Nonverbal Mental Age Research Articles

Executive function abilities in Mexican people with Down syndrome during the COVID-19 pandemic

ABSTRACT Background The aim was to explore the executive function profile of a group of Mexican people with Down syndrome (DS) aged 12–30 years during the COVID-19 pandemic. Aim To analyse the relationships between mental, chronological age and eight domains of executive function. Method Participants were 42 people with DS with a chronological age (CA) of 12–30 years and a mean nonverbal mental age (MA) of 7 years. MA was evaluated with Raven’s Progressive Matrices test and executive function with the Behaviour Rating Inventory of Executive Function (BRIEF-2); both were administered online. Results The Monitor, Emotional Control, Initiative, and Organisation of Materials scales showed strengths, while Working Memory, Plan/Organise, Shift, and Inhibit scales showed weaknesses. CA correlated negatively with seven of the eight executive domains. Chronologically older participants showed less impairment in skills such as inhibition, emotional control, working memory, and monitoring. Nonverbal MA correlated negatively with two domains: emotional control and monitoring. Conclusion Participants’ executive profile during the COVID-19 pandemic was consistent with that reported in studies prior to the pandemic.

Vocabulary and Syntax Reception in Children with Down Syndrome

Introduction: Intellectual disability and specific cognition in down syndrome (DS) affect language development and processing. We assessed vocabulary and syntax reception among children with DS with typically developed (TD) Persian-speaking Iranian children. We also investigated the association between vocabulary and syntax reception in children with DS.
 Materials and Methods: Using the Stanford–Binet intelligence scales test, 18 TD children (4-6 years old) and 18 DS children were matched based on non-verbal mental age. Vocabulary reception was assessed using the receptive picture vocabulary test (RPVT) and syntax reception by the Persian syntax comprehension test.
 Results: Mean total vocabulary reception was lower in children with DS (P<0.001). Syntax reception was also impaired in children with DS compared to the normal values of the test. Among children with DS, vocabulary reception was positively correlated with syntax reception. Every unit increase in total vocabulary reception score was associated with 0.08 (95% confidence interval, CI: 0.04-0.12) improvement in syntax score in children with DS.
 Conclusion: Vocabulary and syntax reception in DS children, especially complex syntax structures, was impaired. The observed association between vocabulary and syntax reception shows that vocabulary reception improvement might result in progressing syntax reception in children with DS.

Predictors of Picture Exchange Communication System (PECS) outcomes.

Although the Picture Exchange Communication System (PECS) has been demonstrated to be an effective intervention to teach people diagnosed with autism spectrum disorder a functional communication system, the research indicates variability in PECS outcomes across people and studies. Therefore, the purpose of the current study was to explore child characteristics and treatment variables that may explain the variation in, and potentially predict, PECS outcomes. A total of 22 children and youth diagnosed with autism or a related developmental disorder, all of whom scored substantially below average on standardized measures of cognitive and adaptive abilities, participated in a PECS intervention. Participants who achieved high phases of PECS (≥PECS phase IIIb) differed significantly from those who mastered lower PECS phases (≤PECS phase IIIa) in terms of overall, verbal, and nonverbal mental age, matching abilities, and adaptive behavior level. Stimulus generalization was also associated with significant variation in PECS outcome. PECS outcomes could be predicted with good accuracy using a combination of these child characteristics and treatment variables. The findings from the current study suggest that children with relatively higher cognitive and adaptive skill levels are more likely to achieve higher phases of PECS; further, approaches to generalization training also play a role. Factors such as autism symptom severity and parental ratings of maladaptive behavior were not associated with significant differences in PECS outcomes. However, more research is needed. Gaining a better understanding of predictors of PECS outcomes is important to inform intervention, provide more accurate outcome expectations for families, and guide PECS teaching procedures. Although participants were more likely to achieve higher phases of PECS if they had a higher mental age, adaptive skill level, and matching skills, the average scores for these measures were well below those expected for same age peers. These results indicate that PECS is appropriate for use with children with clinically significant deficits in cognitive and/or adaptive abilities. Further, results suggest that even children who demonstrate more severe symptoms of autism and exhibit more challenging behavior can achieve higher phases of PECS.

Working memory in pre-school children with autism spectrum disorder: An eye-tracking study.

Working memory (WM) was examined in pre-school children with Autism spectrum disorder (ASD) and children with typical development using eye-tracking technology. The children were presented with a digital A-not-B task (with a short and a long waiting condition) where they passively viewed animations of a moving train. Moreover, the current study investigated the relationship between non-verbal mental age (NVMA) and the performance on the task. No group differences were found in the average looking durations between the ASD and typically developing (TD) groups on either the short or long waiting conditions. Although the NVMA of the ASD group was lower than that of the TD group there were no correlations between NVMA and task performance in either group. The results suggest that WM in young children with ASD might not be different from that of TD children. However, the results might be due to ceiling effects of the task and thus needs to be further investigated.

Visual filtering in time and space among persons with Down syndrome.

Individuals with Down syndrome (DS) appear to perform at a level that is commensurate with developmental expectations on simple tasks of selective attention. In this study, we examine how their selective attention is impacted by target changes that unfold over both time and space. This increased complexity reflects an attempt at greater ecological validity in an experimental task, as a steppingstone for better understanding attention among persons with DS in real-world environments. A modified flanker task was used to assess visual temporal and spatial filtering among persons with DS (n=14) and typically developing individuals (n=14) matched on non-verbal mental age (mental age=8.5years). Experimental conditions included varying the stimulus onset asynchronies between the onset of the target and flankers, the distances between the target and flankers, and the similarity of the target and flankers. Both the participants with DS and the typically developing participants showed slower reaction times and lower accuracy rates when the flankers appeared closer in time and/or space to the target. No group differences were found on a broad level, but the findings suggest that dynamic stimuli may be processed differently by those with DS. Implications of the findings are discussed in relation to the developmental approach to intellectual disability originally articulated by Ed Zigler.

Bias in measurement of autism symptoms by spoken language level and non-verbal mental age in minimally verbal children with neurodevelopmental disorders.

Increasing numbers of children with known genetic conditions and/or intellectual disability are referred for evaluation of autism spectrum disorder (ASD), highlighting the need to refine autism symptom measures to facilitate differential diagnoses in children with cognitive and language impairments. Previous studies have reported decreased specificity of ASD screening and diagnostic measures in children with intellectual disability. However, little is known about how cognitive and language abilities impact the measurement of specific ASD symptoms in this group. We aggregated a large sample of young children (N = 1196; aged 31–119 months) to examine measurement invariance of ASD symptoms among minimally verbal children within the context of the Autism Diagnostic Observation Schedule (ADOS) Module 1. Using confirmatory factor analysis (CFA) and moderated non-linear factor analysis (MNLFA), we examined how discrete behaviors were differentially associated with the latent symptom domains of social communication impairments (SCI) and restricted and repetitive behaviors (RRB) across spoken language levels and non-verbal mental age groupings. While the two-factor structure of SCI and RRB held consistently across language and cognitive levels, only partial invariance was observed for both ASD symptom domains of SCI and RRB. Specifically, four out of the 15 SCI items and one out of the three RRB items examined showed differential item functioning between children with “Few to No Words” and those with “Some Words”; and one SCI item and one RRB item showed differential item functioning across non-verbal mental age groups. Moreover, even after adjusting for the differential item functioning to reduce measurement bias across groups, there were still differences in ASD symptom domain scores across spoken language levels. These findings further underscore the influence of spoken language level on measurement of ASD symptoms and the importance of measuring ASD symptoms within refined spoken language levels, even among those with minimal verbal abilities.

Cardiac Startle Response and Clinical Outcomes in Preschool Children With Fragile X Syndrome and Autism Spectrum Disorder.

Objective: Poor physiological regulation in response to threat is linked to multiple negative developmental outcomes including anxiety, which is highly prevalent and impairing in young children with neurodevelopmental disabilities like fragile X syndrome (FXS) and autism spectrum disorder (ASD). The present study contrasted cardiac startle response in pre-school-aged children with FXS, with and without ASD, to children with non-syndromic ASD (nsASD) and neurotypical controls (NT). The relationship of cardiac startle to non-verbal mental age (NVMA), ASD severity, and parent-reported anxiety was also examined.Method: Four age-matched groups of pre-school children participated including those with FXS without ASD (FXS-Only, n = 21), FXS with ASD (FXS+ASD, n = 17), nsASD (n = 42), and NT children (n = 27). Participants viewed a silent movie during which a single 200 ms 98-decibel white noise burst occurred. Cardiac activity was analyzed for pre-stimulus respiratory sinus arrhythmia (RSA) and the inter-beat intervals (IBI) at the auditory stimulus and 10 s post-stimulus. The Spence Pre-school Anxiety Scale, Autism Diagnostic Observation Schedule-2nd Edition, and Mullen Scales of Early Learning were examined in relation to startle response.Results: The nsASD group demonstrated heightened cardiac activity at the auditory stimulus and 10 s post-stimulus compared to the NT controls. Neither of the FXS groups showed differences from any other group. Higher pre-stimulus RSA was associated with reduced cardiac response across groups, while the relationship between cognitive ability and ASD severity to cardiac response varied between groups. Parent-reported anxiety was not associated with cardiac response for any group.Conclusion: These findings demonstrate group distinctions in cardiac responses to auditory startle. Although FXS and ASD share behavioral characteristics, the nsASD group showed a heightened cardiac startle response compared to the NT group that was not present in the FXS groups with or without ASD. Non-verbal mental age was associated with greater stimulus or post-stimulus reactivity for all groups except the FXS+ASD group, which showed no association between startle response and any clinical outcomes. Increased understanding of the relationship between physiological regulation and clinical outcomes will assist in identifying the timing and targets for effective interventions for individuals with neurodevelopmental disabilities.

Profile of Autism Spectrum Disorder in Tuberous Sclerosis Complex: Results from a Longitudinal, Prospective, Multisite Study.

Tuberous sclerosis complex (TSC) is highly associated with autism spectrum disorder (ASD). Objectives of the study were to characterize autistic features in young children with TSC. Participants included 138 children followed from ages 3 to 36 months with TSC from the Tuberous Sclerosis Complex Autism Center of Excellence Research Network (TACERN), a multicenter, prospective observational study aimed at understanding the underlying mechanisms of ASD in TSC. Developmental and autism-specific assessments were administered, and a clinical diagnosis of ASD was determined for all participants at 36 months. Further analyses were performed on 117 participants with valid autism assessments based on nonverbal mental age greater than 15 months. Prevalence of clinical diagnosis of ASD at 36 months was 25%. Nearly all autistic behaviors on the Autism Diagnostic Observation Schedule-2 (ADOS-2) and Autism Diagnostic Interview-Revised (ADI-R) were more prevalent in children diagnosed with ASD; however, autism-specific behaviors were also observed in children without ASD. Overall quality of social overtures, facial expressions, and abnormal repetitive interests and behaviors were characteristics most likely to distinguish children with ASD from those without an ASD diagnosis. Participants meeting ADOS-2 criteria but not a clinical ASD diagnosis exhibited intermediate developmental and ADOS-2 scores compared to individuals with and without ASD. ASD is highly prevalent in TSC, and many additional individuals with TSC exhibit a broad range of subthreshold autistic behaviors. Our findings reveal a broader autism phenotype that can be identified in young children with TSC, which provides opportunity for early targeted treatments. ANN NEUROL 2021;90:874-886.

Investigating Cognitive Flexibility in Preschool Children With Autism Spectrum Disorder.

The current study investigated cognitive flexibility in preschool children with Autism Spectrum Disorder (ASD) and those with typical development using the Reverse Categorization (RC) task and the Dimensional Change Card Sort (DCCS) task. We further examined the relationship between non-verbal mental age (NVMA) and the performance on the two tasks. While no significant difference in performance on the RC task between the two groups was found, significantly more children in the typical developing group passed the DCCS task than children in the ASD group. NVMA was found to correlate with performance in both tasks in the typical developing group but not in the ASD group. When the children were matched on NVMA, no differences in task performance between the two groups were found. The current study found the disparity in performance in two groups on the RC and the DCCS tasks, hence illuminating the importance related to the selection of tasks when studying cognitive flexibility in preschool children with ASD. The study also cast some light on the involvement of NVMA in the performance on the RC and DCCS tasks.

A single-session behavioral protocol for successful event-related potential recording in children with neurodevelopmental disorders.

Event-related potentials (ERPs) are an ideal tool for measuring neural responses in a wide range of participants, including children diagnosed with neurodevelopmental disorders (NDDs). However, due to perceived barriers regarding participant compliance, much of this work has excluded children with low IQ and/or reduced adaptive functioning, significant anxiety symptoms, and/or sensory processing difficulties, including heterogeneous samples of children with autism spectrum disorder (ASD) and children with fragile X syndrome (FXS). We have developed a behavioral support protocol designed to obtain high-quality ERP data from children in a single session. Using this approach, ERP data were successfully collected from participants with ASD, FXS, and typical development (TD). Higher success rates were observed for children with ASD and TD than children with FXS. Unique clinical-behavioral characteristics were associated with successful data collection across these groups. Higher chronological age, nonverbal mental age, and receptive language skills were associated with a greater number of valid trials completed in children with ASD. In contrast, higher language ability, lower autism severity, increased anxiety, and increased sensory hyperresponsivity were associated with a greater number of valid trials completed in children with FXS. This work indicates that a "one-size-fits-all" approach cannot be taken to ERP research on children with NDDs, but that a single-session paradigm is feasible and is intended to promote increased representation of children with NDDs in neuroscience research through development of ERP methods that support inclusion of diverse and representative samples.

Factors Explaining Deficits in Reading Acquisition: The Case of Williams Syndrome.

Purpose Multiple factors impact reading acquisition in individuals with reading disability, including genetic disorders such as Williams syndrome (WS). Despite a relative strength in oral language, individuals with WS usually have an intellectual disability and tend to display deficits in areas associated with reading. There is substantial variability in their reading skills. While some authors have postulated that phonological deficits are at the source of their reading deficits, others have suggested that they can be attributed to visuospatial deficits. This study was the first to undertake an in-depth exploration of reading skills among French-speaking children and adults with WS. We tested the assumption that some factors influence performance on single-word identification among individuals with WS, with a focus on the roles of phonological awareness and visuospatial skills. Method Participants were 29 French-speaking adults with WS and 192 controls matched for nonverbal mental age and reading level. We administered tests assessing reading (decoding and word recognition), vocabulary (expressive and receptive), and phonological and visuospatial skills. We also controlled for chronological age and nonverbal reasoning. Results Phonemic awareness was the most predictive factor of single-word identification in the WS group. Visuospatial skills also contributed, but not more or beyond other factors. More broadly, reasoning skills may also have accounted for the variability in single-word identification in WS, but this was not the case for either chronological age or vocabulary. Conclusions There is considerable heterogeneity among adults with WS, who may be either readers or prereaders. Similar profiles identified among individuals with other specific learning disabilities suggest that high reading variability is not specific to the neuropsychological profile of WS. We discuss a multidimensional approach to the factors involved in reading deficits in WS.

Assessing processing speed among individuals with intellectual and developmental disabilities: A match-to-sample paradigm

ABSTRACT Speeded Matching (SpM) is a new processing speed match-to-sample test within the NIH Toolbox Cognitive Battery. It was designed to developmentally extend feasibility to younger children or individuals with intellectual or developmental disabilities (IDD). SpM reduces cognitive demands to tapping an identical match as opposed to judging and indicating whether two stimuli are identical. In this study, we piloted SpM among 148 participants with fragile X syndrome, Down syndrome, or other intellectual disabilities (chronological age mean = 17.8 years, sd = 5.4; nonverbal mental age mean = 65 months, sd = 19.4). SpM had a high feasibility (96%) and internal consistency (rxx = 0.98). It converged well with other measures of processing speed, fluid cognition, and nonverbal mental age and diverged appropriately from crystallized cognitive skills. The correlation between nonverbal mental age and SpM in the IDD sample was not significantly different than the correlation between chronological age and SpM in a separate sample of 118 neurotypical children (age mean = 3.9 years sd = 0.8). This study provides initial evidence for the reliability and validity of the new SpM task, which may be appropriate as an outcome measure of processing speed for future clinical trials. It is more feasible than tasks designed for adults; it is brief, easy to administer, and engaging for young children and older individuals with lower mental ages associated with IDD.

Differences and Similarities in Predictors of Expressive Vocabulary Development between Children with Down Syndrome and Young Typically Developing Children.

The purpose of this study was to examine potential differences in the predictors of expressive vocabulary development between children with Down syndrome and typically developing children to support preparation for intervention development. An age cohort of 43 children with Down syndrome and 57 typically developing children with similar nonverbal mental age levels were assessed at three time points. Linear mixed models were used to investigate the predictors of expressive vocabulary over time. Both groups achieved progress in expressive vocabulary. The typically developing children had steeper growth than the children with Down syndrome (1.38 SD vs. 0.8 SD, p < 0.001). In both groups, receptive vocabulary, auditory memory, and the home literacy environment were significant predictors of development. In the children with Down syndrome, the phonological awareness and oral motor skills were also significant. Group comparisons showed that receptive vocabulary, auditory memory and oral motor skills were stronger predictors in the children with Down syndrome than in the typically developing children. These results indicate that children with Down syndrome are more vulnerable when it comes to risk factors that are known to influence expressive vocabulary than typically developing children. Children with Down syndrome therefore require early broad-based expressive vocabulary interventions.

A comparison study of alternative conceptions on impetus theory and projectile motion of adolescents with typical development and high functioning autism spectrum disorder

ABSTRACT The aim of the present study is to explore on the alternative conceptions of impetus theory and projectile motion of students with high functioning autism spectrum disorders and compare them with those of typical development. For this purpose, an experimental investigation was conducted with 19 students with high-functioning autism (age range: 12–16 yrs) and 55 typically development students (age range: 12–16 yrs). The two study groups were equivalent on both sex and non-verbal mental age. Drawing from theoretical approaches that emphasise the study of prior knowledge on the learning process, a structured, computerised tool was developed to explore the alternative conceptions of students with autism (T.E.A.I.A.). Research findings suggest that students with high-functioning autism use the same alternative conceptions with those used by students of typical development, on a different frequency thought. Moreover, they adopt impetus theory at a rate that is statistically different from that of typical development students. Findings of the current research study are likely to contribute to the basis for teaching projectile motion to students with autism spectrum disorder.

Sleep and Cognition in Children with Fetal Alcohol Spectrum Disorders (FASD) and Children with Autism Spectrum Disorders (ASD)

Children with Fetal Alcohol Spectrum Disorders (FASD) and Autism Spectrum Disorders (ASD) experience significantly higher rates of sleep disturbances than their typically developing peers. However, little is known about the association between sleep and the cognitive phenotype in these clinical populations. Structural damage affecting cortical and subcortical connectivity occurs as a result of prenatal alcohol exposure in children with FASD, whilst it is believed an abundance of short-range connectivity explains the phenotypic manifestations of childhood ASD. These underlying neural structural and connectivity differences manifest as cognitive patterns, with some shared and some unique characteristics between FASD and ASD. This is the first study to examine sleep and its association with cognition in individuals with FASD, and to compare sleep in individuals with FASD and ASD. We assessed children aged 6–12 years with a diagnosis of FASD (n = 29), ASD (n = 21), and Typically Developing (TD) children (n = 46) using actigraphy (CamNTech Actiwatch 8), digit span tests of working memory (Weschler Intelligence Scale), tests of nonverbal mental age (MA; Ravens Standard Progressive Matrices), receptive vocabulary (British Picture Vocabulary Scale), and a choice reaction time (CRT) task. Children with FASD and ASD presented with significantly shorter total sleep duration, lower sleep efficiency, and more nocturnal wakings than their TD peers. Sleep was significantly associated with scores on the cognitive tests in all three groups. Our findings support the growing body of work asserting that sleep is significant to cognitive functioning in these neurodevelopmental conditions; however, more research is needed to determine cause and effect.

Narrative and prosodic skills in children and adolescents with Down syndrome and typically developing children

Purpose Children with Down Syndrome (DS) show difficulties in language development, in both basic and complex abilities, as narratives. Less is known about the prosodic competence in DS, but the few available studies highlighted the presence of some deficits. Considering the importance of narratives and prosody in communication, the main aim of this study is to investigate these two competencies in participants with DS. Method 13 children with DS participated (Mean age: 13;04, years; months). Their narrative and prosodic abilities, collected through a storytelling task, were compared with those of two control groups of typically developing (TD) children, one matched for nonverbal mental age (MA, Mean age: 5;03) and the other matched for the mean length of utterance (MLU, Mean age: 5;05). For the narrative competence, we considered both the macrostructural (i.e. quantity of information and story structure) and the microstructural level (i.e. verbal productivity, lexical diversity, syntactic complexity). For the prosodic competence, we took into account acoustic measures linked to intonation (i.e. mean fundamental frequency (f0), pitch range, final speech profile, and speed of speech). Result The results of the Mann-Whitney test showed that participants with DS produced stories comparable to those of TD children in nearly all the variables considered, except for the syntactic complexity when compared with children of the same MA. Differences between participants with DS and TD children were found in the f0 and the final pitch profile used. Conclusion Considering the small size of the samples, these preliminary results should be taken with caution. Nonetheless, this study confirms the presence of difficulties in the prosody of speech and in the syntactic competence of children with DS. These difficulties could have consequences on the possibility to communicate efficiently and should be taken into account in rehabilitation programmes.

Narrative Abilities of Adults' With Down Syndrome as a Window to Their Morphosyntactic, Socio-Cognitive, and Prosodic Abilities.

Down syndrome (DS) is the most common developmental disorder characterized by mild to moderate intellectual disability. Several studies have reported poor language and prosodic skills and contradictory results regarding individuals’ with DS socio-cognitive skills, whereas most of them have focused on children with DS. The present study attempts to explore adults’ with DS language, socio-cognitive and prosodic abilities via the use of story-retellings. Twenty adults with DS and two groups of TD children, one matched to their expressive vocabulary (TD-EVT) and the other matched to their non-verbal mental age (TD-RCPM), took part in the present study. Participants listened to a story while viewing a wordless picture PowerPoint presentation on a computer screen, and then, they were instructed to retell the story while viewing the pictures for a second time. Each participant listened to two stories, one with “lively” and one with “flat” prosody. Results revealed that adults’ with DS performance was comparable with the one presented by the TD-RCPM group, whereas the TD-EVT group performed significantly better in almost all variables. Individuals’ with DS re-narrations, however, contained significantly less complement clauses and internal state terms (related or not related to Theory of Mind–ToM) compared to the re-narrations of both control groups. In contrast, the group with DS performed similarly to both control groups in comprehension questions related to main characters’ internal state terms and significantly better compared to the TD-RCPM group in questions related to ToM. In terms of prosody, all three groups performed significantly better on story structure and comprehension questions when prosody was “lively” compared “flat” prosody. DS group’s re-narrations did not contain enough internal state terms, not due to their inability in recognizing them, but due to their poor morphosyntactic abilities, which did not allow them to find the proper means to express the main characters’ internal states. Prosody facilitated participants with DS in the comprehension and re-narration. This suggests that intervention programs based on prosody could support the language skills of adults with DS.

Young students with Down syndrome: Early longitudinal academic achievement and neuropsychological predictors

ABSTRACT Background: We examined longitudinal academic achievement and neuropsychological functioning across two time points in young students with Down syndrome (DS) and a typically developing (TD) comparison group equated on nonverbal mental age (NVMA). Method: Participants engaged in assessments of academic achievement, executive function (EF), and fine-motor integration. Results: From Time 1 to Time 2, students with DS demonstrated significantly more challenges than the TD group in the acquisition of quantitative skills. Additionally, EF and fine motor integration at Time 1 significantly predicted academic achievement at Time 2 for students with DS. Conclusions: The interpretation of these results extends our understanding of how early neuropsychological disruptions in DS manifest in the educational context and highlights potential targets for new interventions.

Improving Theory of Mind Skills in Down Syndrome? A Pilot Study

Effective communication requires an understanding of the interlocutor's perspective. Being able to infer someone else's knowledge about a situation is a critical skill in any communication and social interaction. These abilities are part of Theory of Mind (ToM) skills and are known to be impaired in Down syndrome (DS). It therefore makes sense to investigate ToM development in this population. In our pilot study, we explore the possibility of improving ToM abilities in participants with DS and typically developing (TD) children matched for nonverbal mental age. Participants were assessed with the French adaptation of the “ToM Inventory” before and after a 10-week training session. Results show that trained groups perform significantly better on ToM tasks than untrained groups, whose performances remain stable between pre- and post-test. These results are encouraging as they suggest that, with a specific training, children with DS can improve their ToM skills.

Problem behavior in young children referred with language difficulties: Relations to language and intentional communication.

This exploratory study aims to examine the relative contribution of language and intentional communication to internalizing and externalizing problem behavior. Twenty-nine Dutch-speaking children (age range 24-46 months) referred with language difficulties participated in this study. For the majority of children, these early language difficulties appeared to be part of a broader neurodevelopmental disorder, mainly autism spectrum disorder. Parent ratings on the Achenbach Child Behavior Checklist 1½-5 were predicted from children's language level and intentional communicative abilities, the latter being assessed by both parent report and direct observation. In all series of hierarchical regression analyses, chronological age and nonverbal mental age were included as covariates. Parents commonly reported withdrawal, emotionally reactive behavior, attention problems, and aggressive behavior. Parent-rated intentional communication was the most important predictor of internalizing problem behavior and played an important role in the prediction of aggressive behavior as well. However, chronological age and/or nonverbal mental age also predicted parent-rated levels of externalizing problem behavior, especially attention problems. The relation between language difficulties and problem behavior may be influenced by maturation and children's ability to communicate intentionally.Implications: Language proficiency should, therefore, be independently assessed from children's intentional communicative abilities which, in turn, may differ across contexts.