Dyspraxia in autism: association with motor, social, and communicative deficits

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1 Dyspraxia in autism: association with motor, social, and communicative deficits MA Dziuk, University of Texas Health Science Center at San Antonio, Texas; JC Gidley Larson; A Apostu; EM Mahone; MB Denckla; SH Mostofsky*,Kennedy Krieger Institute, Departments of Neurology and Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA. *Correspondence to last author at Kennedy Krieger Institute, 707 N Broadway, Baltimore, MD 21205, USA. mostofsky@kennedykrieger.org Impaired performance of skilled gestures, referred to as dyspraxia, is consistently reported in children with autism; however, its neurological basis is not well understood. Basic motor skill deficits are also observed in children with autism and it is unclear whether dyspraxia observed in children with autism can be accounted for by problems with motor skills. Forty-seven high-functioning children with an autism spectrum disorder (ASD), autism, or Asperger syndrome (43 males, four females; mean age 10y 7m [SD 1y 10m], mean Full-scale IQ (FSIQ) 99.4 [SD 15.9]), and 47 typically developing (TD) controls (41 males, six females; mean age 10y 6m [SD 1y 5m], mean FSIQ [SD 12.3], age range 8 4y) completed: (1) the Physical and Neurological Assessment of Subtle Signs, an examination of basic motor skills standardized for children, and (2) a praxis examination that included gestures to command, to imitation, and with tool-use. Hierarchical regression was used to examine the association between basic motor skill performance (i.e. times to complete repetitive limb movements) and praxis performance (total praxis errors). After controlling for age and IQ, basic motor skill was a significant predictor of performance on praxis examination. Nevertheless, the ASD group continued to show significantly poorer praxis than controls after accounting for basic motor skill. Furthermore, praxis performance was a strong predictor of the defining features of autism, measured using the Autism Diagnostic Observation Schedule, and this correlation remained significant after accounting for basic motor skill. Results indicate that dyspraxia in autism cannot be entirely accounted for by impairments in basic motor skills, suggesting the presence of additional contributory factors. Furthermore, praxis in children with autism is strongly correlated with the social, communicative, and behavioral impairments that define the disorder, suggesting that dyspraxia may be a core feature of autism or a marker of the neurological abnormalities underlying the disorder. See end of paper for list of abbreviations. Abnormalities on motor examination have often afforded valuable insights into developmental disorders of the brain. 1 Such abnormalities have been well documented in individuals with autism, and date back to some of the original descriptions of the disorder (see Gidley Larson and Mostofsky 2 for review). Increased insight into brain mechanisms underlying autism can be gained from careful consideration of these motor signs. 3 By using tests of motor function for which the neurological basis is well mapped out, it is possible to gain an understanding of the neural circuits impaired in autism. Motor signs can also serve as markers for deficits in parallel brain systems which are important for control of social and communication skills, impairments which characterize autism. Motor deficits associated with autism appear to be evident as early as infancy, manifesting as problems in sequencing movements to crawl or walk. 4 In older children with autism, problems have been observed in basic motor control, including poor coordination (both axial and limb) and postural control, slow response speed, clumsy gait, and low tone. 5 7 Difficulty with performance of skilled motor gestures has also been observed, and is one of the most consistently reported motor findings in children with autism. 8,9 Impairments in imitation of skilled motor gestures have been particularly emphasized, leading some to suggest that impaired imitation may be a core feature of autism, contributing to abnormal development of functions critical to social and communicative development, such as empathy, joint attention, and theory of mind. 10 Others have since hypothesized that autism may be related to abnormalities in the mirror neuron system critical to imitation, and associated deficits in self other mapping. 11 Comprehensive investigation of skilled motor gestures using a traditional praxis examination, however, reveals that children with autism show deficits in performance not only during imitation, but also in response to command and with tool-use. 8,9 These findings suggest that autism may be associated with a generalized praxis deficit, rather than a deficit specific to imitation. In a developmental context, impaired performance of skilled gestures, including those involving imitation, may, therefore, be secondary to abnormalities in frontal/parietal-subcortical circuits important for acquisition of sensory representations of movement and/or the motor sequence programs necessary to execute them. Given these findings, it is important to consider the association between basic motor skill deficits and impaired performance of skilled motor gestures. In traditional adult models, the terms apraxia and dyspraxia are reserved for individuals who demonstrate impaired ability to perform skilled motor tasks despite relatively normal motor dexterity. 12 In contradistinction to the adult literature, findings from typically developing (TD) children and those with developmental coordination disorder reveal impaired performance on praxis examination and are associated with deficits in motor coordination. 13 Given that children with autism spectrum disorders (ASD), including high-functioning autism and Asperger syndrome, also show deficits in basic aspects of motor execution, 6 a question remains regarding the association between basic motor coordination and dyspraxia in autism: whether dyspraxic errors made by children with ASD are attributable to these basic motor impairments or whether they represent a distinct impairment of gesture. The finding that body-part-for-tool (BPT) errors account for a larger proportion of praxis errors in 734 Developmental Medicine & Child Neurology 2007, 49:

2 children with ASD than in TD controls suggests a distinct impairment of gesture that is unlikely to be due to impaired motor execution. These errors occur when the participant uses a body part as the tool rather than using the body part to hold the tool (e.g. when asked to show how to cut with scissors, the participant moves two fingers in a scissoring motion rather than pretending to actually hold the scissors). 9 There has been limited prior examination of the direct association between basic motor skill deficits and dyspraxia in autism. To understand this association better, the current authors examined the correlation between performance on a traditional praxis examination and a measure of basic motor skill 1,14 in children with ASD and a group of TD children. We hypothesized that children with ASD would show impairments on praxis performance above what could be accounted for by basic motor skill deficits as compared with controls. The association between basic motor skill deficits and dyspraxia in autism was further investigated by examining correlations with the Autism Diagnostic Observation Schedule G (ADOS-G) 15 scores. While basic motor skill deficits and dyspraxia have been reported in several previous studies, none has directly examined the relationship between these findings and the social, communicative, and behavioral impairments that define the disorder. It was hypothesized that for children with autism, worse praxis performance would correlate with higher ADOS-G scores and that this correlation would remain significant after accounting for basic motor skill performance. Further, we hypothesized that higher ADOS-G scores would correlate not only with performance of gestures to imitation, but also with gestures to command and with tool use on the praxis examination. Method PARTICIPANTS Ninety-four children, aged 8 to 14 years, participated. Fortyseven participants were children with ASD (43 males, four females; mean age 10y 7mo [SD 1y 10mo]) and 47 were TD children (41 males, six females; mean age 10y 6mo [SD 1y 5mo]). Children with ASD met Diagnostic and Statistical Manual of Mental Disorders IV 16 criteria for either autism (n=22) or Asperger syndrome (n=25). Children with highfunctioning autism and Asperger syndrome have been found to show similar degrees of impairment on the measures used in this study to assess praxis and basic motor skills; 6,9 they were, therefore, collapsed into a single ASD group. ASD diagnoses were confirmed using the Autism Diagnostic Interview Revised (ADI-R) 17 and the ADOS-G, Module Eight of the children with autism did not receive the ADOS; for five of those participants, diagnosis was confirmed using the ADI R and clinical impression, and for three of those participants, diagnosis was based on clinical impression. ASD participants were recruited from outpatient clinics at the Kennedy Krieger Institute in Baltimore, local Autism Society of America chapters, flyers at schools, social skills groups, pediatricians offices, and by word of mouth. None of the participants had a history of seizures, traumatic brain injury, or mental retardation.* TD controls had no history of neurological or psychiatric diagnoses and no immediate family member with a pervasive developmental disorder. Psychiatric diagnoses were ruled-out *UK usage: learning disability. using a structured parent interview: the Diagnostic Interview for Children and Adolescents IV. 16 Intellectual functioning was assessed using the Wechsler Intelligence Scale for Children 3rd edition (WISC-III) 18 or the 4th edition (WISC-IV). 19 Full-scale IQ (FSIQ) scores from the WISC-III were transposed to the WISC-IV scale as derived from the WISC-IV technical report number Participants had an FSIQ above 80 with the exception of three children. While these three participants had an FSIQ lower than 80, either their verbal or perceptual index scores were greater than 90. TD children had an average FSIQ of (SD 12.3) and children with ASD an average FSIQ of 99.4 (SD 15.9). The Johns Hopkins Medicine Institutional Review Board approved the study. Written consent was obtained from parents of all participants and the participants gave written assent. PRAXIS EXAMINATION A version of the Florida Apraxia Screening Test (Revised), 21 adapted for children, 9 was used to examine the performance of purposeful, skilled movements. The examination consists of three sections: (1) gestures to command (GTC); (2) gestures to imitation (GTI); and (3) gestures with tool use (GTU). The GTC and GTI sections include both transitive gestures (those that act on or with an object, e.g. hammering a nail) and intransitive gestures (those that do not act on or with an object, e.g. waving goodbye); the GTU section contains only transitive gestures. The GTI section also includes meaningless gestures. A detailed description of the praxis battery (including types of gestures) is outlined in Mostofsky et al. 9 Participants were videotaped and later scored by two independent raters blind to participant diagnosis. Gestures were first scored as correct or incorrect. If a gesture was incorrect, it was evaluated for five categories of errors: (1) spatial (external configuration, internal configuration, amplitude, movement); (2) temporal (sequencing, temporal, occurrence); (3) content/concretization (perseverative, related, non-related, hand, concretization); (4) BPT; or (5) other (no response, unrecognizable response). Each gesture could have more than one type of error. The total number of correct gestures on the entire examination was calculated and the number of errors in each of the three sections was totaled for each of the five error categories (i.e. total spatial errors for GTI, total BPT errors for GTC, etc.). Total raw scores in each of the three sections were averaged between the two raters. Acceptable rates of reliability have been established for these measures. Interrater reliability statistics and further details regarding scoring of the praxis examination are outlined in Mostofsky et al. 9 BASIC MOTOR SKILL EXAMINATION Each participant completed the Physical and Neurological Assessment of Subtle Signs (PANESS), a neurological examination for children used to evaluate subtle neurological signs, which is standardized for age, sex, and handedness. 1,14 The revised PANESS 1 includes a lateral preference assessment, measures of axial motor skill, and measures of appendicular (limb) motor skill. Axial tasks include gaits on heels, toes, and sides of feet; tandem gait forward/backward; standing/hopping on one foot; standing heel-to-toe with eyes closed; and standing both feet together, arms outstretched with eyes closed. Limb motor skill assessment comprises timed measures of repetitive and sequential movements of the hands and feet, including toe-tapping, alternating heel-toe tapping, repetitive Dyspraxia Associations in Autism MA Dziuk et al. 735

3 hand patting, hand pronation-supination, repetitive finger tapping, and finger sequencing each of which was performed on the right and left sides. The PANESS has been found to have adequate test retest reliability, 22 interrater reliability, and internal consistency. 23 The PANESS was chosen because it was developed to minimize the need for equipment, to eliminate time-consuming and less reliable sensory tasks, and to be completed in only 15 to 20 minutes. These parameters were considered important factors when studying behavior in children with ASD. Given that praxis involves purposeful limb movements, a measure of timed repetitive movements of the hands and feet was used to examine the effect of basic motor skill on praxis performance. We did not survey all motor elements, choosing to focus on rapid distal limb control reflecting frontal and frontalsubcortical elements basic to incorporation of motor skill into items assessed on the praxis battery. For each repetitive movement (finger tapping, hand patting, and toe-tapping on right and left sides), the time to complete 20 movements was recorded; these times were summed to provide a total measure of speed of timed repetitive movements. STATISTICAL ANALYSES Univariate analysis of variance was used to evaluate for differences between TD children and children with ASD in relation to age, FSIQ, PANESS scores, and praxis examination total. Sex distributions between groups were examined using χ 2 analyses. Throughout the analyses, a significance level of p<0.05 (two-tailed) was used. Total praxis errors score was negatively skewed in the control group, but not the ASD group. Therefore, for analyses comparing groups on praxis performance, a log transformation of the total praxis errors scores was used. For analyses using the autism group alone, the variable was not transformed. All other variables examined were normally distributed. A hierarchical regression analysis was used to examine the association of basic motor skill performance and diagnosis with praxis performance, after accounting for age and FSIQ. For the main regression analysis, assumptions of linear regression were examined. Residuals for each of the predictor variables were consistent across values, showing homoscedasticity. Error terms were normally distributed and were without significant autocorrelation (Durbin Watson statistic for n=94 with four independent variables=1.01). Log transformation of the total errors score on the praxis examination was used as the dependent variable. Age was entered as the first independent variable, followed by FSIQ. Age can be a strong predictor of Table I: Group performance on examinations a Examination Autism Control p η 2 type Mean SD Mean SD Total praxis errors < Log transformation (total praxis errors) < PANESS repetitive total (s) < PANESS total score < a Comparisons are using t-tests (two-tailed). η 2, effect size (eta squared); PANESS, Physical and Neurological Assessment of Subtle Signs. both repetitive movement speed and praxis performance in children, although both reach relative plateaus by 8 years of age. 1,9 Nevertheless, age was entered as the first predictor in the regression model to ensure that any effects of age were controlled. FSIQ has also been shown to correlate with motor skill performance, 24 and the autism group had a significantly lower FSIQ than the control group. Therefore, FSIQ was included as a second predictor in the hierarchical regression model. The measure of basic motor skill (raw score of total timed repetitive movements from the PANESS) was entered third, followed by primary diagnosis as the fourth predictor. The examination of diagnosis as the final predictor variable provided a means of determining whether children with autism continue to show significantly worse praxis performance than controls, even after accounting for age, IQ, and basic motor skill deficits. Within the ASD group, separate linear regression analyses were used to examine the association of both basic motor skill (raw score of total timed repetitive movements from the PANESS) and praxis performance (total praxis errors) with ADOS-G measures of the social, communicative, behavioral deficits that define autism. In addition, this study examined: (1) the correlation between component scores from the praxis examination (i.e. total errors on GTC, GTI, and GTU sections) and total ADOS-G scores which provided a means of addressing the hypothesis that ADOS-G scores in children with autism would correlate not only with performance of GTI, but also with GTC and GTU; and (2) a hierarchical regression examining the correlation between praxis total errors score and total ADOS-G score, after accounting for basic motor skill performance from the PANESS; this provided a means of addressing the hypothesis that the correlation between worse praxis performance and higher ADOS-G scores in children with ASD would remain significant after accounting for deficits in basic motor skill performance. Results PRELIMINARY ANALYSES Comparisons of the ASD and TD groups revealed no significant group difference in age (F[1,92]=0.10, p=0.75) or sex distribution (χ 2 =0.004; p=0.7). Mean FSIQ was significantly lower for the autism group (F[1,90]=23.79, p<0.001). For children given the WISC-IV (22 TD controls, 28 ASD), there was no significant difference between groups on the Verbal Comprehension Index (F(1,48)=1.82, p=0.184) or Perceptual Reasoning Index (F(1,48)=0.26, p=0.613). In contrast, for the children given the WISC-III (24 TD controls, 17 ASD), controls had significantly higher Verbal IQ (VIQ; (F(1,39)=26.38, p<0.001) and Performance IQ (PIQ; F(1,39)=14.68, p<0.001) than the ASD group. The discrepancy between findings from the WISC-III and WISC-IV may be due to VIQ and PIQ, but not Verbal Comprehension and Perceptual Reasoning Indices, including subtests that relate to processing speed and working memory. Children with ASD showed significantly poorer performance than TD controls on the praxis examination (total errors score, F[1,92]=31.06, p<0.001; log transformed errors score F[1,92]=39.85, p<0.001) as well as PANESS (total score, F[1,82]=52.86, p<0.001), with time to complete repetitive movements being significantly slower in children with ASD than TD controls (F[1,86]=13.94, p=0.001; Table I). 736 Developmental Medicine & Child Neurology 2007, 49:

4 Effects of basic motor skills and diagnosis on praxis performance Table II shows results of the hierarchical regression analysis. Age and FSIQ were both significant indicators of praxis performance (log transformed total praxis errors score). After accounting for age and FSIQ, total timed repetitive movements on the PANESS was a significant predictor of praxis performance ( R 2 =0.073, p=0.004). Further, after accounting for age, FSIQ, and basic motor performance, diagnosis (ASD vs control) added a significant proportion of unique variance in prediction of praxis performance ( R 2 =0.128, p<0.001), with controls having significantly higher mean praxis scores than children with ASD. Analysis of association between praxis performance and ADOS scores Linear regression was used to evaluate the association between praxis performance and ADOS scores that reflect social, communicative, and behavioral impairments diagnostic of autism. Total errors from the praxis examination was a significant predictor of total ADOS-G score (R 2 =0.31, p<0.001; Fig. 1). Further, the number of errors on praxis examination significantly predicted each of the ADOS-G component scores: reciprocal social interaction (R 2 =0.13, p=0.026), communication (R 2 =0.25, p=0.001), and stereotyped/repetitive behaviors (R 2 =0.26, p=0.001). Furthermore, there was a significant correlation between total ADOS-G scores and each of the praxis subsections: GTC errors (R 2 =0.28, p<0.001), GTI (R 2 =0.24, p=0.002), and GTU (R 2 =0.35, p<0.001). A separate hierarchical regression was used in the ASD group to predict ADOS-G scores from praxis performance (total errors), after controlling for basic motor skill performance. Basic motor skill performance was not a significant predictor of total ADOS-G score (R 2 =0.07, p=0.12); after accounting for basic motor skill, praxis performance was still a significant predictor of total ADOS-G score ( R 2 =0.237, p=0.002). Discussion After taking into account age and FSIQ, there was a significant effect of basic motor skill (total timed repetitive movements on the PANESS) on praxis performance. However, there remained a significant effect of diagnosis on praxis after accounting for motor skill performance, with the ASD group continuing to show poor praxis performance compared with TD controls. The findings suggest that dyspraxia in the autism group cannot be entirely accounted for by basic motor skill deficits. The observed association between basic motor skill and praxis performance is not surprising, as the praxis examination is, in part, assessing limb motor function. This may indicate that impaired performance of skilled gestures in autism is, at least partially, due to problems with basic motor coordination. Alternatively, the association may be an indication that impairments in basic motor skills and impaired praxis performance in autism are epiphenomena, or secondary symptoms, i.e. that a common neurological abnormality contributes to both basic motor skill deficits and to the dyspraxia observed in autism. Findings also showed that performance on praxis examination is worse than what would be expected from poor basic motor skill performance, or clumsiness, alone, and suggest that additional factors are contributing to dyspraxia observed in autism. Findings from studies of acquired dyspraxia suggest that a neural network within the left hemisphere is important for control of goal-directed skilled movements, including parietal regions (supramarginal and angular gyri) important for storage of learned time space movement representations and premotor regions (in particular the supplementary motor area) important for transcoding of praxic representations into motor programs. 12,25 Movement formulas are stored in the inferior parietal lobe in three-dimensional form. These formulas must be translated into motor plans for movement, and either the storage or the translation could be a contributing factor to the dyspraxia seen in autism. Autism is associated with abnormalities in perception of biological motion 26 and, more generally, in dorsal stream processing involved in detection and analysis of motion. 27 It is possible that these deficits in visual processing may also contribute to impaired development of complex skills and gestures assessed on praxis examination. Examining correlations between these measures of visual impairment and praxis performance is an important area of future study. However, there are limits to how well models suggested by studies of adults with acquired lesions can inform us about the brain basis of dyspraxia in autism. Autism is a developmental disorder; therefore, dyspraxia in autism is unlikely to be due to loss of already acquired skills, but rather it is an impairment in acquisition (learning) of motor sequences involved in performance of skilled gestures. Impaired motor sequence learning has been reported in children with autism, 28 and it is important to consider abnormalities in neural systems involved in motor learning. Motor sequence learning relies on a broad neural network principally involving connections between frontal and parietal cortices and subcortical regions: the basal ganglia and cerebellum. 29,30 Abnormalities in these regions have been reported in several imaging studies of ASD. 31 Particularly compelling is that decreased Purkinje cell count in the cerebellum is the most Table II: Hierarchical regression predicting log (total praxis errors) a Predictor entered β 95% confidence interval for β R 2 F p Age to FSIQ to <0.001 PANESS repetitive total to Group (autism vs control) to <0.001 a Analyses indicate hierarchical regression with age entered first, followed by FSIQ, PANESS total repetitive timed score, and group. FSIQ, Fullscale IQ; PANESS, Physical and Neurological Assessment of Subtle Signs. Dyspraxia Associations in Autism MA Dziuk et al. 737

5 consistent finding in post-mortem studies of autism, 32 which prompts speculation that abnormalities in the cerebellum and/or connections between the cerebellum and frontal/parietal regions may contribute to impaired development of motor skills. ASSOCIATION BETWEEN PRAXIS PERFORMANCE AND DIAGNOSTIC FEATURES OF AUTISM In children with autism, the level of impairment on praxis examination significantly correlated with total ADOS-G score. This correlation remained significant after controlling for basic motor skill performance, providing further evidence that the association between dyspraxia and autism cannot be entirely accounted for by basic motor skill deficits. Development of social communication and interaction involves learning complex motor sequences that parallel those on the praxis examination. The finding of a significant association between praxis performance and ADOS-G scores suggests that the impaired performance of skilled gestures (including social gestures) may contribute to impaired social interaction and communication in autism. More likely, dyspraxia and impaired social interaction/communication seen in autism may be epiphenomena, sharing a common neurological basis. Each individual section of the praxis examination (GTC, GTI, GTU) was significantly associated with total ADOS-G score. This finding provides further evidence that performance of complex skilled gestures in children with autism is not limited only to imitation, 9 but rather that autism is associated with a generalized impairment in performance of skilled complex movements, consistent with dyspraxia. Finally, each ADOS-G subsection (communication, social interactions, and stereotyped/repetitive behaviors) was significantly correlated with performance on the praxis examination, indicating that impaired performance of skilled gestures is broadly associated with the social, communicative, and repetitive behavioral impairments that define autism. This finding suggests that dyspraxia may be a core feature of autism, or that it is a marker of the neurological deficits that underlie the broad features of the disorder. LIMITATIONS AND FUTURE DIRECTIONS The praxis examination was adapted for children from an adult Total praxis errors ADOS-G score (total) Figure 1: Plot showing a significant correlation (R 2 =0.311, p<0.001) between performance on praxis examination (total errors scores) and total scores from Autism Diagnostic Observation Schedule Generic (ADOS-G) in 39 children with autism. apraxia battery. 21 There is no standard evaluation of praxis in children, and an examination tailored for children would be helpful in the future. Such an examination could also be a valuable tool for clinicians. The age range of the children was limited to 8 to 14 years. This allowed for a more homogenous group to evaluate. However, a broader age range would evaluate dyspraxia more comprehensively throughout childhood and adolescence. Studies that may quantify dyspraxia in younger children may also be helpful in detecting deviations from the norm earlier in a clinical setting. The amount of experience the children had in performing these complex gestures is difficult to ascertain. Their individual experiences contribute to their ability to perform meaningful gestures (e.g. using a hammer or waving goodbye), which could increase their number of correctly performed gestures. Nevertheless, difficulty with imitation is the most commonly reported area of dyspraxia in children with autism, and imitation of gestures is the least reliant on prior knowledge of and experience with the gestures. Conclusion Results indicate that a generalized praxis deficit in high-functioning children with ASD cannot be accounted for by impairments in basic motor skills alone. This suggests that abnormalities in neural systems, outside of those that would account for basic motor skill deficits, contribute to dyspraxia in children with ASD. These abnormalities in neural systems would likely involve regions (or connections between regions) within neural networks critical for acquisition of movement patterns necessary for development of skilled tool use and social/communicative gestures. This may include posterior parietal regions important for acquisition and storage of spatial representations of movement or subcortical (cerebellum, basal ganglia) regions central to motor learning. Results also show that the impairment in praxis performance, but not basic motor skill performance, in children with ASD is broadly associated with ADOS-G measures of the social, communicative, and repetitive behavioral impairments that define ASD. This suggests that dyspraxia may be a core feature of autism, or a marker of the neurologic deficits that underlie the disorder. Accepted for publication 22nd May Acknowledgements This research was supported by NIH Grants R01 NS (SHM), K02 NS (SHM), M01 RR00052 (Johns Hopkins General Clinical Research Center), P30 HD (Mental Retardation and Developmental Disabilities Research Center), and a grant from the National Alliance for Autism Research/Autism Speaks (SHM). References 1. Denckla MB. (1985) Revised Neurological Examination for Subtle Signs. Psychopharmacol Bull 21: Gidley Larson JC, Mostofsky SH. (2006) Motor deficits in autism. In: Tuchman R, Rapin I, editors. Autism: A Neurological Disorder of Early Brain Development. Internationa Review of Child Neurology Series. London: Mac Keith Press. p Mostofsky SH, Burgess MP, Gidley Larson JC. Increased motor cortex white matter volume predicts motor dysfunction in autism. Brain 130: Teitelbaum P, Teitelbaum O, Nye J, Fryman J, Maurer RG. (1998) Movement analysis in infancy may be useful for early diagnosis of autism. 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(2000) Mechanisms of motor learning in the cerebellum. Brain Res 886: Penn HE. (2006) Neurobiological correlates of autism: a review of recent research. Child Neuropsychol 12: Bailey A, Luthert P, Dean A, Harding B, Janota I, Montgomery M, Rutter M, Lantos P. (1998) A clinicopathological study of autism. Brain 121(Pt 5): List of abbreviations ADOS-G ASD BPT GTC GTI GTU PANESS Autism Diagnostic Observation Schedule G Autism spectrum disorder Body-part-for-tool Gestures to command Gestures to imitation Gestures with tool use Physical and Neurological Assessment of Subtle Signs Become Tomorrow s Pediatric Rehabilitation Researcher! Join the Rehabilitation Medicine Scientist Training Program Where is the evidence base for rehabilitation treatments? How can we support the value of rehabilitation with payors and policy-makers? Rehabilitation research is the key, and well-trained rehabilitation researchers are needed for the job! 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