Caregiver-reported infant motor and imitation skills predict M-CHAT-R/F.

Altered motor and social-communicative abilities in infancy have been linked to later ASD diagnosis. Most diagnostic instruments for ASD cannot be utilized until 12 months, and the average child is diagnosed substantially later. Imitation combines motor and social-communicative skills and is commonly atypical in infants at risk for ASD. However, few measures have been developed to assess infant imitation clinically. One barrier to the diagnostic age gap of ASD is accessibility of screening and diagnostic services. Utilization of caregiver report to reliably screen for ASD mitigates such barriers and could aid in earlier detection. The present study developed and validated a caregiver-report measure of infant imitation at 4, 6, and 9 months and explored the relationship between caregiver-reported imitation and motor abilities with later ASD risk. Participants (N = 571) were caregivers of term and preterm infants recruited as part of a large multi-site study of PediaTrac™, a web-based tool for monitoring and tracking infant development. Caregivers completed online surveys and established questionnaires on a schedule corresponding to well-child visits from birth to 18 months, including the M-CHAT-R/F at 18 months. Distinct imitation factors were derived from PediaTrac at 4, 6, and 9 months via factor analysis. The results supported validity of the imitation factors via associations with measures of infant communication (CSBS; ASQ). Imitation and motor skills at 9 months predicted 18-month ASD risk over and above gestational age. Implications for assessment of infant imitation, detecting ASD risk in the first year, and contributing to access to care are discussed.

Longitudinal caregiver-reported motor development in infants born at term and preterm.

AIM: To examine the extent to which estimates of a latent trait or underlying construct of motor ability differ in infants born at term and preterm, based on caregiver ratings of the motor domain of PediaTrac v3.0. METHOD: The sample consisted of 571 caregiver-infant dyads (331 born at term, 240 born preterm), 48% female, with 51.7% of caregivers identifying as an ethnic minority. Latent trait of motor ability was estimated based on item response theory modeling. Gestational group differences (term and preterm birth) were examined at the newborn/term-equivalent, 2-, 4-, 6-, 9-, and 12-month time points. RESULTS: Caregiver ratings of latent trait of motor ability were reliably modeled across the range of abilities at each time point. While the group born preterm exhibited significantly more advanced motor abilities at the term-equivalent time point, by 6 months the group born at term was more advanced. Biological sex difference main and interaction effects were not significant. INTERPRETATION: Caregivers provided reliable, longitudinal estimates of motor ability in infancy, reflecting important differences in the motor development of infants born at term and preterm. The findings suggest that significant motor development occurs in infants born preterm from birth to the term-equivalent time point and provide a foundation to examine motor growth trajectories as potential predictors in the early identification of neurodevelopmental conditions and needs.

Caregiver-reported newborn term and preterm motor abilities: psychometrics of the PediaTracTM Motor domain.

BACKGROUND: Approximately 5-10% of children exhibit developmental deviations in motor skills or other domains; however, physicians detect less than one-third of these abnormalities. Systematic tracking and early identification of motor deviations are fundamental for timely intervention. METHODS: Term and preterm neonates were prospectively assessed at the newborn (NB) period in a study of the psychometric properties of the Motor (MOT) domain of PediaTracTM v3.0, a novel caregiver-based development tracking instrument. Item response theory graded response modeling was used to model item parameters and estimate theta, an index of the latent trait, motor ability. Exploratory factor analysis (EFA) was conducted to examine the dimensionality and factor structure. RESULTS: In a cohort of 571 caregiver/infant dyads (331 term, 240 preterm), NB MOT domain reliability was high (rho = 0.94). Item discrimination and item difficulty of each of the 15 items could be reliably modeled across the range of motor ability. EFA confirmed that the items constituted a single dimension with second-order factors, accounting for 43.20% of variance. CONCLUSIONS: The latent trait, motor ability, could be reliably estimated at the NB period. IMPACT: The caregiver-reported Motor domain of PediaTrac provides a reliable estimate of the latent trait of motor ability during the newborn period. This is the first known caregiver-reported instrument that can assess motor ability in the newborn period with high reliability in term and preterm infants. Item response theory methods were employed that will allow for future characterization of developmental subgroups and motor trajectories. The PediaTrac Motor domain can support early identification of at-risk infants. Including caregivers in digital reporting and child-centered monitoring of motor functioning may improve access to care.

The Medical Symptom Validity Test Measures Effort Not Ability in Children: A Comparison Between Mild TBI and Fetal Alcohol Spectrum Disorder Samples.

Inadequate effort during neuropsychological examination results in inaccurate representations of an individual's true abilities and difficulties. As such, performance validity tests (PVTs) are strongly recommended as standard practice during adult-based evaluations. One concern with using PVTs with children is that failure reflects immature cognitive ability rather than non-credible effort. The current study examined performance on the Medical Symptom Validity Test (MSVT) in two large pediatric clinical samples with strikingly different neuropsychological profiles: (1) mild traumatic brain injury (mTBI; n = 510) and (2) fetal alcohol spectrum disorder (FASD; n = 120). Despite higher IQ scores and reading ability, the mTBI group performed significantly worse than the FASD group on all effort indices. Sixteen percent of the mTBI group failed the MSVT, whereas only 5% of the FASD group did. Our findings support the idea that the MSVT measures effort, not ability, in most cases and help to justify incorporating PVTs into pediatric neuropsychological batteries.

The contribution of verbalization to action.

Previous studies have shown that verbalization, in the form of self-guided instruction, is an effective cognitive strategy used to enhance motor skill acquisition and performance. However, past research has not explicitly examined which aspects of motor output are affected (whether beneficially or deleteriously) by verbalization. In the current study, we conducted two separate experiments in which a total of 80 healthy participants, aged 18-27, completed a novel motor sequence learning task. Half of the participants in each experiment were pre-trained in the sequence using verbalization, while the other half was either trained motorically, or not trained at all. Rote memorization of verbal labels facilitated motor sequence learning, motor control, and action maintenance, but not action planning of the motor sequence. Potential underlying mechanisms as well as clinical implications are discussed.

Does language guide behavior in children with autism?

It is unknown if children with high-functioning autism (HFA) employ self-directed speech to guide motor sequencing and motor control, or if they can benefit from using self-directed speech when prompted to do so. Participants performed a three-movement sequence across three conditions: Natural Learning, Task-Congruent Verbalization (TCV), and Task-Incongruent Verbalization (TIV). TIV deleteriously impacted performance in the typically-developing group (n = 22), and not the HFA group (n = 21). TCV improved performance in both groups, but to a greater extent in the HFA group. These findings suggest that children with HFA do not initiate self-directed speech spontaneously, but can use language to guide behavior when prompted to do so.

Neuromotor outcomes at school age after extremely low birth weight: early detection of subtle signs.

OBJECTIVE: Motor impairments are prevalent in children born at extremely low birth weight (ELBW; <1,000 g). Rarely studied are subtle motor deficits that indicate dysfunction or delay in neural systems critical for optimal cognitive, academic, and behavioral function. We aimed to examine quantifiable signs of subtle neuromotor dysfunction in an early school-aged ELBW cohort that coincidentally had age-appropriate cognition and design copying. METHOD: We studied 97 participants born between 1998 and 2001; 74 ELBW (6.7 years ± 0.75) compared with 23 term-born (6.6 years ± 0.29). Neuromotor outcomes were assessed using the Physical and Neurological Examination of Subtle Signs-Revised, and measures of dexterity/coordination and visual-motor integration. RESULTS: ELBW participants performed worse than term-born on design-copying and dexterity, were age-appropriate compared to normative data, and had slower timed movements and more subtle overflow movements. Those ELBW born <26 weeks performed most poorly compared with those born 26-34 weeks and term-born. CONCLUSION: Subtle motor dysfunctions are detectable and quantifiable in ELBW children by school age, even in the presence of average cognition. Early age assessment of incoordination, motor speed, and overflow movements should aid initiation of timely therapies to prepare at-risk ELBW children for subsequent school entry and facilitate design of optimal early treatment strategies.

Understanding design fluency: motor and executive contributions.

Design Fluency (DF) is typically assumed to assess planning, cognitive flexibility, and fluency in generation of visual patterns, above and beyond contributions from motor speed (Delis, Kaplan, & Kramer, 2001; Ruff, 1998). The present study examined these assumptions, as little construct validation research has been done in the past. Sixty one community-dwelling elderly participants were administered the DF, Trail Making, and Letter Fluency tests from the Delis-Kaplan Executive Function System (D-KEFS), as well as electronically administered measures of motor planning and motor sequence fluency. Hierarchical regressions were used to parse out unique variance contributions to DF performance. The results showed that generation of novel designs (i.e., the first two trials on the D-KEFS DF) relied primarily on motor planning, the ability to generate novel motor actions, and, to a lesser extent, speed of drawing with a writing implement. In contrast, generation of unique designs while switching (i.e., the third trial on the D-KEFS DF) relied primarily on visual scanning and perhaps visual-attentional resources. These findings highlight the wisdom of interpreting the switching trial of the D-KEFS DF separately. Interestingly, cognitive flexibility did not contribute to performance on any of the three D-KEFS DF trials.

Age-appropriate early school age neurobehavioral outcomes of extremely preterm birth without severe intraventricular hemorrhage: a single center experience.

BACKGROUND: Extremely low birth weight (ELBW) is an established risk factor for poor neurocognitive outcome, particularly when severe intraventricular hemorrhage (IVH) complicates the neonatal course. Those born <26 weeks gestational age (GA) are at greatest risk, their outcomes poorer than later born ELBW children. Outcomes of GA subgroups of ELBW uncomplicated by severe IVH have not been well described. AIM: To compare neurocognitive and behavioral outcomes of those born < and >or=26 weeks for an ELBW cohort treated in a single center with extremely low IVH incidence. DESIGN: Single center retrospective observational cohort study of or=26 weeks (102.97+/-13.21) subgroups. No neurocognitive, achievement, or behavioral score was impaired (>or=2 SDs below the normative mean). Subgroup comparisons were nonsignificant after controlling for BW and maternal education, except for >or=26 week advantage for phoneme analysis. Poorer, but low average, performances were found for motor dexterity/coordination, spatial working memory, and selective attention. CONCLUSIONS: Age-appropriate neurocognitive and behavioral function of ELBW survivors suggests outcome may be predicted based on IVH incidence as opposed to birth weight or GA. Factors leading to decreased IVH incidence deserve further study, via single- and cross-center methodologies, to enhance decision-making regarding resuscitation and care of these highly at-risk neonates.

Acquisition of internal models of motor tasks in children with autism.

Children with autism exhibit a host of motor disorders including poor coordination, poor tool use and delayed learning of complex motor skills like riding a tricycle. Theory suggests that one of the crucial steps in motor learning is the ability to form internal models: to predict the sensory consequences of motor commands and learn from errors to improve performance on the next attempt. The cerebellum appears to be an important site for acquisition of internal models, and indeed the development of the cerebellum is abnormal in autism. Here, we examined autistic children on a range of tasks that required a change in the motor output in response to a change in the environment. We first considered a prism adaptation task in which the visual map of the environment was shifted. The children were asked to throw balls to visual targets with and without the prism goggles. We next considered a reaching task that required moving the handle of a novel tool (a robotic arm). The tool either imposed forces on the hand or displaced the cursor associated with the handle position. In all tasks, the children with autism adapted their motor output by forming a predictive internal model, as exhibited through after-effects. Surprisingly, the rates of acquisition and washout were indistinguishable from normally developing children. Therefore, the mechanisms of acquisition and adaptation of internal models in self-generated movements appeared normal in autism. Sparing of adaptation suggests that alternative mechanisms contribute to impaired motor skill development in autism. Furthermore, the findings may have therapeutic implications, highlighting a reliable mechanism by which children with autism can most effectively alter their behaviour.

Process examination of executive function in ADHD: sex and subtype effects.

To examine effects of group (Attention-Deficit/Hyperactivity Disorder [ADHD] versus Typically Developing [TD]), sex, and ADHD subtype on "process/optional" measures of executive functioning, children (n = 123; 54 ADHD, 69 TD) aged 8-16 completed subtests from the D-KEFS. No group, sex, or ADHD subtype effects were found on optional measures from the Trail Making, Color-Word Interference, and Tower tests. A significant interaction was found for Verbal Fluency Total Repetition Errors; boys with Combined/Hyperactive-Impulsive (ADHD-C/HI) type ADHD performed better than ADHD-C/HI girls, whereas girls with Inattentive type ADHD (ADHD-I) performed better than ADHD-I boys. Overall, children with ADHD did not differ from TD on most optional measures from the D-KEFS. When sex and ADHD subtype were considered, children with the subtype of ADHD less common for sex were at greater risk for poorer performance.

Brief report: enhanced picture naming in autism.

Language and communication deficits are key diagnostic criteria for autism. However, not all aspects of language are equally affected. Here we present evidence of enhanced performance of a critical aspect of language-word processing-in children with autism. The results have implications for explanatory theories of autism and language, and for the development of therapeutic approaches.

Evidence that the pattern of visuomotor sequence learning is altered in children with autism.

Motor deficits are commonly reported in autism, with one of the most consistent findings being impaired execution of skilled movements and gestures. Given the developmental nature of autism, it is possible that deficits in motor/procedural learning contribute to impaired acquisition of motor skills. Thus, careful examination of mechanisms underlying learning and memory may be critical to understanding the neural basis of autism. A previous study reported impaired motor learning in children with high-functioning autism (HFA); however, it is unclear whether the observed deficits in motor learning are due, in part, to impaired motor execution and whether these deficits are specific to autism. In order to examine these questions, 153 children (52 with HFA, 39 with attention-deficit/hyperactivity disorder (ADHD) and 62 typically developing (TD) children) participated in two independent experiments using a Rotary Pursuit task, with change in performance across blocks as a measure of learning. For both tasks, children with HFA demonstrated significantly less change in performance than did TD children, even when differences in motor execution were minimized. Differences in learning were not seen between ADHD and TD groups on either experiment. Analyses of the pattern of findings revealed that compared with both ADHD and TD children, children with HFA showed a similar degree of improvement in performance; however, they showed significantly less decrement in performance when presented with an alternate ("interference") pattern. The findings suggest that mechanisms underlying acquisition of novel movement patterns may differ in children with autism. These findings may help explain impaired skill development in children with autism and help to guide approaches for helping children learn novel motor, social and communicative skills.

Increased motor cortex white matter volume predicts motor impairment in autism.

Careful consideration of motor impairments, such as those documented in autism, can afford valuable insights into the neurological basis of developmental disorders. Motor signs are highly quantifiable and reproducible and can serve as markers for deficits in parallel systems important for socialization and communication. Correlations of motor signs with anatomic MRI (aMRI) measures therefore offer an important means of investigating brain abnormalities contributing to autism. Prior aMRI studies have revealed increased cerebral volume in young children with autism, particularly in 'outer zone' radiate white matter; however functional correlates of these findings have not been reported. In this study, we examined whether radiate white matter within the primary motor cortex would predict impaired motor performance in children with autism. Subjects included children ages 8-12 years: 20 with autism, 36 typically developing (TD) controls and 20 clinical controls with attention-deficit/hyperactivity disorder (ADHD). Regional tissue volumes were measured using an automated tissue classification algorithm followed by a semi-automated parcellation method. Motor performance was assessed using the Physical and Neurologic Examination of Subtle Signs (PANESS), with higher scores indicating poorer performance. Independent linear regression analyses revealed that for TD controls there was a significant negative correlation between total PANESS score and primary motor cortex white matter volume in both the right and left hemispheres, such that increased white matter volume predicted improved motor skill. In contrast, children with autism showed a robust positive correlation between total PANESS score and left hemisphere primary motor and premotor white matter volumes, such that increased white matter volume predicted poorer motor skill. No significant correlations were found for ADHD. Multivariate regression analyses revealed that the correlation between PANESS score and left motor cortex white matter volume in children with autism significantly differed from those in both ADHD and TD children. The correlation in ADHD did not significantly differ from that in TD children. The findings for the first time demonstrate an association between increasing radiate white matter volume and functional impairment in children with autism, in this case basic motor skill impairment. The observed association, which appears specific to autism, may be representative of global patterns of brain abnormality that not only contribute to motor dysfunction in autism, but also deficits in socialization and communication that define the disorder.