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

Abstract

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 113.8 [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.

What can autism teach us about the role of sensorimotor systems in higher cognition? New clues from studies on language, action semantics, and abstract emotional concept processing

“…Poorer imitation, pantomiming and reproduction of meaningful and meaningless gestures (with or without tools) in autism is ubiquitous across studies (Biscaldi et al, 2014;Cossu et al, 2012;Dewey et al, 2007;Dowell et al, 2009;Dziuk et al, 2007;Green, Baird et al, 2002;Green, Moore et al, 2002, although notably this study did not possess appropriate norms for comparison ;Miller et al, 2014;Stone et al, 1997;Vanvuchelen, Roeyers, & De Weerdt, 2007), especially when they involve simultaneous movements (McAuliffe, Pillai, Tiedemann, Mostofsky, & Ewen, 2017). The ability to perform skilled motor gestures (such as brushing your teeth, using a tool) is known as praxis, with dyspraxia being the inability to perform such learnt skilled movements.…”

“…Precisely 49 studies comparing ASC and typically-developing (TD) control groups answer this question in the affirmative. The more methodologically rigorous studies, those which a) either matched for chronological and/or mental age and/or IQ or b) controlled for these in their analyses, and c) had more sizeable groups (>30 per group) demonstrate that motor impairments occur more often than might be expected in TD children (AbuDahab, Skidmore, Holm, Rogers, & Minshew, 2013;Ament et al, 2015;Dewey, Cantell, & Crawford, 2007;Dowell, Mahone, & Mostofsky, 2009;Duffield et al, 2013;Dziuk et al, 2007;Floris et al, 2016;Sumner, Leonard, & Hill, 2016;Travers et al, 2015Travers et al, , 2016. A meta-analysis of 41 studies confirmed that, despite substantial variation, effect sizes are large with TD participants significantly outperforming individuals with autism in motor coordination, arm movements, gait and postural stability (Fournier, Hass, Naik, Lodha, & Cauraugh, 2010), and that these effects did not seem affected by publication bias.…”

“…Many studies addressed this question with movement assessment batteries with normative percentiles for performance and objective scoring: for example, the PANESS (Dowell et al, 2009;Dziuk et al, 2007;Floris et al, 2016;Jansiewicz et al, 2006;Mostofsky, Burgess, & Gidley Larson, 2007), the M-ABC or M-ABC2 (Ament et al, 2015;Green, Baird et al, 2002;Green, Moore, & Reilly, 2002;Green et al, 2009;Hanaie et al, 2013;Hanaie et al, 2014;Kopp, Beckung, & Gillberg, 2010;McPhillips, Finlay, Bejerot, & Hanley, 2014;Miyahara et al, 1997;Sumner et al, 2016;Whyatt & Craig, 2012), or the Bruininks-Oseretsky test (Dewey et al, 2007;Ghaziuddin & Butler, 1998;Hilton, Zhang, Whilte, Klohr, & Constantino, 2012;Pan, 2014). These measures yield total scores which were sometimes analysed alone, but they each assess a range of fine and gross motor skills, including balance and gait, hopping or jumping, repetitive sequential movements of the hands and feet, manual dexterity and ball skills (catching and throwing).…”

“…The ability to perform skilled motor gestures (such as brushing your teeth, using a tool) is known as praxis, with dyspraxia being the inability to perform such learnt skilled movements. Deficits in gesture and imitation, whether these are of transitive (with an imaginary or real object), intransitive (without an object, e.g., waving) or meaningless gestures, are predictive of autistic symptoms and whilst related to motor skills, remains predictive of diagnosis once motor performance is factored out (Dowell et al, 2009;Dziuk et al, 2007;Miller et al, 2014). It is interesting, however, to consider the most common types of errors that autistic people make: needing more attempts, only partially replicating actions, showing abnormal synkinesias (unintentional movements of other parts of the body in parallel), using part of the body as an object, orientating the hand incorrectly, or misjudging the amplitude, force or size of gestures.…”

“…This practice suggests it may be more prudent to look instead for differences related to language development, autistic regression, or IQ (/mental age). IQ is strongly related to motor skills, with lower IQ associated with poorer performance across a range of measures (Barbeau et al, 2015;Dewey et al, 2007;Dowell et al, 2009;Dziuk et al, 2007;Ghaziuddin & Butler, 1998;Green et al, 2009;Hilton et al, 2012;Kopp et al, 2010); unsurprisingly, where studies classify participants as having low functioning autism (or low IQ), they unanimously perform worse than those with HFA or AS (or autistic participants with high IQ) in many motor tasks (Papadopoulos et al, 2012;Paquet, Olliac, Bouvard, Golse, & Vaivre-Douret, 2016;Vanvuchelen et al, 2007). Failing to match groups of HFA and AS individuals on IQ casts further doubt on supposed differences between them (Ghaziuddin & Butler, 1998), and on the findings of studies which do not control for IQ between groups or consider it in their analysis (problematically, this is not always reported).…”