Typically Developing Toddlers Research Articles

Visual Attention in Joint Attention Bids: A Comparison Between Toddlers with Autism Spectrum Disorder and Typically Developing Toddlers.

Impairments in joint attention are considered core symptoms of autism spectrum disorder (ASD) and are crucial for early assessment and intervention. However, existing information about visual attention during joint attention and its relation to developmental functioning is limited. The current study investigated the visual attention differences between toddlers with ASD and typically developing (TD) toddlers during single and multiple joint attention cue conditions. This study further examined whether visual attention in joint attention Area of Interests (AOIs) is related to cognitive, language, and motor development in participants. Participants included 56 toddlers with ASD and 56 TD toddlers, aged 18-36months. A passive viewing paradigm was used to assess participants' visual attention across four different joint attention conditions. Study results showed that toddlers with ASD displayed limited visual attention towards joint attention AOIs, Target, Face, and Target and Face AOIs, in all conditions. As the joint attention cues increased from Condition 1 to Condition 4, toddlers with ASD showed increased visual attention directed towards the Target AOI over the Face AOI. Moreover, increased visual attention on the joint attention AOIs was associated with improved cognitive and language development in toddlers with ASD. This research broadens our understanding of the positive relationships between visual attention to joint attention AOIs and cognitive as well as language development in toddlers with ASD, suggesting that early interventions targeting joint attention may offer promising pathways for treatment.

Attentional differences in audiovisual face perception between full- and preterm very low birthweight toddlers.

To investigate whether rightward attention to the mouth during audiovisual speech perception may be a behavioural marker for early brain development, we studied very preterm and low birthweight (VLBW) and typically developing (TD) toddlers. We tested the distribution of gaze points in Japanese-learning TD and VLBW toddlers when exposed to talking, silent and mouth moving faces at 12, 18 and 24 months (corrected age). Each participant was categorised based upon the area they gazed at most (Eye-Right, Eye-Left, Mouth-Right, Mouth-Left) per stimulus per age. A log-linear model was applied to three-dimensional contingency tables (region, side and group). VLBW toddlers showed fewer gaze points than TD toddlers. At 12 months, more VLBW toddlers than TD toddlers showed left attentional bias toward any one face; however, this difference in attention asymmetry receded somewhat by 24 months. In talking condition, TD toddlers showed right attentional bias from 12 to 24 months, whereas VLBW toddlers showed such bias upon reaching 24 months. Additionally, more TD toddlers than VLBW toddlers attended to the mouth. Delays in exhibiting the attentional bias for an audiovisual face or general faces displayed by typically developing children might suggest differential developmental timing for hemispheric specialisation or dominance.

A predictive ensemble classifier for the gene expression diagnosis of ASD at ages 1 to 4 years

Autism Spectrum Disorder (ASD) diagnosis remains behavior-based and the median age of diagnosis is ~52 months, nearly 5 years after its first-trimester origin. Accurate and clinically-translatable early-age diagnostics do not exist due to ASD genetic and clinical heterogeneity. Here we collected clinical, diagnostic, and leukocyte RNA data from 240 ASD and typically developing (TD) toddlers (175 toddlers for training and 65 for test). To identify gene expression ASD diagnostic classifiers, we developed 42,840 models composed of 3570 gene expression feature selection sets and 12 classification methods. We found that 742 models had AUC-ROC ≥ 0.8 on both Training and Test sets. Weighted Bayesian model averaging of these 742 models yielded an ensemble classifier model with accurate performance in Training and Test gene expression datasets with ASD diagnostic classification AUC-ROC scores of 85–89% and AUC-PR scores of 84–92%. ASD toddlers with ensemble scores above and below the overall ASD ensemble mean of 0.723 (on a scale of 0 to 1) had similar diagnostic and psychometric scores, but those below this ASD ensemble mean had more prenatal risk events than TD toddlers. Ensemble model feature genes were involved in cell cycle, inflammation/immune response, transcriptional gene regulation, cytokine response, and PI3K-AKT, RAS and Wnt signaling pathways. We additionally collected targeted DNA sequencing smMIPs data on a subset of ASD risk genes from 217 of the 240 ASD and TD toddlers. This DNA sequencing found about the same percentage of SFARI Level 1 and 2 ASD risk gene mutations in TD (12 of 105) as in ASD (13 of 112) toddlers, and classification based only on the presence of mutation in these risk genes performed at a chance level of 49%. By contrast, the leukocyte ensemble gene expression classifier correctly diagnostically classified 88% of TD and ASD toddlers with ASD risk gene mutations. Our ensemble ASD gene expression classifier is diagnostically predictive and replicable across different toddler ages, races, and ethnicities; out-performs a risk gene mutation classifier; and has potential for clinical translation.

Show gestures direct attention to word–object relations in typically developing and Autistic Spectrum Disorder children

Previous research by Rader and Zukow-Goldring (2010, 2012, 2015) on word learning found that infants benefit from a speaker's use of a show gesture. Here we examined whether this benefit exists in typically developing (TD) children aged 24.2–76.7 months, as well as in children with Autism Spectrum Disorder (ASD) aged 5.8–8.2 years. While we recorded eye gaze, children viewed a video showing a speaker introducing two novel objects with nonce words. In the show condition, the speaker moved the object in synchrony with her speech, while in the static condition she held the object stationary. After the speaker introduced the objects, we assessed word learning. Analysis of word learning found that the TD toddlers and the ASD children benefited from the show condition, while preschool and elementary-aged TD children learned equally well in both gesture conditions. We propose that show gestures present metamodal information specifying word reference relationships and that this information is used by TD toddlers and older ASD children in learning words.

Auditory joint attention skills: Development and diagnostic differences during infancy

To date, joint attention skill assessments have focused on children’s responses to multimodal bids (RJA) and their initiation of bids (IJA) to multimodal spectacles. Here we gain a systematic view of auditory joint attention skills using a novel assessment that measures both auditory and multimodal RJA and IJA. In Study 1, 47 typically developing (TD) children were tested 5 times from 12 to 30 months to document auditory joint attention skill development. In Study 2, 113 toddlers (39 TD, 33 autism spectrum disorder [ASD], and 41 non-ASD developmental disorders [DD]; average age 22.4 months) were tested to discern the effects of ASD. Our findings fit well within the established depiction of joint attention skills with one important caveat: auditory items were far more difficult to execute than multimodal ones. By 24 months, TD children passed multimodal RJA items at the near-ceiling level, an accomplishment not reached even by 30 months for auditory RJA items. Intentional communicative IJA bids also emerged more slowly to auditory spectacles than to multimodal spectacles. Toddlers with DD outperformed toddlers with ASD on multimodal RJA items but toddlers in both groups rarely passed any auditory RJA items. Toddlers with ASD often monitored their partner’s attention during IJA items, albeit less often than toddlers with DD and TD toddlers, but they essentially never produced higher-level IJA bids, regardless of modality. Future studies should investigate further how variations in bids and targets affect auditory joint attention skills and probe the relation between these skills and language development.

Attend Less, Fear More: Elevated Distress to Social Threat in Toddlers With Autism Spectrum Disorder.

Differential emotional reactivity to social and nonsocial stimuli has been hypothesized but rarely examined empirically in ASD despite its potential importance for development of social motivation, cognition, and comorbid psychopathology. This study examined emotional reactivity, regulation, and attention to social and nonsocial threat in toddlers with ASD (n= 42, Mage : 22 months) and typically developing (TD) toddlers (n= 22, Mage : 23 months), and their mutual associations with autism symptom severity. Participants were exposed to social (stranger), nonsocial (mechanical objects), and ambiguous (masks) threats, and their intensity of distress (iDistress), attention to threat (Attention), and presence of emotion regulation (ER) strategies were measured. Autism symptom severity was quantified using the Autism Diagnostic Observation Schedule-2. In response to social threat, toddlers with ASD exhibited elevated iDistress (P< 0.038) but lower Attention (P< 0.002) and a wider variety of ER strategies (P< 0.040) compared to TD controls, though their ER strategies were less likely to be social. However, nonsocial and ambiguous threat elicited lower iDistress in ASD than in TD toddlers (P= 0.012 and P= 0.034, respectively), but comparable Attention and ER strategy use. Autism severity was not associated with iDistress. The study demonstrates elevated emotional salience but diminished attentional salience of social threat in ASD. A failure to attend adequately to social threats may restrict opportunities to appraise their threat value and engender often observed in ASD negative emotional responses to novel social situations. Early atypical emotional reactivity may independently contribute to the shaping of complex autism phenotypes and may be linked with later emerging affective and behavioral symptoms. LAY SUMMARY: Compared to typically developing toddlers, toddlers with ASD show diminished attention yet enhanced distress in response to social threat. Poor attention to potential social threat may limit opportunities to assess its threat value and thus contribute to often observed negative emotional responses to novel social situations. Identifying the precursors of atypical emotional reactivity in infancy and its links with later psychopathology will inform about novel treatment targets and mechanisms of change in the early stages of ASD. Autism Res 2021, 14: 1025-1036. © 2020 International Society for Autism Research, Wiley Periodicals, LLC.

Seeing a Page in a Flipbook: Shorter Visual Temporal Integration Windows in 2‐Year‐Old Toddlers with Autism Spectrum Disorder

Individuals with autism spectrum disorder (ASD) experience differences in visual temporal processing, the part of vision responsible for parsing continuous input into discrete objects and events. Here we investigated temporal processing in 2-year-old toddlers diagnosed with ASD and age-matched typically developing (TD) toddlers. We used a visual search task where the visibility of the target was determined by the pace of a display sequence. On integration trials, each display viewed alone had no visible target, but if integrated over time, the target became visible. On segmentation trials, the target became visible only when displays were perceptually segmented. We measured the percent of trials when participants fixated the target as a function of the stimulus onset asynchrony (SOA) between displays. We computed the crossover point of the integration and segmentation performance functions for each group, an estimate of the temporal integration window (TIW), the period in which visual input is combined. We found that both groups of toddlers had significantly longer TIWs (125 ms) than adults (65 ms) from previous studies using the same paradigm, and that toddlers with ASD had significantly shorter TIWs (108 ms) than chronologically age-matched TD controls (142 ms). LAY SUMMARY: We investigated how young children, with and without autism, organize dynamic visual information across time, using a visual search paradigm. We found that toddlers with autism had higher temporal resolution than typically developing (TD) toddlers of the same age - that is, they are more likely to be able to detect rapid change across time, relative to TD toddlers. These differences in visual temporal processing can impact how one sees, interprets, and interacts with the world. Autism Res 2021, 14: 946-958. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

Αλληλοσυντονισμός της προσοχής και γλωσσική ανάπτυξη σε νήπια με σύνδρομο Down

Many studies demonstrate that in typically developing (TD) children joint attention constitutes a prerequisite for language development. However, data on the development of joint attention and its relation to language development in Down syndrome (DS) are contradictory. The present study aims to examine joint attention in toddlers with DS as well as its association with language comprehension and production. Participants were 10 toddlers with DS (mean chronological age: 58 months) and 10 TD toddlers matched for language comprehension (mean chronological age: 32 months). Language Comprehension and language production were assessed using the Müllen Scales of Early Learning, expressive vocabulary was assessed using the Language Development Survey, and the communicative behaviors were assessed through observation of interactions with the mother in a semi-structured condition with toys. According to the findings, toddlers with DS exhibit significantly morejoint attention behaviors compared to TD toddlers. Moreover, it was shown that in toddlers with DS language production was significantly negatively correlated with initiating request gestures. Conclusively, it seems that in toddlers with DS the transition from pre-linguistic to linguistic period follows a similar developmental path as in TD toddlers, although a severe delay is observed.

Characteristics of newly acquired gait in toddlers with unilateral cerebral palsy: Implications for early rehabilitation.

Knowledge of the characteristics of newly acquired gait in toddlers with cerebral palsy (CP) is limited. This study compared gait characteristics (spatiotemporal parameters, kinematics and lower-limb muscle activation) within the first 6months of independent walking in toddlers with unilateral cerebral palsy (UCP) and typically developing (TD) children. The gait of 28TD toddlers and 13toddlers with UCP, all up to 3years old with maximum walking experience of 6 months, was recorded by using a 3-D optoelectronic system and surface electromyography (EMG). Statistical parametric mapping was used to compare the kinematic parameters and EMG envelopes. Mann-Whitney U test was used to compare spatiotemporal parameters between groups. Principal component analysis was used to determine whether the main kinematic results were related to the clinical measures. Toddlers with UCP had bilateral modifications of the spatiotemporal parameters during gait as compared with TD toddlers and temporal asymmetry. The largest kinematic difference between the UCP and TD groups was external pelvic rotation on the affected side (13.3°). Foot progression angle was external during swing phase on the affected side. The groups did not differ in muscle activation for the set of muscles recorded. Pelvic rotation was not associated with any of the clinical measures on the affected or non-affected sides of toddlers with UCP. Alterations in kinematic gait parameters were mostly found at the pelvis in toddlers with UCP and newly acquired gait. At that age, the external pelvic rotation on the affected side is more likely due to primary motor control disorders than compensatory mechanisms. These findings suggest that early rehabilitation should focus on proximal motor control, balance and symmetry to optimize gait development from the early stages in children with UCP.

Validation of the modified checklist for autism in toddlers, revised with follow-up in Taiwanese toddlers

BackgroundThe Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M−CHAT-R/F) is a two-stage screening scale for determining the risk of autism spectrum disorder (ASD) in toddlers. However, the validity of the M−CHAT-R/F for Asian populations has not yet been established. AimsThis study investigated the psychometric properties of the M−CHAT-R/F, Taiwan version (M−CHAT-R/F–T), among low- and high-risk Taiwanese toddlers aged 16–30 months. The associations among M−CHAT-R/F−T scores, developmental performance at 24 and 30 months, and ASD diagnosis prediction at 36 months were examined. Methods and ProceduresA two-stage screening of the M−CHAT-R/F−T was applied to a study sample comprising 25 toddlers with ASD and 71 atypically developing (ATD) and 221 typically developing (TD) toddlers. Outcomes and ResultsThe M−CHAT-R/F–T exhibited acceptable internal consistency and test–retest reliability. The M−CHAT-R/F–T scores were significantly correlated with several syndrome scores of the Child Behavior Checklist for Ages 1.5–5 and were significantly higher among toddlers with ASD than among ATD or TD toddlers. Furthermore, M−CHAT-R/F–T scores were negatively correlated with developmental scores in the Mullen Scales of Early Learning at 24 and 30 months. Moreover, the screening exhibited acceptable predictive validity (sensitivity = 0.86; specificity = 0.96) for ASD diagnosis at 36 months. Conclusions and ImplicationsThe findings indicate that the M−CHAT-R/F–T is a valid and reliable tool for the developmental screening of low- and high-risk Taiwanese toddlers in community and clinical settings.

Temporal-spatial reach parameters derived from inertial sensors correlate to neurodevelopment in toddlers born preterm

Temporal-spatial reach parameters are revealing of upper-limb function in children with motor impairments, but have not been quantified in a toddler population. This work quantitatively characterizes temporal-spatial reach in typically-developing (TD) and very-low-birth-weight (VLBW) preterm toddlers, who are at increased risk of motor impairment. 47 children born VLBW (<1500 g birth-weight; ≤32 weeks gestation) and 22 TD children completed a reaching assessment at 18–22 months of age, adjusted for prematurity. Inertial sensors containing accelerometers, gyroscopes and magnetometers were fixed to toddlers’ wrists while they reached for a cube. Reach time, path length, velocity at contact, peak velocity magnitude and timing, acceleration at contact, and peak acceleration were derived from inertial-sensor and high-speed video data. Preterm children also received the Bayley Scales of Infant Development—3rd Edition (BSID-III). Compared to TD toddlers, preterm toddlers had significantly different reach path length, velocity at contact, peak velocity magnitude and timing, acceleration at contact, and peak acceleration. Among preterm toddlers, decreased reach time (rho = −.346, p = .018), decreased time to peak velocity (r = −.390, p = .007), and increased peak acceleration (r = .298, p = .044) correlated to higher BSID-III fine motor scores. Toddlers with below-average fine motor scores had significantly higher peak and contact velocity. Preterm toddlers demonstrated substantial differences in temporal-spatial reach parameters compared to TD toddlers, and evidence indicated several reach parameters were revealing of function and may be useful as a clinical assessment.

Prefrontal Hemodynamics in Toddlers at Rest: A Pilot Study of Developmental Variability

Functional near infrared spectroscopy (fNIRS) is a non-invasive functional neuroimaging modality. Although, it is amenable to use in infants and young children, there is a lack of fNIRS research within the toddler age range. In this study, we used fNIRS to measure cerebral hemodynamics in the prefrontal cortex (PFC) in 18–36 months old toddlers (n = 29) as part of a longitudinal study that enrolled typically-developing toddlers as well as those “at risk” for language and other delays based on presence of early language delays. In these toddlers, we explored two hemodynamic response indices during periods of rest during which time audiovisual children's programming was presented. First, we investigate Lateralization Index, based on differences in oxy-hemoglobin saturation from left and right prefrontal cortex. Then, we measure oxygenation variability (OV) index, based on variability in oxygen saturation at frequencies attributed to cerebral autoregulation. Preliminary findings show that lower cognitive (including language) abilities are associated with fNIRS measures of both lower OV index and more extreme Lateralization index values. These preliminary findings show the feasibility of using fNIRS in toddlers, including those at risk for developmental delay, and lay the groundwork for future studies.

Phonological Process Occurrence in Typically Developing Toddlers

Background/Aims: The study examined the phonological development in Cypriot Greek (CG)-speaking, typically developing (TD) toddlers for the purpose of observing occurrences of initial consonant deletion (ICD), regressive assimilation (RAS), and their interactive relationship as a function of time. Participants and Methods: Subjects were 8 CG-speaking TD toddlers assessed longitudinally at ages 24-28 and 32-36 months. Word targets from spontaneously produced utterances via language sample collection were analyzed for the percentage of occurrence of ICD and RAS. Results: Results revealed a significant change of phonological process occurrence as a function of time as well as an antagonistic relationship between ICD and correct onset production. Comparisons between measures showed that trisyllabic (three-syllable) words exhibited higher rates of ICD than disyllabic words. Conclusions: Early patterns of phonological development and phonological assessment should include a hierarchical account of phonological behavior in the form of word structure shapes and a possible interaction among phonological process occurrence.

“You’re telling me!” The prevalence and predictors of pronoun reversals in children with autism spectrum disorders and typical development

Social and linguistic explanations have been proposed for pronoun reversals in young typically developing (TD) children and those with autism spectrum disorders (ASD). The current study breaks new ground in investigating both explanations, comparing 18 TD toddlers and 15 children with ASD at similar language levels. Spontaneous speech was sampled every four months for six visits. Vocabulary and joint attention were also measured. Both groups produced pronoun reversals at low rates. The ASD group produced somewhat more reversals than the TD group, overall and at multiple visits. In the ASD group, early language and joint attention scores contributed significantly and independently to the incidence of reversal. Both linguistic and social factors seem implicated; moreover, reversals seem to occur when children’s language and social abilities develop asynchronously. These findings can help clinicians devise both linguistic and social interventions for the relevant children.

Temporal-spatial gait parameters and neurodevelopment in very-low-birth-weight preterm toddlers at 18–22 months

Children born preterm with very-low birth-weight (VLBW) have increased risk of motor impairment. Early identification of impairment guides treatment to improve long-term function. Temporal-spatial gait parameters are an easily-recorded assessment of gross motor function. The objective of this study was to characterize preterm toddlers’ gait and its relationship with neurodevelopment. Velocity, cycle time, step width, step length and time asymmetry, %stance, %single-limb support, and %double-limb support were calculated for 81 VLBW preterm and 43 typically-developing (TD) toddlers. Neurodevelopment was assessed with Bayley Scales of Infant Development-3rd Edition (BSID-III) motor composite and gross motor scores. Mean step width (p=.009) was wider in preterm compared to TD toddlers. Preterm toddlers with <85 BSID-III motor composite scores, indicating mild-to-moderate delay, had significantly increased step width, step length asymmetry, and step time compared to TD toddlers. Step time was also significantly longer for lower-scoring compared to higher-scoring (≥85 BSID-III motor composite scores) preterm toddlers, suggesting that step time may be particularly sensitive to gradations of motor performance. Velocity, cycle time, step length asymmetry, %stance, step length, and step time significantly correlated with BSID-III gross motor scores, suggesting that these parameters may be revealing of gross motor function. The differences in gait between lower-scoring preterm toddlers and TD toddlers, together with the correlations between gait and BSID-III motor scores, suggest that temporal-spatial gait parameters may be useful in building a clinically-relevant, easily-conducted assessment of toddler gross motor development.

Concern for Another's Distress in Toddlers at High and Low Genetic Risk for Autism Spectrum Disorder.

We examined concern for others in 22-month-old toddlers with an older sibling with autism spectrum disorder (ASD) and low risk typically-developing toddlers with older siblings. Responses to a crying infant and an adult social partner who pretended to hurt her finger were coded. Children with a later diagnosis of ASD showed limited empathic concern in either context compared to low risk toddlers. High risk toddlers without a later diagnosis fell between the ASD and low risk groups. During the crying baby probe the low risk and high risk toddlers without a diagnosis engaged their parent more often than the toddlers with ASD. Low levels of empathic concern and engagement with parents may signal emerging ASD in toddlerhood.

Discrimination and Reversal Learning by Toddlers Aged 15-23 Months.

Few studies have investigated simple discrimination and discrimination reversal learning by children younger than 2 years. Extant research has shown that teaching discrimination reversals may be challenging with this population. We used social reinforcement and correction procedures to teach simple simultaneous discrimination and discrimination reversal tasks involving three pairs of animal pictures displayed in a paper notebook. Participants were eight typically-developing toddlers aged 15-23 months. All learned at least one simple discrimination/discrimination reversal problem. Four children learned all problems and showed evidence of learning set formation. Perhaps surprisingly, discrimination reversals were sometimes learned more rapidly than original discriminations. The procedures suggest a potentially efficient methodology for investigating more complex aspects of relational learning in toddlers.

Face-viewing patterns in young children with autism spectrum disorders: speaking up for the role of language comprehension.

The aim was to examine whether viewing patterns toward the mouth, eyes, and nonmouth-noneyes areas differed between young children with autism spectrum disorder (ASD) and typically developing (TD) children when viewing a person speaking. The role of language comprehension in such viewing patterns was also examined. Eleven children with ASD (approximately 4.5 years old) and 29 TD toddlers (approximately 2.5 years old) participated. The groups were matched on language comprehension raw scores from the Reynell Developmental Language Scales III. All children viewed short films of a woman speaking while their eye movements were recorded with eye-tracking equipment. Children with ASD spent proportionally less time viewing the mouth and more time viewing the nonmouth-noneyes areas. Time viewing the eyes did not differ between groups. Increased mouth viewing was associated with lower language comprehension in the group with ASD. Variability in language comprehension is an important factor to monitor when interpreting face-viewing patterns in young children with ASD, particularly with regard to mouth viewing. The results may help explain divergent findings in this field of research.

Rating parent-child interactions: joint engagement, communication dynamics, and shared topics in autism, Down syndrome, and typical development.

A battery of 17 rating items were applied to video records of typically-developing toddlers and young children with autism and Down syndrome interacting with their parents during the Communication Play Protocol. This battery provided a reliable and broad view of the joint engagement triad of child, partner, and shared topic. Ratings of the child's joint engagement correlated very strongly with state coding of joint engagement and replicated the finding that coordinated joint engagement was less likely in children with autism. Ratings of other child actions, of parent contributions, and of shared topics and communicative dynamics also documented pervasive variations related to diagnosis, language facility, and communicative context.

Training Toddlers Seated on Mobile Robots to Drive Indoors Amidst Obstacles

Mobility is a causal factor in development. Children with mobility impairments may rely upon power mobility for independence and thus require advanced driving skills to function independently. Our previous studies show that while infants can learn to drive directly to a goal using conventional joysticks in several months of training, they are unable in this timeframe to acquire the advanced skill to avoid obstacles while driving. Without adequate driving training, children are unable to explore the environment safely, the consequences of which may in turn increase their risk for developmental delay. The goal of this research therefore is to train children seated on mobile robots to purposefully and safely drive indoors. In this paper, we present results where ten typically-developing toddlers are trained to drive a robot within an obstacle course. We also report a case study with a toddler with spina-bifida who cannot independently walk. Using algorithms based on artificial potential fields to avoid obstacles, we create force field on the joystick that trains the children to navigate while avoiding obstacles. In this "assist-as-needed" approach, if the child steers the joystick outside a force tunnel centered on the desired direction, the driver experiences a bias force on the hand. Our results suggest that the use of a force-feedback joystick may yield faster learning than the use of a conventional joystick.