Abnormal Gait Patterns in Autism Spectrum Disorder and Their Correlations with Social Impairments

Exploring Motor Speech Disorders in Low and Minimally Verbal Autistic Individuals: An Auditory-Perceptual Analysis

PURPOSE

Motor deficits are widely documented among autistic individuals, and speech characteristics consistent with a motor speech disorder have been reported in prior literature. We conducted an auditory-perceptual analysis of speech production skills in low and minimally verbal autistic individuals as a step toward clarifying the nature of speech production impairments in this population and the potential link between oromotor functioning and language development.

METHOD

Fifty-four low or minimally verbal autistic individuals aged 4-18 years were video-recorded performing nonspeech oromotor tasks and producing phonemes, syllables, and words in imitation. Three trained speech-language pathologists provided auditory perceptual ratings of 11 speech features reflecting speech subsystem performance and overall speech production ability. The presence, attributes, and severity of signs of oromotor dysfunction were analyzed, as were relative performance on nonspeech and speech tasks and correlations between perceptual speech features and language skills.

RESULTS AND CONCLUSIONS

Our findings provide evidence of a motor speech disorder in this population, characterized by perceptual speech features including reduced intelligibility, decreased consonant and vowel precision, and impairments of speech coordination and consistency. Speech deficits were more associated with articulation than with other speech subsystems. Speech production was more impaired than nonspeech oromotor abilities in a subgroup of the sample. Oromotor deficits were significantly associated with expressive and receptive language skills. Findings are interpreted in the context of known characteristics of the pediatric motor speech disorders childhood apraxia of speech and childhood dysarthria. These results, if replicated in future studies, have significant potential to improve the early detection of language impairments, inform the development of speech and language interventions, and aid in the identification of neurobiological mechanisms influencing communication development.

Enhancing early autism diagnosis through machine learning: Exploring raw motion data for classification

In recent years, research has been demonstrating that movement analysis, utilizing machine learning methods, can be a promising aid for clinicians in supporting autism diagnostic process. Within this field of research, we aim to explore new models and delve into the detailed observation of certain features that previous literature has identified as prominent in the classification process. Our study employs a game-based tablet application to collect motor data. We use artificial neural networks to analyze raw trajectories in a "drag and drop" task. We compare a two-features model (utilizing only raw coordinates) with a four-features model (including velocities and accelerations). The aim is to assess the effectiveness of raw data analysis and determine the impact of acceleration on autism classification. Our results revealed that both models demonstrate promising accuracy in classifying motor trajectories. The four-features model consistently outperforms the two-features model, as evidenced by accuracy values (0.90 vs. 0.76). However, our findings support the potential of raw data analysis in objectively assessing motor behaviors related to autism. While the four-features model excels, the two-features model still achieves reasonable accuracy. Addressing limitations related to sample size and noise is essential for future research. Our study emphasizes the importance of integrating intelligent solutions to enhance and assist autism traditional diagnostic process and intervention, paving the way for more effective tools in assessing motor skills.

Implicit motor learning in children with autism spectrum disorder: current approaches and future directions

Motor dysfunction is increasingly being viewed as a core characteristic of autism spectrum disorder (ASD) in children. In particular, children with ASD have difficulty in learning new motor skills and there is a need to develop effective methods to improve this. Previous research has found that children with ASD may retain the ability to implicitly learn motor skills in comparison to their explicit learning of motor skills, which is typically impaired. This literature mini review focuses on summarizing the study of implicit learning in the acquisition of motor skills in children with ASD. First, we briefly introduce several common implicit learning methods in children's motor skill learning. Second, we focus on the role of two important implicit learning approaches in motor skill learning, namely, an external focus of attention and analogy learning. Finally, based on our review of the existing studies, we present an outlook for future research and the areas that need to be improved in the practical teaching of implicit learning in the acquisition of motor skills in children with ASD.

The relationship between executive function and the association of motor coordination difficulties and social communication deficits in autistic children

Background

Motor coordination difficulties could contribute to social communication deficits in autistic children. However, the exploration of the mechanism implicated in these claims has been limited by the lack of potential confounders such as executive function (EF).

Methods

We investigated the role that EF plays in the relationship between motor coordination and social communication in a school-aged autistic population via a structural model in a statistically robust manner. The results of questionnaires, including the Developmental Coordination Disorder questionnaire, the Behavior Rating Inventory of Executive Function, and the Social Responsiveness Scale, were collected to measure motor coordination, social communication deficits, and EF.

Results

A total of 182 autistic children (7.61±1.31 years, 87.9% boys) were included in the final analysis. In the model with EF as a mediator, the total effect (β=-0.599, P<0.001) and the direct effect (β=-0.331, P =0.003) of motor coordination function on social communication were both significant among autistic children without intellectual disability (ID), as were indirect effects through EF (β=-0.268, P<0.001).

Conclusion

EF partially mediates the motor coordination and social communication correlation among autistic children. We suggest that motor coordination should be included in the routine evaluation of autistic surveillance and rehabilitation procedures.

Effects of Parent-Delivered Traditional Thai Massage on Gait and Heart Rate Variability in Children with Autism: A Randomized Controlled Trial

Aim: To examine the effects of parent-delivered traditional Thai massage (TTM) intervention on heart rate variability (HRV) and gait in children with autism. Methods: This was a two-armed, randomized controlled trial conducted at the Haikou Special Education School in Haikou Province, China, between October 2021 and March 2022. A total of 48 children with autism, aged between 7 and 12 years, were selected from the school and randomly divided into either the parent-delivered TTM group or the control group (no intervention) in a 1:1 ratio. In addition to their regular daily school routines, the TTM group received 16 TTM interventions (twice a week), with each session lasting ∼50 min. HRV and gait parameters were measured at baseline, completion of the 8-week intervention, and 2 months follow-up. Results: The results of this study showed that the TTM intervention had a notable positive effect on HRV, with a significant reduction in low-frequency value (p = 0.001), and increased high-frequency value (p = 0.001), compared with the controls, and the advantages persisted during the follow-up period. However, only the stride length in the TTM group was significantly longer than that in the control group at the post-test (p = 0.039) and follow-up test (p = 0.043), while none of the other parameters of gait comparison showed statistical significance. Conclusions: Parent-delivered Thai massage increased HRV levels and stride length in comparison to the control group, and some effects of the intervention were maintained over the follow-up period. Clinical Trials Registry Identifier ChiCTR2100051355; September 21, 2021.

NSF DARE-transforming modeling in neurorehabilitation: a patient-in-the-loop framework

In 2023, the National Science Foundation (NSF) and the National Institute of Health (NIH) brought together engineers, scientists, and clinicians by sponsoring a conference on computational modelling in neurorehabiilitation. To facilitate multidisciplinary collaborations and improve patient care, in this perspective piece we identify where and how computational modelling can support neurorehabilitation. To address the where, we developed a patient-in-the-loop framework that uses multiple and/or continual measurements to update diagnostic and treatment model parameters, treatment type, and treatment prescription, with the goal of maximizing clinically-relevant functional outcomes. This patient-in-the-loop framework has several key features: (i) it includes diagnostic and treatment models, (ii) it is clinically-grounded with the International Classification of Functioning, Disability and Health (ICF) and patient involvement, (iii) it uses multiple or continual data measurements over time, and (iv) it is applicable to a range of neurological and neurodevelopmental conditions. To address the how, we identify state-of-the-art and highlight promising avenues of future research across the realms of sensorimotor adaptation, neuroplasticity, musculoskeletal, and sensory & pain computational modelling. We also discuss both the importance of and how to perform model validation, as well as challenges to overcome when implementing computational models within a clinical setting. The patient-in-the-loop approach offers a unifying framework to guide multidisciplinary collaboration between computational and clinical stakeholders in the field of neurorehabilitation.

Quantitative assessment of tip-toe behavior in individuals with autism spectrum disorder and intellectual disability: A cross-sectional study

The term "toe walking" describes walking on the toes with a lack of heel strike upon initiation of the stance phase of gait. In individuals with autism spectrum disorder (ASD), this phenomenon, or "tip-toe behavior" (TTB), can be present in a substantial proportion of subjects even during standing. In this study, we investigated TTB in 50 persons with ASD (age range 4-26 years). We evaluated TTB through an observational/report-based assessment protocol. Subsequently, we employed a new structured video-based coding protocol based on standardized video recordings, focusing on static and dynamic conditions. Finally, the findings of the two protocols were compared. Twenty-four subjects with TTB were identified and classified according to three functional groups: TTB1, present only during running (6 subjects); TTB2, present during walking and running (11 subjects); and TTB3, present during standing, walking, and running (7 subjects). Moreover, we found that TTB3 subjects exhibited a significantly higher quantity of TTB compared with subjects in the TTB1 and TTB2 groups during both standing and walking tests. Additionally, a high quantity of TTB in the static test was found to be related to a high quantity of TTB in the dynamic test. Variables such as age, autism severity, intellectual disability, and gender were not significantly associated with the mean percent of TTB both in static and dynamic tests in multivariate analysis. This structured video-based coding approach appears feasible and useful for assessing TTB in individuals with ASD and it has the potential to provide insights into TTB trajectories and aid in designing possible interventions.

A deep learning latent variable model to identify children with autism through motor abnormalities

Introduction

Autism Spectrum Disorder (ASD) is a by-birth neurodevelopmental disorder difficult to diagnose owing to the lack of clinical objective and quantitative measures. Classical diagnostic processes are time-consuming and require many specialists' collaborative efforts to be properly accomplished. Most recent research has been conducted on automated ASD detection using advanced technologies. The proposed model automates ASD detection and provides a new quantitative method to assess ASD.

Methods

The theoretical framework of our study assumes that motor abnormalities can be a potential hallmark of ASD, and Machine Learning may represent the method of choice to analyse them. In this study, a variational autoencoder, a particular type of Artificial Neural Network, is used to improve ASD detection by analysing the latent distribution description of motion features detected by a tablet-based psychometric scale.

Results

The proposed ASD detection model revealed that the motion features of children with autism consistently differ from those of children with typical development.

Discussion

Our results suggested that it could be possible to identify potential motion hallmarks typical for autism and support clinicians in their diagnostic process. Potentially, these measures could be used as additional indicators of disorder or suspected diagnosis.

Oromotor skills in autism spectrum disorder: A scoping review

Oromotor functioning plays a foundational role in spoken communication and feeding, two areas of significant difficulty for many autistic individuals. However, despite years of research and established differences in gross and fine motor skills in this population, there is currently no clear consensus regarding the presence or nature of oral motor control deficits in autistic individuals. In this scoping review, we summarize research published between 1994 and 2022 to answer the following research questions: (1) What methods have been used to investigate oromotor functioning in autistic individuals? (2) Which oromotor behaviors have been investigated in this population? and (3) What conclusions can be drawn regarding oromotor skills in this population? Seven online databases were searched resulting in 107 studies meeting our inclusion criteria. Included studies varied widely in sample characteristics, behaviors analyzed, and research methodology. The large majority (81%) of included studies report a significant oromotor abnormality related to speech production, nonspeech oromotor skills, or feeding within a sample of autistic individuals based on age norms or in comparison to a control group. We examine these findings to identify trends, address methodological aspects hindering cross-study synthesis and generalization, and provide suggestions for future research.

Balance rehabilitation for postural control in children with Autism Spectrum Disorder: A two-case report study

OBJECTIVE

This study aimed to investigate the effect of balance rehabilitation on postural control in both low and increased cognitive load conditions in two children with Autism Spectrum Disorders (ASD).

METHODS

Two children diagnosed with ASD participated in a 4-week personalized balance rehabilitation program with two sessions per week. We assessed postural control in two single task (ST) conditions with low cognitive load: Eyes Closed (EC), Eyes Open (EO); and in five increased cognitive load conditions. Those dual task (DT) conditions consisted of presenting images representing a neutral condition, sadness, anger, happiness, and fear. Postural control parameters (surface, velocity, medio-lateral and antero-posterior sway amplitudes of the center of pressure (CoP)) were collected by a posturographic platform before and after the balance rehabilitation.

RESULTS

The rehabilitation program resulted in a 30-96% improvement of postural control parameters in the ST condition for both participants. In DT, participant 1 progressed on all conditions while participant 2 progressed on 3 of the 5 conditions (sadness, anger and fear).

CONCLUSION

This suggests that these two children with ASD improved their balance control in both low and increased cognitive load conditions. These encouraging results need to be replicated before recommending balance rehabilitation as standard health rehabilitation in children with ASD.

Physiological and Psychological Effects of Parent-Delivered Traditional Thai Massage in Children With Autism: Protocol for a Randomized Controlled Trial

BACKGROUND

Although many autistic children receive massage as a complementary therapy, it is not included in evidence-based practice for autism because evidence of its efficacy is lacking. Further, prior studies have failed to identify objective indicators of core symptoms or elucidate their mechanisms.

OBJECTIVE

We developed a parent-delivered traditional Thai massage (TTM) intervention for children with autism, aiming to experimentally determine whether children with autism truly experience positive effects from parent-delivered TTM and determine possible mechanisms of the observed effects.

METHODS

A 2-armed, parallel randomized controlled trial was conducted between February 2022 and June 2022. Forty-eight children with autism (aged 7-12 years) were recruited from the Hainan Special Education School and randomly assigned to either a parental TTM or control group at a ratio of 1:1 based on random numbers generated with Online Research Randomizer. The generated sequences were concealed in an opaque envelope. Individuals in the parental TTM group received 16 parent-delivered TTM sessions over 8 weeks at the school's health room after school, and the control group maintained a normal daily routine. Outcomes were assessed on admission, after 8 weeks, and at a 2-month follow-up and included the effect of massage treatment on autism symptoms, measured with the Autism Treatment Evaluation Checklist score (evaluated by parents and a blinded teacher), physiological parameters (ie, heart rate variability and gait), and the Parenting Stress Index, Fourth Edition-Short Form.

RESULTS

We finished all data collection on June 20, 2022. Data analysis will be started, and we expect to publish results in 2023.

CONCLUSIONS

This study will provide further evidence for massage treatment of autism and provide support for family-based care.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2100051355; https://tinyurl.com/3dwjxsw5.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/41839.

A tablet-based game for the assessment of visual motor skills in autistic children

Increasing evidence suggests that early motor impairments are a common feature of autism. Thus, scalable, quantitative methods for measuring motor behavior in young autistic children are needed. This work presents an engaging and scalable assessment of visual-motor abilities based on a bubble-popping game administered on a tablet. Participants are 233 children ranging from 1.5 to 10 years of age (147 neurotypical children and 86 children diagnosed with autism spectrum disorder [autistic], of which 32 are also diagnosed with co-occurring attention-deficit/hyperactivity disorder [autistic+ADHD]). Computer vision analyses are used to extract several game-based touch features, which are compared across autistic, autistic+ADHD, and neurotypical participants. Results show that younger (1.5-3 years) autistic children pop the bubbles at a lower rate, and their ability to touch the bubble's center is less accurate compared to neurotypical children. When they pop a bubble, their finger lingers for a longer period, and they show more variability in their performance. In older children (3-10-years), consistent with previous research, the presence of co-occurring ADHD is associated with greater motor impairment, reflected in lower accuracy and more variable performance. Several motor features are correlated with standardized assessments of fine motor and cognitive abilities, as evaluated by an independent clinical assessment. These results highlight the potential of touch-based games as an efficient and scalable approach for assessing children's visual-motor skills, which can be part of a broader screening tool for identifying early signs associated with autism.

4-hydroxyisoleucine mediated IGF-1/GLP-1 signalling activation prevents propionic acid-induced autism-like behavioural phenotypes and neurochemical defects in experimental rats

Autism is a neuropsychiatric disorder characterized by a neurotransmitter imbalance that impairs neurodevelopment processes. Autism development is marked by communication difficulties, poor socio-emotional health, and cognitive impairment. Insulin-like growth factor-1 (IGF-1) and glucagon-like growth factor-1 (GLP-1) are responsible for regular neuronal growth and homeostasis. Autism progression has been linked to dysregulation of IGF-1/GLP-1 signalling. 4-hydroxyisoleucine (HI), a pharmacologically active amino acid produced from Trigonella foenum graecum, works as an insulin mimic and has neuroprotective properties. The GLP-1 analogue liraglutide (LRG) was employed in our investigation to compare the efficacy of 4-HI in autism prevention. The current study explores the protective effects of 4-HI 50 and 100 mg/kg orally on IGF-1/GLP-1 signalling activation in a PPA-induced experimental model of autism. Propionic acid (PPA) injections to rats by intracerebroventricular (ICV) route for the first 11 days of the experiment resulted in autism-like neurobehavioral, neurochemical, gross morphological, and histopathological abnormalities. In addition, we investigated the dose-dependent neuroprotective effects of 4-HI on the levels of several neurotransmitters and neuroinflammatory cytokines in rat brain homogenate and blood plasma. Neuronal apoptotic and anti-oxidant cellular markers were also studied in blood plasma and brain homogenate samples. Furthermore, the luxol fast blue (LFB) staining results demonstrated significant demyelination in the brains of PPA-induced rats reversed by 4-HI treatment. Rats were assessed for spontaneous locomotor impairments, neuromuscular coordination, stress-like behaviour, learning, and memory to assess neurobehavioral abnormalities. The administration of 4-HI and LRG significantly reversed the behavioural, gross and histological abnormalities in the PPA-treated rat brains. After treatment with 4-HI and LRG, LFB-stained photomicrographs of PPA-treated rats' brains demonstrated the recovery of white matter loss. Our findings indicate that 4-HI protects neurons in rats with autism by enhancing the IGF-1 and GLP-1 protein levels.

Motor impairments in Chinese toddlers with autism spectrum disorder and its relationship with social communicative skills

OBJECTIVE

Motor impairments are prevalent in children with autism spectrum disorder (ASD) and persistent across age. Our current study was designed to investigate motor deficits in Chinese toddlers with ASD and to explore the relationships between motor deficits and social communication skills.

METHODS

For this cross-sectional study, we recruited a total of 210 Chinese toddlers with ASD aged between 18 and 36 months in the study during December 2017 to December 2020. Griffiths Developmental Scales-Chinese (GDS-C), Autism Diagnostic Observation Schedule-Second Edition (ADOS-2) and Communication and Symbolic Behavior Scales Developmental Profile-Infant-Toddler Checklist (CSBS-DP-ITC) were administered in these toddlers to evaluate their development, social communicative skills, and autism severity. We compared the developmental and social communicational profiles of ASD toddlers in different gross and fine motor subgroups, and explored potential associated factors. The univariate generalized linear model tested the relationship of fine and gross motor skills and social communicative skills.

RESULTS

The prevalence of gross and fine motor deficits were 59.5 and 82.5%, respectively, which are almost equivalent in boys and girls. The motor impairments tended to be more severe with age in toddlers. After adjusting for age, sex, non-verbal development quotient (DQ) and restricted, repetitive behaviors, severer gross motor impairments were significantly related to higher comparison score of ADOS-2 and higher social composite score of CSBS-DP-ITC, without interactions with other variables. Meanwhile, lower fine motor skills were associated with more deficits of social communication and higher severity of ASD, also depending on non-verbal DQ. In the lower non-verbal DQ subgroup, both fine motor deficits and restricted repetitive behaviors (RRBs) might have effects on autism symptomology.

CONCLUSION

Motor impairments are common in Chinese toddlers with ASD. Toddlers with weaker gross and fine motor skills have greater deficits in social communicative skills. Gross motor impairment might be an independent predictor of the severity of autism and social communication skills, while the effect of fine motor deficits might be affected by non-verbal DQ and RRBs of toddlers with ASD. We provide further justification for the inclusion of motor impairments in the early intervention for toddlers with ASD.

Are Gait Biomechanics Related to Physical Activity Engagement? An Examination of Adolescents with ASD

PURPOSE

Adolescents with autism spectrum disorder (ASD) rarely meet physical activity (PA) guidelines, thus not reaping associated health benefits. Although many barriers exist, abnormal or inefficient gait biomechanics could negatively impact engagement in PA. This study has two purposes: first, to compare total body mechanical work between adolescents with ASD and neurotypical age, sex, and body mass index matched controls, and second to determine whether gait biomechanics are significantly related to engagement in PA.

METHODS

Twenty-five adolescents (age 13-18 years) with ASD and seventeen neurotypical controls (eight with ASD had no match) participated in the study. Three-dimensional motion capture and force platforms were used to record and analyze gait biomechanics at self-selected speeds and a standardized 1.3 m/s. Total body mechanical work (sum of joint works across lower extremity, low back, torso, and shoulders) was compared between groups (n = 17 for each) and speeds using a mixed model analysis of variance. Average daily light (LPA), moderate to vigorous (MVPA), and total PA was recorded for the entire dataset with ASD using triaxial accelerometers worn for one week. Regression analyses were performed between work, stride time variability, speed, and stride length with each PA variable.

RESULTS

Adolescents with ASD generated 9% more work compared to the controls (p=0.016). Speed and stride length were significant regressors of LPA, MVPA, and total PA, explaining greater than 0.20 variance (p<0.02 for all regressions).

CONCLUSION

Although adolescents with ASD walked with significantly greater work, the complex full-body variable is not significantly related to engagement in PA. In agreement with research spanning multiple populations and ages, speed and stride length are indicative of PA engagement in adolescents with ASD.

Visual and somatosensory feedback mechanisms of precision manual motor control in autism spectrum disorder

BACKGROUND

Individuals with autism spectrum disorder (ASD) show deficits processing sensory feedback to reactively adjust ongoing motor behaviors. Atypical reliance on visual and somatosensory feedback each have been reported during motor behaviors in ASD suggesting that impairments are not specific to one sensory domain but may instead reflect a deficit in multisensory processing, resulting in reliance on unimodal feedback. The present study tested this hypothesis by examining motor behavior across different visual and somatosensory feedback conditions during a visually guided precision grip force test.

METHODS

Participants with ASD (N = 43) and age-matched typically developing (TD) controls (N = 23), ages 10-20 years, completed a test of precision gripping. They pressed on force transducers with their index finger and thumb while receiving visual feedback on a computer screen in the form of a horizontal bar that moved upwards with increased force. They were instructed to press so that the bar reached the level of a static target bar and then to hold their grip force as steadily as possible. Visual feedback was manipulated by changing the gain of the force bar. Somatosensory feedback was manipulated by applying 80 Hz tendon vibration at the wrist to disrupt the somatosensory percept. Force variability (standard deviation) and irregularity (sample entropy) were examined using multilevel linear models.

RESULTS

While TD controls showed increased force variability with the tendon vibration on compared to off, individuals with ASD showed similar levels of force variability across tendon vibration conditions. Individuals with ASD showed stronger age-associated reductions in force variability relative to controls across conditions. The ASD group also showed greater age-associated increases in force irregularity relative to controls, especially at higher gain levels and when the tendon vibrator was turned on.

CONCLUSIONS

Our findings that disrupting somatosensory feedback did not contribute to changes in force variability or regularity among individuals with ASD suggests a reduced ability to integrate somatosensory feedback information to guide ongoing precision manual motor behavior. We also document stronger age-associated gains in force control in ASD relative to TD suggesting delayed development of multisensory feedback control of motor behavior.

Motor Skill Differences in Autism Spectrum Disorder: a Clinically Focused Review

PURPOSE OF REVIEW

This review synthesizes recent, clinically relevant findings on the scope, significance, and centrality of motor skill differences in autism spectrum disorder (ASD).

RECENT FINDINGS

Motor challenges in ASD are pervasive, clinically meaningful, and highly underrecognized, with up to 87% of the autistic population affected but only a small percentage receiving motor-focused clinical care. Across development, motor differences are associated with both core autism symptoms and broader functioning, though the precise nature of those associations and the specificity of motor profiles to ASD remain unestablished. Findings suggest that motor difficulties in ASD are quantifiable and treatable, and that detection and intervention efforts targeting motor function may also positively influence social communication. Recent evidence supports a need for explicit recognition of motor impairment within the diagnostic framework of ASD as a clinical specifier. Motor differences in ASD warrant greater clinical attention and routine incorporation into screening, evaluation, and treatment planning.

Walking lower extremity biomechanics of adolescents with autism spectrum disorder

Although the literature indicates children with autism spectrum disorder (ASD) walk at slower speeds and altered kinematics compared to neurotypical controls, no research has examined walking at matched speeds. This study examined biomechanical differences between adolescents with ASD and matched (age, sex, and body mass index) neurotypical controls. Lower extremity biomechanics of seventeen adolescents with ASD and seventeen controls were compared at matched speeds: self-selected and a standardized 1.3 m/s. Controls exhibited greater eversion angles and hip abduction moments compared to those with ASD. This study found adolescents, which may have a more mature gait than young children, walk with a similar pattern in the propulsive plane (i.e. sagittal) as neurotypical controls, but with alterations in the supportive plane (i.e. frontal).

Major motor and gait deficits with sexual dimorphism in a Shank3 mutant mouse model

Background

Contrasting findings were reported in several animal models with a Shank3 mutation used to induce various autism spectrum disorder (ASD) symptoms. Here, we aimed at investigating behavioral, cellular, and molecular consequences of a C-terminal (frameshift in exon 21) deletion in Shank3 protein in mice, a mutation that is also found in clinical conditions and which results in loss of major isoforms of Shank3. A special focus was made on cerebellar related parameters.

Methods

All three genotypes were analyzed [wild type (WT), heterozygote (Shank3+/ΔC) and homozygote (Shank3 ΔC/ΔC)] and males and females were separated into two distinct groups. Motor and social behavior, gait, Purkinje cells (PC) and glutamatergic protein levels were determined. Behavioral and cellular procedures used here were previously validated using two environmental animal models of ASD. ANOVA and post-hoc analysis were used for statistical analysis.

Results

Shank3 ΔC/ΔC mice showed significant impairments in social novelty preference, stereotyped behavior and gait. These were accompanied by a decreased number of PC in restricted cerebellar sub-regions and decreased cerebellar expression of mGluR5. Females Shank3 ΔC/ΔC were less affected by the mutation than males. Shank3+/ΔC mice showed impairments only in social novelty preference, grooming, and decreased mGluR5 expression and that were to a much lesser extent than in Shank3 ΔC/ΔC mice.

Limitations

As Shank3 mutation is a haploinsufficiency, it is of interest to emphasize that Shank3+/ΔC mice showed only mild to no deficiencies compared to Shank3 ΔC/ΔC.

Conclusions

Our findings indicate that several behavioral, cellular, and molecular parameters are affected in this animal model. The reported deficits are more pronounced in males than in females. Additionally, male Shank3 ΔC/ΔC mice show more pronounced alterations than Shank3+/ΔC. Together with our previous findings in two environmental animal models of ASD, our studies indicate that gait dysfunction constitutes a robust set of motor ASD symptoms that may be considered for implementation in clinical settings as an early and quantitative diagnosis criteria.