Recently I found myself returning to the postural control literature regarding children with Autism Spectrum Disorder to improve my understanding of the issues. Although motor impairment is not a diagnostic characteristic of ASD, Fournier¹ noted:  

“An immature postural control system can be a limiting factor on the emergence of other motor skills, may constrain the ability to develop mobility and manipulatory skills, and is of significant importance to quality of life.”  

One of the widely quoted research articles regarding early movement in ASD is by Teitelbaum et al ².   The study noted that disturbances in movement could be detected sometimes at birth but certainly by 4 to 6 months.  These disturbances were characterized by prolonged asymmetry in arms and legs, delayed righting reflexes, lack of rotation and delayed milestones.  When Esposito³  studied infants between the 3^rd and 5^th month, he identified that supine was an active posture and one that was worth observing because infants with a risk of ASD displayed a higher level of asymmetry in supine than those without. Bhat et al ⁴ also identified increased asymmetry in supine, prone and sitting. The trend clearly is the idea that not just the assessment of milestones, but also the assessment of symmetry is important when we are looking at infants and Autism Spectrum Disorder.  Further, Nickel et al⁵ noted that infants at high risk of ASD initiated changes in posture less than typically developing infants.

(As an aside, we understand that typical infants use early asymmetry as a means of stability and many postulate that the Asymmetric Tonic Neck Reflex (ATNR) serves a stability purpose (among others).  We also understand that retained reflex activity is a signal of inefficient postural control.)

Studies looking at postural control in standing concluded that children with ASD experience decreased stability in this position, particularly in the frontal plane ^1,6,7.  It was noted that these difficulties were consistent with problems integrating sensory information for balance ⁶ (see Every Motor Event is a Sensory Event First).

Looking at postural control from another point of view, Schmitz’ group⁸ noted decreased postural anticipation during an unloading task.  This indicates that, as with other neurological challenges (see Horton Hears a Who), children with ASD substitute reactive postural control for anticipatory postural control and this can lead to timing and coordination issues. 

Not often discussed in the literature is the impact of hypotonia on postural control in ASD.  However Ming et al⁹ noted that it was the most common early motor symptom in ASD.  Therapists understand that hypotonia creates challenges to early postural control and necessitates various levels of compensation which work in the short term (see Oh Baby and Detour on the Road to Oz) but which interfere with further development of function over time.  I also know from clinical experience, that children with ASD compensate with altered alignment at their rib cage and pelvis and this disrupts their ability to activate their inner core musculature for central stability which negatively impacts all functional skills.  These issues with alignment influence vestibular, proprioceptive, visual and tactile inputs as well.   

Finally, Marko et al ¹⁰ noted that children with ASD seem to learn from their errors more through proprioceptive feedback, rather than visual feedback.  Clinically that could translate into helping my clients with ASD work through feeling movement for motor learning, rather than watching others.  

Overall, we’ve learned there are similarities as well as differences in how children with ASD organize postural control when compared to other groups of children.  I’m hopeful that as we go forward, researchers will begin to ask and answer more specific clinical questions.  The more insight we have into how children with ASD organize their movement, the better informed our treatment can be.  

PRACTICAL APP:

Movement ABCs in ASD

• It is important to assess how often and how well a child performs a motor skill, not just how much they can do (i.e. milestones).  Early assessment of the quality of motor skills, particularly symmetry, is important to consider during treatment.
• Postural control is multi-sensory in nature. Understanding the contributions of muscle tone, alignment, touch, hearing, vision, vestibular and proprioception and the typical/atypical development of mature balance are all essential pieces of the puzzle.
• Children with ASD are less stable in standing and are therefore, this is a layer that can contribute to difficulty with higher-level balance skills. 
• Addressing experiences of symmetry and rotation during movement earlier in development for children with ASD may have the potential to support improved balance later in standing.

References

1.  Fournier KA, Kimberg CI, Radonovich KJ, Tillman MD et al.  Increased static and dynamic postural control in children with Autism Spectrum Disorders.  Gait Posture. 2010; 32(1): 6-9.

2.  Teiltelbaum P, Teitelbaum O, Nye J, Fryman J, Maurer RG.  Movement analysis in infancy may be useful for early diagnosis of autism.  Proc Natl Acad Sci. USA. 1998; 95(23): 13982-7.

3. Esposito G, Venuti P, Maestro S, Muratori F.  An exploration of symmetry in early autism spectrum disorders: Analysis of lying. Brain Dev. 2009; 31(2): 131-8.

4.  Bhat AN, Landa RJ, Galloway JC.  Current perspectives on motor functioning in infants, children and adults with Autism Spectrum Disorders.  Phys Ther. 2011; 91(7): 1116-29.

5. Nickel LR, Thatcher AR, Keller F, Wozniak RH, Iverson JM. Posture development in infants at heightened risk for Autism Spectrum Disorders.  Infancy. 2013; 18(5): 639-61.

6. Malloy CA, Dietrich KN, Bhattacharya A.  Postural stability in children with Autism Spectrum Disorder. J Autism Dev Disord. 2003; 33(6): 643-52.

7. Fournier KA, Amano S, Radonovich KJ, Bleser TM, Hass CJ.  Decreased dynamical complexity during quiet stance in children with Autism Spectrum Disorder. Gait Posture. 2014; 39: 420-3. 

8.  Schmitz C, Martineau J, Barthelemy C, Assaiante C.  Motor control and children with autism: deficit of anticipatory function?  Neurosci Lett. 2003; 348(1): 17-20.

9.  Ming X, Brimacombe M, Wagner CG.  Prevalence of motor impairment in autism spectrum disorders.  Brain Dev 2007; 27: 565-570.

 10.  Marko MK, Crocetti D, Hulst T, Donchin O, Shadmehr R et al.  Behavioral and neural basis of anomalous motor learning in children with autism. Brain. 2015; 138(pt3): 784-97.