I recall JAMA saying a baseline MRI should be done on all children dx with autism back in 99-00 I guess doctors still don't do that. Everyone should have chiari ruled out, they should get the MRI and get multiple opinions from renown pediatric brain surgeons, because often they just ignore it when they see it anyway.

Check this:

"The CSF Project to Analyze the Prevalence of Chiari Malformation Within the ASD Population
There appears to be an underserved population of children and adults with Chiari malformation and autism the size of which is yet to be determined. Recent data suggests that a greater than expected overlap of findings in children diagnosed with Chiari Malformation and those diagnosed with Autism Spectrum of Disease (ASD).
Children with Chiari frequently have tendency to headaches, neck pain, speech and swallowing difficulties, sensori-motor disorders, gastro-esophageal reflux, disordered respiration and sleep apnea - the same findings that characterize ASD (Rimland,B..Autism Research Review International, 2005). Other shared deficits include loss of smooth ocular pursuit, dysarthria, abnormal motor initiation, disordered neuro-endocrine modulation within the reticular activating system and possibly cerebellar mediated alterations of cerebral activity (Courchesne, E. Neuroanatomic Imaging. Suppl 781-790, 2001). This overlap of characteristics suggests that these disorders may be co-morbid conditions. Furthermore, in the course of routine surgical correction of Chiari disorders, members of CSF have measured substantial improvement in pain, function, and quality of life in ASD patients ( Bolognese, Kula 2010; Henderson, 2008,2010).


Unfortunately, patients once diagnosed with ASD, usually at 1 -3 years age , rarely undergo neurological assessment and MRI to look for other co-morbidities, such as Chiari Malformation. Therefore, an opportunity for diagnosis and treatment is potentially missed. CSF investigators are presently investigating the prevalence of radiological abnormalities in the population of ASD subjects. If preliminary evidence confirms a critical threshold of radiological abnormalities, then the CSF will work with the Investigational Review Boards of two prominent Universities with three goals : 1. To establish the prevalence of Chiari related disorders within the population of ASD; 2. To develop clinical biomarkers to more readily select which patients within the ASD population need further evaluation; and 3. To determine in a randomized, prospective manner whether surgical correction of these established neurological disorders provides a significant improvement in neurological function, pain and quality of life in the affected children and adults.

http://csfinfo.org/research/csf-fund...mation-within/