Joanne, how would I know what the difference is between these two? 

Mag 

Both have many over lapping chacteristics. Hope this helps

Post traumatic stress seems to have a definite trauma involved .
http://mentalhealth.about.com/health/mentalhealth/library/weekly/aa062899.htm


Sensory integration dysfunction has a neurological basis in that the brain has trouble with the sensory input. Many autistic kids seem to have this but having SID does not mean you are autistic ( make sense?)
http://www.autism.org/si.html
Joanne