How does early motor development influence subsequent cognitive ability?

Neurodevelopmental disorders (e.g., developmental delays, autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD)) affect 3-4% of children in England. Although some neurodevelopmental disorders can be diagnosed before or at birth (e.g., Down's syndrome), early diagnosis is challenging in others (e.g., autism), when it relies on atypical development of children's social and communication skills. However, by this relatively late developmental stage, these deficits can become highly debilitating. Currently, screening for neurodevelopmental disorders is based on cognitive deficits (DSM-5), neglecting potential early markers of risk for neurodevelopmental conditions embedded within the quality and quantity of early motor development. This clinical practice results in relatively late diagnoses and inhibits early intervention due to a lack of focus on the unfolding and supporting processes giving rise to development of cognitive abilities.
A growing literature has demonstrated early motor abilities to be fundamental across all cognitive domains. For example, the earliest examples of general motor abnormalities precede cognitive deficits, with the quality (i.e., a normal variable motor repertoire vs a monotonous repertoire) of early motor repertoire is consistently found to be a powerful predictor of not only motor-related disorders but poor cognitive performance in later childhood. For example, clinical assessments indicate that children with consistently abnormal motor behaviour (e.g., fidgety movements) during the first 8 weeks of life have lower cognitive scores at school age, while abnormal posture between 3-5 months is associated with poor cognitive outcomes at 7-10 years. To interact with their environment effectively, infants must obtain a complex and variable motor repertoire. Spontaneous exploration of their environment allows an infant to access rich perceptual and social information that is useful for developing social and communication abilities. This implies that the absence of a "smooth" variable motor repertoire in early infancy may hinder an infant's ability to interact with the environment. These examples illustrate a key feature of the developmental cascade framework - it links developing motor and cognitive behaviours in seemingly unrelated domains. Importantly, it raises open questions regarding the potential effects of early disruptions in one domain on development of another. Thus, from the development cascade perspective, early motor repertoire may provide valuable information about later cognitive skills acquisition.
Evidence of disrupted motor ability can be found across a range of behaviours and modalities (e.g., postures, manual dexterity, eye gaze). For example, neurotypical infants tend to orient towards faces, prefer faces over other stimuli and prefer biological over non-biological motion. However, retrospective studies indicate that children who later receive a neurodevelopmental diagnosis take longer to habituate to faces, spend less time looking at faces, and prefer non-biological motion. Moreover, while neurotypical children develop smooth movements during object interaction, children with neurodevelopmental disorders often show manual coordination deficits (e.g., dyslexia, dyspraxia, developmental coordination disorder). This research implicates a central role of early motor development in emerging cognitive abilities, and their cascading disruption in neurodevelopmental disorders. Further, it suggests that differences and delays in early motor and communication abilities may have downstream effects on later social-communication and cognitive skills, as well as on the development of behaviours in other domains.