Nonverbal Mental Age Research Articles

Understanding and production of prosody in children with Williams syndrome: A developmental trajectory approach

This study investigated the development of three aspects of linguistic prosody in a group of children with Williams syndrome compared to typically developing children. The prosodic abilities investigated were: (1) the ability to understand and use prosody to make specific words or syllables stand out in an utterance (focus); (2) the ability to understand and use prosody to disambiguate complex noun phrases (chunking); (3) the ability to understand and use prosody to regulate conversational behaviour (turn-end). The data were analysed using a cross-sectional developmental trajectory approach. The results showed that, relative to chronological age, there was a delayed onset in the development of the ability of children with WS to use prosody to signal the most important word in an utterance (the focus function). Delayed rate of development was found for all the other aspects of expressive and receptive prosody under investigation. However, when non-verbal mental age was taken into consideration, there were no differences between the children with WS and the controls neither with the onset nor with the rate of development for any of the prosodic skills under investigation apart from the ability to use prosody in order to regulate conversational behaviour. We conclude that prosody is not a ‘preserved’ cognitive skill in WS. The genetic factors, development in other cognitive domains and environmental influences affect developmental pathways and as a result, development proceeds along an atypical trajectory.

Phonological Accuracy and Intelligibility in Connected Speech of Boys With Fragile X Syndrome or Down Syndrome

To compare the phonological accuracy and speech intelligibility of boys with fragile X syndrome with autism spectrum disorder (FXS-ASD), fragile X syndrome only (FXS-O), Down syndrome (DS), and typically developing (TD) boys. Participants were 32 boys with FXS-O (3-14 years), 31 with FXS-ASD (5-15 years), 34 with DS (4-16 years), and 45 TD boys of similar nonverbal mental age. We used connected speech samples to compute measures of phonological accuracy, phonological process occurrence, and intelligibility. The boys with FXS, regardless of autism status, did not differ from TD boys on phonological accuracy and phonological process occurrence but produced fewer intelligible words than did TD boys. The boys with DS scored lower on measures of phonological accuracy and occurrence of phonological processes than all other groups and used fewer intelligible words than did TD boys. The boys with FXS and the boys with DS did not differ on measures of intelligibility. Boys with FXS, regardless of autism status, exhibited phonological characteristics similar to those of younger TD children but were less intelligible in connected speech. Boys with DS showed greater delays in all phonological measures than the boys with FXS and the TD boys.

Jealousy and emotional responsiveness in young children with ASD

We investigated manifestations of jealousy in preschoolers (n=32) with autism spectrum disorder (ASD) and in a group of typically developing children (n=18) matched on mental age, verbal mental age, nonverbal mental age, and mother's education. Main results revealed explicit indices of jealousy in two thirds of the children with ASD compared with 94.5% in the typical group. In addition, different manifestations of this emotion emerged in the ASD group compared with the matched control group. Regarding mental and affective correlates of jealousy, expressions of jealousy correlated with IQ only for the children in the ASD group, and the ASD group revealed deficient emotional responsiveness (ER) capabilities. Significant correlations emerged between jealousy and ER in both the ASD and control groups. Discussion focuses on implications of these findings for understanding the core emotional deficit in autism.

Syntactic Complexity During Conversation of Boys With Fragile X Syndrome and Down Syndrome

This study compared the syntax of boys who have fragile X syndrome (FXS) with and without autism spectrum disorder (ASD) with that of (a) boys who have Down syndrome (DS) and (b) typically developing (TD) boys. Thirty-five boys with FXS only, 36 boys with FXS with ASD, 31 boys with DS, and 46 TD boys participated. Conversational language samples were evaluated for utterance length and syntactic complexity (i.e., Index of Productive Syntax; H. S. Scarborough, 1990). After controlling for nonverbal mental age and maternal education levels, the 2 FXS groups did not differ in utterance length or syntactic complexity. The FXS groups and the DS group produced shorter, less complex utterances overall and less complex noun phrases, verb phrases, and sentence structures than did the TD boys. The FXS with ASD group and the DS group, but not the FXS-only group, produced less complex questions/negations than did the TD group. Compared with the DS group, both FXS groups produced longer, more complex utterances overall, but on the specific complexity measures, they scored higher only on questions/negations. Boys with FXS and DS have distinctive language profiles. Although both groups demonstrated syntactic delays, boys with DS showed greater delays.

Characterizing communicative development in children referred for Autism Spectrum Disorders using the MacArthur-Bates Communicative Development Inventory (CDI)

Characterizing early communicative development in children with Autism Spectrum Disorders (ASD) is valuable for understanding profiles of ability in this population. The current investigation was modeled on Charman, Drew, Baird & Baird (2003b). Analyses explored parent report of early vocabulary, non-verbal communication, functional object use and play skills on the MacArthur-Bates Communicative Development Inventory (CDI) in 93 children with ASD, 31 children with developmental delay (DD) and 29 typically developing children. Results were generally consistent with those of Charman and colleagues (2003b), suggesting that skills improve with increasing non-verbal mental age and chronological age but that most children with ASD are delayed in receptive and expressive vocabulary and non-verbal communication, functional object use and play skills. Vocabulary profiles in the ASD sample were similar to those in the comparison samples, as was the developmental pattern of gesture and vocabulary mastery. However, when compared to published norms, children with ASD may show less of a discrepancy between their receptive and expressive vocabulary.

When less is more: Poor discrimination but good colour memory in autism

In two experiments children with autism and two groups of controls matched for either chronological or non-verbal mental age were tested on tasks of colour discrimination and memory. The results from experiment 1 showed significantly poorer colour discrimination in children with autism in comparison to typically developing chronological age matched controls. However, in experiment 2, children with autism, retained unlabelled perceptual colour information to a significantly higher level than either group of controls. The findings suggest that enhanced performance on perceptual tasks relate to a reduced tendency to encode verbal information in memory.

Exceptional reading among young people with Down syndrome

It seems unlikely that a child with Down syndrome will have age-appropriate reading skills yet show significant delay on measures of verbal and non-verbal mental age yet this is the pattern reported by Margriet Groen and colleagues in a detailed case study of KS aged 8 years. The paper reports three studies exploring different facets of the reading skills shown by KS.

Impairments in monkey and human face recognition in 2‐year‐old toddlers with Autism Spectrum Disorder and Developmental Delay

Face recognition impairments are well documented in older children with Autism Spectrum Disorders (ASD); however, the developmental course of the deficit is not clear. This study investigates the progressive specialization of face recognition skills in children with and without ASD. Experiment 1 examines human and monkey face recognition in 2-year-old children with ASD, matched for nonverbal mental age (NVMA) with developmentally delayed (DD) children, and typically developing children (TD), using the Visual Paired Comparison (VPC) paradigm. Results indicate that, consistent with the other-species effect, TD controls show enhanced recognition of human but not monkey faces; however, neither the ASD nor the DD group show evidence of face recognition regardless of the species. Experiment 2 examines the same question in a group of older 3- to 4-year-old developmentally disabled (ASD and DD) children as well as in typical controls. In this experiment, both human and monkey faces are recognized by all three groups. The results of Experiments 1 and 2 suggest that difficulties in face processing, as measured by the VPC paradigm, are common in toddlers with ASD as well as DD, but that these deficits tend to disappear by early preschool age. In addition, the experiments show that higher efficacy of incidental encoding and recognition of facial identity in a context of passive exposure is positively related to nonverbal cognitive skills and age, but not to overall social interaction skills or greater attention to faces exhibited in naturalistic contexts.

Psychological well‐being of mothers of youth with fragile X syndrome: syndrome specificity and within‐syndrome variability

Research on parental well-being has focused largely on Down syndrome and autism; however, fragile X syndrome is likely to pose different challenges for parents compared with these other diagnostic conditions. Moreover, there is considerable variability among youth with fragile X syndrome; for example, 25% to 33% of affected youth meet criteria for a co-morbid diagnosis of autism. It is likely that parents of youth with fragile X syndrome will experience different degrees and patterns of stress, depending on whether their offspring do or do not have a co-morbid diagnosis of autism. In the present study, we compared mothers of three groups of young males on measures of psychological well-being and stress: those with fragile X syndrome and a co-morbid diagnosis of autism; those with fragile X syndrome alone; and those with Down syndrome. The sample consisted of mothers of adolescent and young adult males with fragile X syndrome and co-morbid autism (n=9), fragile X syndrome alone (n=19), and Down syndrome (n=19). We screened all youth for autism using the Autism Behavior Checklist, which was completed by mothers, fathers and teachers, and the youth who scored above the suggested cut-off were evaluated by a licensed psychologist to determine autism status. The three groups of youth did not differ in chronological age (16.4, 15.8 and 16.0 years, respectively) or non-verbal mental age (3.8, 3.9 and 3.8 years, respectively). Several self-report measures were completed by mothers. These measures assessed current mental health status (e.g. the Center for Epidemiological Studies Depression Scale), perceptions of their son's and family's functioning (e.g. the Positive Affect Index, which measures closeness felt by the mother to her son and also reciprocated closeness felt by the son towards the mother, as perceived by the mother), and approach to coping with their son's disability [e.g. the Multidimensional Coping Inventory (COPE), which measures emotion-focused and problem-solving focused coping]. The results suggest that fragile X syndrome creates more challenges to maternal psychological well-being than Down syndrome, and that the combination of fragile X syndrome and autism can be particularly challenging. Differences among groups, however, were manifested mainly as concerns about the affected son and about relationships within the family rather than as lower levels of mental health. Thus, mothers of sons with fragile X syndrome, regardless of the son's autism status, reported more pessimism about the son's future and more conflict within the family than mothers of sons with Down syndrome. Additionally, mothers of sons with fragile X syndrome and co-morbid autism reported lower levels of reciprocated closeness than the other two groups of mothers. We consider possible causes of these maternal differences, the implications for clinical practice, needs for future research, and the importance of understanding child and contextual factors as well as the dynamics leading to these differences.

Beyond Pragmatics: Morphosyntactic Development in Autism

Language acquisition research in autism has traditionally focused on high-level pragmatic deficits. Few studies have examined grammatical abilities in autism, with mixed findings. The present study addresses this gap in the literature by providing a detailed investigation of syntactic and higher-level discourse abilities in verbal children with autism, age 5 years. Findings indicate clear language difficulties that go beyond what would be expected based on developmental level; specifically, syntactic delays, impairments in discourse management and increased production of non-meaningful words (jargon). The present study indicates a highly specific pattern of language impairments, and importantly, syntactic delays, in a group of children with autism carefully matched on lexical level and non-verbal mental age with children with developmental delays and typical development.

Language learning in Down syndrome: The speech and language profile compared to adolescents with cognitive impairment of unknown origin

Children and adolescents with Down syndrome show an emerging profile of speech and language characteristics that is typical of the syndrome (Chapman & Hesketh, 2000; Chapman, 2003; Abbeduto & Chapman, 2005) and different from typically developing children matched for nonverbal mental age, including expressive language deficits relative to comprehension that are most severe for syntax, and, in adolescence, strengths in comprehension vocabulary, improvements in expressive syntax, but losses in comprehension of syntax (Chapman, Hesketh & Kistler, 2002). Here we compare 20 adolescents with Down syndrome to 16 individuals with cognitive impairment of unknown origin, statistically matched for age and nonverbal mental age, to show that the age-related strengths in vocabulary comprehension are not limited to the Down syndrome phenotype, but are limited to a certain type of vocabulary test: for both groups, performance on the Peabody Picture Vocabulary Test-3 is significantly greater than performance on the vocabulary subtest of the Test of Auditory Comprehension of Language-3, which does not differ from the syntax comprehension subtests. Vocabulary size, but not conceptual level, is a strength for adolescents with cognitive impairment. In contrast, deficits in auditory-verbal working memory, syntax and vocabulary comprehension, and narration of picture-books without an opportunity to preview them are all specific to the adolescent group with Down syndrome. The expressive language deficit disappears when a preview opportunity and picture support is given.

A Comparison of Phonological Skills of Boys With Fragile X Syndrome and Down Syndrome

In this study, the authors compared the phonological accuracy and patterns of sound change of boys with fragile X syndrome, boys with Down syndrome, and typically developing mental-age-matched boys. Participants were 50 boys with fragile X syndrome, ages 3 to 14 years; 32 boys with Down syndrome, ages 4 to 13 years; and 33 typically developing boys, ages 2 to 6 years, who were matched for nonverbal mental age to both the boys with fragile X syndrome and the boys with Down syndrome. All participants were administered a standardized articulation test, and their sound accuracy, phonological process, and proportion of whole-word proximity scores were analyzed. Although boys with fragile X syndrome were delayed in their speech development, they did not differ from the typically developing, mental-age-matched boys in the percentage of correct early-, middle-, and late-developing consonants; phonological processes; or whole-word proximity scores. Furthermore, boys with fragile X syndrome had fewer errors on early-, middle-, and late-developing consonants; fewer syllable structure processes; and higher whole-word proximity scores than did boys with Down syndrome. Boys with Down syndrome also were delayed in their speech development, yet their phonological inventories, occurrences of phonological processes, and proportion of whole-word proximity scores indicated greater delays in their phonological development than the younger, typically developing boys. These results suggest that males with fragile X syndrome display phonological characteristics in isolated words similar to younger, typically developing children, whereas males with Down syndrome show greater delays as well as some developmental differences compared with both the males with fragile X syndrome and typically developing males.

Performance of young people with Down syndrome on the Leiter‐R and British picture vocabulary scales

The British picture vocabulary scales (BPVS-II) and the Leiter international performance scales (Leiter-R), both restandardised in 1997, are often used in experimental studies to match individuals with intellectual impairment. Both provide a brief measure of mental age, and cover a wide ability range using a simple format. The BPVS-II assesses verbal comprehension and the Leiter nonverbal abilities. The issue is which to choose. People with Down syndrome (DS), for example, have particular problems in language and so the BPVS may provide an underestimation of ability. The present study investigated this by comparing the performance of 46 young people with DS (21 females, 25 males, mean age 19 years 10 months) on the BPVS-II (verbal mental age - VMA) and the Leiter-R brief IQ (nonverbal mental age - NVMA). Contrary to expectations VMAs were significantly higher than NVMAs (6 years 6 months and 5 years 2 months, respectively). There was a significant correlation of 0.61 between the VMA and NVMA, and both discriminated participants at all levels of ability. However, the Leiter-R brief IQ scores provided poor discrimination at the bottom end of the IQ range (IQ 36). Both the BPVS-II and the Leiter-R provide mental age equivalent scores that are useful for plotting developmental progress, although absolute mental ages may differ.

Executive functions in children with communication impairments, in relation to autistic symptomatology

Although impairment in executive functions has been described in autism, there has been debate as to whether response inhibition is specifically affected. We compared four groups: high-functioning autism; pragmatic language impairment; specific language impairment; and control. Inhibition was assessed using two subtests from the Test of Everyday Attention for Children, one requiring a verbal response and the other a non-verbal response. Although we found evidence of inhibitory deficits, these were neither specific to autism, nor linked to particular aspects of autistic symptomatology. Rather, they appeared to be associated with poor verbal skills and inattention. It is suggested that future studies need to control for structural language skills and attention deficit when evaluating cognitive deficits in autism. Reliance on control groups matched solely on vocabulary level or nonverbal mental age may obscure the important role played by language skills in executive functions.

Gamma Abnormalities During Perception of Illusory Figures in Autism

This experiment was designed to test the hypothesis that perceptual abnormalities in autism might be associated with alteration of induced gamma activity patterns overlying visual cortical regions. EEG was recorded from six adolescents with autism and eight controls matched on chronological age, and verbal and nonverbal mental age, whilst identifying the presence or absence of an illusory Kanizsa shape. Although there were no reaction time or accuracy differences between the groups there were significant task-related differences in cortical activity. Control participants showed typical gamma- band activity over parietal regions at around 350 msec post onset of shape trials, similar to gamma patterns found in previous studies with non-impaired adults. In contrast, autistic participants showed overall increased activity, including an early 100 msec gamma peak and a late induced peak, 50 to 70 msec earlier than that shown by the control group. We interpret the abnormal gamma activity to reflect decreased “signal to noise” due to decreased inhibitory processing. In this experiment we did not establish a link between altered perception and abnormal gamma, as the autistic participants' behaviour did not differ from the controls. Future work should be designed to replicate this phenomenon and establish the perceptual consequences of altered gamma activity.

Fast Mapping of Words and Story Recall by Individuals With Down Syndrome

This study compared adolescents with Down syndrome to nonverbal mental-age matched controls in their ability to fast map new noun vocabulary in spoken story contexts. Context for novel words varied within subjects in the distance between mentions (close-distant) and the ease of inferring a real word for the referent (specificity). The 23 participants with Down syndrome (DS) were aged 12.8-20.3 years. The 24 typically developing (TD) children, matched on visual nonverbal mental age (MA), were 4.1 to 6.1 years old. Participants listened to 4 tape-recorded stories, each containing 3 mentions of 2 novel words in close or distant proximity and with clear or uncertain reference, and recalled each story after presentation. Fast-mapping production was measured by the occurrence of the novel word in story recall. Fast-mapping comprehension was measured by asking children to define the novel words. The DS group did not differ from the TD group in novel word production but seemed to have more difficulty with novel word definition. For both groups, novel word production was higher in the nonspecific than the specific referent condition, suggesting that availability of a real word label interfered with fast mapping. Recall of story propositions was poorer for the DS group. For both groups, story recall was better for text units not directly associated with novel words than for text units containing novel words, suggesting a trade-off effect in processing. Regression analyses indicated that syntax comprehension, rather than mean length of utterance, predicted novel word production in both groups; MA additionally contributed to predict DS story recall.

Exploring block construction and mental imagery: Evidence of atypical orientation discrimination in Williams syndrome

The visuospatial perceptual abilities of individuals with Williams syndrome (WS) were investigated in two experiments. Experiment 1 measured the ability of participants to discriminate between oblique and between nonoblique orientations. Individuals with WS showed a smaller effect of obliqueness in response time, when compared to controls matched for nonverbal mental age. Experiment 2 investigated the possibility that this deviant pattern of orientation discrimination accounts for the poor ability to perform mental rotation in WS (Farran, Jarrold, & Gathercole, 2001). A size transformation task was employed, which shares the image transformation requirements of mental rotation, but not the orientation discrimination demands. Individuals with WS performed at the same level as controls. The results suggest a deviance at the perceptual level in WS, in processing orientation, which fractionates from the ability to mentally transform images.

Spontaneous measures of morphosyntax in children with specific language impairment

Fifteen children with specific language impairment (SLI) were matched in gender, age, and nonverbal mental age to one comparison group and in gender and standardized expressive language age to another comparison group. Their spontaneous speech was recorded while they narrated a cartoon and described their classroom. No group differences were found in mean length of utterance in morphemes or in syntactic complexity. SLI children had a lower percentage of correct irregular past tense forms but were equivalent to controls on regular past tense forms and noun plurals. Lexical diversity in terms of the number of different verbs expressed in the past tense and the number of different nouns pluralized did not differ. Some problems in generating complex sentences were found in the speech of SLI children. The importance of task constraints is stressed in explaining the discrepant performance of SLI children on spontaneous versus standardized measures of language, as well as the contribution of auditory memory limitations.Editor's Note: This article was reviewed and accepted by the previous Editor in Chief, Dr. John Locke.

The impact of context on pattern category learning and representation

The visuospatial perceptual abilities of individuals with Williams syndrome (WS) were investigated in two experiments. Experiment 1 measured the ability of participants to discriminate between oblique and between nonoblique orientations. Individuals with WS showed a smaller effect of obliqueness in response time, when compared to controls matched for nonverbal mental age. Experiment 2 investigated the possibility that this deviant pattern of orientation discrimination accounts for the poor ability to perform mental rotation in WS (Farran, Jarrold, & Gathercole, 2001). A size transformation task was employed, which shares the image transformation requirements of mental rotation, but not the orientation discrimination demands. Individuals with WS performed at the same level as controls. The results suggest a deviance at the perceptual level in WS, in processing orientation, which fractionates from the ability to mentally transform images.

An overview of imitation skills in autism: Implications for practice.

Research findings suggest certain forms of imitation may be relatively more difficult for individuals with autism compared to typically developing peers. Findings of deficits in imitation skills have significant implications for intervention approaches given the critical nature of imitation to one's ability to learn from the environment. This article provides an overview of the research findings in behavioral and cognitive developmental psychology on imitation skills in autism. Implications of current findings for intervention are presented and recommendations for practice-relevant research are also made. Implications for Practice Autism spectrum disorders involve a complex array of learning and behavioral deficits and excesses. Although autism is characteristically heterogeneous, individuals with autism display these deficits and excesses in the following three areas: communication, social relationships, and behavioral perseveration and rigidity. The heterogeneity of autism allows for few conclusive statements about learning styles of individuals with autism. The learning characteristics that have been identified include problems with perseverative responding (e.g. position preferences), overselective responding, and poor skill generalization. Recent research in cognitive developmental and neuropsycholgy suggests that another possible characteristic learning deficit in individuals with autism may include imitation. Much of the research on imitation deficits in individuals with autism is drawn from between-group designs comparing the skills of primarily children with autism to children matched on verbal or non-verbal mental age. In various studies, children with autism underperform on various imitation tasks compared to the control groups (Heimann, et al., 1992; Ohta, 1987; Jones & Prior, 1985; Hammes & Langdell, 1981). However, these findings appear to be in contradiction with clinical observations of excessive imitative ability (e.g. echolalia) and findings from applied behavior analytic research indicating success in teaching imitation to children with autism. Given the critical nature of imitation to learning, understanding the nature of imitation skills in individuals with autism is necessary to developing effective early intervention and instructional practices. This article will highlight relevant research and practices on imitation skills in individuals with autism. Behavioral and cognitive developmental disciplines have been the most prolific in the study of imitation skills in individuals with autism. As such this article will focus primarily on the contributions of these disciplines. Our fairly limited understanding of the nature and impact of deficient imitation skills in children with autism are in part due to disparate theoretical and methodological approaches between behavioral and cognitive developmental research. Cognitive developmental theories view imitation as a keystone skill representing a child's understanding of the relationship between himself and the environment. Imitation represents a child's first understanding of person-environment relationships within cognitive developmental theories. Thus, imitation is thought to allow for the development of other critical person-environment relationships such as communication and social skills. While the focus of cognitive theories on hypothetical constructs such as theory of mind are less useful, studies of typical and atypical development of imitation in autism is an important contribution of this approach. The methods employed in cognitive developmental research typically evaluate whether the imitation skills of children with autism are typical for their intellectual level. Thus, between-group designs are almost exclusively used by cognitive developmental researchers matching control and experimental groups on standardized test variable reflecting either verbal or non-verbal mental age. …