Occupational Therapy (otherwise known as O.T.) acts as a support for Special Education students. OT's focus on sensory, perceptual and/or motor issues which may be impacting the way a student learns.
Sensory issues may be difficulties with noise, touch, movement, etc. that go beyond what "typical" responses might be.
Perceptual issues may be the letter/number reversals (past the 1st grade), difficulty copying from the board or a book, etc.
Motor issues may be difficulties holding a pencil, fatigueing easily with writing, difficulties sitting upright for a reasonable amount of time in their seat, etc..
OT's work closely the Special Education teachers (writing, adapted equipment and assistive technology), speech clinicians (oral motor excercises), and the social worker (calming techniques, organizational support). OT's also spend alot of time in the student's classroom and consulting with his/her classroom teacher about strategies to help them get the most out of their classroom environment.
If any of these behaviors sound like your child, talk to your child's classroom teacher first! They will help guide you as to whether it may be a developmental stage or a concern.