Crossing the Midline of the Body: Meaning, Signs and Why It Matters

What is the midline, and what does crossing it mean?

What is the midline of the body?

The midline of the body is an imaginary vertical line running from the top of the head down between the feet, dividing the body into left and right halves.⁠¹⁰ In anatomy, the vertical plane that runs straight down the middle is the midsagittal or median plane; anything toward it is medial and anything away from it is lateral.⁠^5,6 Anatomists also use a frontal plane, dividing front from back, and a transverse plane, dividing upper from lower, but when therapists talk about crossing the midline they mean the vertical line between left and right.⁠^1,5

What does crossing the midline mean?

Crossing the midline means a body part, usually a hand, a foot or the eyes, moving over to the opposite side of the body to do something there.⁠^1,7 Everyday examples:

• Reaching across the body with one hand for something on the far side
• Drawing a horizontal line all the way across a page without switching hands
• Scratching the opposite elbow, or crossing the legs when sitting
• Following a moving object with the eyes as it passes the center
• Reading a full line of text from left to right

The important word is spontaneously. A child who has difficulty here can still reach across when asked; what is missing is the automatic choice to do it when a task calls for it, so the child switches hands instead. Ayres described it as more often a tendency than an inability, one a child can overcome with effort.⁠^1,8

Does putting picked produce in a basket cross the midline?

It does when the basket sits on the other side of the body from the hand doing the picking, and the child does not switch hands. Occupational therapy leaflets build games on the same idea: objects to sort on one side and containers on the other, or sand scooped from one side of the body into a bucket on the opposite side without switching hands.⁠¹⁰

What does neuroscience say about crossing the midline?

Each side of the brain controls the opposite hand: the right hand is under left hemisphere control and the left hand under right hemisphere control. Working in the space on the other side of the body is thought to draw on communication between the hemispheres, at some cost to efficiency.⁠⁷ In 6- to 10-year-olds, movements were more accurate on the same side as the hand than on the opposite side, even when the hand did not have to cross the midline to work there, and overall accuracy rose by 42% over those years. In a small study of 4-year-olds, tasks on the opposite side took longer to process.⁠^16,17

Not every study finds a cost. In one experiment with 4- to 8-year-olds, moving pegs did not slow down when the hand crossed the midline, and the authors found their results incompatible with the idea of an immature corpus callosum in young left-handers.⁠¹⁸

How do the two sides of the brain connect?

Mainly through the corpus callosum, the largest bundle of nerve fibers linking the two cerebral hemispheres. Its fibers come from nerve cells in the cortex of each hemisphere that send axons across the midline to the other side, and that crossing begins during embryonic development.⁠^19,20

In developmental neuroscience, “crossing the midline” describes that wiring step. As the nervous system forms, many axons first grow toward its midline and then move on to targets on the opposite side. In the spinal cord, Netrin-1 from cells at the midline attracts them; in fruit flies, the repellent Slit, acting through Robo receptors, governs which axons cross; and these axons cross only once.⁠²¹ When this wiring goes wrong it can contribute to conditions including horizontal gaze palsy, congenital mirror movement disorder and autism.⁠²² It is a different event from a child's hand crossing the body's midline, though both use the same words.⁠²¹

Does the corpus callosum keep developing in childhood?

Yes. It keeps growing through the first three decades of life; in 428 children scanned between ages 4 and 11, the back of the corpus callosum thickened by up to 0.19 mm a year, and an earlier long-term study found its midsagittal area increased robustly from ages 5 to 18.⁠^23,24

Researchers have suggested links with hand use: the appearance of reaching across the body in infancy has been described as a shift toward control through the corpus callosum, and one researcher argued that its maturation is a prerequisite for hand preference and two-handed coordination.⁠⁷ The brain also has other routes. Children born without a corpus callosum show typical integration between the hemispheres, which is impaired in adults whose corpus callosum has been surgically cut.⁠¹⁹

How does crossing the midline develop, and at what age?

Gradually, from the first months of life to the end of elementary school. The ages below come from research and the CDC's milestone checklists and are not deadlines: in one large study, age explained under 5% of the differences between children.⁠³ The milestone tracker can help you note what your child is doing at each stage.

Crossing does not switch on at one age. In 432 children aged 3 to 10 reaching for cards, older children crossed the midline more often, with clear differences between 3- and 4-year-olds and 8- to 10-year-olds, and crossing was less frequent for cards at the far edges.⁠³ An earlier study of 150 children aged 4 to 8 found the same rise with age, with so much variation at each age that the age groups did not differ significantly in how often they used the preferred hand.⁠³¹ Children from 2 to 6 crossed more readily when the task made them use one particular hand.⁠²⁸ For the wider picture of the early years, see developmental milestones by age.

When is hand dominance established?

Later than many parents expect, and researchers disagree on the exact age. Some place the direction of hand preference at about 3 and reliable measurement at 4; others find that 3- and 4-year-olds do not reliably pick their preferred hand and that a clear preference appears around 6. Adult-like patterns emerge between about 10 and 12.⁠⁷ About 90% of people end up right-handed; a 2020 meta-analysis put left-handedness at 9.3% to 18.1% depending on the definition, with 10.6% as the best overall estimate.⁠^7,32

So a 4- or 5-year-old who still switches hands is within the range the research describes. What therapists look for is different: a child who uses each hand only on its own side of the body, or swaps hands partway through a task to avoid reaching across.⁠^4,8

Is a strong hand preference in a baby a concern?

It can be, which is the opposite of the late-preference worry. The CDC lists a baby older than 6 months who reaches out with only one hand while keeping the other fisted among the possible signs of cerebral palsy, while noting that some children without cerebral palsy show some of these signs. In infants, an obligatory asymmetrical tonic neck reflex that persists past 4 to 6 months can also stop a baby bringing both hands to the midline or reaching across it.⁠^33,34 Both are for your pediatrician.

Crossing the midline vs bilateral coordination: how do they relate?

Bilateral coordination, also called bilateral integration, means using both sides of the body together to do an activity effectively.⁠⁴ NHS children's therapy services describe three kinds:⁠^4,35

• Symmetrical: both hands or feet doing the same movement together, such as clapping, jumping or catching a ball with two hands.⁠^4,35
• Reciprocal: the two sides taking turns in a rhythm, as in crawling, walking, skipping or pedaling a bike.⁠^4,35
• Asymmetrical: the two sides doing different jobs, one leading and one supporting, as in cutting with scissors, writing while the other hand steadies the paper, or threading beads.⁠^4,35

Crossing the midline sits inside this skill: therapists list avoiding the midline among the signs of bilateral coordination difficulty, alongside trouble with buttons, zips, laces, cutlery and opening containers.⁠⁴ Many hand milestones of the preschool years are two-sided too: stringing large beads at 3, unbuttoning some buttons at 4 and buttoning some at 5.⁠^36,37,38

Jean Ayres, whose sensory integration theory held that disordered sensory integration accounts for some aspects of learning disorders, called poor midline crossing one of the more reliable signs of what she described as a disorder of postural and bilateral integration.⁠⁸ She also saw everyday play as building the skill: a baby's hand reaching across the body, she wrote, develops the ability to cross the midline.⁠³⁹ A 2011 analysis of test results from 273 children aged 4 to 9 found a pattern similar to hers, labeled vestibular and proprioceptive bilateral integration and sequencing.⁠⁴⁰

What does difficulty crossing the midline look like?

None of these signs settles anything on its own; Ayres wrote that midline difficulty is subtle and best judged across many structured observations.⁠⁸ Signs therapists describe include:

• Switching hands mid-task, such as starting a drawing with one hand and finishing with the other, or passing an object from hand to hand instead of reaching across.⁠^4,35
• Turning the trunk or whole body to avoid reaching across.⁠¹⁰
• Using each hand only on its own side, consistently rather than by preference.⁠⁸
• Trouble with two-handed tasks: buttons, zips, laces, cutlery, opening packets, or steadying the paper while writing or cutting.⁠⁴
• Trouble following a moving object from one side to the other, or tracking a line of text from left to right.⁠¹⁰
• Harder gross motor skills, such as climbing stairs, catching, or riding a bike or scooter.⁠⁴
• No settled preferred hand well into the school years; one NHS leaflet notes that avoiding the midline interferes with hand dominance developing.⁠^7,10

What causes difficulty crossing the midline?

Often nothing is wrong: young children naturally use the hand nearest the object, and crossing grows more frequent with age.⁠^3,7 When the pattern persists, the explanations depend on the framework. In Ayres' account, poor midline crossing belongs with weak postural responses in a disorder of postural and bilateral integration, so therapists who use her framework look at posture as well, including habits such as W-sitting and postural difficulties.⁠⁸ The evidence for that link is thin: children with learning disabilities in one study scored lower on both a body-righting test and a midline-crossing test, but the two scores were not significantly correlated.⁠⁴¹

Is trouble crossing the midline a sign of autism, ADHD or dyspraxia?

Not on its own, though weaker or less consistent hand use shows up in several conditions as a group finding. On a reaching test, 7- to 11-year-olds with developmental coordination disorder or specific language impairment, like younger children, mostly used the right hand on the right and the left hand on the left, while typical children their age used the preferred hand across the body; the authors called the test sensitive but non-specific.⁠¹¹ Young autistic children often lack a definite hand preference, and in one study those who had one did better on motor, language and cognitive tasks.⁠⁴² In a Finnish cohort of 7,871 children, mixed-handed 8-year-olds had about twice the odds of language and school difficulties, and at 16 of language difficulties and ADHD symptoms.⁠⁴³

None of this makes midline difficulty a diagnostic sign. Developmental coordination disorder, which some organizations call dyspraxia, affects an estimated 5% to 6% of children and is diagnosed with a history, an examination and standardized motor tests such as the MABC-2 or BOT-2; the diagnosis is hard to make reliably before age 5.⁠¹⁴

What does the evidence support about crossing the midline?

A lot of what is written about midline crossing goes further than the evidence does.

How to hold it. Difficulty crossing the midline is a useful signal that a child may benefit from an assessment. It is not a diagnosis and not a brain-training target. The activities below are good play regardless; just don't expect them to do more than they do.

Has Brain Gym been tested in trials?

A few small trials have tested its exercises. In 30 preschoolers, eight weeks of Brain Gym did not improve balance more than usual kindergarten activities.⁠⁴⁶ In 36 autistic children, ten sessions reduced behavior problems compared with no intervention, and in 52 children with cerebral palsy affecting one side, adding Brain Gym to physical therapy improved coordination and cognitive scores more than physical therapy alone.⁠^47,48 In older adults, a meta-analysis found no greater benefit to cognition than control activities.⁠⁴⁹ These trials measured balance, behavior, coordination or cognition; none tested the program's claim that the movements integrate the two hemispheres.

Which activities encourage crossing the midline?

Most of these come from NHS children's occupational therapy leaflets. They need little or no equipment and work best framed as play, not practice.⁠^4,10,35

• Whole-body
  • Beanbag throws to a target off to one side, or standing sideways to it
  • Walking sideways, crossing one foot over the other
  • The knee-slap walk: lift each knee and tap it with the opposite hand
  • Bending to tap the right hand to the left foot, then the left hand to the right foot
  • Balloon tennis with one hand, and frisbee throws to the opposite side
  • Simon Says, hand-clapping games and Twister
• Seated and tabletop
  • Large figure eights on paper, in sand or in the air
  • A figure-eight road to drive a toy car around with one hand
  • A big rainbow across a page on the floor, with the same hand all the way
  • Sorting games: objects on one side, containers on the other
  • Board games that move pieces around the whole board
  • Threading, lacing and playdough: one hand holds, one works
• Everyday
  • Placing a toy or snack slightly to one side so reaching across comes naturally
  • Scooping sand or water from one side into a bucket on the other without switching hands
  • Washing the car, a window or a table in big sweeps
  • Pretend driving with a plate as a steering wheel, crossing the arms on the turns
  • Cutting while the other hand holds and turns the paper; pouring and stirring in cooking
  • Dressing: pulling up socks, doing buttons, threading laces

Which activities help babies and toddlers cross the midline?

For babies, the CDC's tips are simple: give your baby time on the floor or a play mat every day, and put toys just out of reach so your baby rolls or reaches to get them.⁠^25,26 Offer toys at the middle and to each side. Reaching across the body normally appears at about 18 to 20 weeks, so there is nothing to push before then.⁠^2,7 In floor play, leaning on one hand with the toys placed on that side brings the other hand across.⁠¹⁰

Which activities suit preschool and school-age children?

Table and art play does a lot. The CDC suggests playdough at 3, noting it builds the hand and finger muscles used for writing, buttoning and cutting, and a box of crayons, paper and child scissors at 5.⁠^36,38 Two-handed activities such as threading and lacing, construction toys and tearing paper build bilateral coordination, and ball games, climbing and riding a bike or scooter use both sides of the body together.⁠^4,35

Two notes. Keep it play: AOTA advises occupational therapists against intervention activities that are not purposeful, and in a 2019 review of pediatric occupational therapy, the approaches with strong evidence shared a pattern: they start from the child's own goals and practice real activities in everyday settings, with plenty of repetition.⁠^15,50 For more ideas, see our sensory activities and exercises for kids.

How do occupational therapists assess crossing the midline?

Mostly by watching, without telling the child what they are watching for. Ayres advised many structured observations made that way; one of hers asks a child to catch a ball swinging back and forth in front of them, which takes alternate crossing of the midline.⁠⁸

Formal measures exist too. Ayres' original test battery included a Crossing the Mid-line of the Body test, and researchers later scored how often children reach across during her space visualization test; that score separated children with learning disabilities from others at younger ages, and its authors advised using it with other observations.⁠^8,51 Card-reaching tasks such as Bishop's measure hand preference and record midline crossing at the same time.⁠^3,52 Among standardized motor tests, the Bruininks-Oseretsky Test of Motor Proficiency, second edition (BOT-2), has a bilateral coordination subtest and covers ages 4 to 21, and international recommendations name the BOT-2 or the Movement Assessment Battery for Children (MABC-2) for diagnosing developmental coordination disorder.⁠^14,53

A good assessment also looks at how the child manages everyday life: self-care, schoolwork, play and sport.⁠¹⁴ If sensory differences are part of the picture, the guide to how sensory processing is assessed explains that side.

When should a child be assessed for midline difficulties?

An occupational therapist can assess bilateral coordination properly, with midline crossing as one observation among many.⁠⁸ Under 3, you can contact your state's early intervention program yourself: a doctor's referral is not necessary, and services are free or low cost for eligible children. From 3, call your local public elementary school and ask for an evaluation for preschool special education services, or put the request in writing with a school evaluation request letter.⁠⁵⁴ Where difficulties extend to focus and organization, our guide on executive function strategies may also help.

Frequently Asked Questions

RelatedW-sittingpostural disordervestibular and proprioceptive processingsensory processing disorder

Sources

1. Jacobs J, Heymann R, Greeff JJ. A telehealth system incorporating a serious game intervention to aid occupational therapists in identifying and treating children with difficulty crossing the body's midline: key informant interviews among occupational therapists. JMIR Serious Games. 2021;9(4):e27761. PMID 34723821. Checked October 10, 2026.
   Show the passageHide the passage

   “The midline is an imaginary line that isolates the left and right parts of the body. Crossing the midline infers that a body part (eg, hand or foot) can spontaneously move over to the opposite side of the body to perform an action. A child who has difficulty crossing the midline can physically perform actions that cross the center of the body; however, they do not intuitively cross the midline when challenged with a task that requires this movement.”
2. Provine RR, Westerman JA. Crossing the midline: limits of early eye-hand behavior. Child Development. 1979;50(2):437–441. PMID 487884. Checked October 10, 2026.
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   In 48 full-term infants aged 9 to 20 weeks, with one arm restrained: “infants can first contact objects placed in front of the ipsilateral shoulder, then at the body midline, and later in front of the contralateral shoulder. Between 9 and 17 weeks, success at contacting objects at the midline progressed from 33% to 93%. During this interval, the success in contacting objects presented in front of the contralateral shoulder increased from 0% to 71%. By 18–20 weeks, all infants contacted objects in all three positions.”
3. Carlier M, Doyen AL, Lamard C. Midline crossing: developmental trend from 3 to 10 years of age in a preferential card-reaching task. Brain and Cognition. 2006;61(3):255–261. PMID 16513237. Checked October 10, 2026.
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   In 110 left-handed and 322 right-handed children aged 3 to 10, “older children crossed the body midline more frequently when reaching for cards than did younger children. The factor age explained 4.9% of the variance. Significant differences appeared between 3-4 years old children and 8-10 years old children ... the contralateral hand was used less often to reach cards at the most extreme positions.”
4. Berkshire Healthcare NHS Foundation Trust. Bilateral coordination (coordinating left and right side). Advice and resources, children's services. Checked October 10, 2026.
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   “Bilateral coordination (also known as bilateral integration) means using both sides of the body together to do an activity effectively”; children with difficulty may “Struggle using their hands in a coordinated manner to complete functional tasks such as dressing, including tying shoelaces and doing up buttons and zips, finger feeding or using a knife and fork together, or opening packets and containers”, find it hard “to use their other hand to support or assist their dominant or preferred hand”, “Have difficulty mastering some skills like climbing stairs, catching or riding a bike or scooter” and “Struggle to adjust their bodies and avoid crossing the midline ... as a result, they may switch hands during a fine motor task or ignore one hand.” Types: symmetrical (“jumping, clapping, catching a ball”), reciprocal (“the same motion or movement in an alternating pattern. For example, crawling or walking, skipping, riding a bike”) and asymmetrical (“both sides of the body are working together but doing different movements. This involves one side supporting or assisting the other. For example, writing or cutting activities”).
5. OpenStax. 1.6 Anatomical Terminology. In: Anatomy and Physiology 2e. OpenStax, Rice University. Checked October 10, 2026.
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   “The sagittal plane is the plane that divides the body or an organ vertically into right and left sides. If this vertical plane runs directly down the middle of the body, it is called the midsagittal or median plane”; “The frontal plane is the plane that divides the body or an organ into an anterior (front) portion and a posterior (rear) portion”; “The transverse plane is the plane that divides the body or organ horizontally into upper and lower portions.”
6. National Cancer Institute. Anatomical Terminology. SEER Training Modules. “Medial - toward the midline of the body”; “Lateral - away from the midline of the body”; “Median plane - Sagittal plane through the midline of the body; divides the body or any of its parts into right and left halves.” Checked October 10, 2026.
7. Scharoun SM, Bryden PJ. Hand preference, performance abilities, and hand selection in children. Frontiers in Psychology. 2014;5:82. PMID 24600414; PMCID PMC3927078. Checked October 10, 2026.
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   “Approximately 90% of the population is right handed”; “Control of the hands is contralateral, such that the right hand is under left hemisphere control and the left hand is under right hemisphere control”; “no general consensus exists surrounding the age at which adult-like handedness is actually attained”, some placing the direction of preference at age 3 and reliable assessment at 4, others finding that “children 3–4 years of age do not reliably select the preferred hand ... and that it is not until the age of 6 that a clear preference can be observed”; “Contralateral reaching begins to emerge between 18 and 20 weeks ... It has been suggested that this period represents a shift from extracallosal to callosal control of interhemispheric communication. In particular Liederman (1983) noted that maturation of the corpus callosum is a required prerequisite for development of hand preference and bimanual coordination”; “Manual midline crossing is well established in various tests by the age of 2 (Stilwell, 1987); however, reaching into contralateral space is a skill that gradually improves with age”; young children display “symmetrical neglect”, typically “from 4-years-old to 7- or 8-years-old”; “To act in contralateral space requires interhemispheric communication, therefore results in decreased movement efficiency”; and “Children aged 3- to 5-years-old ... using the hand that is closest to the task to be performed in most cases ... Children between the ages of approximately 6 and 10 years have learnt through experience which hand is more efficient and thus select this hand overwhelmingly ... Between the ages of 10 and 12 years, an adult-like pattern of handedness emerges.”
8. Ayres AJ. Sensory Integration and Learning Disorders. Western Psychological Services; 1972. Checked October 10, 2026.
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   “Essentially, the theory holds that disordered sensory integration accounts for some aspects of learning disorders”; in the chapters on integration of function of the two sides of the body and on disorder in postural and bilateral integration: “Failure or difficulty in crossing the mid-line (a theoretical plane which is an extension of the mid-sagittal plane of the face or, in the case of hand function, of the body) with the eyes is of great significance, for it is one of the more reliable signs of the syndrome of disorders in postural and bilateral integration”; the tests “Bilateral Motor Coordination, Crossing the Mid-line of the Body, and Right-left Discrimination” help, but “this dimension of neural dysfunction is so subtle that it is best evaluated by many formally structured clinical observations. This abnormal behavioral phenomenon is more often a tendency rather than an inability and, furthermore, the tendency can be volitionally overcome. Therefore astute observation without calling to the child's attention the objective of the evaluation is often essential”; “Asking the child to use both hands to catch a ball swinging back and forth in front of him requires alternate crossing of the body's mid-line. The child who has a tendency to want to use one hand only and that hand only on the ipsilateral side is probably showing a deficiency in crossing the mid-line of the body”; and “Although children with this type of dysfunction tend not to cross the mid-line of the body with either hand, when faced with the necessity of crossing, certainly do so.”
9. Dekker S, Lee NC, Howard-Jones P, Jolles J. Neuromyths in education: prevalence and predictors of misconceptions among teachers. Frontiers in Psychology. 2012;3:429. PMID 23087664; PMCID PMC3475349. Checked October 10, 2026.
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   In 242 teachers in the United Kingdom and the Netherlands, the statement “Short bouts of co-ordination exercises can improve integration of left and right hemispheric brain function”, classed as a myth, was believed by 88% (UK) and 82% (Netherlands); “Exercises that rehearse co-ordination of motor-perception skills can improve literacy skills”, also a myth, by 78% and 63%; Brain Gym was encountered in schools by 82% of the UK teachers and 8% of the Dutch; “The left and right hemisphere of the brain always work together” was among the correct statements.
10. Alder Hey Children's NHS Foundation Trust, Occupational Therapy Department. Crossing Midline: Information for Parents and Carers. Leaflet PIAG 266; review date May 2025. Checked October 10, 2026.
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    “Imagine a line drawn down from your child's head to your feet which separates the right and left halves of the body”; “Children who have difficulty reaching across their middle may have to switch hands when doing an activity. Or they may compensate by turning their trunk to reach toward the opposite side. Poor midline crossing also makes it difficult to visually track a moving object from one side to the other, or to fully track from left to right when reading. If they avoid crossing midline it will interfere with their development of hand dominance”; and strategies including “Play sorting games: place objects to sort on the left side and containers to place them in on the right side”, “scooping sand from one side of the body and putting it into a bucket on the opposite side of the body without switching hands”, floor play leaning on one hand with “the toys or games on the side being leaned on”, large figure eights, a figure-eight track for a toy car, a rainbow drawn across a page with the same hand, popping bubbles with one hand, balloon tennis, throwing a frisbee to the opposite side, washing the car, a pretend steering wheel, crossing one foot over the other while walking sideways, the knee slap walk and tapping each hand to the opposite foot.
11. Hill EL, Bishop DV. A reaching test reveals weak hand preference in specific language impairment and developmental co-ordination disorder. Laterality. 1998;3(4):295–310. PMID 15513093. Checked October 10, 2026.
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    In 7- to 11-year-olds, “Right-handed children with SLI, DCD, and the younger controls reached predominantly with the right hand to spatial positions located to the right of their body's midline and with the left hand to positions situated to its left. Right-handers in the age-matched control group showed a significantly greater tendency to use their right hand to reach to all spatial positions ... The QHP task appears to be a sensitive, but non-specific, indicator of developmental disorders.”
12. Hyatt KJ. Brain Gym: building stronger brains or wishful thinking? Remedial and Special Education. 2007;28(2):117–124. doi:10.1177/07419325070280020201. Checked October 10, 2026.
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    “Brain Gym is a popular commercial program claiming that adherence to its regimen will result in more efficient learning in an almost miraculous manner. However, a review of the theoretical foundations of Brain Gym and the associated peer-reviewed research studies failed to support the contentions of the promoters of Brain Gym.”
13. Kroeze K, Hyatt KJ, Lambert MC. Brain Gym: pseudoscientific practice. Journal of the American Academy of Special Education Professionals. Spring-Summer 2016:75–80. Brain Gym is “one commercial program used in schools in over 80 countries under the assumption that it will improve student learning ... There is no quality empirical evidence supporting this claim.” Checked October 10, 2026.
14. Blank R, Barnett AL, Cairney J, et al. International clinical practice recommendations on the definition, diagnosis, assessment, intervention, and psychosocial aspects of developmental coordination disorder. Developmental Medicine and Child Neurology. 2019;61(3):242–285. PMID 30671947; PMCID PMC6850610. Checked October 10, 2026.
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    “Prevalence estimates of 5% to 6% of children are most frequently quoted”; “there are considerable problems for the diagnosis of DCD in children below 5 years of age”; “We suggest criterion I be satisfied by using the MABC-2 or the BOT-2”; the complete assessment should consider “ADL (e.g., self-care and self-maintenance), academic/school productivity ... leisure, sports, and play”; “we recommend that activity-oriented and participation-oriented approaches be used as a means to improve general, fundamental, and specific motor skills” (level A); “many children are referred to the therapies specifically for handwriting issues”; on terms, “the Dyspraxia Foundation (UK) uses the term 'dyspraxia', stipulating that this incorporates DCD”, while “The international consensus does not recommend use of the term 'dyspraxia'”; and “Other approaches used in children with DCD (e.g. brain-gym, complementary and alternative therapies) have not been systematically evaluated so cannot be recommended.”
15. Novak I, Honan I. Effectiveness of paediatric occupational therapy for children with disabilities: a systematic review. Australian Occupational Therapy Journal. 2019;66(3):258–273. PMID 30968419; PMCID PMC6850210. Checked October 10, 2026.
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    The effective ‘top-down’, activity-level interventions “all have the following key ingredients in common: (i) begin with the child's goal ... (ii) practice of real-life activities in natural environments ... (iii) intense repetitions ... and (iv) scaffolded practice to the ‘just right challenge’”; of seven motor interventions rated below the “worth it line”, “7/7 (100%) were ‘bottom-up’ approaches.”
16. Smits-Engelsman BC, Swinnen SP, Duysens J. Are graphomotor tasks affected by working in the contralateral hemispace in 6- to 10-year-old children? Motor Control. 2004;8(4):521–533. PMID 15585905. Checked October 10, 2026.
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    In 48 right-handed children, “movements were more accurate in ipsilateral than in contralateral space and their overall accuracy increased by 42% between 6 and 10 years of age ... Lower accuracy of movements in contralateral workspace is also present when participants do not have to cross the midline but only move within this workspace.”
17. Screws DP, Eason BL, Surburg PR. Crossing the midline: a study of four-year-old children. Perceptual and Motor Skills. 1998;86(1):201–203. PMID 9530733. In 9 four-year-old children, “contralateral tasks required more processing time than similar tasks placed ipsilaterally.” Checked October 10, 2026.
18. Bradshaw JL, Spataro JA, Harris M, Nettleton NC, Bradshaw J. Crossing the midline by four to eight year old children. Neuropsychologia. 1988;26(2):221–235. PMID 3399040. Checked October 10, 2026.
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    On line bisection, “The youngest groups displayed symmetrical neglect, erring to the left with the left hand and to the right with the right”; “A timed peg-moving task in Experiment II showed that performance did not slow when crossing the midline ... These and other findings were incompatible with the idea of callosal immaturity in young sinistrals.”
19. Siffredi V, Preti MG, Obertino S, et al. Revisiting brain rewiring and plasticity in children born without corpus callosum. Developmental Science. 2021;24(6):e13126. PMID 34060677. Checked October 10, 2026.
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    “The corpus callosum is the largest white matter pathway connecting homologous structures of the two cerebral hemispheres. Remarkably, children and adults with developmental absence of the corpus callosum (callosal dysgenesis, CD) show typical interhemispheric integration, which is classically impaired in adult split-brain patients, for whom the corpus callosum is surgically severed”; the authors discuss “very early disruption of embryological callosal development.”
20. Fame RM, MacDonald JL, Macklis JD. Development, specification, and diversity of callosal projection neurons. Trends in Neurosciences. 2011;34(1):41–50. PMID 21129791; PMCID PMC3053014. Checked October 10, 2026.
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    “Callosal projection neurons (CPN) are a diverse population of neocortical projection neurons that connect the two hemispheres of the cerebral cortex via the corpus callosum”; “progress has been made in identifying cellular and molecular controls over midline crossing.”
21. Dickson BJ, Zou Y. Navigating intermediate targets: the nervous system midline. Cold Spring Harbor Perspectives in Biology. 2010;2(8):a002055. PMID 20534708; PMCID PMC2908764. Checked October 10, 2026.
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    “In a bilaterally symmetric animal, the midline plays a key role in directing axon growth during wiring of the nervous system ... For some axons, the midline is an intermediate target. They first seek it out, but then move on towards their final targets on the opposite side”; the floor plate secretes Netrin-1, which promotes “both the outgrowth and attractive turning of commissural axons”; “The major midline repellent in Drosophila is Slit, which acts through Robo family receptors ... Robo1 is the key to the midline crossing decision”; and commissural axons “cross only once.”
22. Gorla M, Bashaw GJ. Molecular mechanisms regulating axon responsiveness at the midline. Developmental Biology. 2020;466(1-2):12–21. PMID 32818516. Checked October 10, 2026.
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    “During embryonic development in bilaterally symmetric organisms, correct midline crossing is important for the proper formation of functional neural circuits. The aberrant development of neural circuits can result in multiple neurodevelopmental disorders, including horizontal gaze palsy, congenital mirror movement disorder, and autism spectrum disorder.”
23. Westerhausen R, Fjell AM, Krogsrud SK, et al. Selective increase in posterior corpus callosum thickness between the age of 4 and 11 years. NeuroImage. 2016;139:17–25. PMID 27288321. Checked October 10, 2026.
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    “The corpus callosum, the major white-matter structure connecting the hemispheres, has been shown to increase in size throughout the three first decades of life”; from 732 scans of 428 children aged 4.1 to 10.9, “a growth in callosal thickness of up to 0.19mm per year in the posterior corpus callosum.”
24. Giedd JN, Blumenthal J, Jeffries NO, et al. Development of the human corpus callosum during childhood and adolescence: a longitudinal MRI study. Progress in Neuro-Psychopharmacology and Biological Psychiatry. 1999;23(4):571–588. PMID 10390717. Checked October 10, 2026.
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    From 251 scans of 139 healthy children and adolescents, “Midsagittal area of the CC, especially the posterior regions, increased robustly from ages 5 to 18 years.”
25. Centers for Disease Control and Prevention. Milestones by 4 Months. Learn the Signs. Act Early. Page dated May 15, 2026. Checked October 10, 2026.
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    Movement milestones include “Uses his arm to swing at toys” and “Brings hands to mouth”; tips: “Let your baby have time to move and interact with people and objects throughout the day” and “Playing on the floor or play mat with your baby every day helps him to move, learn, and explore.”
26. Centers for Disease Control and Prevention. Milestones by 6 Months. Learn the Signs. Act Early. Page dated May 15, 2026. Milestones include “Reaches to grab a toy she wants”; the tip “Put your baby on her tummy or back and put toys just out of reach. Encourage her to roll over to reach the toys.” Checked October 10, 2026.
27. Centers for Disease Control and Prevention. Milestones by 9 Months. Learn the Signs. Act Early. Page dated May 15, 2026. Movement milestones include “Moves things from one hand to her other hand.” Checked October 10, 2026.
28. Stilwell JM. The development of manual midline crossing in 2- to 6-year-old children. American Journal of Occupational Therapy. 1987;41(12):783–789. PMID 3503597. Checked October 10, 2026.
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    In 160 children aged 2 to 6, tested with a pegboard: “The results identified a developmental age trend in crossing the body midline in 2- to 6-year-old children. Biasing the hand used for object manipulation significantly increased the probability of eliciting manual midline crossing.”
29. Centers for Disease Control and Prevention. Milestones by 30 Months. Learn the Signs. Act Early. Page dated May 15, 2026. Movement milestones include “Uses hands to twist things, like turning doorknobs or unscrewing lids.” Checked October 10, 2026.
30. Bryden PJ, Roy EA. Preferential reaching across regions of hemispace in adults and children. Developmental Psychobiology. 2006;48(2):121–132. PMID 16489592. Checked October 10, 2026.
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    In 80 right-handed participants aged 3 to 20, “the 6 and 7 year olds and the 9 and 10 year olds relied heavily on their preferred hand to perform the task ... In comparison, the youngest children and adults used their nonpreferred hand more frequently in contralateral space.”
31. Cermak SA, Quintero EJ, Cohen PM. Developmental age trends in crossing the body midline in normal children. American Journal of Occupational Therapy. 1980;34(5):313–319. PMID 7405768. Checked October 10, 2026.
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    In 150 children aged 4 to 8, observed during the Space Visualization Test of the Southern California Sensory Integration Tests, “spontaneous midline crossing increased with age. Although the percent of preferred hand responses increased with age, there was enough variability at each age that there were no significant differences among age groups.”
32. Papadatou-Pastou M, Ntolka E, Schmitz J, Martin M, Munafò MR, Ocklenburg S, Paracchini S. Human handedness: a meta-analysis. Psychological Bulletin. 2020;146(6):481–524. PMID 32237881. “Left-handedness prevalence lies between 9.3% (using the most stringent criterion of left-handedness) to 18.1% (using the most lenient criterion of nonright-handedness), with the best overall estimate being 10.6%.” Checked October 10, 2026.
33. Centers for Disease Control and Prevention. About Cerebral Palsy. Page dated June 12, 2026. Checked October 10, 2026.
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    “The main sign that a child might have CP is a delay reaching motor or movement milestones (such as rolling over, sitting, standing, or walking)”; “some children without CP may also show some of these signs”; in a baby younger than 6 months, “Their head lags when you pick him up while he's lying on his back,” “They feel stiff,” “They feel floppy”; in a baby older than 6 months, “They reach out with only one hand while keeping the other fisted.”
34. Chamarthi VS, Gunasekaran V, Daley SF. Primitive Reflexes: Comprehensive Neurological Assessment Across the Lifespan. In: StatPearls. StatPearls Publishing; last updated June 17, 2026. PMID 32119493. Checked October 10, 2026.
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    “The central nervous system gradually inhibits these reflexes between 4 and 6 months of age as the cortex matures and voluntary motor control develops”; “No single universally accepted instrument exists exclusively for primitive reflex assessment”; the Hammersmith Infant Neurological Examination “is a standardized neurologic assessment for infants aged 2 to 24 months and is recognized by the American Academy of Pediatrics for early detection of cerebral palsy”; “For preschool- and school-age children, the Sally Goddard-Blythe battery is commonly used to assess retained primitive reflexes”; “Improper technique can yield false-negative or false-positive results”; the Moro reflex “persists until approximately 4 to 6 months of age” and can be elicited “by suddenly extending the infant's head backward (approximately 30 degrees) while supporting the body”, by “a loud noise near the infant or sharply striking the examination table surface near the infant's head”; clinicians “should document symmetry (bilateral equal response), completeness (both phases present), and vigor (strong, moderate, weak, or absent)”; an asymmetric response “suggests unilateral pathology, eg, a brachial plexus injury ... a clavicle fracture (pain inhibits movement on the affected side), or hemiparesis from a cerebral injury”; “Persistence of primitive reflexes beyond 4 to 6 months strongly correlates with neurodevelopmental conditions, particularly cerebral palsy and autism spectrum disorders”; “Children with a retained Moro reflex often demonstrate hypervigilance, anxiety, sensory processing difficulties, and poor impulse control” (the chapter's reference 20 for that sentence is Melillo et al., 2022); “Generalized hypotonia associated with an absent Moro reflex suggests conditions, eg, spinal muscular atrophy, congenital myopathies, or chromosomal disorders”; and “An exaggerated or hyperactive Moro reflex occurs in infants with neonatal opioid withdrawal syndrome, hypoglycemia, hypocalcemia, or intracranial pathology causing increased intracranial pressure. These infants show a low threshold for reflex elicitation, with prolonged or repetitive responses to minimal stimulation.” On the asymmetrical tonic neck reflex: it “typically integrates by 3 to 4 months of age”, and “An obligatory ATNR persisting beyond 4 to 6 months prevents the infant from bringing both hands to the midline ... reaching across the midline, and eventually rolling, sitting, and crawling”; the Galant reflex “typically disappears by 4 to 6 months.”
35. Sandwell and West Birmingham NHS Trust, Children's Therapies. Developing Bilateral Skills. Leaflet. Checked October 10, 2026.
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    “Symmetrical movements: Each leg or hand do the same action at the same time such as clapping hands or jumping”; “Reciprocal movements: One hand or leg goes first and then the other repeats the movement rhythmically for example skipping, wheelbarrow walk or pedalling a bike”; “Leading and supporting hand movements: One hand plays the supporting role while the other hand does more skilled work, such as cutting with scissors or threading beads”; “some children pass an object from one hand to the other rather than reach across their body”; and activities including tearing paper, construction toys, threading and lacing, “Throwing beanbags, hoops, balls where the child is sideways to the target”, “Board games that require the child to move his pieces around the entire board”, “Hand clapping games involving crossing midline, Simon says” and Twister.
36. Centers for Disease Control and Prevention. Milestones by 3 Years. Learn the Signs. Act Early. Page dated May 15, 2026. Checked October 10, 2026.
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    Movement milestones include “Strings items together, like large beads or macaroni”; the tip “Let your child play with playdough by squishing it, pressing it, pinching it, and making balls in different colors. This builds her hand and finger muscles for writing, buttoning, and cutting.”
37. Centers for Disease Control and Prevention. Milestones by 4 Years. Learn the Signs. Act Early. Page dated May 15, 2026. Movement milestones include “Unbuttons some buttons” and “Holds crayon or pencil between fingers and thumb (not a fist).” Checked October 10, 2026.
38. Centers for Disease Control and Prevention. Milestones by 5 Years. Learn the Signs. Act Early. Page dated May 15, 2026. Movement milestones include “Buttons some buttons”; the tip “Keep a box of crayons, paper, paint, child scissors, and glue for creative play.” Checked October 10, 2026.
39. Ayres AJ. Sensory Integration and the Child. Western Psychological Services; 1979. On a baby's play: “Very often one of his hands reaches across to the other side of his body. These motions develop his ability to cross the midline, a very important ability that is sometimes poor in children with sensory integrative dysfunctions.” Checked October 10, 2026.
40. Mailloux Z, Mulligan S, Roley SS, et al. Verification and clarification of patterns of sensory integrative dysfunction. American Journal of Occupational Therapy. 2011;65(2):143–151. PMID 21476361. Checked October 10, 2026.
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    In 273 children aged 4 to 9, factor analysis “identified patterns similar to those found in early studies by Ayres ... namely Visuodyspraxia and Somatodyspraxia, Vestibular and Proprioceptive Bilateral Integration and Sequencing, Tactile and Visual Discrimination, and Tactile Defensiveness and Attention.”
41. Stilwell JM. Relationship between development of the body-righting reaction and manual midline crossing behavior in the learning disabled. American Journal of Occupational Therapy. 1981;35(6):391–398. PMID 7246716. Checked October 10, 2026.
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    In 23 children with learning disabilities and 23 controls aged 6 to 8, “the learning-disabled subjects exhibited significantly reduced performance on both test measures ... A correlation between scores on the two tests did not reach significance.”
42. Hauck JA, Dewey D. Hand preference and motor functioning in children with autism. Journal of Autism and Developmental Disorders. 2001;31(3):265–277. PMID 11518481. Checked October 10, 2026.
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    Twenty autistic children, matched with 20 with developmental delays and 20 typically developing, studied for “the high rates of ambiguous hand preference in young children with autism”: “children with autism with a definite hand preference displayed better performance on motor, language, and cognitive tasks than children with autism who did not display a definite hand preference.”
43. Rodriguez A, Kaakinen M, Moilanen I, et al. Mixed-handedness is linked to mental health problems in children and adolescents. Pediatrics. 2010;125(2):e340–e348. PMID 20100759. Checked October 10, 2026.
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    In the Northern Finland Birth Cohort 1986 (N = 7871), “Mixed-handed children, relative to right-handed, had approximately a twofold increase in odds of having difficulties with language and scholastic performance at the age of 8 years. Eight years later, as 16-year-olds, adolescents had twofold increase in odds concerning difficulties in school with language and with ADHD symptoms.”
44. American Academy of Pediatrics, Committee on Children with Disabilities (Ziring PR, Brazdziunas D, Cooley WC, et al.). The treatment of neurologically impaired children using patterning. Pediatrics. 1999;104(5 Pt 1):1149–1151. PMID 10545565. Checked October 10, 2026.
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    “This treatment is based on an outmoded and oversimplified theory of brain development. Current information does not support the claims of proponents that this treatment is efficacious, and its use continues to be unwarranted.”
45. Nielsen JA, Zielinski BA, Ferguson MA, Lainhart JE, Anderson JS. An evaluation of the left-brain vs. right-brain hypothesis with resting state functional connectivity magnetic resonance imaging. PLoS One. 2013;8(8):e71275. PMID 23967180. Checked October 10, 2026.
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    In “publicly available resting state scans for 1011 individuals between the ages of 7 and 29”, “our data are not consistent with a whole-brain phenotype of greater 'left-brained' or greater 'right-brained' network strength across individuals.”
46. Elbasuony Elbanna ST, Kamal HM, Maksoud Mahgoub EA, Elshennawy S. Effect of Brain Gym exercises on balance in preschool children: a randomized controlled trail [sic]. Journal of the Pakistan Medical Association. 2023;73(4 Suppl 4):S17–S21. PMID 37482822. Checked October 10, 2026.
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    Thirty children aged 4 to 6, Brain Gym three times a week for eight weeks against usual kindergarten activities: “No significant benefits were seen in the balance of preschool children exposed to Brain Gym exercise.”
47. Roodbarani M, Tagharrobi Z, Sharifi K, Sooki Z, Zare M. Influence of Brain Gym on children's behavioral problems with autism spectrum disorder: a randomized controlled clinical trial. Journal of Bodywork and Movement Therapies. 2024;40:1248–1254. PMID 39593442. Checked October 10, 2026.
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    In 36 children, “The intervention group received ten sessions of BG ... There was no intervention in the control group”; there was “a significant difference in the severity of behavioral disorders between the two groups.”
48. Al-Nemr A, Abd El-Hady SS. Effect of brain gym exercises on functional abilities in children with cerebral palsy. Applied Neuropsychology: Child. Published online August 27, 2026. PMID 42658919. Checked October 10, 2026.
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    Fifty-two children aged 6 to 9 with hemiplegic cerebral palsy, all in a conventional physical therapy program, half also doing Brain Gym: “significant differences were observed when comparing groups in all measured outcomes in favor of the BG group” (cognitive functions, motor coordination, quality of life).
49. Varela S, Ayán C, Bidaurrazaga-Letona I, Diz JC, Duñabeitia I. The effect of Brain Gym on cognitive function in older people: a systematic review and meta-analysis. Geriatric Nursing. 2023;53:175–180. PMID 37540913. Checked October 10, 2026.
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    “Findings from the metaanalysis indicated changes in the BG groups, on cognitive function by means of the Mini-Mental State Examination, were not greater than those reported in the control/comparison groups.”
50. American Occupational Therapy Association. Practice Smart! (formerly Choosing Wisely). AOTA; 2026. Checked October 10, 2026.
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    The ten recommendations, published from 2018 to 2021 and reviewed annually, include “1. Don't provide intervention activities that are non-purposeful (e.g., cones, pegs, shoulder arc, arm bike)”, “2. Don't provide sensory-based interventions to individual children or youth without documented assessment results of difficulties processing or integrating sensory information” and “8. Don't use reflex integration programs for individuals with delayed primary motor reflexes without clear links to occupational outcomes.” The rationale for recommendation 8, as published on the Choosing Wisely list on July 27, 2021: “Interventions designed solely to integrate retained reflexes do not promote participation in occupation, and while they may be observed in clients with difficulties in occupational performance, the presence of retained reflexes does not necessarily equate to functional impairment. If reflex integration techniques ... are being considered for intervention, standardized tools and assessment approaches are necessary to connect impairment to occupational performance. Intervention should focus on improving occupational participation and performance rather than solely on reflex integration.”
51. Cermak SA, Ayres AJ. Crossing the body midline in learning-disabled and normal children. American Journal of Occupational Therapy. 1984;38(1):35–39. PMID 6702992. Checked October 10, 2026.
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    Comparing 179 children with learning disabilities and 120 others aged 5 to 8: “The SVCU measure clearly differentiated between groups at the younger ages, although the difference was not as clear for the older age groups. It was suggested that the SVCU score be used in conjunction with other observations of midline crossing.”
52. Musalek M, Scharoun SM, Bryden PJ. Using Bishop's card reaching task to assess hand preference in 8- to 10-year-old Czech children. PLoS One. 2016;11(11):e0166337. PMID 27835677. In 376 children, “The factor validity (.89) and sensitivity of Bishop's card reaching task (90% to 97%) provided a very good identification of hand preference.” Checked October 10, 2026.
53. Pearson. Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2). Pearson Assessments, product page. “Age range: 4:0-21:11”; eight subtests, the gross motor kit including “Bilateral Coordination, Balance, Running Speed and Agility, and Strength.” Checked October 10, 2026.
54. Centers for Disease Control and Prevention. Early Intervention. Learn the Signs. Act Early. Page dated February 16, 2026. Checked October 10, 2026.
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    “These publicly funded programs provide services for free or at reduced cost for any child who is eligible”; “If your doctor is not able to connect you, you can reach out yourself. A doctor's referral is not necessary”; and “If your child is age 3 or older: call any local public elementary school ... I would like to have my child evaluated through the school system for preschool special education services.”

Medical disclaimer. This page is for general educational purposes and does not constitute medical advice, diagnosis, or treatment. Developmental variation is wide and normal. Always consult a qualified healthcare provider about your child.