using the Trail-Walking-Test

BACKGROUND AND AIMS

The dual-task (DT) paradigm is an ecologically valid approach to assess cognitive function in relation with motor demands, particularly for children with Down syndrome (DS). This study aimed to determine DT performance for a complex Change-of-Direction (CoD_W) walking task in children with DS.

METHODS

The sample included 12 children with DS (10.2 ± 1.19 years), 12 typically developing (TD) children matched for chronological (TD-CA: 10.2 ± 1.19 years) and 12 TD children matched for mental age (TD-MA: 5.50 ± 1.24 years). We examined DT performance with the Trail-Walking-Test (TWT): participants (1) walked along a fixed pathway, following a prescribed path, delineated by target markers of (2) increasing sequential numbers, and (3) increasing sequential numbers and letters. Motor and cognitive dual-task costs (DTC) were calculated.

RESULTS

For the TWT, an ANOVA with repeated measures revealed significant differences between DS and the CA, but not the MA group. Overall, there were significant decreases in speed with increasing cognitive demands. In addition, all children produced higher cognitive compared to motor DTC, which were more pronounced in the cognitively more challenging condition.

CONCLUSION

The assessment of motor and cognitive performance in a DT paradigm provided insight in how motor and/or cognitive impairment constrains the ability of children to successfully perform activities in a complex and dynamical environment.

Systematic Review of Recent Pediatric Down Syndrome Neuropsychology Literature: Considerations for Regression Assessment and Monitoring

OBJECTIVES

To conduct a systematic review of recent pediatric Down syndrome (DS) neuropsychology research that may be useful to clinicians and researchers examining regression in this population.

METHODS

We reviewed original peer-reviewed articles published between 2013 and 2018 studying neuropsychological profiles in DS.

RESULTS

Thirty-one articles (of 1231 included in the original search) passed all inclusion criteria, were evaluated for bias, and were included in the analysis.

CONCLUSION

Findings argued against a single "DS profile" and revealed multiple within-group differences as well as expected and unexpected differences relative to typically developing children and children with other intellectual and developmental disabilities. Areas identified as most germane to regression monitoring included working memory, inhibition, letter and word identification, navigational route learning, motor skills (when strong at baseline), single word receptive/expressive vocabulary, and adaptive function.

Does the Development of Syntax Comprehension Show a Premature Asymptote Among Persons With Down Syndrome? A Cross-Sectional Analysis

Uncertainty persists regarding the post-childhood trajectory of syntactic acquisition of persons with Down syndrome (DS). In some studies, asymptote is reached in the early teens, whereas others find syntax continuing to develop at least into early adulthood. This study addressed the issue using a cross-sectional approach. Receptive syntax and vocabulary were tested in 62 children, adolescents and young adults with DS matched on chronological age and cognitive level with 62 participants with intellectual disability (ID) of undifferentiated etiology. On both tests there were significant effects of chronological age and diagnosis, but the chronological age × diagnosis interactions were nonsignificant. We concluded that comprehension of vocabulary and syntax does not asymptote prematurely in individuals with DS relative to those with other forms of ID.

Verb production by individuals with Down syndrome during narration

BACKGROUND

Despite research identifying verb knowledge as a strong predictor of later syntactic skills in typical development, virtually no research has examined verb development in Down syndrome.

AIMS

The purpose of this study was to examine verb production (density, diversity, and type-token ratios) by individuals with Down syndrome in the context of story generation relative to two comparison groups - nonverbal cognitive ability level matches with typical development and chronological age matches with mixed-etiology intellectual disability.

METHODS AND PROCEDURES

Thirty-five participants with Down syndrome (11-21 years), 27 participants with intellectual disability (13-20 years), and 29 participants with typical development (4-6 years) completed a narrative story generation task. Transcripts were coded and analyzed for verb production.

OUTCOMES AND RESULTS

Examining overall verb production, participants with Down syndrome produced narratives with less verb density than participants with typical development and had smaller verb type-token ratios than participants with intellectual disability. Upon examining lexical verb production, participants with Down syndrome produced narratives with less lexical verb density than participants with typical development.

CONCLUSIONS AND IMPLICATIONS

The results indicate that individuals with Down syndrome have a developmentally appropriate diversity of verbs in their lexicon but are not using verbs as frequently as comparison groups.

Receptive Language Skills in Slovak-Speaking Children With Intellectual Disability: Understanding Words, Sentences, and Stories

PURPOSE

The study aims to describe receptive language skills in children with intellectual disability (ID) and to contribute to the debate on deviant versus delayed language development. This is the 1st study of receptive skills in children with ID who speak a Slavic language, providing insight into how language development is affected by disability and also language typology.

METHOD

Twenty-eight Slovak-speaking children participated in the study (14 children with ID and 14 typically developing [TD] children matched on nonverbal reasoning abilities). The children were assessed by receptive language tasks targeting words, sentences, and stories, and the groups were compared quantitatively and qualitatively.

RESULTS

The groups showed similar language profiles, with a better understanding of words, followed by sentences, with the poorest comprehension for stories. Nouns were comprehended better than verbs; sentence constructions also showed a qualitatively similar picture, although some dissimilarities emerged. Verb comprehension was strongly related to sentence comprehension in both groups and related to story comprehension in the TD group only.

CONCLUSION

The findings appear to support the view that receptive language skills follow the same developmental route in children with ID as seen in younger TD children, suggesting that language development is a robust process and does not seem to be differentially affected by ID even when delayed.

Joint attention in Down syndrome: A meta-analysis

BACKGROUND

Some studies have indicated that joint attention may be a relative strength in Down syndrome (DS), but other studies have not.

AIM

To conduct a meta-analysis of joint attention in DS to more conclusively determine if this is a relative strength or weakness when compared to children with typical development (TD), developmental disabilities (DD), and autism spectrum disorder (ASD).

METHODS AND PROCEDURES

Journal articles published before September 13, 2016, were identified by using the search terms "Down syndrome" and "joint attention" or "coordinating attention". Identified studies were reviewed and coded for inclusion criteria, descriptive information, and outcome variables.

OUTCOMES AND RESULTS

Eleven studies (553 participants) met inclusion criteria. Children with DS showed similar joint attention as TD children and higher joint attention than children with DD and ASD. Meta-regression revealed a significant association between age and joint attention effect sizes in the DS vs. TD contrast.

CONCLUSIONS AND IMPLICATIONS

Joint attention appears to not be a weakness for children with DS, but may be commensurate with developmental level. Joint attention may be a relative strength in comparison to other skills associated with the DS behavioral phenotype. Early interventions for children with DS may benefit from leveraging joint attention skills.

Growth and Decline in Language and Phonological Memory Over Two Years Among Adolescents With Down Syndrome

Forty-two adolescents with Down syndrome (DS) ages 10 to 21 years completed a battery of language and phonological memory measures twice, 2 years apart. Individual differences were highly stable across two years. Receptive vocabulary scores improved, there was no change in receptive or expressive grammar scores, and nonword repetition scores declined. Digit memory and expressive vocabulary scores improved among younger adolescents, but generally held steady among older adolescents. These patterns may reveal key points in development at which interventions may be best applied. Further research is needed to understand specific processes in tasks that appear to be slowing or declining during adolescence. They may be important for understanding early aging and dementia in DS.

Memory profiles in Down syndrome across development: a review of memory abilities through the lifespan

Down syndrome (DS) is associated with a variety of cognitive impairments, notably memory impairments. Due to the high prevalence rates of early-onset dementia associated with DS, it is imperative to understand the comprehensive development of memory impairments beginning in childhood and into adulthood, as this may help researchers identify precursors of dementia at earlier stages of development and pinpoint targets for memory intervention. The current paper provides a systematic, developmentally focused review of the nature of memory difficulties in DS across the lifespan. Specifically, this review summarizes what is known about long-term, short-term, and working memory abilities (distinguishing between verbal and nonverbal modalities) in DS, compared to both mental age-matched typically developing peers and individuals with other forms of intellectual disability (ID) at three developmental stages (i.e., preschool, adolescence, and adulthood). Additionally, this review examines the degree of impairment reported relative to typically developing mental age-matched peers in the existing literature by examining effect size data across memory domains as a function of age. With few exceptions, memory abilities were impaired across the lifespan compared to mental age-matched typically developing peers. Relative to other groups with ID, research findings are mixed. Our review of the literature identified a scarcity of memory studies in early childhood, particularly for STM and WM. In adulthood, research was limited in the LTM and WM domains and very little research has compared memory abilities in older adults with DS to those with typical development. Looking to the future, longitudinal studies could provide a better understanding of the developmental trajectory of memory abilities in DS, and the possible associations between memory abilities and real-world functioning. This research could ultimately inform interventions to improve independence and overall quality of life for those with DS and their families.

Emotion Recognition in Adolescents with Down Syndrome: A Nonverbal Approach

Several studies have reported that persons with Down syndrome (DS) have difficulties recognizing emotions; however, there is insufficient research to prove that a deficit of emotional knowledge exists in DS. The aim of this study was to evaluate the recognition of emotional facial expressions without making use of emotional vocabulary, given the language problems known to be associated with this syndrome. The ability to recognize six emotions was assessed in 24 adolescents with DS. Their performance was compared to that of 24 typically developing children with the same nonverbal-developmental age, as assessed by Raven’s Progressive Matrices. Analysis of the results revealed no global difference; only marginal differences in the recognition of different emotions appeared. Study of the developmental trajectories revealed a developmental difference: the nonverbal reasoning level assessed by Raven’s matrices did not predict success on the experimental tasks in the DS group, contrary to the typically developing group. These results do not corroborate the hypothesis that there is an emotional knowledge deficit in DS and emphasize the importance of using dynamic, strictly nonverbal tasks in populations with language disorders.

Language comprehension in children, adolescents, and adults with Down syndrome

BACKGROUND

There is conflicting evidence as to whether receptive language abilities of individuals with Down syndrome (DS) continue to improve into adulthood, reach a plateau in late adolescence, or even start to decline.

AIM

The study aims to shed light on the question whether receptive syntactic skills change from childhood/adolescence to adulthood and provides a detailed qualitative analysis of the receptive abilities of adults with DS.

METHODS

58 individuals with DS participated in the study: 31 children/adolescents (aged: 4;6-19;0 years) and 27 adults (aged: 20;8-40;3 years). They completed measures of grammar comprehension, nonverbal cognition, and phonological working memory.

RESULTS

There was no significant correlation between comprehension performance and chronological age in the overall sample. Separate correlational analyses for the subgroups of children/adolescents and adults yielded a significant positive result for the former subgroup but not for the latter. We also found significant positive correlations between grammar comprehension scores and nonverbal mental age as well as measures of phonological working memory. Qualitative analyses showed various limitations in the receptive syntactic abilities of adults with DS. Difficulties increase with sentence length and grammatical complexity, but are also apparent in simple sentences.

CONCLUSION

The results suggest that syntactic comprehension abilities of individuals with DS continue to improve through childhood and adolescence and that thereafter a plateau is reached and maintained. Language comprehension in adults with DS is impaired for a variety of grammatical structures and receptive performance seems to be related to nonverbal cognitive abilities, phonological working memory, and grammatical complexity.

The NIH Toolbox Cognitive Battery for intellectual disabilities: three preliminary studies and future directions

BACKGROUND

Recent advances in understanding molecular and synaptic mechanisms of intellectual disabilities (ID) in fragile X syndrome (FXS) and Down syndrome (DS) through animal models have led to targeted controlled trials with pharmacological agents designed to normalize these underlying mechanisms and improve clinical outcomes. However, several human clinical trials have failed to demonstrate efficacy of these targeted treatments to improve surrogate behavioral endpoints. Because the ultimate index of disease modification in these disorders is amelioration of ID, the validation of cognitive measures for tracking treatment response is essential. Here, we present preliminary research to validate the National Institutes of Health Toolbox Cognitive Battery (NIH-TCB) for ID.

METHODS

We completed three pilot studies of patients with FXS (total n = 63; mean age 19.3 ± 8.3 years, mean mental age 5.3 ± 1.6 years), DS (n = 47; mean age 16.1 ± 6.2, mean mental age 5.4 ± 2.0), and idiopathic ID (IID; n = 16; mean age 16.1 ± 5.0, mean mental age 6.6 ± 2.3) measuring processing speed, executive function, episodic memory, word/letter reading, receptive vocabulary, and working memory using the web-based NIH-TB-CB, addressing feasibility, test-retest reliability, construct validity, ecological validity, and syndrome differences and profiles.

RESULTS

Feasibility was good to excellent (≥80 % of participants with valid scores) for above mental age 4 years for all tests except list sorting (working memory). Test-retest stability was good to excellent, and convergent validity was similar to or better than results obtained from typically developing children in the normal sample for executive function and language measures. Examination of ecological validity revealed moderate to very strong correlations between the NIH-TCB composite and adaptive behavior and full-scale IQ measures. Syndrome/group comparisons demonstrated significant deficits for the FXS and DS groups relative to IID on attention and inhibitory control, a significant reading weakness for FXS, and a receptive vocabulary weakness for DS.

CONCLUSIONS

The NIH-TCB has potential for assessing important dimensions of cognition in persons with ID, and several tests may be useful for tracking response to intervention. However, more extensive psychometric studies, evaluation of the NIH-TCB's sensitivity to change, both developmentally and in the context of treatment, and perhaps establishing links to brain function in these populations, are required to determine the true utility of the battery as a set of outcome measures.