Repetitive Motor Behaviors Research Articles

Characterizing associations between emotion dysregulation, anxiety, and repetitive behaviors in autistic youth with intellectual disability.

There is a paucity of research that explores associations between emotion dysregulation and the expression and severity of core and co-occurring characteristics of autism spectrum disorder (ASD), especially in autistic youth with co-occurring intellectual disability (ID). This study explored the interplay between developmental characteristics and emotion dysregulation, anxiety, and specific subtypes of RRBs that are elevated in autistic youth with co-occurring ID. Generalized additive models demonstrated that age, sex, language level, dysregulation, and anxiety showed unique patterns of association with subtypes of RRBs in a sample of 150 autistic youth with co-occurring ID who are non-speaking or minimally verbal. More specifically, higher anxiety levels were significantly associated with elevations in repetitive sensory motor behaviors (RSMB), self-injurious behaviors (SIB), insistence on sameness (IS), and unusual interests (UI). While emotion dysregulation was a significant predictor of UI, it demonstrated positive, albeit not significant, associations with the intensity of SIB and RSMB. Language level was a significant predictor of RSMB, such that the intensity of RSMB was higher for individuals who were non-speaking relative to those who spoke in single words. These findings provide preliminary insights into patterns of associations between emotion dysregulation, anxiety, and specific subdomains of RRBs in autistic youth with ID.

Environmental enrichment reduces restricted repetitive behavior by altering gray matter microstructure.

Restricted, repetitive behaviors are common symptoms in neurodevelopmental disorders including autism spectrum disorder. Despite being associated with poor developmental outcomes, repetitive behaviors remain poorly understood and have limited treatment options. Environmental enrichment attenuates the development of repetitive behaviors, but the exact mechanisms remain obscure. Using the C58 mouse model of repetitive behavior, we performed diffusion tensor imaging to examine microstructural alterations associated with the development of repetitive behavior and its attenuation by environmental enrichment. The C57BL/6 mouse strain, which displays little or no repetitive behavior, was used as a control group. We observed widespread differences in diffusion metrics between C58 mice and C57BL/6 mice. In juvenile C58 mice, repetitive motor behavior displayed strong negative correlations with fractional anisotropy in multiple gray matter regions, whereas in young adult C58 mice, high repetitive motor behavior was most strongly associated with lower fractional anisotropy and higher radial diffusivity in the striatum. Environmental enrichment increased fractional anisotropy and axial diffusivity throughout gray matter regions in the brains of juvenile C58 mice and overlapped predominantly with cerebellar and sensory regions associated with repetitive behavior. Our results suggest environmental enrichment reduces repetitive behavior development by altering gray matter microstructure in the cerebellum, medial entorhinal cortex, and sensory processing regions in juvenile C58 mice. Under standard laboratory conditions, early pathology in these regions appears to contribute to later striatal and white matter dysfunction in adult C58 mice. Future studies should examine the role these regions play in the development of repetitive behavior and the relationship between sensory processing and cerebellar deficits and repetitive behavior.

A New Star in the Sky of Tic Pathophysiology: The Role of Astrocytes in Repetitive Motor Behaviors.

A New Star in the Sky of Tic Pathophysiology: The Role of Astrocytes in Repetitive Motor Behaviors.

Human mutations in high-confidence Tourette disorder genes affect sensorimotor behavior, reward learning, and striatal dopamine in mice

Tourette disorder (TD) is poorly understood, despite affecting 1/160 children. A lack of animal models possessing construct, face, and predictive validity hinders progress in the field. We used CRISPR/Cas9 genome editing to generate mice with mutations orthologous to human de novo variants in two high-confidence Tourette genes, CELSR3 and WWC1. Mice with human mutations in Celsr3 and Wwc1 exhibit cognitive and/or sensorimotor behavioral phenotypes consistent with TD. Sensorimotor gating deficits, as measured by acoustic prepulse inhibition, occur in both male and female Celsr3 TD models. Wwc1 mice show reduced prepulse inhibition only in females. Repetitive motor behaviors, common to Celsr3 mice and more pronounced in females, include vertical rearing and grooming. Sensorimotor gating deficits and rearing are attenuated by aripiprazole, a partial agonist at dopamine type II receptors. Unsupervised machine learning reveals numerous changes to spontaneous motor behavior and less predictable patterns of movement. Continuous fixed-ratio reinforcement shows that Celsr3 TD mice have enhanced motor responding and reward learning. Electrically evoked striatal dopamine release, tested in one model, is greater. Brain development is otherwise grossly normal without signs of striatal interneuron loss. Altogether, mice expressing human mutations in high-confidence TD genes exhibit face and predictive validity. Reduced prepulse inhibition and repetitive motor behaviors are core behavioral phenotypes and are responsive to aripiprazole. Enhanced reward learning and motor responding occur alongside greater evoked dopamine release. Phenotypes can also vary by sex and show stronger affection in females, an unexpected finding considering males are more frequently affected in TD.

Porphyria Presenting with Psychotic Symptoms and Developmental Regression: A Diagnostic Dilemma

Abstract We report a case of a 12-year-old boy who presented with acute onset of psychotic symptoms and later developed developmental regression and repetitive motor behavior. A number of investigations were done and urine was noted to be positive for porphobilinogen. A diagnosis of acute intermittent porphyria (AIP) was considered. AIP usually presents with abdominal pain, gastrointestinal disturbances, peripheral neuropathy, and psychiatric disturbances. The most common psychiatric symptoms include irritability, depression, anxiety, insomnia, hallucinations, and paranoia or altered consciousness. This case is unique as the only clinical manifestations were psychotic symptoms and developmental regression.

Rhythmic motor behavior explains individual differences in grammar skills in adults

A growing body of literature has reported the relationship between music and language, particularly between individual differences in perceptual rhythm skill and grammar competency in children. Here, we investigated whether motoric aspects of rhythm processing—as measured by rhythmic finger tapping tasks—also explain the rhythm-grammar connection in 150 healthy young adults. We found that all expressive rhythm skills (spontaneous, synchronized, and continued tapping) along with rhythm discrimination skill significantly predicted receptive grammar skills on either auditory sentence comprehension or grammaticality well-formedness judgment (e.g., singular/plural, past/present), even after controlling for verbal working memory and music experience. Among these, synchronized tapping and rhythm discrimination explained unique variance of sentence comprehension and grammaticality judgment, respectively, indicating differential associations between different rhythm and grammar skills. Together, we demonstrate that even simple and repetitive motor behavior can account for seemingly high-order grammar skills in the adult population, suggesting that the sensorimotor system continue to support syntactic operations.

Environmental interventions reduced repetitive behavior in a mouse model

Repetitive motor behaviors are associated with several neurodevelopmental disorders including autism spectrum disorder. Non-invasive environmental interventions that can ameliorate repetitive behavior and be introduced in early development could benefit many. In Experiment 1, we characterized the development of repetitive circling in mice reared in standard and enriched environments. Environmental enrichment was associated with reduced repetitive behavior. In Experiment 2, two weekly injections of an A2A adenosine receptor agonist reduced repetitive behavior in mice fed a ketogenic diet. Together, these two approaches modified the environment and reduced repetitive behavior with potential implications for increased functioning of the indirect basal ganglia pathway.

The Partial M1 Muscarinic Cholinergic Receptor Agonist, CDD-0102A, Differentially Modulates Glutamate Efflux in Striatal Subregions during Stereotyped Motor Behavior in the BTBR Mouse Model of Autism.

The BTBR T+ Itpr3tf/J (BTBR) mouse displays elevated repetitive motor behaviors. Treatment with the partial M1 muscarinic receptor agonist, CDD-0102A, attenuates stereotyped motor behaviors in BTBR mice. The present experiment investigated whether CDD-0102A modifies changes in striatal glutamate concentrations during stereotyped motor behavior in BTBR and B6 mice. Using glutamate biosensors, change in striatal glutamate efflux was measured during bouts of digging and grooming behavior with a 1 s time resolution. Mice displayed both decreases and increases in glutamate efflux during such behaviors. Magnitude of changes in glutamate efflux (decreases and increases) from dorsomedial and dorsolateral striatum were significantly greater in BTBR mice compared to those of B6 mice. In BTBR mice, CDD-0102A (1.2 mg/kg) administered 30 min prior to testing significantly reduced the magnitude change in glutamate decreases and increases from the dorsolateral striatum and decreased grooming behavior. Conversely, CDD-0102A treatment in B6 mice potentiated glutamate decreases and increases in the dorsolateral striatum and elevated grooming behavior. The findings suggest that activation of M1 muscarinic receptors modifies glutamate transmission in the dorsolateral striatum and self-grooming behavior.

Assessing Restricted and Repetitive Behaviours in Online-Sampled Autistic and Non-autistic Individuals: Factor Structure of the Repetitive Behaviours Questionnaire for Adults (RBQ-2A)

The Repetitive Behaviours Questionnaire for Adults (RBQ-2A) measures two factors of restricted and repetitive behaviours (RRBs) associated with autism. However, the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) provides four criteria for RRBs: repetitive motor behaviours, insistence on sameness, restricted interests, and interest in sensory aspects of the environment (or atypical sensitivity). The current paper aimed to examine whether the RBQ-2A is a psychometrically sound measure of these four factors. Study 1 had university students (N = 368) complete the RBQ-2A and other related measures online and revealed that the RBQ-2A can assess the factors highlighted in the DSM-5 and that these four factors comprise a general RRB construct. Study 2 had individuals disclosing a diagnosis of autism (N = 283) complete the RBQ-2A and other related measures online and supported that this four-factor structure provided good psychometric properties. While the current paper provides findings for an online autistic population, further research is needed to generalize these findings to autistic individuals less likely to partake in online studies (e.g., those with intellectual or language disabilities). Overall, the results suggest that the RBQ-2A reliably and validly assesses RRBs.

Special Report: Autism Spectrum Disorder and Inflexible Thinking—Affecting Patients Across the Lifespan

Special Report: Autism Spectrum Disorder and Inflexible Thinking—Affecting Patients Across the Lifespan

Neural Network-Based Method for Early Diagnosis of Autism Spectral Disorder Head-Banging Behavior from Recorded Videos

Autism spectrum disorder (ASD) is a mental developmental disorder associated with social and communicational defects and Stereotypical Motor Movements (SMM). SMM is a set of repetitive motor activities associated with several mental developmental disorders like Autism. SMM has several forms like arm flapping, head banging, ear covering, and spinning with various degrees of severity that might lead to self-injury in severe cases. Developing a computer-vision-based technology to detect noticeable SMM behaviors can help in the early diagnosis of autism. In this paper, a computer vision-based neural network model was proposed to detect and recognize repetitive motor behaviors. The proposed model went through three main stages: First, data preparation. Second, human body features extraction using deep learning pose estimation and the skeleton representation model, and finally, multiclass classification to distinguish between several classes of headbanging. The proposed solution was evaluated using the Self Stimulatory Behavior Dataset (SSBD) which is a public dataset of three classes of repetitive motor behaviors associated with autism. We also collected a set of 40 videos of autistic children exhibiting headbanging from public domains like YouTube. In addition to that, we captured 25 videos of typically developing subjects mimicking headbanging. The collected and the videoed videos were used to evaluate the proposed model. This work proves the applicability of diagnosing mental developmental syndrome symptoms using vision-based techniques in cooperation with neural networks. The produced results prove that the used techniques can operate well in real-world challenging applications. The proposed model achieved 85.5% accuracy on SSBD and 93% on the collected and recorded videos.

Restricted and repetitive behaviors and their developmental and demographic correlates in 4-8-year-old children: A transdiagnostic approach.

Background: Restricted and repetitive behaviors (RRBs) are a broad class of behaviors characterized by frequent action repetition and intense preference for sameness. Research has predominantly focused on RRBs in diagnosed clinical groups, particularly in autism spectrum disorder and genetic disorders. Using a transdiagnostic approach, the current study examined RRBs in a diverse sample of children in relation to developmental and demographic correlates (age, language, non-verbal ability, child anxiety, sex, and socioeconomic status). Separate analyses examined two RRB subtypes; repetitive sensory and motor behaviors (RSMB) and insistence on sameness (IS). Method: Children (N = 260, age 4-8 years, 174 male, 86 female) in mainstream schools identified by teachers as having behavioral, emotional, and/or cognitive difficulties, were assessed using the Repetitive Behavior Questionnaire-2 (RBQ-2), the British Picture Vocabulary Scale (BPVS), Lucid Ability Scale, the Welsh Index of Multiple Deprivation (WIMD) and the Screen for Child Anxiety Related Emotional Disorders (SCARED). Recruitment excluded diagnosed clinical conditions. The Strengths and Difficulties Questionnaire (SDQ) was used to assess children's difficulties. Results: RRB scores were of high frequency and the scores for the IS were higher than for RSMB. The severity of anxiety symptoms and male sex were significantly associated with both RRB subtypes, and younger age and SES scores were associated with IS. Elevated RRB total and subtype scores were significantly related to SDQ scores for emotion, conduct, hyperactivity, and peer-relations. Discussion: The study provides the first evidence of RRBs in a diverse sample of young children with emerging difficulties in behavior, cognition, and/or emotion. The results contribute to proposals about psychological development in RRB and indicate that RRBs are best represented on a continuum of severity found across children in the early school years. The results support previous findings of a relation between RRB and anxiety reported in clinical samples and importantly, they indicate that it is time to move beyond the study of categorically defined groups and consider correlates of RRBs that include broad indices of mental health and well-being.

Dimensional Assessment of Restricted and Repetitive Behaviors: Development and Preliminary Validation of a New Measure

This study aimed to provide initial validation of the Dimensional Assessment of Restricted and Repetitive Behaviors (DARB), a new parent-report measure designed to capture the full range of key restricted and repetitive behaviors (RRB) subdomains. Parents of 1,892 children and adolescents with autism spectrum disorder (mean [SD] age= 10.81 [4.14] years) recruited from the SPARK (Simons Foundation Powering Autism Research for Knowledge) research match completed the DARB, several existing RRB instruments, and measures of social and communication impairments and anxiety. A subsample of 450 parents completed the DARB after 2 weeks to evaluate the test-retest stability. Exploratory graph analysis conducted in the exploratory subsample identified 8 dimensions that were aligned with hypothesized RRB subdomains: repetitive sensory motor behaviors, insistence on sameness, restricted interests, unusual interests, sensory sensitivity, self-injurious behaviors, obsessions and compulsive behaviors, and repetitive language. The confirmatory application of the exploratory structural equation modeling conducted in the confirmatory subsample showed that the derived factor structure had a good fit to the data. Derived factors had excellent reliability, convergent and divergent validity, and very strong test-retest stability and showed a distinct pattern of associations with key demographic, cognitive and clinical correlates. The DARB will be useful in a variety of research and clinical contexts considering the prominence and clinical impact of RRB in autism spectrum disorder. Strong preliminary evidence indicates that the new scale is comprehensive and captures a wide range of distinct RRB subdomains not simultaneously captured by any of the existing instruments.

Application of intervention strategies for behavior management in autism spectrum disorder in childhood and adolescence. a systematic review

Introduction and objectives: autism spectrum disorder (ASD) is a neurodevelopmental disorder, which exhibits symptoms such as early-onset impairment of interaction and social communication, as well as repetitive and restricted sensory and motor behavior. This study aims to carry out a systematic review regarding the application of intervention strategies for behavior management in autism spectrum disorder in childhood and adolescence. Methods: A systematic search of Randomized Controlled Clinical Trials conducted between January 2016 and June 2021 found in PubMed, Scient direct y Scopus was performed. Keywords used were “Psychomotor, disorder, autism, behavior, intervention”. Results: 2 845 records were found, and, after further analysis, 45 articles were obtained for the final analysis, with a number of participants (n=3 439), age range: 8-17 years of age, confirmed diagnosis of autism spectrum disorder. As a result, we found The use of technological resources is associated with a significant reduction in clinical severity of ASD, functioning global assessment, and social manifestations of anxiety. Conclusions: the authors to conclude that there are several strategies used for behavior management in autism spectrum disorder, the use of technological tools stands as a promising option as they are highly beneficial and contribute to achieve behavioral therapeutic objectives. Keywords: Psychomotor, disorder, autism, behavior, intervention.

Big Data Approach to Characterize Restricted and Repetitive Behaviors in Autism.

Despite being a core diagnostic feature of autism spectrum disorder (ASD), demographic, developmental and clinical correlates of restricted and repetitive behaviors and interests (RRB) remain poorly characterized. This study aimed to utilize the largest available RRB data set to date to provide a comprehensive characterization of how distinct RRB domains vary according to a range of individual characteristics. Data were obtained from 17,581 children and adolescents with ASD (meanage= 8.24 years, SDage= 4.06) from the Simons Foundation Powering Autism Research for Knowledge cohort. Caregivers completed the Repetitive Behavior Scale-Revised questionnaire as a measure of repetitive motor behaviors, self-injurious behaviors, compulsions, insistence on sameness, and circumscribed interests RRB domains. Caregivers also provided information on children's cognitive functioning, language ability, and social and communication impairments. Male sex was associated with higher severity of repetitive motor behaviors and restricted interests and with lower severity of compulsions and self-injurious behaviors; no sex differences were found for the insistence on sameness domain. Although repetitive motor behaviors showed a mostly linear (negative) association with age, other RRB domains showed more complex and nonlinear pattern of associations. Higher severity of social and communication impairments provided significant independent contribution in predicting higher severity of all RRB domains at the p< .001 level; however, these effects were small (d< 0.25). The strongest of these effects was observed for insistence on sameness (d= 0.24), followed by repetitive motor behaviors (d= 0.21), compulsions (d=0.17), restricted interests (d= 0.14), and self-injurious behaviors (d= 0.12). Findings reported here provide further evidence that RRB subdomains show a somewhat distinct pattern of associations with demographic, developmental, and clinical variables, with a key implication that separate consideration of these domains can help to facilitate efforts to understand diverse ASD etiology and to inform the design of effective interventions.

Subdomains of restricted and repetitive behaviors within autism: Exploratory structural equation modeling using the diagnostic interview for social and communication disorders.

The current study aimed to explore the factor structure of a broad range of restricted and repetitive behaviors (RRB) within the autism spectrum. Exploratory structural equation modeling was conducted using individual item‐level data from the Diagnostic Interview for Social and Communication Disorders (DISCO). DISCO is a comprehensive semi‐structured interview used by clinicians to elicit information from caregivers about the individual's profile of development and behavior. Data from a sample of 226 individuals with a clinical diagnosis of autism spectrum disorder (ASD) (189 males; M age = 11.82 years, SDage = 7.87) were analyzed. The six‐factor structure provided the most optimal and interpretable fit (comparative fit index = 0.944, Tucker–Lewis index = 0.923, root mean square error of approximation = 0.018). Derived factors were interpreted as repetitive motor behaviors (RMB), unusual sensory and object focused interests (USOI), sensory sensitivity (SS), insistence on sameness (IS), circumscribed interests (CI) and stereotyped language (SL). Age was significantly negatively associated with RMB, USOI and SL but not with SS, IS or CI factor scores. None of the factors were associated with sex. ASD individuals with intellectual disability (ID) had the highest RMB, USOI, SS and SL scores while those without ID had the highest IS and CI scores. Our findings provide preliminary evidence for the utility of the DISCO as a comprehensive measure of several distinct RRB domains in both research and clinical contexts. Importantly, the current investigation highlights crucial areas for measurement development.Lay SummaryThe diagnostic Interview for Social and Communication Disorders (DISCO) is a detailed caregiver report clinical interview designed to capture a wide range of key features associated with autism spectrum disorder, including restricted and repetitive behaviors (RRB). This paper provides initial evidence that the DISCO is a promising measure for assessing a wide range of RRB including repetitive motor behaviors, insistence on sameness, circumscribed interests, unusual interests in sensory stimuli, sensory sensitivity and stereotypic language.

Benefits of a ketogenic diet on repetitive motor behavior in mice

Repetitive motor behaviors are repetitive and invariant movements with no apparent function, and are common in several neurological and neurodevelopmental disorders, including autism spectrum disorders (ASD). However, the neuropathology associated with the expression of these abnormal stereotypic movements is not well understood, and effective treatments are lacking. The ketogenic diet (KD) has been used for almost a century to treat intractable epilepsy and, more recently, disorders associated with inflexibility of behavioral routines. Here, we show a novel application for KD to reduce an abnormal repetitive circling behavior in a rodent model. We then explore potential mediation through the striatum, as dysregulation of cortico-basal ganglia circuitry has previously been implicated in repetitive motor behavior. In Experiments 1 and 2, adult FVB mice were assessed for levels of repetitive circling across a 3-week baseline period. Mice were then switched to KD and repetitive circling was assessed for an additional 3 weeks. In Experiment 1, time on KD was associated with reduced repetitive behavior. In Experiment 2, we replicated these benefits of KD and assessed dendritic spine density in the striatum as one potential mechanism for reducing repetitive behavior, which yielded no differences. In Experiment 3, adult female circling mice were given a single administration of a dopamine D2 receptor antagonist (L-741,646) that was associated with reduced repetitive behavior over time. Future research will explore the relationship between KD and dopamine within basal ganglia nuclei that may be influencing the benefits of KD on repetitive behavior.

The use of Multi-Sensory Environments with autistic children: Exploring the effect of having control of sensory changes.

Multi-Sensory Environments (also called sensory or Snoezelen® rooms) are specialised spaces that contain equipment to modify the environment. They are commonly used in special-needs schools with autistic children, but empirical investigation into how to best use Multi-Sensory Environments with autistic children has been limited. Based on converging evidence that autistic children may benefit from having control, we tested 41 autistic children (8 female) aged 4–12 years (mean = 8 years, standard deviation = 2.05 years) who used the Multi-Sensory Environment both with and without control over the sensory changes. Behavioural coding of video data showed that having control was associated with increased attention and reduced repetitive motor behaviours, sensory behaviours, activity levels, stereotyped speech and vocalisations. Social behaviour, anxiety, positive affect and arousal were not significantly affected by condition. Our findings demonstrate that how a Multi-Sensory Environment is used can affect autistic children’s behaviours. They also suggest that providing control of sensory changes to autistic children may help create better conditions for learning.Lay abstractMulti-Sensory Environments (also called sensory or Snoezelen® rooms) are rooms that contain equipment which can create light, sound and touch experiences. Multi-Sensory Environments are often used with autistic children, particularly in schools, but there is no evidence for how best to use them. We investigated whether having control over the sensory equipment in the Multi-Sensory Environment affected how a group of 41 (8 female) autistic children aged 4–12 years behaved. We found that when autistic children could control the sensory equipment, they paid more attention and performed fewer repetitive and sensory behaviours. They also used less stereotyped speech, produced fewer vocalisations and showed lower levels of activity. Other behaviours were not affected. Our findings demonstrate that how a Multi-Sensory Environment is used can impact behaviour and that providing control of sensory changes to autistic children may help create better conditions for learning.

Toward better characterization of restricted and repetitive behaviors in individuals with germline heterozygous PTEN mutations.

This study aimed to further our understanding of restricted and repetitive behaviors (RRB) among individuals with germline pathogenic mutations in PTEN by providing multimethod characterization and comparison of key RRB subdomains across individuals with PTEN mutations with autism spectrum disorder (ASD) (PTEN-ASD), with PTEN mutations without ASD (PTEN-No ASD) and with ASD and macrocephaly but without PTEN mutations (Macro-ASD). Of 86 total research participants, 38 had PTEN-ASD (Mage = 8.93 years, SDage = 4.75), 25 Macro-ASD (Mage = 11.99 years; SDage = 5.15), and 23 PTEN-No ASD (Mage = 8.94 years; SDage = 4.85). The Repetitive Behavior Scale-Revised (RBS-R) and the Autism Diagnostic Interview-Revised (ADI-R) were used as measures of distinct RRB domains. There were significant group differences in the RBS-R repetitive motor behaviors (RMB; F= 4.52, p= 0.014, ω2 = 0.08), insistence on sameness (IS; F= 4.11, p= 0.02, ω2 = 0.05), and circumscribed interests (CI; F= 7.80, p= 0.001, ω2 = 0.14) scales. Post hoc comparisons showed that the PTEN-No ASD group had significantly lower RMB, IS, and CI scores compared to both PTEN-ASD and Macro-ASD groups. Importantly, PTEN-No ASD group still showed elevated RRB levels. Furthermore, there was a portion of individuals in PTEN-No ASD group whose Full-Scale Intelligence Quotient (FSIQ) was >70 that did not show floor level scores in the RMB domain. After adjusting for age and FSIQ scores, group differences were no longer statistically significant. RMB, IS, and CI domains showed distinct association patterns with sex, age, and FSIQ. This investigation provides the largest and most comprehensive characterization of distinct RRB domains in individuals with PTEN mutations to date. Despite the limitations, our findings have important assessment and treatment implications.

An Explanation for Repetitive Motor Behaviors in Autism: Facilitating Inventions via Trial-and-Error Discovery.

Clare Harrop, a leading researcher of restricted and repetitive behaviors (RRBs), wrote with her colleagues, “.as a field we do not understand what causes RRBs, and this is particularly difficult to ascertain when children are minimally verbal.” (1). The current account is a response to this request for new ideas about the cause of repetitive behaviors. Motor repetitions in autism are an alternative phenotype which has adaptive and functional consequences: fueling trial-and-error tinkering which could lead to inventions, i.e., novel, useful configurations of objects. This hypothesis is consistent with the proposed mechanism of heterochrony (11), and is complementary to other theories which take a strength-based approach to autism (8, 19). This hypothesis helps explain similarities between motor repetitions and circumscribe interests, illuminates parents' observations of their child's motor repetitions [e.g., (30)], and has heuristic value in providing ideas for therapists to introduce flexibility into the motor routines of minimally verbal children.