This is another wonderful frequently asked question! As you know there are so many variations to the theme of ASD and so really we are lumping a group of children together who someday may be differentiated like apples and oranges. Motor control issues are a prevalent aspect of challenge for many children with austim spectrum disorder and increasing research is helping to validate these observations.
Researcher Philip Teitelbaum of the University of Florida, has researched early signs of autism in infants through investigation of their motor patterns. In 1998, Dr. Teitelbaum, evaluated 17 autistic children aged 4-6 months through videotape analysis. The videotapes were tapes of children made by parents long before they had been diagnosed with autism. The movement patterns of these infants were compared to patterns observed in 15 typical developing children. Every single child in the study who was later diagnosed with ASD demonstrated a motor disturbance!
Disturbances were revealed in the quality of their motor milestones; demonstrating difficulties in movements requiring rotation (turning over from lying to side), difficulties in maintaining trunk control in sitting, asymmetries of posture and floppy muscle tone!
Dr. Eric Courchesne, neurobiologist and colleagues have also performed extensive research using neuroimaging on the brain of clients with autism. These studies have emphasized a morphological differences in the cerebellum, exhibiting a cerebellum that is smaller in size and different in cellular configuration. Suggestion has been made that these alterations may in fact contribute to the subtle motor control challenges experienced by this distinct population of clients.
Teitelbaum, P., Teitelbaum, O., Nye, J., Fryman, J. & Maurer, R. (1998). Movement analysis in infancy may be useful for early diagnosis of autism. Psychology, 95: 23, 13982-13987.